A case of the Shimmies?

[bimmerman]

I am posting this question on behalf of a friend of mine who also drives a E34 but is not a forum member. (not computer and internet savvy)He changed his rims from 16 inch to 17 inch and suddenly when driving at about 80KPH, the steering begins to vibrate slightly. Then at about 85KPH the steering is vibrating left-right-left-right. At about 90KPH the car (not only the steering) vibrates voilently and becomes very unstable like driving offroad.From what I know: (The car is E34 1995 model. Rims are AC replica used but looks new with no signs of damage)1. Alignment and wheel balancing was performed when changing the rims2. Tires are used Firenza 225/45/17 with 80% thread (yikes firenza!)3. No cone necessary as the rim has the exact hub size4. Rim offset is correct at ET18Is this a case of the shimmies caused by a worn upper control arm? Does upsizing your rims magnify the shimmies? My friend says his car has no shimmies previously except when there is a bump mid corner where the car will shimmer for a while before stlling back to normal.Any ideas?

 

[ehoe]

Well since u mention that the hub size is correct (the most common cause for vibration on E34), then the next thing to look at usually is worn out suspension components.

Check the upper and lower arm bushes and tie rod too. I had the same bad vibration at around the 90km/h a while back and found it was caused by a worn out tie rod. Had it replaced and now its super smooth.

 

[doink]

for the best result then go and do a on wheel balancing...they jack ur car up and run the tires on the car itself according to the speed u mentioned that have problem...it is much more accurate...

 

[ALBundy]

Similar to what I had experienced when I changed mine from 16s to 17s. Possible causes 1) Tires - When you go to 17s and 18s, invest in a set of good tires, the cheaper ones just wont make the cut. 2) Static Balancing - As I mentioned previously, if the vibration occurs in the 80-100 km/hr region, chances are the wheels are not statically balanced. Ask your regular tire mechanic to do static balancing before on wheel balancing. If after performing task 2) and it still vibrates then only move to check on the more expensive items suspension components. The tire shop also be able to check whether your tires are smooth and the surface is flat.

Remember, when trouble shooting, always start with the cheapest and easiest option. :yes:

 

[535i]

I will still check the center hub fit. Might not be a tight fit .. really tight fit ...

 

[bimmerman]

Thanks guys! Swapped cars during lunch hour with my friend today and drove his car to do an on wheel balancing. (the things i do for friends)

1. I noticed the wheel was bouncing up and down quite violently when the tire guy was spinning the wheel with the balancer thingy.

2. After the balancing machine showed the correct balance when the guy applied the necessary weights, the wheel was still bouncing noticably when spun.

3. The guy said it's now OK so I paid him and left.

Seems to run well but it was hard to tell because traffic was heavy. So I drove into a toll road. Hmmm... seems ok. Then came 80KPH and the steering did not vibrate like before. So far so good.....82, 83, 85KPH and the front of the car started shaking again! By 90KPH it was like driving rally!

Well, there was an improvement but only by about 5kph.

Well, it's time for the more expensive stuff now! Going to try replacing the thrust arm and bushing tomorrow. I read somewhere that fitting a 750 bushing will do wonders! So much fun learning new stuff when someone else is paying for it. Gonna try it and report.....

 

[bimmerman]

Originally posted by 535i@Mar 7 2005, 09:21 AM
I will still check the center hub fit. Might not be a tight fit .. really tight fit ...

Quite possible! When I loosened the 5 nuts yesterday, 1 nut was tighter than the other 4 which could mean the wheel was not centered correctly. But the alignment guy does not think so. :dunno:

 

[OSFlanker]

As they are replica rims I won't be so sure that the hub size is "correct" - after all they already ripped off AC by copying their design so they can also rip the customers off by poor quality - the BMW wheel hub is very sensitive to minor imperfections hence all the problems with shimmies.

Also, try to look closely at the lug nuts - are they worn out?

 

[bimmerman]

Originally posted by OSFlanker@Mar 7 2005, 08:06 PM
As they are replica rims I won't be so sure that the hub size is "correct" - after all they already ripped off AC by copying their design so they can also rip the customers off by poor quality - the BMW wheel hub is very sensitive to minor imperfections hence all the problems with shimmies.

Also, try to look closely at the lug nuts - are they worn out?

Hey Flankster! Welcome to the shimmy party!!

Did look at the lug nuts. Looks ok to my untrained eyes. My friend says the rims are made in Japan and not of the taiwanese variety. So should be quite ok right? :dunno:

Should good tires and rims spin perfectly smooth when you do an onwheel balancing? From what I saw, these rims were bobbing up and down after being balanced. But at least not sideways so can rule out rim bengkok right? But the hub precision still is questionable if it's bobbing up and down. Unless it's the fault of the worn thrust arm which cannot dampen the bobbing motions. :dunno:

 

[wolverine]

Hi bimmerman,I recently bought the front stabilizer bar 4 E34 fr u
If u noticed,my E34 was & still on the AC replicas fr Japan.I never had these problem.However, I'm using cones coz the center hub fit looked tight but actually it was not tight enough.
Be very particular about the cone quality as there are a lot which look tight but they are not...I paid RM140 or RM160 4 mine.

