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  1. #26
    Ozzie Ozzie Ozzie Peter Aawen's Avatar
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    Oh come on!! Have you even read what I've written PMK, not just here but earlier too?

    I repeatedly say that the 'one size fits all conditions/users' thing DOES NOT TRULY WORK, and that the 4psi rule or whatever other repeatable & responsive to condition/load changes method you prefer is better than the 'thumb in bum, mind in neutral, follow the one-size-fits-all-loads-&-conditions idiot guide pressure' shown on your tire placard; and that every rider should check and adjust their tires to suit their particular/current conditions/load/variables more than just every now & then, and adjust their pressures accordingly - it's just that I've not yet met anyone who can load a Spyder up enough to put a load of 1000kgs or more on EACH tire of their Spyder, so the 'usual range' that fairly closely works within the bounds of the 4psi rule's indicated pressures on most Spyders is 16-18 psi, with some (few) who impose lighter loads going as low as 14 psi, and some (few) with heavier loads needing to go up as high as about 20 psi, especially on the rear; and that you shouldn't be fooled by the 'look' of the tire, or by the 'feel' of the tire, because it's very easy to be fooled into thinking the 'look' or 'feel' might be correct instead of the measurable, repeatable, and verifiable results that repeatedly show that 'look' and 'feel' are extremely subjective and quite frequently incorrect, if not dangerously so! And the info re the relationship between pressures and loading is generally printed on the sidewalls of most tires too, so you can weigh your Spyder and using that info do the rough calcs yourself to arrive at a good 'starting pressure' for you to work with when using the 4psi rule, THEN ADJUST YOUR TIRE PRESSURE UP &/OR DOWN TO SUIT WHATEVER YOUR PREVAILING &/OR PARTICULAR NEEDS/WANTS/CONDITIONS!! Ps: those conditions may change daily, or even more often, and in an ideal world, you'd change your cold start pressures, or maybe even your operating pressures to suit those changes, but there's frequently a (justifiable & acceptable) trade off in how often you feel you can do that vs simply remaining 'reasonably close' rather than 'exact' - and besides, the 4psi 'rule of thumb' is a GUIDE, not a 'set in stone' PRESCRIPTION!

    The '4psi rule' is just one 'rule of thumb' that allows people to repeatedly and consistently set their tire pressures to suit THE CONDITIONS THEY ARE RIDING OR DRIVING IN!! It takes into account ALL of the variables effecting their tires, including road temps, ambient temps, AND the load on your tires, and it reacts accordingly BECAUSE YOU MUST RIDE IN THOSE CONDITIONS in order to achieve any increase, let alone the 4psi increase that's the 'initial target'. You can choose to accept a little over 4psi if you like, you can even purposefully choose to aim for something a bit higher if you are chasing better traction in marginal conditions; just as you can choose to accept a little less than 4psi if you like, or purposefully choose to aim for something lower because you want to spin the rear tire at every set of traffic lights and be damned with the excessive wear; but at least you should be able to do that knowing that varying too much outside of that 3psi tp 6psi range previously mentioned is very likely to bring compromises that may not be beneficial (or safe) into how your tires are able to work for you.

    PeteOz's 3.5 psi increase is PERFECTLY acceptable FOR HIM/His Use/His Conditions and it conforms very well with the 4psi rule; it could be fine for you too, or not!! But the pressure he uses in the height of our summertimes is almost certainly not going to be the ideal pressure Joe Bloggs needs to run in his Spyder in the depths of an Ontario winter!! Altho, unless there's some other factor peculiar to either case (Pete's size & weight for instance!?) it's become apparent from the hundreds of thousands of miles ridden by a significant number of Spyder Ryders under a wide range of conditions, that it's very likely the 'ideal' pressure for both sets of 'normal auto tires' will be fairly close to that 16-18 psi range that gets tossed around a lot!! Pete is quite tall, and heavier than most, so HIS particular 'ideal' is a touch higher, but it's still very close to the recommended range for auto tires, rather than the 'over 30 psi' recommendation for that same tire if it's carrying the load of a full sized car!!

    As for running 30+psi in a tire that needs that much air in it to carry maybe 1000kgs under a full sized auto when it's only carrying maybe a third of that when it's fitted to a Spyder, yeah, FFS do that if you want to, but don't come crying to me when your tires hydroplane whenever a gnat spits on the road in front of you; if your steering is so precisely direct that you almost understeer off the road on every tight corner that you try to take at more than 40mph; or if you drive the shadow of a matchstick straight thru the tread cos your tire's blown up sooo drum tight that it can't conform over anything; or when you only get 5 or 6,000 miles out of a tire that those people running a 'more reasonable for the Spyder's load' pressure of 16-18 psi manage to run safely for over 30,000 miles....

