Tire Wear

[schwalby]

This will probably be a question that you guys are going to say you need more info for but going to ask anyways.

This is not my tire but since I can't get a picture of my tire right now this is as close as I could get. My tire has the same "chopping" as this tire does but mine is only on the center lugs, doesn't go from side wall to side wall.





Went through the front end and everything seems to be tight and fine so could an alignment be the fix?

Back story, I had noticed my front passenger tire was wearing oddly and when I checked into it I was told that it was the tire going "bad" They are 35" LTBs so not a tire that is built for road use so it made sense. I switched my front two tires in an effort to round out the bad one. As soon as I put the driver tire on the passenger side it started doing the same thing. This is when I had the front end looked at and everything seemed fine. Then winter came and I had to put the 33" A/T on and was hoping I could figure out what was wrong with the front end. Life went the way life does and the Jeep has been running on the A/Ts for at least 3K miles... there is no uneven tire wear on the 33s, everything looks totally normal. Talking about this with some guys while out one night the theory is that there is an alignment issue and the larger soft tires are just showing it more. No idea how well that logic holds true so I ask you guys. Whatcha think?

[nostaw]

If the wear followed the tire when you swapped it I would have said a bad/bent wheel. Wrong tire pressure could do it, but it should follow the tire, so that probably isn't it.

Does the Jeep pull to the side at all, or track straight?

If you've already checked the linkages are tight...

1) Check the toe measurements (probably not it, but easy to do)

2) Check the unit bearings and see if they are worn out (jack up the wheel, grab tire top and bottom and look for play... pull/push towards / away from the fender)

3) Check the ball joints for play (jack up and see if you can wiggle the knuckle with a pry bar)

You need to jack up the vehicle to check 2 & 3.

My guess is the ball joints or unit bearing is bad on that corner allowing the tire to wobble while you're driving it.

Because of the wonderful road characteristics of a 35" LTB you may not have noticed the wobble...

JW

[schwalby]

With the 33s on it know it tracks pretty straight, slight pull but nothing I wouldn't expect from a lifted Jeep on 33s. It is very minamal.

How do you check the toe?

The bearings and ball joints were checked but it wouldn't hurt to check them again.

What gets me is that there is no signs of wear at all on the 33s and they have been on there for at least 3K miles.

[ZAEDOCK]

Check toe. Did your tie rod take a hit recently?

Excess toe causes the tires to be pushed and "scrub" the road. This is more pronounced with a lugged tire of biased construction. Pay strict attention to air pressure with bias on the street as well.

Edit - when I built my front tie rod I was "dialing in" the width with the CJ knuckles. I had excess tow out and my 15.5" wide 38's started to chop as pictured (not as bad but I could feel it) very quickly.

[Frank]

Usually you get more chopping with a tight turning vehicle on block tires. When you get it more towards the center of the tire only , its air pressure. You cant compare the two types of tires as the structure is completely different. Alignment of the front end will help. You will find insufficient caster on the knuckles. Wear on the inside or outside edge only , indicates toe in or out. Wear on both outside edges indicates low psi. Vs.In the middle only.is to much air. I would think if there was a bad tie rod or ball joint , Youd see the damage more on one side or the other. My 2 pennies ! FjR68

[schwalby]

These are the times I wish I knew a lot more about Jeeps and you guys lived closer ;\

[nostaw]

Read this web page... it explains toe / caster / camber it better than I can (and has pics):
http://www.anewtoronto.com/wheel%20alignment.html

You can measure it yourself with a tape measure... Pick 2 points on the front of the tires (one on each side) and two points on the back (the points should be the same vertical distance). Measure the front / front and rear / rear distance. From there you can figure out how much toe you've got. The rear should be slightly wider than the front if you're aligned correctly (slight = 1/16" to 3/16")

JW

[Frank]

Nothing to do with Jeeps. Vehicles in general. Steering is an important thing that we laymen cant fully understand untill shown or taught. Anyone know what the ackerman degree is on a TJ ? Me either ! But its a critical measurement that has to do with how far ahead the inside tire is while in a turn. Thats what we have friends for ! No worries mate . FjR68

[ZAEDOCK]

Along with ackerman, I'm familiar with steering axis inclination(SAI), set back, scrub radius, included angle, & thrust angle


I used to do alignments, with our Hunter alignment machines serviced by none other than Lou from Elias. I remember when Gypsy would visit too. She was a good dog.

[schwalby]

Thanks guys. I'll take a look at the site in the morning and take the measurements.

thrust angle

I know that one

[Carl McFly]

You can measure it yourself with a tape measure... The rear should be slightly wider than the front if you're aligned correctly (slight = 1/16" to 3/16")

JW

Or you can cheat and use bungee cords and a cut up 1 x 12 from HD.....

I was able to dial my toe-in real easy

[ZAEDOCK]

...and then Carl practices his Karate Kick.....

[Frank]

Then all this would change with rear steer ! FjR68

[ZAEDOCK]

Then all this would change with rear steer ! FjR68

Actually, it wouldn't change too much. You just set the rear first and then go to the front. Did plenty of alignments on Honda Preludes with the late 80's/early 90's rear steer option and other similar imports. It added time and complexity to the upkeep of the car and seemed more like a techno fad than anything else.

[schwalby]

Another question. Once I figure out what caused this can I still run the tires? I don't have the money to get replacements and really can't wheel on the ATs