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Ozzie Ozzie Ozzie
 with Blueknight911 on this! The other thing to bear in mind is that most cars are a lot heavier than Spyders, and their tires generally have a Maximum Load @ Maximum pressure placard stamped on the side. This means that if your local tire supplier can't get the Load/Pressure table for that particular tire from the manufacturer & show you on that table what pressure you need to run in the tire to carry the load your Spyder imposes on it, you can fairly easily weigh each end of your Spyder (any weigh-bridge or garden mulch centre etc will have a weigh-bridge) and do the math yourself!! 
Quickly looking at the OE Spec Kendas first, I have a recently failed front Kenda in the workshop that's a few years old now, and it's marked Maximum Load 175 kgs @ Maximum Pressure 30 psi. The front end of my 2013 Spyder RT Ltd at its 'Rider & Pillion plus all our travelling gear' heaviest weighs in at 230kgs, so each front tire carries a static load of about 115kgs (and I believe that's pretty damn heavy for a 2013 Spyder  ) which (if I do the math) means that my Spyder imposed load is just 0.66 of the tires Max load so it only NEEDS 0.66 of the Max pressure or about 19-20 psi to carry the load I place upon it, and that's pretty close to what the BRP Recommended Tire Pressure is for those OE Spec lightly constructed tires (btw, this particular Kenda, which admittedly is not one of the latest versions from the factory, shows that it has 3 polyester tread plies and only 1 (yep, just ONE!) Sidewall ply... and all those plies are made up of 'thread' which is only 66% as thick or if you like, approx 1/3 thinner/weaker than the 'threads' used by most Automotive tire manufacturers as plies in their tires - some go even heavier again!! So the Kendas are clearly quite lightly constructed, even before you add in the poor quality control & lack of consistency in their construction! )
Moving on to the tires that I actually run and explaining the calculation needed in more detail, the sidewall Max Load/Max Pressure placard on my 175/60R15 Kumhos state Max Load = 495kgs @ 50psi... So my front tires would require 50 psi in them to carry 495 kgs, but they only need to carry 115 kgs when fitted to my Spyder and I want to know what pressure I should run in them?! What follows is admittedly a little bit of a 'ready reckoner', but it's pretty close and far better than just whacking whatever pressure your bum tells you feels good in there!!
Here's the calc - the tires Max Load is 495 kgs but it only needs to carry 115 kgs, so 115 ÷ 495 = 0.2323 repeating, but anything beyond 2 decimal points really isn't important, so I'll round that off at 0.23... The tires Max Pressure is 50psi & that's only required to carry 495 kgs, and we now know that the Spyder load is only 0.23 of the Tire's Max, so applying that to the Max pressure 50 × 0.23 = 11.5...... which means that my front tires will be quite safe carrying my loaded Spyder if I run them at 11.5 psi.... Now be aware that presuure is, strictly speaking, just that required for a static load. For ease of explanation & minimal additional confusing calculations, there is a way to work out how much more pressure you need to add to cater for dynamic loads, altho I usually just round it all out and simply add 4psi to that static load value, to cater for how hard I ryde my Spyder (largely because 4psi is the same value used by the '4psi Rule' to confirm that the tire is at it's optimum traction pressure and not over heating thru use & it's handy to remember just the one number - 4psi!) so even tho I now KNOW the tire will likely be safe at 11.5 psi because I've done the calcs to show me the pressure the tire needs for the less than Max load, adding the extra 4psi to cater for dynamic loading increases gives me a working pressure of 15.5 psi up front.... and I usually run between 14 & 16 psi.  The same sort of calc will work for your rear tire, and it'll give you a 'very close to ideal' pressure to run in your Auto tires when they are only carrying a light load instead of something more than 3 times as heavy! 
It's fine by me if you knowingly choose to run higher pressures than what ^^ that type of calc indicates should be necessary in your 'normal' Auto tire, but please, know that when/if you do run higher pressures, you ARE compromising the ride, handling, traction, and the potential longevity of your tires, and don't complain if you hydroplane at the first sign of water on the road, or can't avoid some obstacle because your dry &/or wet braking distance has been extended significantly due to the lack of grip your tires have on the road! Get your Auto tire pressures right and they can work with your suspension to give you a safe & comfortable ride with far better traction, handling, cornering, and braking than whatever you got from the OE spec Kendas.... fail to set them right &/or run them too high for the lighter than expected load your Spyder imposes on them, and your steering might feel direct &/or crisp to the `less aware`, but you`ll actually be scrubbing tires thru corners, riding harshly & bouncing the tire off of the road surface, risking punctures, and you will be getting less than ideal traction, ride, & handling, with compromised wet & dry braking too.... it's your choice tho! 
