Thread: Tyres scalloping (cupping) Causes?

Some pics of the issue with the tyres might be helpful, and also the brand and version.

Some tyres are prone to this.

Has anyone checked the wheel bearings?

From memory the P38 style rear diff didn't have a properly adjustable wheel bearing preload.

I really don't know why they did that.

Most have now been converted to the old style with 2 nuts and 2 washers and no spacer.

Usually pressure or alignment. How are all the bushes?
Aggressive tread paterns are more prone to scalloping.

Cupping is often a symptom of worn shocks, but usually in the front. Yours are cupping on the rear? Have you checked tha A frame thingy? Dunno what else to call it but it can put the rear alignment out IIRC.

Originally Posted by shack

Some pics of the issue with the tyres might be helpful, and also the brand and version.

Some tyres are prone to this.

Has anyone checked the test wheel bearings?

From memory the P38 style rear diff didn't have properly adjustable wheel bearing preload.

I really don't know why they did that.

Most have now been converted to the old style with 2 nuts and 2 washers and no spacer.

Thanks Shack. The car has been at the mechanics quite a few times recently and rthey havent mentiojed bearings. I will try to organise some photos. The tyres are Toyo Open Country ATII. They've been pretty good on bitumen and dirt and good in the wet though.

Thanks everyone for your comments. The technical ones (eg bushings, bearings etc) I will take up with the mechanic. If anything the car is over-serviced so there shouldn't be mechanical problems but you never know with a Defender. Hopefully there are two photos attached - one shows a section of the spare, which the tyre bloke rotated out because he said it's the worst. The other from the front shows what the tread pattern looks like. The tyres are Toyo Open Country ATII, light truck construction. They're about 4.5 years old with 44,000 km. Pretty good tyres generally from my experience.


Thanks again

The second tyre pic looks like it's on the front of the car?

If it's always been there it'll be an alignment issue.

Probably camber.

And if it's the camber, it's Probably king pin bearings/pre-load.

Or bent diff housing.

If they were rotated onto the front from the back, then again check the rear wheel bearings.

Originally Posted by shack

The second tyre pic looks like it's on the front of the car?

If it's always been there it'll be an alignment issue.

Probably camber.

And if it's the camber, it's Probably king pin bearings/pre-load.

Or bent diff housing.

If they were rotated onto the front from the back, then again check the rear wheel bearings.

Thanks Shack. Unfortunately the tyre bloke didn't write down the rotation this time but one of the fronts made it to the back because I'd marked it with white pen where a screw got caught in the tread. I'll have a look at it in light of your comments. In any event it looks like it's back to the mechanic yet again.

Cheers

geez, if my MTs wear as uniform as those tyres, i'd be happy. Every set of MTs i've run on each defender i have owned have a rounded profile like that. I had always assumed it was inherent in the MT tyre. Many moons ago, i had an aging but not old and not worn out set of BFG MTs. I had a vibration in the driveline that no matter what i replaced did not resolve it. Car was in for another problem and the LR machanic working on it said, sometimes the tyres go out of round and nothing will fix it but replace them. I did and the problem went away. Long and short, don't overlook that the tyre is the cause when all else fails to remedy the problem. If you have a spare set of rubber to test, it's worth the effort to eliminate.