Need a tire pressure reminder?

[fulltimer]

I am getting a little uneven wear on the rear of my ST. Wearing more in the center than the edges. I have about 11K on the tires. I am running Vredesteins all around. Riding 2 up most of the time. Total weight about 320 lbs. Probably to much information. Running 17 lbs. in the rear and keep it pretty close. Do I want to add or reduce a pound to try to even out the wear?

[Peter Aawen]

I am getting a little uneven wear on the rear of my ST. Wearing more in the center than the edges. I have about 11K on the tires. I am running Vredesteins all around. Riding 2 up most of the time. Total weight about 320 lbs. Probably to much information. Running 17 lbs. in the rear and keep it pretty close. Do I want to add or reduce a pound to try to even out the wear?

If you can see the different wear rates already, then you won't really ever be able to 'even out the wear' as such, cos the wear pattern will already be established & it'll continue that way regardless of any reasonable pressure you might run - you'd have to go down to dangerously low pressures to 'even out the wear'!

But you will probably be able to reduce the accelerated wear rate in the middle of the rear tire somewhat by reducing your rear tire pressure another psi or so. Only after doing that, please do ensure that you make sure to check that the tire's pressure doesn't increase from it's cold start pressure by too much more than 4 psi or so after an hour's ryding! . Anything much more than a 4psi increase after an hour's ryde means your cold start pressure is too low; anything much less than that 4psi increase means your cold start tire pressure is still too high! That said, unless it's extremely cold & you are ryding carefully & slowly for short periods in conditions where you REALLY need traction over most other considerations, then I wouldn't recommend you drop your Spyder's rear tire pressure much below about 14psi... even if the tire seems to handle it OK & it's still wearing in the middle.

Over to you. Good Luck!

Ps: as their compound has become harder with age & wear, I've had to drop Kumho's down to 14 psi to minimise that centre tread wear.

[BLUEKNIGHT911]

I am getting a little uneven wear on the rear of my ST. Wearing more in the center than the edges. I have about 11K on the tires. I am running Vredesteins all around. Riding 2 up most of the time. Total weight about 320 lbs. Probably to much information. Running 17 lbs. in the rear and keep it pretty close. Do I want to add or reduce a pound to try to even out the wear?

Well this wear pattern is contrary to how wear will be affected by LOW tire pressure. Higher PSI usually causes pre-mature in the center of the tire. ... If they were Kenda's that type of wear is normal because the tire casing is so weak ..... Try upping the psi to 19 .... Both Peter and I recommend 18 tp 19 psi for any Auto tire ..... Mike

[2dogs]

That's a tuff one to answer. Certainly wouldn't go up in pressure as that causes center wear for sure. 320 lbs is not even close to overload, and at 17 cold PSI he's probably at 20 hot. Seems he's, right in the ballpark for PSI. I'm running 18 PSI on an Altimax and at 26K I'm showing a bit more center wear. Peter is correct. Once a wear pattern starts, it can't be corrected. Unless it's cupping.

[Mikey]

Just one question for you, have you checked the calibration of your tire gauge with another one just to see if it's apples to apples? That way you can make sure that 17 is 17 It just seems like we are acting like Indy racers with these things, were we are trying to get it to +- a half pound! How far can you take a tire down before it will unseat itself anyway? Makes me a little antsy!

[Peter Aawen]

Just one question for you, have you checked the calibration of your tire gauge with another one just to see if it's apples to apples? That way you can make sure that 17 is 17 It just seems like we are acting like Indy racers with these things, were we are trying to get it to +- a half pound! How far can you take a tire down before it will unseat itself anyway? Makes me a little antsy!

Well, unless you're sliding it sideways a lot, lighting up the rear while over-loaded, or maybe running a 195/75/15 on a rear rim that's better suited to 205's or 215's & usually wears a 225... .... then you could most probably go down to about 8psi or so. It might not feel all that great, but it should work - & has for some.

But if 14psi gives you an increase of just 4 psi after an hour's ryding, as it did in the Kumhos I ran, then that's pretty close to the optimum pressure for that tire under those conditions & is usually pretty much the lowest working pressure that I've found works well across the board for all the car tires I've tested on a Spyder rear so far. . So trying 16psi as I suggested above, and confirming that you don't get anything more than the 4 psi increase as I mentioned above should be good with a pretty reasonable safety margin too!

[2dogs]

Good thread Peter, thanks. Have you experienced a rear tire ever wearing out totally even all across the entire tread?

[BLUEKNIGHT911]

This type of wear on a Vredestein tire has not been re-ported here by any users ... In fact I don't remember anyone using any Auto tire has re-ported this type of wear ..... another member here " teninospyder " has done extensive re-porting on His Vredestein's and He rides mostly two-up .... also His weight load is about 100 more than yours .... so far He re-ports getting Excellent mileage and " even " Tread wear ..... Mike

[Peter Aawen]

Good thread Peter, thanks. Have you experienced a rear tire ever wearing out totally even all across the entire tread?