    There IS a lot of science that goes into working out the 'correct' pressure for any given set of conditions, use, load, etc, and IF you can get enough of a handle on all the variables that impact, one can actually work out fairly closely what the 'optimal' pressure for a given tire and a given set of all those variables is; you can do a rough calculation given some of those variables; or you can use a WAG if you prefer....... or maybe you can use one of the 'measurable & repeatable' tools that have proven to be very successful at getting pretty close to the 'optimal' pressure for any pnuematic tire over the last 120 or so years and the billions of miles travelled that we've been using them - the 4psi rule being just one of those tools, a tool that gets better and closer when it's used often and properly, even more so when your pressures are adjusted accordingly. Or you could simply set and forget, using the pressures recommended on your tire placard, despite the obvious differences in the tires now fitted; or possibly you could use the recommendations given by people who've done/used one or more of those 'non-WAG' methods and arrived at a 'generally useful' range that's proven to be fairly close & useful for most & probably millions of miles now?? Hell, you could even set your Spyder tire pressures at 30-35 psi cos that's what's recommended by the idiot guide when they're fitted to your car - but if that's what you want to do, why not use the 45 psi you'd possibly use in a heavier/higher loaded radial LT tire fitted to your pick-up; or better yet, the 60 psi or so you might put in the really Heavy Truck Radials that most (in Oz, anyway) Mack Trucks & other semi's & heavy transport vehicles run?? (pnuematic tires btw - there's a reason no-one much runs solids anymore - the soft & grippy compounds wear too quick while the harder stuff won't flex enough to get their tread compound up to operating temps so they've got good enough traction! No 4psi increase. )

    I try to help people based upon MY knowledge, skills, experience, and learning - hopefully, some will benefit from it, even if just a little. If anyone wants to ignore what I've put out there, that's fine by me too - go right ahead; ignore it, but don't argue over things you don't want to use &/or even try to understand! Genuine questions, I'll certainly try to answer, but maybe we should take them off-line - or hasn't this epic been long enough? I got more - I've done a number of studies, dissertations, a thesis or two, and a whole bunch of essays... but I'm sorry, none of them have been 'peer reviewed' on facebook! .
    Last edited by Peter Aawen; 08-07-2020 at 06:46 PM.
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  2. #27
    Very Active Member BLUEKNIGHT911's Avatar
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    Quote Originally Posted by Claimbo View Post
    Auto tires require more air in them than the OEM. Your working with different compounds in the make up of the tire. I ran 33 to 35 in my rear tire because this is what it would be on the car. Some like a softer ride so some use lower pressures. Remember, lower pressure equals more heat on the rubber and quicker wear. So I lead on the higher pressure side.
    ....ABSOLUTELY .... WRONG .... .... that's not what " tire science " says ..... you need to match ( or close ) the weight of the vehicle to the Weight carrying ability of the tire you are using ..... I'm sure Peter, will type at least 500 words on this one ...... Mike

  3. #28
    Very Active Member PMK's Avatar
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    Quote Originally Posted by Peter Aawen View Post
    Oh come on!! Have you even read what I've written PMK, not just here but earlier too?

    I repeatedly say that the 'one size fits all conditions/users' thing DOES NOT TRULY WORK, and that the 4psi rule or whatever other repeatable & responsive to condition/load changes method you prefer is better than the 'thumb in bum, mind in neutral, follow the one-size-fits-all-loads-&-conditions idiot guide pressure' shown on your tire placard; and that every rider should check and adjust their tires to suit their particular/current conditions/load/variables more than just every now & then, and adjust their pressures accordingly - it's just that I've not yet met anyone who can load a Spyder up enough to put a load of 1000kgs or more on EACH tire of their Spyder, so the 'usual range' that fairly closely works within the bounds of the 4psi rule's indicated pressures on most Spyders is 16-18 psi, with some (few) who impose lighter loads going as low as 14 psi, and some (few) with heavier loads needing to go up as high as about 20 psi, especially on the rear; and that you shouldn't be fooled by the 'look' of the tire, or by the 'feel' of the tire, because it's very easy to be fooled into thinking the 'look' or 'feel' might be correct instead of the measurable, repeatable, and verifiable results that repeatedly show that 'look' and 'feel' are extremely subjective and quite frequently incorrect, if not dangerously so! And the info re the relationship between pressures and loading is generally printed on the sidewalls of most tires too, so you can weigh your Spyder and using that info do the rough calcs yourself to arrive at a good 'starting pressure' for you to work with when using the 4psi rule, THEN ADJUST YOUR TIRE PRESSURE UP &/OR DOWN TO SUIT WHATEVER YOUR PREVAILING &/OR PARTICULAR NEEDS/WANTS/CONDITIONS!! Ps: those conditions may change daily, or even more often, and in an ideal world, you'd change your cold start pressures, or maybe even your operating pressures to suit those changes, but there's frequently a (justifiable & acceptable) trade off in how often you feel you can do that vs simply remaining 'reasonably close' rather than 'exact' - and besides, the 4psi 'rule of thumb' is a GUIDE, not a 'set in stone' PRESCRIPTION!

    The '4psi rule' is just one 'rule of thumb' that allows people to repeatedly and consistently set their tire pressures to suit THE CONDITIONS THEY ARE RIDING OR DRIVING IN!! It takes into account ALL of the variables effecting their tires, including road temps, ambient temps, AND the load on your tires, and it reacts accordingly BECAUSE YOU MUST RIDE IN THOSE CONDITIONS in order to achieve any increase, let alone the 4psi increase that's the 'initial target'. You can choose to accept a little over 4psi if you like, you can even purposefully choose to aim for something a bit higher if you are chasing better traction in marginal conditions; just as you can choose to accept a little less than 4psi if you like, or purposefully choose to aim for something lower because you want to spin the rear tire at every set of traffic lights and be damned with the excessive wear; but at least you should be able to do that knowing that varying too much outside of that 3psi tp 6psi range previously mentioned is very likely to bring compromises that may not be beneficial (or safe) into how your tires are able to work for you.