 

[bimmerman]

Originally posted by wolverine@Mar 8 2005, 02:39 AM
Hi bimmerman,I recently bought the front stabilizer bar 4 E34 fr u
If u noticed,my E34 was & still on the AC replicas fr Japan.I never had these problem.However, I'm using cones coz the center hub fit looked tight but actually it was not tight enough.
Be very particular about the cone quality as there are a lot which look tight but they are not...I paid RM140 or RM160 4 mine.

Hey Wolvie! Nice of you to chime in I say, you car more stable because got stabilizer bar mah.

About the cones, you mean your rim hub is E34 fit and you can still use cones? As I understand, one can only use cones if you're fitting E39 rims on E34. Are your rims E39 fit? Can E34 rims still use cones on an E34? :dunno:

 

[ALBundy]

If its wobbling when the tire mechanic was doing the balancing then it could be the tires or the rims are off centered.

I suggest you try these two tire shops which I have find knowledgable and truthful. First shop is the one located at Segambut Industrial Area where UMW and BMW are located. Name of the shop is Heap Soon (or Hup Soon) a falken dealer. They also can repair your rims as they have all the equipment. Second shop is along Jln Loke Yew called Soon Lee Hin.
Hope this helps.

Rgds

 

[wolverine]

Originally posted by bimmerman+Mar 8 2005, 08:18 AM-->QUOTE (bimmerman @ Mar 8 2005, 08:18 AM)

 

[ehoe]

Originally posted by bimmerman@Mar 7 2005, 06:44 PM
Well, it's time for the more expensive stuff now! Going to try replacing the thrust arm and bushing tomorrow. I read somewhere that fitting a 750 bushing will do wonders! So much fun learning new stuff when someone else is paying for it. Gonna try it and report.....

Yes if you are going to replace the bushings, might as well go for the 750 bushings which are supposedly a lot harder. But don't just do a 'trial and error' by replacing suspension components to resolve your problem, that is a costly way to do it. Got to make sure the part is in need of replacement before replacing it else you will be wasting $$.

From your description your vibration problem is very severe so if it is a worn out suspension component, it should be quite easy to identify. With the car jacked up, just simply grab hold of each tyre/rim and start rocking or turning it. If the suspension ball joints or bushing are badly worn out, you should be able to see the freeplay in the joints visually. Again a good mechanic should be able to check for these, a bad mechanic will just ask you to replace everything leaving a big fat hole in your wallet. :huh:

But as Albundy and Wolverine suggested, double check if the hub size is correct first. I too have had friends that used replica rims and they vibrated like crazy.

 

[bimmerman]

PROBLEM SOLVED!!!!! :yahoo:

A very big thank you to all who participated in this thread. :yes:

It was a rim centering problem afterall. Put in some hub centric cones 72.6mm and the shimmies have all but disappeared. There is still a small shimmer at around 95KPH but it disappears at 100KPH and is non-existant below 95KPH. Just a tire balancing issue I suspect. The thrust arm should also be replaced but at least it does not need to be replaced immediately.

Once again thank you :yahoo: thank you :yahoo: thank you :yahoo: to all who participated. And for those who did not participate you now have a reference should the shimmies ever happen to you.

 

[OSFlanker]

Congratulations!

Sorry couldn't meet you yesterday. I had a meeting until quite late. Did you get the cones from Stamford?

 

[bimmerman]

Originally posted by OSFlanker@Mar 10 2005, 04:12 PM
Congratulations!

Sorry couldn't meet you yesterday. I had a meeting until quite late. Did you get the cones from Stamford?

Hey Flank! Got the cones from a place called Hupshun Tyres. RM30 each. Still got some small time shimmer but could be the balancing since a static balance was not done. Or could be the thrust arm and bushing.

 

[bimmerman]

Pleased to report that after changing a pair of upper arms (thrust arms) and bushings made for the BMW 750 for the front suspension. All traces of shimmies, even the most minute have been totally irradicated!!! :yahoo:

Total cost of repairs for the suspension parts is:

Upper arms (Thrust arms) RM210ea X2 = RM420
BMW 750 bushings RM65 X2 = RM130
Workmanship = RM70

Total RM630!!! :beaten:

Source of parts is Bavarian Auto SS2

So, if any of you ever get the shimmies here's what i've learnt and it could help solve your problem as well.

Always start from the cheapest item and work your way up to the more expensive stuff.

1. Check your alignment and balancing - still shimmering?
2. Check your hub. Need cone? - still shimmering?
3. Does your cones provide a tight fit? A really tight fit? - still shimmering?
4. Check your thrust arms - Knuckle loose? Bushings worn? - still shimmering?
5. Check the long shaft, engine mounts, gearbox mounts!!! - Hopefully you won't need to go there :beaten:

Lucky for me the problem was solved at step 4.

To all who have participated, a very big thank you!!! May this thread benefit all in the future.

 

[e23_728i]

Just wondering what is the exact name for this 750 bushing? In case mine needs replacing as well?

 

[bimmerman]

Go for Lemgforder parts obtainable from Bavarian Auto.

As for the part numbers:

BMW Thrust arm Left/Right: 31 12 1 141 097/098
BMW 750i bushings: 31 12 1 136 607

The bushings are from the E32 750. Since the bushings are so popular, you can only buy 750 bushings from Bavarian. They have stopped selling 5 series bushings althogether. If you order bushings from them it will be 750 bushings by default. :yes: