Exige Wheel Shake

[AndyC]

Hi,
I think I may be opening the floodgates here, judging by some of the comments/queries on other forums, but I have an issue since changing the brakes on my car.

I now have considerable wheel vibration between speeds that maybe I shouldn't list, but it starts not far over 70. I have had both fronts very carefully balanced with no effect, I know that there may be an issue with the new EBC disks, although their QA should make sure none get out that aren't balanced? So any ideas on what is best to go with next?

The problem seems to be common, I have heard out of shape tyres, A048's being a problem, out of round wheels, wheel bearings etc. etc. Logically it would be something to do with the brakes as the problem was not there before, the only thing I need to try yet is fixing in some screw heads as the retaining screws for the discs naturally sheared off when trying to remove them, but this must only be about a gram and very close to the hub.

Any thoughts/advise appreciated.

(would have come to my first meeting this week but away working, maybe in the new year!)

Many Thanks
Andy

[SimonE]

Andy never had probs previously with 48's but last set of fronts have been an absolute nightmare. Between 75 and 80mph steering wheel shake has been really severe (over 100mph it goes away - trackdays only ). Tried rebalancing wheels - no effect, just put spare set of wheels with a039s on - no problem at all. Others I know have had similar probs with front 48s...There are various theories why it happens

[AndyC]

Thanks Simon,
The speeds you mention are exactly as it happens, I just can't understand why it is only after changing the brake discs that it has manifested itself, haven't touched the wheels or tyres.
I still need to invest in a new set of rears yet anyway, might have to re-mortgage and get a full set. As A048s are the recommended tyres, would 39s cause insurance problems? Any sites you know of where the problems of the 48s are listed?
Cheers

[M7EXG]

I had a very similar problem with my spare set of wheels,ie vibration around 70-80mph,I fitted my other set and no vibration at all.

I took the spare set to be rebalanced and was told they were only very slightly out of balance,I have never got round to driving the car since but if you know anyone else with the same wheels,I would try theirs on your car and see if the vibration goes away.

[AndyC]

Seems like I have solved the problem - yesterday fixed a screw head in each of the retaining screw holes for the brake discs (the originals haveing sheared off when trying to remove them for the new brakes), they must be at the most a gram in weight each, and only about 30mm from the centre of the hub, but it seems to have done the trick!

No more shake, it now drives great again. I guess there is so little unsprung mass and such direct steering (mine has the quick rack as well) that the slightest problem is highlighted. Maybe a thought for others if they have changed the brakes as well, because it is almost certain that the retaining screws will shear.

I can get back to fine tuning the damper settings on the Ohlins now!

Many Thanks

[SimonE]

- excellent, cheap fix too

[Dennis]

Pleased you fixed it but if a screw can make that much difference what about locking wheel nuts?

Did you put the wheel wheel on exactly the same as it came off or might you have turned it a quarter or put the locker in a different position to what it was before?