    PeteOz's 3.5 psi increase is PERFECTLY acceptable FOR HIM/His Use/His Conditions and it conforms very well with the 4psi rule; it could be fine for you too, or not!! But the pressure he uses in the height of our summertimes is almost certainly not going to be the ideal pressure Joe Bloggs needs to run in his Spyder in the depths of an Ontario winter!! Altho, unless there's some other factor peculiar to either case (Pete's size & weight for instance!?) it's become apparent from the hundreds of thousands of miles ridden by a significant number of Spyder Ryders under a wide range of conditions, that it's very likely the 'ideal' pressure for both sets of 'normal auto tires' will be fairly close to that 16-18 psi range that gets tossed around a lot!! Pete is quite tall, and heavier than most, so HIS particular 'ideal' is a touch higher, but it's still very close to the recommended range for auto tires, rather than the 'over 30 psi' recommendation for that same tire if it's carrying the load of a full sized car!!

    As for running 30+psi in a tire that needs that much air in it to carry maybe 1000kgs under a full sized auto when it's only carrying maybe a third of that when it's fitted to a Spyder, yeah, FFS do that if you want to, but don't come crying to me when your tires hydroplane whenever a gnat spits on the road in front of you; if your steering is so precisely direct that you almost understeer off the road on every tight corner that you try to take at more than 40mph; or if you drive the shadow of a matchstick straight thru the tread cos your tire's blown up sooo drum tight that it can't conform over anything; or when you only get 5 or 6,000 miles out of a tire that those people running a 'more reasonable for the Spyder's load' pressure of 16-18 psi manage to run safely for over 30,000 miles....

    There IS a lot of science that goes into working out the 'correct' pressure for any given set of conditions, use, load, etc, and IF you can get enough of a handle on all the variables that impact, one can actually work out fairly closely what the 'optimal' pressure for a given tire and a given set of all those variables is; you can do a rough calculation given some of those variables; or you can use a WAG if you prefer....... or maybe you can use one of the 'measurable & repeatable' tools that have proven to be very successful at getting pretty close to the 'optimal' pressure for any pnuematic tire over the last 120 or so years and the billions of miles travelled that we've been using them - the 4psi rule being just one of those tools, a tool that gets better and closer when it's used often and properly, even more so when your pressures are adjusted accordingly. Or you could simply set and forget, using the pressures recommended on your tire placard, despite the obvious differences in the tires now fitted; or possibly you could use the recommendations given by people who've done/used one or more of those 'non-WAG' methods and arrived at a 'generally useful' range that's proven to be fairly close & useful for most & probably millions of miles now?? Hell, you could even set your Spyder tire pressures at 30-35 psi cos that's what's recommended by the idiot guide when they're fitted to your car - but if that's what you want to do, why not use the 45 psi you'd possibly use in a heavier/higher loaded radial LT tire fitted to your pick-up; or better yet, the 60 psi or so you might put in the really Heavy Truck Radials that most (in Oz, anyway) Mack Trucks & other semi's & heavy transport vehicles run?? (pnuematic tires btw - there's a reason no-one much runs solids anymore - the soft & grippy compounds wear too quick while the harder stuff won't flex enough to get their tread compound up to operating temps so they've got good enough traction! No 4psi increase. )

    I try to help people based upon MY knowledge, skills, experience, and learning - hopefully, some will benefit from it, even if just a little. If anyone wants to ignore what I've put out there, that's fine by me too - go right ahead; ignore it, but don't argue over things you don't want to use &/or even try to understand! Genuine questions, I'll certainly try to answer, but maybe we should take them off-line - or hasn't this epic been long enough? I got more - I've done a number of studies, dissertations, a thesis or two, and a whole bunch of essays... but I'm sorry, none of them have been 'peer reviewed' on facebook! .
    To start this reply, I will say I do not appreciate being essentially attacked by you.

    In regards to your words in your reply, first off, I have read many of the posts made by you regarding tire pressures. So I suggest you cut that statement free.

    Additionally, and correct me if wrong, but, in your reply, you stated that, the correct tire pressure when tires are cold can vary, depending upon ambient temps and road temps. So, if I understand you correctly, to achieve this optimized target of 4 psi increase at a stabilized heated tire temp, the Spyder owner may need to alter pressures up or down somewhat for local conditions at that time.

    As for the rest, in my best Sargent Hulka impersonation, “lighten up Francis”. Your remarks regarding hydroplaning on bug spit, biblical references to the 4 psi guideline and more are not a focus of my posts nor needed to retain the technical merit of your words.

    As for your words at me about tire feel or how they look, not once have I mentioned the look of tires in regards to inflation pressure. Regarding how the machine feels, had you read some of my posts, you would have seen where I post that we run 20 psi in each tire. Determined not by a 4 psi rule, but rather by the amount of confidence in how the Spyder corners. I have tested pressures up and down after switching away from Kendas. Finding a balance of feel between front and rear in regards to how the tires sidewalls flex, plus comfort over small road irregularities helped determined a pressure that, yes, felt good. When testing and pressures were lowered into the 18 psi or lower pressure the amount of sidewall flex gave an uneasy feeling as the machine tended to move about too much. Straight line was ok, but cornering was not. These lower pressures also gave the feeling that front tires were tucking slightly under the rim, and gave a more vague feeling into the grips.

    Regardless, it was enlightening to read your reply, and also see you mention differences based on ambient conditions.