Last edited by Peter Aawen; 12-12-2019 at 04:23 AM.
2013 RT Ltd Pearl White
Ryde More, Worry Less!
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So, if I understand correctly, the original post / topic was where the owner had a car tire installed by a Can Am dealer. The dealer inflated the tire, and it was above the customers requested pressure and also inaccurately inflated over the oem recommended pressure based on TPMS readings.
Several points.
First, finding a dealer that will install a car tire on a Spyder would be a huge blessing for many on this forum and FB groups.
Second, from a liability standpoint, a smart tech would not release a vehicle knowingly under inflating a tire.
Third, gage accuracy, that of the tech, or the TPMS comes to mind. Yes, the techs gage could read incorrectly or the tech was lazy, both could result in the higher than oem pressure. Saying that though, if it were me, I would validate and check the accuracy of the TPMS pressure readings to ensure they are accurate.
I will not offer up my ideas on a best brand / model of tire, or my ideas on tire pressure to run. Merely, amazed at the lightning fast speed a finger is pointed and a person criticized for the job they did. So many are frustrated that a shop only installs oem tires at a high cost, and blames it on the shop being greedy. A shop that installs a car tire risks liability. Not saying the car tire is inferior, but rather if the Spyder is involved in a crash, a lawyer could ask the simple question, what makes the shop more qualified than BRP regarding tires to run.
Consider and think about how fortunate you are to get that car tire installed. Adjusting the pressure as you see fit afterwards is minor.
Yes, the shop does know better than you in this case, likely covering their ass a bit.
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 Originally Posted by Peter Aawen
When any tire tech fits a tire onto a rim, they should use a quick blast of high pressure air initially, then for 'car tires', inflate the tire to at least 40 psi to 'seat' the tire bead firmly over the little raised ridges inside the rim so that it pushes the tire bead evenly hard up against the edge of the rim & the rim's 'bead profile' ( altho that '40 psi' is often +/- saaay 10 psi.... it's usually just a pretty rough guesstimate by the poorly trained/less skilled tech's a lot of the time! ) and they should do that before they insert the valve in the stem.... Then once the bead is correctly seated & the tire is mounted evenly onto the rim, the competent & skilled tech with any pride in doing their job properly/correctly will adjust the tire's pressure to whatever the customer wants &/or is recommended for the vehicle/the load on the tire.... 
But the 'lazy' or less competent tire tech will often simply leave the tire pressure at whatever it ends up at once they've seated the bead, removed the air chuck, & then screwed the valve down into the stem.... So your brand new tires can end up on your vehicle with anywhere between saaay a high pressure of about 45-50 psi or maybe a low pressure of 25-30 psi, or possibly anywhere in-between... and your newly fitted tires may often be at different pressures for each tire, too!! 
So unless you KNOW & completely TRUST your tire fitters/techs to do the right thing (yes, there are some of those out there, often more than you'd think - but there are also LOTS of the other types too! ) you should check and correctly set your tire pressures yourself BEFORE you leave the tire fitting bay or workshop! BTW, for many w'shops/operators, you just being seen doing that ONCE will make them a WHOLE LOT more 'profressional' about how they fit your tires & set the pressures next time/forever after... well, that is of course, only if you ever go to the same place again &/or build up a relationship with any one place/tech!
Good Luck! 
Yes i can tell you that is true. at my shop we 'pop' the bead, then when it goes on to the balancer the pressure is adjusted. our machines have air hose with computer setting to do the correct pressure.
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No Biggee, I just put new rear tires on the RT and F3 so they would be ready for next season. I only got 21,000 out of the last General but it wore even at 26 psi and probably could have gotten a couple more thousand, but its good to get the maintenance done during "down" season. Walmart tech asked what pressure I wanted, and I said 35 psi, as it is always easy enough to let some out when I want.
IMG_0616[1].jpg
I will probably let the pressure ride over winter until spring and then adjust. Right now the temp is in the low 50s in the garage, so it lost a little due to cooling. At least now I have some fresh tread for the 4" of snow predicted on Saturday..IMG_0617[1].jpg
Right now I have Nankang 155/60's on the front and a General Altimax 215/60 on the rear of the 15 RT. Its time for maintenance and trip planning unless the temps get in the 50's or better for me
07 Shadows, Aero, Spirit gone but not forgotten
03 Harley Sportster, 07 RK moved on
11 RT- 76,000 mi, 15 RT-S- 44,000 mi, traded for current 15 base RT and 16 F3T
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Originally Posted by pegasus1300
I have a set of those on the front of my Spyder. I have over 30,000 miles on them and I think they will go at least another 10,000. I think I paid $70.00 for the pair.