Sure have 2dogs - because I was very closely monitoring tread depth changes (& a bunch of other stuff too - cos that's what I do.. ) I realised early on that the Kumhos pressures needed to be dropped lower as time/miles progress; but I've run 2 of them now that wore pretty flat & even right across the tread! Plus, beyond the tires that I've only had access to testing/running for a few thousand kms, there's also been a couple of others that I've personally run for much longer with similar results, & there's even more tires I've seen run in the 16-18 psi range wear very evenly across the entire tread face on other's Spyders too! In fact, I'd go so far as to say that most car tires that're run mainly at the right pressure for them, their load, conditions, and the ryder's ryding style, which generally means in that 16-18 psi range, will wear pretty flat & even, altho the ryder's style &/or load variations can make some (usually minor) differences (see that 4psi increase after an hour's ryde info to help determine what's going to be right for you. )

Altho that said, as I collect data from my own tire wear, shorter term testing, and the tire wear I see others getting, I'm also noticing that especially with the 'wider makes' of car tire (cos not ALL 225's are actually 225mm wide! ) & some of the higher performance &/or softer compound tires in 225 width, they can still be a little more prone to this centre wear despite running what should be the ideal pressure for them.... I've mentioned before that this may be because the 225 width is juust a tad too wide for the rear rim width & the light weight of our Spyders, so even if you do run at the appropriate pressure for the conditions etc in that 16-18 psi range, the tire might still be 'bagging in the middle' a bit due to the sidewalls being 'pinched in' on the rim rather than anything else... But that's a 'study in progress' & of late I haven't been up to running the testing miles that I used to be able to do a whole lot easier.... . As Mike has mentioned, this centre of tread wear is not at all common to that reported on the Vredesteins running at 16-18 psi, so this MIGHT be at least part of the reason fulltimer's tire is showing accelerated wear in the centre of the tread - what size is your rear Vredestein fulltimer?? But for everyone else thinking of changing to car tires, maybe if you really want the best possible tire life and traction out of your tires, it might be smarter to run a tire that's a bit narrower than a 225 - I'm currently running an Michilen tire in 205/65R15 to help test just this; I'm monitoring more; and I've done some short term testing on a few other widths as well; so hopefully, in time we'll get to see what the data gathered reveals.

Btw Mikey, I don't think that exact accuracy in a tire pressure gauge is really necessary - consistency within a pound or so is far more important; altho if your tire pressure gauge shows you that your tire's sitting at 16 psi but it's actually reading 4psi over the true pressure, then that is probably going to be of concern! So yeah, even if you don't get it calibrated, checking &/or comparing it with at least a couple of others might be insightful - altho I wouldn't bother doing that comparison with the notoriously unreliable &/or abused gauges in a service station.

Ps: another thought on your particular tire wear issue fulltimer - have you recently done any long trips, fast runs, &/or hot/high temp runs on your Spyder?? Have you done any of that on these tires?? . It generally pays to add 1 or 2 pounds of pressure to your tires if you are really loaded up (not just adding a pillion, but definitely if adding a pillion AND filling all the storage spaces! ); if you're leaving on a trip that'll involve more than an hour or so of higher than usual speeds; or if your trip will see you running at your normal speeds but for much more of the day than you'd usually ryde; and this need for adding 1-2 psi is especially so if you are doing any of that in much hotter ambient temps or on hotter road temps than the conditions you usually ryde in! . Those heavier/longer/hotter conditions will cause the rear tire in particular to flex more than usual, thereby heating up more & so increasing the tire's pressure beyond that ideal 4psi increase after an hour's ryding you should be aiming for; and THAT will cause the tire to balloon out in the centre of the tread more than usual! So if your cold starting pressure is OK for your usual lighter/shorter/cooler runs, then adding a pound or two of pressure for those heavier/longer/hotter runs before you leave can help counteract the pressure increase. It's not normally necessary/much of a biggie for general daily running or weekend ryding - but if you've worked out the pressure that works best for you while doing that with your normal pillion/load state while ryding within saaay, a hundred miles from home, then it's probably going to need that extra 1-2 psi of air if you are heading out on a 200 mile plus trip while fully loaded, maybe also with a pillion aboard, &/or when ryding at saaay 70-90 mph for more than an hour or so instead of your usual 50-60ish mph, & especially so if the ambient temp is in/above the 90's (°F) or above/road surface temps above 120°F instead of in the mid 60-70's or whatever..... if you get my drift?!? Those heavier/longer/hotter runs generally warrant increasing your tire pressures by 1 to 2 psi or you risk over-heating the tires & getting more than that 4psi increase after an hour's ryding which is going to contribute to accelerated wear in the centre of the tread! Does all that make sense to you?!?

Sorry about the saga, but I hope it helps some, even if just a little?!

[fulltimer]

Thanks to all. I will drop 1 lb. and watch the psi increase as it warms. BTW. I have compared my gauge to other ones and it seems to be pretty accurate. I do use the same gauge all the time for the obvious reasons.

Thanks again. I will probably re-open this thread in 4 to 5 months and report.