Yet some more tire questions

[spyderdavee]

. First off I'm a spirited rider who pushes the twisties to try and get the nanny to kick in everytime. Strictly stock suspension on my 17 RT. Got use to the front end lifting and when it does just crank on the throttle more.

Anyway first question is what size and tire brand have you gotten the best handling and longevity? OEM kenda I got about 5800 miles the kumho I put on after that I got 13000 on before it felt unstable on wet roads. Then a General 43RT it was a 225/60 that barely made 13000. I've got the kenda kanine on now with about 6000 miles that I doubt will make 8k.

2nd question is on my 17 RT every tire has worn an area where the center of the tread is bald and 180 degrees across the tread is at least 3/32nds. What causes this? Out of round rim? Mismounted tires? Or is it as the dealer says my spirited riding? I've always tried to set the cold psi 3.5-4 pounds below the hot psi.

 

[RICZ]

Are you talking about all 3 tires or just the rear? Kumhos all around, or just the rear? Sounds like Kumho is the way to go unless one wants to pay more.

 

[Mikey]

And it sounds like you may be using a little to much air, if you are burning your centers out! You have used a couple descent tires, but because of your air pressures and driving habits, don't know if any tires going to give you the mileage your looking for! My 2 cents, sorry!!:dontknow:

 

[Peter Aawen]

Firstly, and just to get it out of the way for those who may not yet know &/or forget/misunderstand.... With the stock Kenda rear tire AND it's apparently 'slightly better tread compound but otherwise very similar in construction' Kanine clone, the 'full circumference' tread wear in the centre of the tread & the subsequent relatively short tire life is largely due to the lightweight construction allowing the face/centre of the tread to 'throw out' as the tire revolves, and there's not much you're going to be able to do about that!! It's the nature of the beast & a result of the way the tires are constructed so lightly/ with a low load capacity - DO NOT assume that centre tread wear is due to over-inflation & reduce the Kenda tires from their specified pressure - they NEED that much air pressure to work as well as they do (which isn't really all that great! ) and running lower pressures in them will be risking tire failure &/or handling compromises that you don't risk by running lower, more appropriate for the Spyder's lightweight load in auto tires that are constructed well enough to allow them to safely carry much higher loads!! :thumbup:

That said, and knowing that Kendas tend to be 'fairly small' in their sizing when related to the size printed on their sidewwalls, and also that many other tires are larger for the same nominal size, there's a growing body of evidence to support the idea that a 'generally not as small for the nominal 225 wide auto tires' out there may be just a touch too wide for the std BRP rear rims, so that their larger size, heavier tread, & stiffer sidewalls all team together to tend to force the tread surface to bow out a tad when fitted onto the (slightly too) narrow-ish rear rim (despite it being within the generally 'recommended rim width' range for that size tire ) causing what might LOOK like apparently the same centre of the tread wear that you get on the Kendas due to centrifugal force &/or what you might get in other applications due to over-inflation!! :shocked: But also, if you're running much more than 18 psi in an auto tire under a Spyder, you are probably running a bit too much air!!

However, it is also worth noting that in general, Kumhos tend to start out pretty grippy when they're new, so a 4psi increase in pressure after about an hours' ryde over their cold start pressure might seem to be enough to reach their optimal operating temperature, but they also tend to harden up fairly quickly as they age, so that after a year or so &/or by about half their tread life (15,000 or so miles, give or take) they seemingly 'go off', mainly because they are no longer getting warm enough to stay 'sticky' and do their job properly, especially in the wet!! Yet all it really takes to keep them working properly at that stage of their 'hardening/aging' is to drop another pound or two of pressure out of them and aim for a 6 psi increase after an hours ryde instead of just 4 psi! hyea: I just retired a Kumho 225/60R15 at 35,000 km; with the last half of that milage running on a cold start pressure of 14psi & aiming for/achieving a 6 psi increase in an hour's ryde; and it STILL wore out the centre few inches of tread first!! :banghead: But I could actually see the 'raised bow' in the centre of the tread due to the 'too narrow a rim' for that particular tire!! :lecturef_smilie:

So all up, if you don't want to drop your tire pressure a bit lower as the tread ages & hardens, then you might be better off choosing a narrower auto tire to start out with - I'm currently testing a Michelin 205/65R16, running 16 psi cold cos that's what the calcs suggest is the optimal pressure to help them reach their ideal operating temps for my loads & ryding in our current ambient temps - only while it LOOKS to hold the tread face/contact patch flatter on the road surface all the time, it's early days yet, and the paint on it hasn't even dried properly, so it'll be a while before I can tell you if it's making any worthwhile difference! :dontknow: