Sumatoma 315/35/17's Tire Pressure???

joshheat25

Member
Nov 8, 2004
871
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16
Delaware
I have these tires and they wore in the middle. I know that if a tire wears in the middle the psi is too high and you need to lower it, but I only had 28 psi in there. When they were first on there I might have had more psi I am not sure. I was wondering what everyone else runs in them and also would running at the track, doing a burnout at the track only wear them in the middle? Thanx
 
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I ran my kumhos for the first few months at 35PSI (its what discount tire put in there) then before I went to the track for fun ford a few eeks ago I lower to 30PSI...I know not a big deal and still alot but my wear looks great.
 
hotmustang331 said:
I ran my kumhos for the first few months at 35PSI (its what discount tire put in there) then before I went to the track for fun ford a few eeks ago I lower to 30PSI...I know not a big deal and still alot but my wear looks great.



that's exactly where i have mine at as well
 
I see you have Cobra R wheels, are they 10.5" or 9"s wide? If they are the 9" that would be the reason.
If you run 30-32 lbs of air on a 10.5" wide rim the wear should be pretty equal all the way across the tread.
Some times if you run too little tire pressure and do a lot of higher speed driving a tire will wear in the middle because the center is allowed to grow more than the edges. This is from the side walls being pulled in from not having enough air to support them and the centrifigaul forces being applied to the tire.
 
I was told by discount to run them at 30 since that's what the sticker on the door jamb says. My 1st set I ran at 35 (tire sidewall) and also wore out the center while the edges still had lotsa tread left.
 
I'm on my second set of Sumatoma 315/35/17's on my 17x10.5. First pair I ran at 30 and they wore out in the middle. This pair I"m running at 32, so far so good, but still to early to tell. Can't beat the price of the Sumatoma's.
 
yea the tire looks cupped in the middle and there is still plenty of tread left on them??? I wonder if I wasn't running enough pressure and the centrifugal force wore the middles out??? as other people have said. So what tire pressure should I run on my new ones?? Any one else have an opinion on this.
 
HAHA, thats the bad part. I think they were about 560 mounted and balanced. Probably twice what the sumitomos would have cost.

I bought the goodyears instead because the treadwear was better, and I heard the wet traction of the sumi's was pretty bad (according to tirerack reviews). I daily drive my stang, and that had me worried, so I shelled out for the more expensive rubber.

Who know's....maybe next time I will try the sumitomo's to see how they are. For you guys that have had them a while, how long do they seem to last and how is the wet traction?
 
My set lasted a year and a half and about 10 runs at the track and very good wet traction with tread on the whole tire! I still have about 1/4 inch of tread on the sides of these tires it is insane!!!
they are 115 at tirerack.com
 
Probably the tire isnt reinforced enough, your in a catch...you run 25PSI they will probably wear on the outside at slow speeds then in the middle at high speeds, but maybe it will balance itself out.....I say run 26 PSI and see what happens. Also, how do those tires hook in the dry? Like if your rolling in 1st gear and nail it, what happens, spin or just go? What about from a stand still launch, mine with the stock gears would spin 1st real good, then just after i hit 2nd would bog the engine...now 2nd just holds its own and then hooks.