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Discussion Starter #1
I have a 98 Tacoma that's lifted 3" with a OME kit. I went to Discount Tire a couple weeks ago and bought some BFGs in 33x10.50x15 ATs. I was told that I had a 10" wide wheel and this combo would work together. I drove about 100 miles and noticed that all 4 tires were crowning. I could see the center was much higher than the outer tread of the tire. I checked the tire pressure and it was 36psi. So I called them and they told me to bring it in, so I did. They told me that since all 4 of the tires were doing it that it was my truck and also my rims were to big that it is suppose to have 7 to 9" rims. They said inflating the tire to 50 lbs would make it ride more even and to wait 5000 miles before I would notice the change for the better. He also told me it was more likely something was wrong mechanically wrong with my truck. As I was driving home the really pissed me off telling me that its my truck. What a bunch of crap. Well I drove to another tire shop and asked them about all this crap I was just told. He looked at it showed me my rims were actually 8" instead of 10s like they told me. He couldn't figure out why they were wearing like that so he said to deflate the tire to 30 psi and see how it wears. Now I understand about alignments just I just had it done 2 weeks ago also I've got new axles and new rack and pinion steering. New brakes with new roters. So can someone tell me how this is mechanical a problem. Does anyone have any ideas?
 

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It sounds like it is not a mechanical problem.

IMO 36psi is way to high for the rear tires when unloaded. I run less than that in the front too.

I have 2 sets. One set is KM2s on stock rims(15x7) w/ 31x10.5x15 and the other, BFG A/T 32x11.5x15 on 15x8s.

What rims are you running?

Have you checked the contact patch by using chalk across the tread?
 

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if Discount sold/mounted that sized tire to a 10" wheel...
I'd demand replacement tires that fit properly or my money back.

No wait... I'd never let them do that in the first place

that narrow of tire fits acceptably on 7"-8" wheel widths
but mounting them to a 10" width isn't all that smart IMO

or is this a superficial island truck ? :dunno: :D
 

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Sounds like they are jerking you off over there at Discount. Does not sound like a mechanical problem. The chalk method mentioned could help find the appropriate PSI if PSI is causing it.

What wheels are you running?

Got pics that show the issue?
 

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Discussion Starter #6
Second tire shop showed me the stamp on the back of the rim it says 15x8. I went from the Dura Track 33 x 12.50 x 15 to this new set up cause I want a thinner tire. What's a chalk method because if its finding out what part of the tire is in contact with the ground no need you can see it plan as day. There's not even any dirt on the about an inch on both sides of the tread. That's on all 4 tires. The whole thing just piss's me off when they tried to blame my truck.
 

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What is the load range of the tires?
You need load range "C" rating for light trucks with 32 psi as the max recommended pressure..

Heavy rated tires at proper pressure will crown and wear center tread faster.

All you can do is drop to 28-30 psi to see if you get full tread contact.
 

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Discussion Starter #8
They are load range C but it says on the tire max pressure is 50 psi but I've got it down to 30 psi now. Doesn't that wear the tires faster having them so low? When I drive on some dirt roads ill get some pics and you all will see what I'm talking about.
 

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"Chalk Method" Your guess is correct. It is to show what part of the tires is in contact with the ground. You need a smooth flat road, and some chalk. Rub a thick line across the tires and roll straight for a bit, then get out and check it. Based on the information you've given, I'd run a lower pressure, 28-30 psi, and see what that does for you.

Lower tire pressure can cause excessive or uneven wear problems, but you are at that point already, as the center of your tires will be wore out well before the edges. 30 psi isn't really that low anyway.
 

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Second tire shop showed me the stamp on the back of the rim it says 15x8. I went from the Dura Track 33 x 12.50 x 15 to this new set up cause I want a thinner tire. What's a chalk method because if its finding out what part of the tire is in contact with the ground no need you can see it plan as day. There's not even any dirt on the about an inch on both sides of the tread. That's on all 4 tires. The whole thing just piss's me off when they tried to blame my truck.
You have too much pressure in them.

These days I run the tires on my tacoma at about 25psi in the front, and 22-23psi in the rear. Smoother ride, better tire wear, but slight loss in MPG.
 

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I would just run lower air pressure, you are way high, especially in the back. Seems to me like it is an okay setup, a 10.5 on an 8" rim. Even if it was on a 10" rim like you said, that wouldn't make the middle bulge out, it'd be the other way around. If you were running the old Toyota 6.5" rim, then it might make the middle of the tread bulge out. I think you just need to drop your air pressure.
 
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