40-60 mph wheel wobble under braking.

30csl

30csl

Well-Known Member
Site Donor
Messages
1,345
Reaction score
15
Location
London/Herts
Ok - i hear you all yawn but my car has had this wobble with 16" wheels for ages. Strangely it doesnt wobble at all with 14" wheels.

So i have tried two sets of 16" front wheels - no difference.
New tyres on the front - no difference.
Checked calipers - all pistons move very freely.
Dics run true - would wobble with 14's if were culprit i guess.
Wheel bearings - nicely adjusted.
Strut top mount - new/no play
New control arms
New steering box, tie rods, idler arm bush.

I am about to do the wheel alignment today post new steering but previously it was aligned and was the same.

I really am at a loss - my father was saying it is perhaps just the harmonics of the set up but a lot of people run the 16 inch alpinas.

I really am at a loss and about to give up and revert to the 14's!

Any ideas?
 
I hear your pain!!!
Many years ago My wifes Toyota Starlet did the same thing, 13 inch wheels were fine, but when I went to 14's they really shook badly under braking, never did sort the problem, so good Luck with yours.
 
Thanks for sentiment Kasbatts!

By strut rod bushings, do you mean the two big round bushings in the front of the subframe? These were new 6000 miles ago but also 12 years ago and they look very good still. Plus the 'wobble' has been there all of that time.

Thanks,

Rohan
 
I fought one of those in my E24, eventually solved using 740i bushings.

My wobble could be triggered by stepping on the brakes but continued even if not braking. It went away by going a bit faster or a bit slower.
 
30csl said:
thanks for sentiment kasbatts!

By strut rod bushings, do you mean the two big round bushings in the front of the subframe? These were new 6000 miles ago but also 12 years ago and they look very good still. Plus the 'wobble' has been there all of that time.

Thanks,

rohan
Click to expand...

yes,,,, usually the problem is under light braking from 60-40. Hard braking, it shouldnt wobble ?
 
Last edited:
Brakes are never perfectly even, so I think what may be happening is that there is an unbalanced initial braking force that is within the range of harmonic vibration for the system. Any static or dynamic unbalance in the tires, or if they are not perfectly round, or the wheels aren't fantastically true, or imperceptible variations in individual car construction still within production specifications, could all contribute.

E32 735I, e28 5 series and the six series (built on the 5 series chassis) were justifiably famous for front end vibration. Even the 320i's of the 70's were famous. Back in the day, a set of Richard Bayston's control arm bushings were the hot ticket for the 320i. Vibration stories were all over the Roundel back then. For the E28s, E32s and early sixers, use 750i bushings. There are aftermarket suppliers of these as well. For a coupe, dunno but the usual suspects can be contacted. For the adventurous, there are urethanes of various stiffnesses that one can pour to make your own bushings.

But so what? You got a vibration and want to get rid.

Stiffer bushings can help. Back when TRX tires were all that, sometimes the shaking stopped when one changed away from them and put 15" rims on.

Your best bet is to ship me the 16" wheels and tires, contact off list for further instructions.
 
Mmmm???? maybe try giving the discs a really good sand or have them machined (both faces) to de glaze and then find a nice bit of smooth concrete and give the pads a really good rub (face down) on this to de glaze as well (or replace with new), when you refit, make sure there is anti seize (copper coat) between the pistons and the back of the pads, also anti seize on all the pad slides etc, wont cost you anything to try this but your time


worth a try
 
CSLCOUPE - i am taking it for an MOT tomorrow but from memory i do not think it does it under hard braking as you suggest.

Honolulu - i am at the stage now of just giving up and going back to 14's! I wouldnt mind but the 16's were brand new in the box and the tyres are new!

Kasbatts - the brakes seem good both in terms of disc and pad surface and i recently did as you suggest and copper eased everything and made sure operation was nice and smooth.

I am thinking it must be the main subframe bushes now and will have a look at them tomorrow when its up on the ramp. I guess i can test them by seeing if i can move the bar that locates in them?
 
New tires and rims will be okay with me, they don't have to be used and scuffed up. I try so hard to be reasonable...
 
30csl said:
Ok then, I will give them a polish before I crate them up :)
Click to expand...

Just send him the front wheels, there is no wobble in the rear.

Using smaller rims in the front is very practical, makes it much easier to figure out if the car is coming or going.
 
Yes, tried other 16s with new tyres and they were the same. Maybe its telling me it wants to be more stock and that i should donate these 16s to the group!
 
Have you put a dial indicator on the discs while installed on the car? Also need to dial check the wheel mounting face.
I had a car do this where the guy that installed the new rotors didn't clean the mounting face on the hub. A small burr made the disc wobble just slightly.
But.... My bet is on a bent hub.
DaveG
 
I had this problem on my wife's 99 Cougar. I had the rotors turned and the problem went away for about 8,000 miles. Upon close inspection of the rotors I found there was a local hard spot that did not wear evenly with the rest of the rotor. I tossed those rotors and installed some new ones. Problem solved for many years. I am sure a slightly warped rotor would show similar symptoms.

It did have a slightly different but similar problem at about 100K miles on the car. That time it turned out to be worn wheel bearings.

These are two possibilities from my experience.
 
You must log in or register to reply here.
Back
Top