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How much wobble is "normal" with AT's ?
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=8&t=40494
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Author:  dgeist [ Sat Feb 21, 2009 11:00 am ]
Post subject:  How much wobble is "normal" with AT's ?

I have a set of Dueler AT-Revos that I'm very happy with...performance wise. I am experiencing a wobble in the cab at slow speed, though, so I've been troubleshooting where it's coming from. It's only noticeable at 15-25 mph and it's definitely cyclic with wheel rotation (doesn't match engine or driveshaft rotation).

Last night I put the rear axle up on jackstands and let the jeep idle in 2W-H-Drive There didn't appear to be any vibration I could see or feel, so I think my wobble is an out-of-round condition. The right side wheel was dead-on round, but the tire seemed to have some variation in its radius. There was a spot about 4 mm taller than the rest that was easily visible when viewed at ground level.

The left wheel seemed like the wheel itself was either out of round/bent/not mounted straight. There was a little variation in the tire to ground clearance, but not much more than I could see the rim of the wheel wobbling.

Now, this is my first vehicle with AT tires, so how much of it is me being neurotic and how much is likely a real problem with the tire / wheel / both? I've never felt anything like the wobble before having driven vans, cars, pickups, and SUVs. What's my next step to figure out the wobble, preferably things I can do in the driveway. I'd like to avoid shops as they tend to leave scratches, scrapes, and dirt in places I don't want them.

Thanks.
Dan

Author:  SweepnChoke [ Sat Feb 21, 2009 11:17 am ]
Post subject: 

Doesn't sound fun at all, can't say I have experienced any of this type of issue with my BFG AT's and I have run many sets for over a decade.

The right wheel has no deviation, but the tire seems to have a proud point.

The left wheel appears to have deviation, and the tire seems to follow the rim deviation.

Correct the above if I am wrong.

First thing I would likely do is change the right and left rim/tire. Check to see if the left side rim deviation now appears on the right. If the deviation followed the rim then the rim is likely deformed, and you can swap it out with your spare rim/tire. If the rim deviation still appears on the left despite it being a different rim/tire then you have bigger issues, not rim/tire.

The right tire proud point isn't good, but I suppose 4mm isn't too bad (though the wobble would certainly drive me insane). I would likely swap the right tire for my spare, if you haven't used it already for the left issue.

Kind of suprised that the issue only appears at low speed, I would expect higher speeds to magnify the issue, not dampen it.

Author:  dgeist [ Sat Feb 21, 2009 12:09 pm ]
Post subject:  good points

That's a good thought on swapping left/right to figure out if the wobble follows the wheel or the (gasp) axle....

I have all the good warranties (lifetime ballance, rotation, alignment) and the tires only have 7k miles on them, so the local bridgestone/firestone place should honor the tire warranty if it's a manufacturer defect. Would you consider the "proud" spot a defect (again, having little experience with non-road tires)?

Dan

Author:  Dave08 [ Sat Feb 21, 2009 1:07 pm ]
Post subject: 

I'd think something is wrong. My Revo's are perfect untill you are in the 85mph area, then they have a bit of steering input but thats not a common speed anyhow. I'd look at getting them rebalanced or look for other issues.

Author:  2006 KJ [ Sat Feb 21, 2009 1:25 pm ]
Post subject: 

my bfg at's have been great... there is a slight steering wheel vibration 65-70 but that's it.. and they prob. just need rebalanced.

Author:  tommudd [ Sat Feb 21, 2009 2:44 pm ]
Post subject: 

you could have a belt that has slipped/ tread sepration starting or something else going on with the tire , take them in right away to where you bought them and let them check them out.

Author:  JeepinJarhead03 [ Sun Feb 22, 2009 9:10 am ]
Post subject: 

that sounds very familiar
i had a set of bias bfg AT's on my bronco II that were horrid for vibration and wobbles, though for the most part it seems that their newer AT's are much much better than what i had in the late 90's

it took rotating the tires on the rim to find the 'sweet spot' so many times i don't care to remember and even after i got them ballanced without having 50,000 lbs of weights on them they still vibrated/wobbled so bad at the speed range of 45 to 65 mph that my molding screws would fall out

from the reviews other people here at LOST have given the newer bfg at's it does sound like you've got a bad tire

i certainly hope it's nothing worse!

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