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Discussion Starter · #1 ·
First off I'd like to say Hi since I haven't been around for like the last 2 years, looks like things have been busy!! I've still got my same 03 sahara and still love it! My question is I just replaced the 35x12.50 Procomp X-Terrains with 35X12.50 R15 BFG AT K/O's. I got the wheels and tires home to put them on the jeep and they looked funny, the tread was like rounded across the top, like they had WAY to much air in them. They were at about 35 psi. I aired them all down to about 25 before I ever even drove the jeep. It feels like it drives a little funny, like it wants to wander on the road. After about 100 miles on the tires the outside inch to inch and a half on the inside and outside look like they have never touched the road! I wouldn't think I should have to run the pressure any lower than 25psi but it looks like they are way over pressure. Any advice. Oh and they are on 15x8 steels wheels, guessing this is part of the problem but my procomps always made good contact on the same wheels at about 27 psi. Thanks in advance!!
 

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25 psi for 35" tires is about right. I am not quite sure if I understand your exact wear issue but anytime there is unusual/uneven wear, I would immediately suspect the toe-in is bad. Check/adjust to insure the toe-in is correct.
 

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Discussion Starter · #3 ·
It's not a wear isssue yet, the tires have only bee on 2 days it's just the the whole tread patch isn't touching the road. I drove home on salty roads and probably the center 8 inches of the tread was white from dirt and salt, about an inch and a half on both the inside and outside of the tire were jet black, like they had never touched the road. It is like this on all 5 tires, looks as if they are way overinflated making them balloon out across the tread instead of being flat against the road.
 

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sidewalls are pretty thick on those BFG's. Untill they get broke in I would go 23+-lbs or so.
 

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Well, if it drives "funny" I would still check the toe-in to make sure it's correct. A bad toe-in can cause it to wander. But 25 psi is definitely not overinflating them.
 

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Discussion Starter · #6 ·
Here are some pics, maybe it will make some more sense this way! Thanks!!


 

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Don't worry about it, they are inflated correctly... what you are seeing is perfectly normal. :)
 

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Discussion Starter · #8 ·
Thanks Jerry, I knew that 25 PSI wasn't to high I just didn't understand why they were so rounded on the top. You can see in the pics how rounded they are, I guess this could be from the brand new sidewalls being so stiff, hopefully this will work itself out some quickly, if not I might as well be running 8 inch wide tires on the road!! Oh and for the toe in, I have an alignment coming monday or tuesday!
 

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The only thing an alignment shop can adjust is your toe-in, nothing else like the caster or camber angles are even adjustable. If you have a tape measure and a wrench, you can easily set your own toe-in just as accurately as any of the latest laser whiz-bang alignment racks can do.

Interested?
 

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Discussion Starter · #10 ·
very, I took on this task once before but obviously wasn't doing something right as I could get the adjuster ?? To turn. I'll listen to any advice on how to do it right!!
 

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Adjuster? Do you mean the tie rod? Rotating the tie rod is how the toe-in is adjusted.

The method at Basic Jeep Front End Alignment gives the basic information. It involves measuring the distance between the tires at the front and rear to achieve the desired 1/16" to 1/8" of toe-in at the front.

A more accurate/repeatable method of measuring the exact amount of toe-in is shown below. Simply mark a pair of 1" square aluminum or steel tubes at points equal to your tire diameter and clamp them centered on the rotors and you'll be able to set a very precise amount of toe-in.

If you had trouble rotating the tie rod before, that's pretty common as the threads can seize if you live where the roads are salted. Try spraying the threads through the slot at the ends of the tie rod for a couple days with Liquid Wrench to help loosen them up. Then use a big set of channel lock pliers, vise grips, or if you have it, a pipe wrench is the best of all tools to get it to rotate.
 

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He's saying it's only making contact in the center of the tread

Those tires are really stiff - and rounded. To show just how stiff they are you can drop the tire pressure to near 0 and they'll still look OK.

The rims for those should be at least 10" wide for them to run evenly across - even then they still wear more in the center.
Notice the load rating on them. If your rig was lots heavier they would wear more evenly too.

As it is, crowned in the center, it's really an advantage - on pavement and hard dirt they handle like narrower tires - easier to turn, less drag (mileage) etc. When you get in the soft stuff the outside portions touch and go to work.

The wandering - experiment with pressure for the street. And check the toe-in.


But the sidewall stiffness is good - Finally BFG makes a tire that the sidewalls don't slice up just because there's a sharp rock a 1/2 mile away. I went through 10 of them in about a year.

Even my fav tire wears like that - Goodyear MTR's.
 

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Discussion Starter · #13 ·
Thanks for that reply rrich, makes perfect sense. I guess I just never noticed that with my procomps but they did wear out in the center. Jerry, Thanks for those pictures on how to check the alignment. That way seems a LOT more precise! I will definitely be doing this. I used to read that I needed 1/8 to 1/16" toe in in the front, is this correct or do I need to be perfectly square? Thanks again!
 

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Have the same issue with my BFG 35's, thought was a 7 inch wheel. Just replaced wheels with 8 inch and same thing. So this is normal and will not make tires wear out prematurely?
 

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Have the same issue with my BFG 35's, thought was a 7 inch wheel. Just replaced wheels with 8 inch and same thing. So this is normal and will not make tires wear out prematurely?
The concern comes when the edges are wearing out and not the center. If the tires are not over inflated, like Jerry was saying, it is a non issue.
 
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