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  5. #30
    Ozzie Ozzie Ozzie Peter Aawen's Avatar
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    I do find it interesting in what other people read into the written word, intended or not.... There was no intention from me of 'attacking' anyone, but there was an expression of extreme frustration!! Nothing I've said today is anything different in essence from what I've said repeatedly all along.... but it seems that you haven't really taken in some of the points that I thought I'd made strongly enough that they should've answered your initial questions/concerns! And if you read Claimbo's comnent re running more than 30 psi in auto tires fitted onto a Spyder, then that might throw juuust a little more light on where the gentle dig re the bug spit etc was aimed.

    But you are absolutely right about the owner/rider possibly needing to adjust their cold start pressures up or down depending upon the ambient road & air temps - and that holds true generally, with the caveat that because the load of a Spyder/Ryker on the tires is relatively light, the variation required to stay within that range is usually quite small, and for most riders &/or less extreme variations in ambient temps, conditions etc, an acceptable start pressure will still remain within the generally recommended pressures here... And I will gladly admit that I don't KNOW if your 20 psi is actually 'correct' for you & your riding, but given the feedback & results of many thousands of miles in a wide range of conditions from many many riders (& drivers) out there, unless you are as tall & large framed as PeteOz or possibly a whole lot smaller/lighter, then I wouldn't think it really possible! Could be wrong tho - willing to stand corrected?! Do you want to tell me the tires you're running, the max load & pressure info printed on their sidewalls, and the weight on the front & rear tires for your 'usual load inc rider/pillion' Spyder? I can do a rough calc with all that & given some further info on your general riding style & the roads/conditions/temps etc you generally ride in, I can make a bit of an educated guess?

    However, and I cannot stress this STRONGLY enough, neither the LOOK nor the FEEL of your tires/riding are really useful in this discussion, and even if you didn't raise it this time around, the Look almost always crops up eventually!! Both are often raised as reasons for not following the science 'Look' is almost useless since the advent of radial construction tires - they can look dangerously flat and still actually be quite over-inflated; while 'Feel' is simply NOT a good way of optimising your tire's pressures &/or performance, altho it does come into play a little. On any machine pretty much besides a 2 wheel m/c, where you only have two tiny areas of high traction contact patch in an oval cross-section tire that relies on little or NO deformation of the tire carcass to maintain the size of that contact patch, if you run for long enough on over-inflated tires, then dropping them to anything closer to the correct &/or a pressure that can demonstrably provide better & safer performance can 'feel' odd, until you are used to it instead of the former 'feel' you got from 'over-inflation'. Once you are used to the 'feel' from correctly inflated tires, you might be surprised at how well they corner, astounded at how well they brake, and just as surprised at how comfortably they ride and work WITH your suspension to give you a phenomenal balance between ride, handling, performance, and even tire wear!! Yeah, the various authorities go on about the risks of under-inflation, but that's only because most of the time, the bad effects of under-inflated tires are quite quicky noticeable, while you can often get away with over-inflation for longer, sometimes a lot longer.... until you really NEED the greater traction, braking, or cornering that running 'closer to the correct pressure for load etc' brings with it... or you wear them out at half their expected life!

    Many people these days ride (& drive!) on over-inflated tires because it 'feels' right to them, they like the 'feel' of slightly more direct steering, the 'feeling' of being more aware of the road's surface, and even the 'feel' of the slightly harsh feedback they get thru their seat, cos that's what they've been programmed to expect!! But just about everyone we teach about running correct pressures in their auto tires doesn't take too long to realise that they can actually corner better, brake harder, and even 'feel' better & more comfortable, more planted, & have greater confidence in their machine once they've run 'closer to correct pressures' for a reasonable while. I've done track days for groups of 'advanced drivers &/or riders' where the ONLY thing that's been discussed and changed has been their usual tire pressures; and so far, there has not been ONE attendee out of quite literally hundreds (if not thousands) who hasn't ended up getting better performance and measurably faster track times after they've got used to running 'closer to correct' tire presures, regardless of whether we've adjusted their particular pressure up or down!! (And yep, we've seen both - but there's been a lot more over-inflated in recent years.... probably ever since tire fitters stopped learning/caring so much about setting tire pressures properly for their customers needs & paying more attention to over-inflating tires to 'set the bead' properly! )

    And all of this comes back once again to fact that the pressures that a few of us have recommending for most Spyder/Ryker riders running auto tires for years almost invariably fall within the same sort of range - simply because the machines are very similar; the riding conditions for most of us aren't all that extreme either way; the auto tires we can fit are all fairly similar in size as well as load & speed ratings (& therefore construction); and almost all of us fall within roughly the 'expected' or 'acceptable' load parameters for these machines. So very few of us impose loads much lower or higher than the rest; very few of us ride in the extremities of conditions; and very few of us seriously stress the performance envelope of these machines, except maybe in emergency braking. So despite the relatively minor variations that one should expect to see in either extremes of quite hot or quite cold conditions, there's a fairly small range of suitable pressures that will return results in the 'optimal' range.... with a few specific outliers just to prove the rule.

    Besides, Tire pressures are just ONE of the variables in this equation, another is how much/often you flex your right wrist; then there's how early/late or hard/soft you step on that brake pedal; and there are more!! So taking PeteOz for example, with his 3.5 psi increase after an hour's riding - that 'little bit less than 4psi increase' doesn't necessarily mean he MUST change his tire pressures (altho he could, if he thought it warranted) or even that he SHOULD (again, if he...) but it does mean that he has ample scope to push his Spyder just a little harder, IF he 'feels' like it, and still be safely within the 'close to optimal' range of tire pressure so that he needn't worry too much about them!