WOW!!! And I thought I was a good negotiator.
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Originally Posted by PMK
So, if I understand correctly, the original post / topic was where the owner had a car tire installed by a Can Am dealer. The dealer inflated the tire, and it was above the customers requested pressure and also inaccurately inflated over the oem recommended pressure based on TPMS readings.
Several points.
First, finding a dealer that will install a car tire on a Spyder would be a huge blessing for many on this forum and FB groups.
Second, from a liability standpoint, a smart tech would not release a vehicle knowingly under inflating a tire.
Third, gage accuracy, that of the tech, or the TPMS comes to mind. Yes, the techs gage could read incorrectly or the tech was lazy, both could result in the higher than oem pressure. Saying that though, if it were me, I would validate and check the accuracy of the TPMS pressure readings to ensure they are accurate.
I will not offer up my ideas on a best brand / model of tire, or my ideas on tire pressure to run. Merely, amazed at the lightning fast speed a finger is pointed and a person criticized for the job they did. So many are frustrated that a shop only installs oem tires at a high cost, and blames it on the shop being greedy. A shop that installs a car tire risks liability. Not saying the car tire is inferior, but rather if the Spyder is involved in a crash, a lawyer could ask the simple question, what makes the shop more qualified than BRP regarding tires to run.
Consider and think about how fortunate you are to get that car tire installed. Adjusting the pressure as you see fit afterwards is minor.
Yes, the shop does know better than you in this case, likely covering their ass a bit.
Actually, the PSI was checked with two gauges in addition to the TPMS. ALL were in the 32psi range. As far as the shop, not a CanAm dealer, CYA, the work order specified 18 psi and there was never a mention of not doing it for legal purposes. So, if you look at Peter Aawen's analysis above, at full up load with my wife, and the specs on the tire, the pressure should be 19psi. Since 90% of my riding is solo, the 18psi I asked for was probably a little high. The actual calculation comes out to 17psi.
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Originally Posted by Baron14y
Actually, the PSI was checked with two gauges in addition to the TPMS. ALL were in the 32psi range. As far as the shop, not a CanAm dealer, CYA, the work order specified 18 psi and there was never a mention of not doing it for legal purposes. So, if you look at Peter Aawen's analysis above, at full up load with my wife, and the specs on the tire, the pressure should be 19psi. Since 90% of my riding is solo, the 18psi I asked for was probably a little high. The actual calculation comes out to 17psi.
Well that’s good, accuracy is not the issue.
Service writers are not techs. Asking them to put 18 psi in is no different than asking them to under torque the axle nut, they may write it on the paperwork, but the tech can simply follow the approved documents / manuals. I guess if Peters pressure were in the tech pubs, the tech that worked on your Spyder would put in that pressure.
I have read pretty much all the posts and arguments regarding lower tire pressures and how they determine what is correct. Glad it works for you.
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You could run zero PSI in the OEM Kenda rear tire and it would still wear it out in the middle, (Assuming it would stay on the rim). This is because the Kenda has only 2 ply in the tread area. It does not have enough integrity to keep the center from ballooning out at speed. If you do most of your riding at 45 mph or less. Then your Kenda rear tire will tend to wear more evenly. But if you are running freeway speeds, the tire balloons out due to centrifugal force, your contact patch is about 2.5~3" in the middle, and it wears out quickly leaving the sides basically untouched.
The tire I replaced was an Arachnid that I kept at 30 psi. Was actually wearing out on the sides of the tread, not the center.
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Originally Posted by 2dogs
"With the Ace 1330 power house and near bullet proof tranny setting on/in the "Y" designed frame, why O why do they cover it with cheap unreliable parts? I guess its one of those bean counter things.
I wonder if it has to do with Canadian trade policy. I read somewhere that economically, Canada is tied very closely with China, in contrast to the US which is dialing back its Chinese investments. Granted that Kenda is Taiwanese, not mainland China, but still. So perhaps there is some internal political pressure to keep trade with China, hence BRP's corporate reluctance to use a different OEM tire.
