14 replies to this topic

[rawky]

Hi all,

Was checking tyre pressures tonight and found quite peculiar wear on my rear N/S tyre, bald on the outside with still healthy tread on the inside. The tyre as I remember is about 9 months old, so this is obviously quite aggressive wear.

I haven't smacked any curbs or similar, and the radius arm bearings don't appear to have play. Could someone point me to the cause of this, and maybe also the solution? If something is bent in the subframe, I suppose adjustable radius arm brackets are the only way to dial the +ve camber out?

Cheers

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[Algordo1100]

If your tracking is out it can cause wear like that.

(EDIT) But this is on the back of your car

Al

Edited by Algordo1100, 17 April 2013 - 08:05 PM.

[rawky]

Am I right though that toe isn't adjustable at the rear?

[Algordo1100]

Am I right though that toe isn't adjustable at the rear?

Perhaps I should have read your post properly

Al

[rawky]

With a bit of research, it would seem I have excessive toe in for some reason. This can be fixed with shims, but what's odd is that I don't know why the tracking has changed!

Edited by rawky, 17 April 2013 - 08:18 PM.

[Bungle]

has a cheap replacement rear subframe been fitted in the past ?

[rawky]

It was changed before my ownership in 2007(ish), origin unknown!

[Alex_B]

I have a non genuine rear subby and I have positive camber on my rear, tends to be common on non gen subbys

[Noah]

It's due to the rear subframe, as you say, it can be sorted with shims, but you're merely compensating for the subby, The problem will still be there, a bit like using adjustable bottom arms to compensate for a bent front subframe.

I proper fix would be a genuine rear subframe, but thats not exactly cheap.

Edited by Noah, 17 April 2013 - 09:27 PM.

[tiger99]

There is normally some positive camber at the rear, which ideally can be changed to a small amount of negative, especially if you are using some negative at the front.

If the subframe is non-genuine please check very carefully that it is not coming apart at the welds, as many are known to be inadequately welded. I would advise always seam welding the critical joints on any non-genuine replacement for that reason.

Assuming the subframe is structurally ok, you can correct the alignment by filing the hole in either the outer bracket or the inner subframe web, to move the position of the pivot pin. You weld a thick washer on afterwards, or fill the unwanted part of the hole with weld afterwards, so that the pin can not move.

[Cooperman]

Aim for zero to 0.5 degrees negative and 1/16" to 1/8" toe-in on the rear.

[rawky]

Using a spirit level, it does seem there is a small amount of positive camber. Could it be that if the tracking was brought back in, the camber would right itself too?

[Cooperman]

No, camber and tracking are not related as the Mini rear suspension is parallel trailing arms.

[rawky]

So if the radius arm is twisted or the frame is bent, is there any way to right it without replacement? Or would a bit of percussive persuasion be a solution?

[Cooperman]

A bent trailing arm needs replacing as you can't straighten it by heating and hammering.