    And that's the end of today's lesson; there'll be a test on all this at the end of.... oh, hang on - sorry, minor flashback!
    Last edited by Peter Aawen; 08-08-2020 at 02:34 AM.
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  6. #31
    Very Active Member Peteoz's Avatar
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    Quote Originally Posted by Claimbo View Post
    Auto tires require more air in them than the OEM. Your working with different compounds in the make up of the tire. I ran 33 to 35 in my rear tire because this is what it would be on the car. Some like a softer ride so some use lower pressures. Remember, lower pressure equals more heat on the rubber and quicker wear. So I lead on the higher pressure side.
    It is not “lower pressure” that leads to “quicker wear”, Claimbo. Overinflate your tyres, and they will wear quicker in the middle. Underinflate your tyres, and they will wear quicker on the outer edges. Pure “Lower pressure” has nothing to do with it....... and that correct inflation level for aftermarket tyres on the Spyder is where the jury is out. I like 18psi in my tyres and I, and many, many others who run similar pressures have NO problems with tyres wearing unevenly or quickly, so the claim that “lower pressures” cause ‘quicker wear” is disproven in real life.

    Pete
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  7. #32
    Very Active Member Mikey's Avatar
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    Tires and oil!!!! Got to love them!!! Best way to have a cup of coffee and get your engine going!
    2012 RTL , Pearl

  8. #33
    Very Active Member PMK's Avatar
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    Quote Originally Posted by Peter Aawen View Post
    I do find it interesting in what other people read into the written word, intended or not.... There was no intention from me of 'attacking' anyone, but there was an expression of extreme frustration!! Nothing I've said today is anything different in essence from what I've said repeatedly all along.... but it seems that you haven't really taken in some of the points that I thought I'd made strongly enough that they should've answered your initial questions/concerns! And if you read Claimbo's comnent re running more than 30 psi in auto tires fitted onto a Spyder, then that might throw juuust a little more light on where the gentle dig re the bug spit etc was aimed.

    But you are absolutely right about the owner/rider possibly needing to adjust their cold start pressures up or down depending upon the ambient road & air temps - and that holds true generally, with the caveat that because the load of a Spyder/Ryker on the tires is relatively light, the variation required to stay within that range is usually quite small, and for most riders &/or less extreme variations in ambient temps, conditions etc, an acceptable start pressure will still remain within the generally recommended pressures here... And I will gladly admit that I don't KNOW if your 20 psi is actually 'correct' for you & your riding, but given the feedback & results of many thousands of miles in a wide range of conditions from many many riders (& drivers) out there, unless you are as tall & large framed as PeteOz or possibly a whole lot smaller/lighter, then I wouldn't think it really possible! Could be wrong tho - willing to stand corrected?! Do you want to tell me the tires you're running, the max load & pressure info printed on their sidewalls, and the weight on the front & rear tires for your 'usual load inc rider/pillion' Spyder? I can do a rough calc with all that & given some further info on your general riding style & the roads/conditions/temps etc you generally ride in, I can make a bit of an educated guess?

    However, and I cannot stress this STRONGLY enough, neither the LOOK nor the FEEL of your tires/riding are really useful in this discussion, and even if you didn't raise it this time around, the Look almost always crops up eventually!! Both are often raised as reasons for not following the science 'Look' is almost useless since the advent of radial construction tires - they can look dangerously flat and still actually be quite over-inflated; while 'Feel' is simply NOT a good way of optimising your tire's pressures &/or performance, altho it does come into play a little. On any machine pretty much besides a 2 wheel m/c, where you only have two tiny areas of high traction contact patch in an oval cross-section tire that relies on little or NO deformation of the tire carcass to maintain the size of that contact patch, if you run for long enough on over-inflated tires, then dropping them to anything closer to the correct &/or a pressure that can demonstrably provide better & safer performance can 'feel' odd, until you are used to it instead of the former 'feel' you got from 'over-inflation'. Once you are used to the 'feel' from correctly inflated tires, you might be surprised at how well they corner, astounded at how well they brake, and just as surprised at how comfortably they ride and work WITH your suspension to give you a phenomenal balance between ride, handling, performance, and even tire wear!! Yeah, the various authorities go on about the risks of under-inflation, but that's only because most of the time, the bad effects of under-inflated tires are quite quicky noticeable, while you can often get away with over-inflation for longer, sometimes a lot longer.... until you really NEED the greater traction, braking, or cornering that running 'closer to the correct pressure for load etc' brings with it... or you wear them out at half their expected life!

    Many people these days ride (& drive!) on over-inflated tires because it 'feels' right to them, they like the 'feel' of slightly more direct steering, the 'feeling' of being more aware of the road's surface, and even the 'feel' of the slightly harsh feedback they get thru their seat, cos that's what they've been programmed to expect!! But just about everyone we teach about running correct pressures in their auto tires doesn't take too long to realise that they can actually corner better, brake harder, and even 'feel' better & more comfortable, more planted, & have greater confidence in their machine once they've run 'closer to correct pressures' for a reasonable while. I've done track days for groups of 'advanced drivers &/or riders' where the ONLY thing that's been discussed and changed has been their usual tire pressures; and so far, there has not been ONE attendee out of quite literally hundreds (if not thousands) who hasn't ended up getting better performance and measurably faster track times after they've got used to running 'closer to correct' tire presures, regardless of whether we've adjusted their particular pressure up or down!! (And yep, we've seen both - but there's been a lot more over-inflated in recent years.... probably ever since tire fitters stopped learning/caring so much about setting tire pressures properly for their customers needs & paying more attention to over-inflating tires to 'set the bead' properly! )