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Ozzie Ozzie Ozzie
Originally Posted by BLUEKNIGHT911
Interesting about the Arachnid …. the manufacturer copied the Kenda, so it's construction should be similar …. Rear Kenda's always wear in the center ….. I don't know what caused the Arachnid to wear on the sides, this should not have occurred at …. 30 psi …. Mike …… Mike
I may be able to throw some light on this.... Altho I`ve only managed to get my hands on a few (fairly recent) Arachnids, each of those I`ve `dissected` to look at how they`ve been constructed has had just one ply sidewalls like the Kendas but with `normal` dia threads in the sidewall plies, unlike the Kendas that have just one ply with `about 30% lighter` threads....From what I can see, it appears the tread plies are the same lightweight threads/plies as the Kendas, just the Arachnid sidewalls are a little stronger than the Kendas (by about 30%). 
Stronger sidewalls generally means less flex at the edge of the tread, especially if it`s a lightly constructed tread, plus fairly high pressure with a light load, that all adds up to likely mean more tendency for the sides of the tire to stand up & scrub during cornering instead of flexing to keep the tread on the road surface.... So the sides of the tread get caned! I`d really hafta look a LOT closer to be sure, but that could be at least a contributing factor. If I could actually run an Arachnid thru some testing it`d probably help, but so far I can`t find anyone willing to provide a tire or fund the track/skid pan time & testing (me included!) so all I`m doing is cutting up worn out, used, or `get this crap off my Spyder RIGHT NOW` type tires! And as most can guess from the previous, all of the tires I get are pretty much already considered to be fairly crappy tires anyway! 
Last edited by Peter Aawen; 12-13-2019 at 12:07 AM.
2013 RT Ltd Pearl White
Ryde More, Worry Less!
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Originally Posted by Fat Baxter
I wonder if it has to do with Canadian trade policy. I read somewhere that economically, Canada is tied very closely with China, in contrast to the US which is dialing back its Chinese investments. Granted that Kenda is Taiwanese, not mainland China, but still. So perhaps there is some internal political pressure to keep trade with China, hence BRP's corporate reluctance to use a different OEM tire.
Taiwan is not politically connected to mainland China in any way. They do not have any ties and do not get along at all. I used to live in Taiwan. I am not saying that Canada has no trade agreements with Taiwan, but if they do it would be completely separate and not related in any way to a trade agreement with mainland China.
The mainland is "The People's Republic of China" and Taiwan is simply "The Republic Of China".............. different flag, different form of government, different countries.
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Originally Posted by Gwolf
Taiwan is not politically connected to mainland China in any way. They do not have any ties and do not get along at all. I used to live in Taiwan. I am not saying that Canada has no trade agreements with Taiwan, but if they do it would be completely separate and not related in any way to a trade agreement with mainland China.
The mainland is "The People's Republic of China" and Taiwan is simply "The Republic Of China".............. different flag, different form of government, different countries.
I understand that. But the one Canada has to please is the old PRC, and since mainland China regards Taiwan as an erring province and still part of China, Canada may still be reluctant to remove any trade from China in general. Politicians everywhere don't seem to be the smartest or most discerning.
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Member
Originally Posted by PMK
[...]
[F]rom a liability standpoint, a smart tech would not release a vehicle knowingly under inflating a tire.
[...]
I will not offer up my ideas on a best brand / model of tire, or my ideas on tire pressure to run. Merely, amazed at the lightning fast speed a finger is pointed and a person criticized for the job they did. So many are frustrated that a shop only installs oem tires at a high cost, and blames it on the shop being greedy. A shop that installs a car tire risks liability. Not saying the car tire is inferior, but rather if the Spyder is involved in a crash, a lawyer could ask the simple question, what makes the shop more qualified than BRP regarding tires to run.
[...]
Yes, the shop does know better than you in this case, likely covering their ass a bit.
This. I would never let any vehicle leave my shop with pressures that low. Too much liability.
I agree with PMK. The shop does know better than you do, in this case. If you want to run your tire at that pressure, I'd recommend setting the pressures yourself after any repair visits.
One thing I'm curious about, though: What did OP's repair invoice say regarding tire pressures?
Motorcycle rider since 2011, Spyder owner since 2019
BMW Service Manager/Advisor - 2011 to 2014
Independent Automotive Repair Service Writer - 2014 to 2018
Small Engine Repair Shop Manager - 2018 to 2019
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Originally Posted by Knight
This. I would never let any vehicle leave my shop with pressures that low. Too much liability.
I agree with PMK. The shop does know better than you do, in this case. If you want to run your tire at that pressure, I'd recommend setting the pressures yourself after any repair visits.
One thing I'm curious about, though: What did OP's repair invoice say regarding tire pressures?
