MA61 Front Tyre scrubbing dilemma

[RyleyMA61]

Guys

For the life of me and the guy who works on my car, the source for all the front tyre scrubbage cannot be found.

It scrubs severly on the wheel opposite to the direction you are turning, and sounds like the inside of the tyre.

All the plastic guards have been removed as have any little hanging bolts etc. We even tried removing the rear mudflaps and shaving a little off the inside of the flare lip.

Anywhere that looks even suspiciously like it has seen scrubbage has been painted bright so any further marks can be seen. Which they can't.

There are NO visual signs of scrubbing anywhere on the car.

Has anyone else had this sort of trouble?

Here are the car specifications:

Kings standard springs
Tokico shocks
RA60 strut tubes
MS65 Crown front hubs
WRX STi 326mm brembo rotors w/ Z32 calipers
17x7.5" wheels, +0 ET, with 205/40/17 tyres on it. These are around 30mm smaller in diameter than the stock 14x7" +8 ET with 225/60 tyres.

The stock setup never scrubbed and since having this gear on.

Here is the link to the front hubs tech articles:

http://users.tpg.com.au/users/loats/.../fronthub.html

http://forums.toymods.org.au/index.p...t=180&count=60

When the car is jacked up on the opposite rear wheel and then pressed down on the front strut to simulate scrubbing under body roll, there is shitloads of room everywhere.

I was figured it must have something to do with the slight track increase or the MA61 springs not sitting 100% coirrectly on the celica strut hats. Could the castor rods be funny?

It's a very strange problem. Any help or advice would be fantastic.

[blacktop]

put some paint on your tire and then go for a drive, where ever it is scrubbing will show up with the paint,
paint will completely wear away after a few more K's

[Norbie]

I've had plenty of issues with tyres scrubbing, but it's always been pretty obvious where it's been happening (eg dirt and/or paint worn off the inner guard). If you can't find any visual evidence I'm not sure if we can add anything useful?

[thechuckster]

not touching the strut or a brake-line bracket?

[M.J.H]

Guys

For the life of me and the guy who works on my car, the source for all the front tyre scrubbage cannot be found.

It scrubs severly on the wheel opposite to the direction you are turning, and sounds like the inside of the tyre.

All the plastic guards have been removed as have any little hanging bolts etc. We even tried removing the rear mudflaps and shaving a little off the inside of the flare lip.

Anywhere that looks even suspiciously like it has seen scrubbage has been painted bright so any further marks can be seen. Which they can't.

There are NO visual signs of scrubbing anywhere on the car.

Has anyone else had this sort of trouble?

Here are the car specifications:

Kings standard springs
Tokico shocks
RA60 strut tubes
MS65 Crown front hubs
WRX STi 326mm brembo rotors w/ Z32 calipers
17x7.5" wheels, +0 ET, with 205/40/17 tyres on it. These are around 30mm smaller in diameter than the stock 14x7" +8 ET with 225/60 tyres.

The stock setup never scrubbed and since having this gear on.

Here is the link to the front hubs tech articles:

http://users.tpg.com.au/users/loats/.../fronthub.html

http://forums.toymods.org.au/index.p...t=180&count=60

When the car is jacked up on the opposite rear wheel and then pressed down on the front strut to simulate scrubbing under body roll, there is shitloads of room everywhere.

I was figured it must have something to do with the slight track increase or the MA61 springs not sitting 100% coirrectly on the celica strut hats. Could the castor rods be funny?

It's a very strange problem. Any help or advice would be fantastic.

How much lock does it need to do this? or is it on full lock only?

It could be that with the slight increase in track one wheel is in effect turning slighty more than the other and this is what you are hearing.

[Norbie]

One wheel turning more than the other is known as Ackerman angle, and increasing the car's track does not affect this. What it can affect though is scrub radius, but even with a very high scrub radius you wouldn't actually hear scrubbing.

[RyleyMA61]

thanks for all the advice guys, most appreciated.

i know its a slut of a thing to ask help with re: no evidence... im kind of hoping some else had had similar experiences...

it scrubs badly going around a roundabout and any more than about 35-40kmh....

chuckster, not sure about strut or brake line... pretty sure not on the strut but don't know about brake line... ill check it.

thanks again guys rep for all

[M.J.H]

thanks for all the advice guys, most appreciated.

i know its a slut of a thing to ask help with re: no evidence... im kind of hoping some else had had similar experiences...

it scrubs badly going around a roundabout and any more than about 35-40kmh....

chuckster, not sure about strut or brake line... pretty sure not on the strut but don't know about brake line... ill check it.

thanks again guys rep for all

Something that might be worthwhile doing is to get it on an alinger and see what the numbers for the toe,camber etc are doing at various amounts of lock.
Will give you something to work with and some refrence numbers for eveyone else as well.

[Enchanter]

..it scrubs badly going around a roundabout and any more than about 35-40kmh....

So it only happens with body roll ?

[RyleyMA61]

So it only happens with body roll ?

BINGO

but it also does it up driveways taken on angles etc.

and the car doesn't have much body roll (swaybars on stiffest) so i don;t know

Norbie:

could the changing of hubs, rotors, etc etc somewhere along the lines played with the ackermann angle? if something wasn't put together correctly???

thanks for the help though guys

[82MKII]

I know this isn't likely , but is there any chance it's a wheel bearing that only groans under certain load?

[RyleyMA61]

dunno pete, don't think so.... its definately a tyre scrubbing kind of noise and the wheel bearings are new with the brake upgrade...

it sounds like it's the inside wall of the tyre. but fucked if i can see any wear or anything!

however ive been doing a bit of reading and perhaps it's something to do with the negative camber? when the car corners and the tyres "straighten out" perhaps they are straightening out into something?

ive got a set of non-buggered strop tops that im going to put in and see if it gives a bit more ride height and helps at all....

cheers guys any advice is brilliant
ryley

[Norbie]

Ackermann angle would only be affected by steering arms, eg if you somehow managed to put them on backwards or upside down or something? Dunno if that's possible though.

I've run 3 degrees of camber on my MA61 with no problems like you describe, how much does yours have? Tyres slipping on the road tend to sound very different to tyres scrubbing against guards etc though.

[whatthe?]

82MKII may be onto something. When my wheel bearing shagged out badly on the ovlov it made a noise exactly like a tyre fouling on something, but only on left hand turns.

Is there any evidence on the tyre of scrubbing? Have you jacked it up and given the wheel a shake to check the bearing?

I had 235s on the front of my MA61 and never got any scrapage, except when cornering really hard

[Mathew]

Bent stub axle - maybe? - happened to me - wheel aligned everything lined up and looked good on the computer, but still scrubbed tyres and felt weird turning. Eventually after checking everything a million times found a small difference in some measurements from side to side - took it off and compared it to one from the wreckers, yep small bend in the stub axle. Something to have a look at anyway!

cheers Matt