    And all of this comes back once again to fact that the pressures that a few of us have recommending for most Spyder/Ryker riders running auto tires for years almost invariably fall within the same sort of range - simply because the machines are very similar; the riding conditions for most of us aren't all that extreme either way; the auto tires we can fit are all fairly similar in size as well as load & speed ratings (& therefore construction); and almost all of us fall within roughly the 'expected' or 'acceptable' load parameters for these machines. So very few of us impose loads much lower or higher than the rest; very few of us ride in the extremities of conditions; and very few of us seriously stress the performance envelope of these machines, except maybe in emergency braking. So despite the relatively minor variations that one should expect to see in either extremes of quite hot or quite cold conditions, there's a fairly small range of suitable pressures that will return results in the 'optimal' range.... with a few specific outliers just to prove the rule.

    Besides, Tire pressures are just ONE of the variables in this equation, another is how much/often you flex your right wrist; then there's how early/late or hard/soft you step on that brake pedal; and there are more!! So taking PeteOz for example, with his 3.5 psi increase after an hour's riding - that 'little bit less than 4psi increase' doesn't necessarily mean he MUST change his tire pressures (altho he could, if he thought it warranted) or even that he SHOULD (again, if he...) but it does mean that he has ample scope to push his Spyder just a little harder, IF he 'feels' like it, and still be safely within the 'close to optimal' range of tire pressure so that he needn't worry too much about them!

    And that's the end of today's lesson; there'll be a test on all this at the end of.... oh, hang on - sorry, minor flashback!
    Regarding your statement that nothing you have said has changed, well that is not quite exact or true. Never before have I read in any of your posts that ambient conditions as they change throughout the year can and will alter the initial cold tire pressure. With that, for a person to persistently recommend specific pressures without explaining this ambient factor or without regard to to first learning the Spyder model and “payload” weight complicates the often posted pressures to be inaccurate even further. I explain this knowing that there is differences in empty vehicle weights between say an F3 and an RT, or even the other models.

    Regarding the very recent post where the owner operates at 30 psi. Comparing his 30 psi to me running 20 psi is a long reach, likely one that even you should avoid. You know I run 20 psi that you deem can hydroplane on bug spit, then group me in the same category as the guy running 30 psi. As a counterpoint, not once have I seen or read where you suggest owners buy and correctly use a calibrated tire pressure gage. So possibly, since I should be allowed to grab straw remarks, maybe my high quality gage is accurately indicating the 20 psi I run, while others, possibly yourself has an inaccurate gage and could be running outside that 16 to 18 psi range repeated here on Spyderlovers. Taking that a step further, are all owners and yourself ensured the gage accurately shows this 4 psi increase?

    Regarding the look of the tire, not once have I endorsed that as a means to correct pressures. You presented that and continue to return to it in regards to your replies towards me. Simply stop, there is no validity regarding tire looks in replies towards me.

    In regards to tire feel, and that not being a valid means of narrowing in on a correct pressure, consider, if the motorcycle or car does not inspire confidence, how can a person enjoy the vehicle or even attempt to push its limits as you bring up in your later paragraphs?

    With this reply, I must introduce more for you to consider, this confidence associated with how the vehicle feels can be also be related to chassis setup or options. Our machine does not have stock suspension. The front of the Spyder is supported by aftermarket shocks and additional chassis roll concerns are addressed by a firmer swaybar. Both of these items alter the feel and handling of the vehicle. Add to this automotive tires all around and even more handling differences occur compared to oem.

    Yes, some folks can stretch a throttle cable while others do not. Some riders can rip corners, while others may not. With that I can agree that a spirited ride on a twisty road with high grip surface may generate more heat and pressure increase into the tires than a simple run along an interstate with a lower grip concrete surface.

    So many variables, so little time, enough from me, thank you for validating several concerns I have had for a while regarding finding optimum pressure and the deviations that may affect constantly reading 16 to 18 psi is correct. Nope, merely a possible starting point to work from. And with that, like all sciences, even tire science is merely that...

    All the best and be safe.

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    Quote Originally Posted by Mikey View Post
    Tires and oil!!!! Got to love them!!! Best way to have a cup of coffee and get your engine going!

    The best substitute for brains & knowledge is....................silence.

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    Quote Originally Posted by PMK View Post
    Regarding your statement that nothing you have said has changed, well that is not quite exact or true. Never before have I read in any of your posts that ambient conditions as they change throughout the year can and will alter the initial cold tire pressure. With that, for a person to persistently recommend specific pressures without explaining this ambient factor or without regard to to first learning the Spyder model and “payload” weight complicates the often posted pressures to be inaccurate even further. I explain this knowing that there is differences in empty vehicle weights between say an F3 and an RT, or even the other models.

    Regarding the very recent post where the owner operates at 30 psi. Comparing his 30 psi to me running 20 psi is a long reach, likely one that even you should avoid. You know I run 20 psi that you deem can hydroplane on bug spit, then group me in the same category as the guy running 30 psi. As a counterpoint, not once have I seen or read where you suggest owners buy and correctly use a calibrated tire pressure gage. So possibly, since I should be allowed to grab straw remarks, maybe my high quality gage is accurately indicating the 20 psi I run, while others, possibly yourself has an inaccurate gage and could be running outside that 16 to 18 psi range repeated here on Spyderlovers. Taking that a step further, are all owners and yourself ensured the gage accurately shows this 4 psi increase?