18 psi
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Politics
Originally Posted by Fat Baxter
I wonder if it has to do with Canadian trade policy. I read somewhere that economically, Canada is tied very closely with China, in contrast to the US which is dialing back its Chinese investments. Granted that Kenda is Taiwanese, not mainland China, but still. So perhaps there is some internal political pressure to keep trade with China, hence BRP's corporate reluctance to use a different OEM tire.
Yep, sometimes politics trumps everything else. I try and keep my distance from the subject because for onlookers it can be difficult at times to distinguish who's the most misinformed.
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Member
Originally Posted by Baron14y
18 psi
No, I mean, what *exactly* did it say? Normally, on a repair invoice, you'd see something like this:
Inflate rear tire to 18 PSI per customer request
Tech notes: Inflated front tires to * PSI, rear tire to 18 PSI per customer request
Or, it might have said this:
Inflate rear tire to 18 PSI per customer request
Tech notes: Unable to set rear tire pressure to 18 PSI, too far below spec. Set pressure to * PSI per manufacturer recommendations
Or, it might not mention the pressures at all, which would also be telling.
Motorcycle rider since 2011, Spyder owner since 2019
BMW Service Manager/Advisor - 2011 to 2014
Independent Automotive Repair Service Writer - 2014 to 2018
Small Engine Repair Shop Manager - 2018 to 2019
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Originally Posted by knight
no, i mean, what *exactly* did it say? Normally, on a repair invoice, you'd see something like this:
Or, it might have said this:
Or, it might not mention the pressures at all, which would also be telling.
it exactly said "rear tire - set pressure to 18lbs(customer supplied tire)"
Inflate rear tire to 18 PSI per customer request
Tech notes: Unable to set rear tire pressure to 18 PSI, too far below spec. Set pressure to * PSI per manufacturer recommendations
What is the recommended pressure from the mfg for an auto tire on a Spyder? And where do you find it?
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Originally Posted by Baron14y
it exactly said "rear tire - set pressure to 18lbs(customer supplied tire)"
If that's the case, my guess what happened was an error on the service writer's part. The tech probably saw the work order, thought to himself, "No way am I gonna do that," then set the pressures normally. Then the tech either didn't write any notes, or the writer misread the notes and instead assumed the tech did the work & typed it up himself. Either way, that's on the service writer. I'd bring it to the shop's attention, just to let them know about the error, and hopefully they'll catch it in the future.
Originally Posted by Baron14y
What is the recommended pressure from the mfg for an auto tire on a Spyder? And where do you find it?
The only recommended pressure that a shop has to go by is either the pressure recommended on the tire pressure sticker on the vehicle, or the max pressure listed on the tire. Like Blueknight said, neither is going to take into account that you're putting a car tire on a motorcycle. In that instance, the shop is going to err on the side of caution, and go with a pressure that's standard for the tire.
Motorcycle rider since 2011, Spyder owner since 2019
BMW Service Manager/Advisor - 2011 to 2014
Independent Automotive Repair Service Writer - 2014 to 2018
Small Engine Repair Shop Manager - 2018 to 2019
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Originally Posted by Knight
If that's the case, my guess what happened was an error on the service writer's part. The tech probably saw the work order, thought to himself, "No way am I gonna do that," then set the pressures normally. Then the tech either didn't write any notes, or the writer misread the notes and instead assumed the tech did the work & typed it up himself. Either way, that's on the service writer. I'd bring it to the shop's attention, just to let them know about the error, and hopefully they'll catch it in the future.
The only recommended pressure that a shop has to go by is either the pressure recommended on the tire pressure sticker on the vehicle, or the max pressure listed on the tire. Like Blueknight said, neither is going to take into account that you're putting a car tire on a motorcycle. In that instance, the shop is going to err on the side of caution, and go with a pressure that's standard for the tire.
You know that somewhere sometime in the future, there's going to be a accident involving a spyder running vehicle tires and the victims are going to hire an attorney who will reach out to find the deepest pockets possible. Afterwards we'll have to take our car tires and rims to Mexico to get them mounted. CA will likely be the first state to pass a law against placing/installing car tires on a motorcycle.
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I won't be taking mine to Mexico.......... not as long as Harbor Freight makes a tire changing stand. It is pretty much the same thing I was using in the lube bay of the service station I worked at 55 years ago. Rim savers will protect the wheels. They got bubble balances too. Sure, the electric over hydraulic is convenient and the spin balancers do a great job, but we used to do it with muscle power and still can. I still got a couple different sets of tire spoons in my shop. Have used them on motorcycles wheels fairly recently too.
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Originally Posted by BLUEKNIGHT911
 ... No - Auto tire manufacturer has this number because it doesn't exist...…. Mike
Was asked tongue in cheek!
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