    Regarding the look of the tire, not once have I endorsed that as a means to correct pressures. You presented that and continue to return to it in regards to your replies towards me. Simply stop, there is no validity regarding tire looks in replies towards me.

    In regards to tire feel, and that not being a valid means of narrowing in on a correct pressure, consider, if the motorcycle or car does not inspire confidence, how can a person enjoy the vehicle or even attempt to push its limits as you bring up in your later paragraphs?

    With this reply, I must introduce more for you to consider, this confidence associated with how the vehicle feels can be also be related to chassis setup or options. Our machine does not have stock suspension. The front of the Spyder is supported by aftermarket shocks and additional chassis roll concerns are addressed by a firmer swaybar. Both of these items alter the feel and handling of the vehicle. Add to this automotive tires all around and even more handling differences occur compared to oem.

    Yes, some folks can stretch a throttle cable while others do not. Some riders can rip corners, while others may not. With that I can agree that a spirited ride on a twisty road with high grip surface may generate more heat and pressure increase into the tires than a simple run along an interstate with a lower grip concrete surface.

    So many variables, so little time, enough from me, thank you for validating several concerns I have had for a while regarding finding optimum pressure and the deviations that may affect constantly reading 16 to 18 psi is correct. Nope, merely a possible starting point to work from. And with that, like all sciences, even tire science is merely that...

    All the best and be safe.
    Don't forget if the driver or passenger has a Bowel movement !!!!! .... Then everything has to be re-calibrated ...... PS, I think you forgot to mention .... Humidity .......... ride safe - ride happy annnnnnnnnnnnnnnnnnnnnnnnd ride more ..... Mike

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    Quote Originally Posted by AdyB View Post
    A question from England. Going to put a Toyo Proxes TR1 225/50/15 car tyre on the rear of my 2016 Spyder RT Limited.Usually ride 2 up, I weigh 80 kilos and my wife weighs 60 kilos. Reading others posts, people use anything from 18 psi to 28 psi pressure. Would appreciate replies stating what pressure you use so I can start off with the most popular. Thanks in advance.

    I have a 2017 RTL, and my wife and I weigh collectively about the same as you guys, but I run Nankang's

    In the dry I run 26psi (28 seems a bit harsh) and drop it to 25psi in the wet 1 or 2 up. I find this a good combination/compromise for the different conditions
    2017 RTL
    2017 RTL , White

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    Quote Originally Posted by BLUEKNIGHT911 View Post
    Don't forget if the driver or passenger has a Bowel movement !!!!! .... Then everything has to be re-calibrated ...... PS, I think you forgot to mention .... Humidity .......... ride safe - ride happy annnnnnnnnnnnnnnnnnnnnnnnd ride more ..... Mike
    Obviously real tire science you are referring too.

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    Quote Originally Posted by PMK View Post
    Obviously real tire science you are referring too.
    What I posted, was said " in jest "..... Yes I'm a firm believer in " tire science " .... I'm also a believer in " is this absolutely necessary " to achieve a purpose .... It's like the Covid virus thing ..... Millions of people have been tested, for the folks who didn't have it, What does it mean ? ... it means they didn't have it at the time of the test .... but later that day they could have gotten it , or maybe the next day etc. It really only matters for those who did test " positive " - they may or may not actually need treatment..... What I've posted about " tire pressure " is for average, everyday guidelines to folks who have switched to Auto tires. I would not pertain to RACING vehicles used only for Racing situations. One criteria doesn't need to match All criteria. ... Peter is very technical in what He says, and if you needed EVERY ounce of performance that it provides, it is important .... but everyone doesn't need every ounce, not me nor most others here. .... like balancing front tire psi's, to me it can't be done UNLESS you use a DUAL fill hose set-up..... I'll bet there are folks here who will WASTE ( imho ) a lot of time trying to achieve perfect balance without using a Dual fill Hose - if the left and right tire arn't exactly the same, what will happen ? ... practically speaking - nothing !!!. Unless they are Vastly different. My point to what I've said is, achieving Perfection should be a Goal, but less than Perfection ( reasonably ) can be good enough for most applications ...... Mike

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    How about a simple "inflate it until it blows up. Inflate the replacements to 5 psi less"?

    .
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    My rides:
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    Quote Originally Posted by BLUEKNIGHT911 View Post
    What I posted, was said " in jest "..... Yes I'm a firm believer in " tire science " .... I'm also a believer in " is this absolutely necessary " to achieve a purpose .... It's like the Covid virus thing ..... Millions of people have been tested, for the folks who didn't have it, What does it mean ? ... it means they didn't have it at the time of the test .... but later that day they could have gotten it , or maybe the next day etc. It really only matters for those who did test " positive " - they may or may not actually need treatment..... What I've posted about " tire pressure " is for average, everyday guidelines to folks who have switched to Auto tires. I would not pertain to RACING vehicles used only for Racing situations. One criteria doesn't need to match All criteria. ... Peter is very technical in what He says, and if you needed EVERY ounce of performance that it provides, it is important .... but everyone doesn't need every ounce, not me nor most others here. .... like balancing front tire psi's, to me it can't be done UNLESS you use a DUAL fill hose set-up..... I'll bet there are folks here who will WASTE ( imho ) a lot of time trying to achieve perfect balance without using a Dual fill Hose - if the left and right tire arn't exactly the same, what will happen ? ... practically speaking - nothing !!!. Unless they are Vastly different. My point to what I've said is, achieving Perfection should be a Goal, but less than Perfection ( reasonably ) can be good enough for most applications ...... Mike
    Your post regarding having a bowel movement, humidity, and recalibration added nothing to further this topic along. My reply mentioning real tire science was in jest too, though you answered with a serious reply.

    There is good and valuable information learned from Peters posts. He stated that ambient conditions will alter the required cold tire pressure setting in order to achieve the 4 psi change riders are looking for. With that said by Peter, the suggestion of 16 to 18 psi would be, or could be considered somewhat specific for certain ambient conditions, payload weight, vehicle weight and road surface induced heat into the tires.

    Seems as though the suggestion to tell others to run 16 to 18 psi without actually verifying they obtain an accurate 4 psi increase when the tire reaches stabilized hot temp could even be dangerous for some owners. 16 to 18 psi may be ideal for your weight, your vehicles weight, the load in the trunks, your road surface, the tires you choose to roll on, and your ambient conditions. Outside of that, a person could be overinflated to possibly hydroplane on Bug Spit, or be underinflated, and overheat their tires.

    This tire science can be very interesting. More intriguing to add more to the topic is when is a using a tire pyrometer or even a non contact temp gun needed. And will the temp readings be even across the tires tread surface at the correct psi, knowing the Spyders run essentially 0.0 degrees of camber?

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    Quote Originally Posted by BLUEKNIGHT911 View Post
    What I posted, was said " in jest "..... Yes I'm a firm believer in " tire science " .... I'm also a believer in " is this absolutely necessary " to achieve a purpose .... It's like the Covid virus thing ..... Millions of people have been tested, for the folks who didn't have it, What does it mean ? ... it means they didn't have it at the time of the test .... but later that day they could have gotten it , or maybe the next day etc. It really only matters for those who did test " positive " - they may or may not actually need treatment..... What I've posted about " tire pressure " is for average, everyday guidelines to folks who have switched to Auto tires. I would not pertain to RACING vehicles used only for Racing situations. One criteria doesn't need to match All criteria. ... Peter is very technical in what He says, and if you needed EVERY ounce of performance that it provides, it is important .... but everyone doesn't need every ounce, not me nor most others here. .... like balancing front tire psi's, to me it can't be done UNLESS you use a DUAL fill hose set-up..... I'll bet there are folks here who will WASTE ( imho ) a lot of time trying to achieve perfect balance without using a Dual fill Hose - if the left and right tire arn't exactly the same, what will happen ? ... practically speaking - nothing !!!. Unless they are Vastly different. My point to what I've said is, achieving Perfection should be a Goal, but less than Perfection ( reasonably ) can be good enough for most applications ...... Mike
    Avoiding bringing any political or COVID remarks that may have this topic shutdown. We all have our own opinions regarding politics and COVID and this is not the place for it.

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    Quote Originally Posted by PMK View Post
    Your post regarding having a bowel movement, humidity, and recalibration added nothing to further this topic along. My reply mentioning real tire science was in jest too, though you answered with a serious reply.

    There is good and valuable information learned from Peters posts. He stated that ambient conditions will alter the required cold tire pressure setting in order to achieve the 4 psi change riders are looking for. With that said by Peter, the suggestion of 16 to 18 psi would be, or could be considered somewhat specific for certain ambient conditions, payload weight, vehicle weight and road surface induced heat into the tires.

    Seems as though the suggestion to tell others to run 16 to 18 psi without actually verifying they obtain an accurate 4 psi increase when the tire reaches stabilized hot temp could even be dangerous for some owners. 16 to 18 psi may be ideal for your weight, your vehicles weight, the load in the trunks, your road surface, the tires you choose to roll on, and your ambient conditions. Outside of that, a person could be overinflated to possibly hydroplane on Bug Spit, or be underinflated, and overheat their tires.

    This tire science can be very interesting. More intriguing to add more to the topic is when is a using a tire pyrometer or even a non contact temp gun needed. And will the temp readings be even across the tires tread surface at the correct psi, knowing the Spyders run essentially 0.0 degrees of camber?
    Well I guess you missed my point ...... and some people can find political meanings in everything any one says .... I had NO political agenda ..... Covid just happens to a current fact of life ...... Mike

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    Quote Originally Posted by BLUEKNIGHT911 View Post
    Well I guess you missed my point ...... and some people can find political meanings in everything any one says .... I had NO political agenda ..... Covid just happens to a current fact of life ...... Mike
    Well, actually, no I did not miss any point you made, unless it was covertly and stealthy within you emojis.

    I get it, you have had some type of formal training regarding tires. I find that excellent, not sure what certification or qualifications it allows you. Your training apparently has you schooled to use 4 psi from cold to hot, I get that too.

    Bringing COVID into this topic was uncalled for. Trained in tires or not, you have no way of knowing if anyone here has been seriously infected or may have lost a loved one or friend from COVID. In my opinion, there are many things you don’t get and you owe not me, but this group and those reading this topic a sincere apology.

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    Quote Originally Posted by AdyB View Post
    Thanks for your replies, I didn't expect such technical answers. I just thought people would just give me a figure and I would use that as a base point. It seems somewhere between 20 psi and 25 psi would be a good starting point. Many thanks again for your time and experience in answering my question.
    Thanks! AdyB I'll close this thread for you.
    Last edited by CopperSpyder; 08-09-2020 at 07:01 PM.
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