I bought a set of Mahle with tyres.
I brought them to a shop to have them balanced.
When I put them on the car it started to vibrate at 90 to 120 kmh (55 to 75 Mph)
Brought it back to the shop, redid the balance, didn't help. They say, the tyres may be warped. I bought them a new set of tyres, let it balance ... didn't help.
They sent me to another shop that has a better machine. They put (a lot of)weigths inside and outside the rim (ugly), but it didn't helped.
The problem occured when I bought these rims I figure they may be bent ...
Could this old and wise guy be right ?
http://www.youtube.com/watch?v=PeclYZQCyso

Any advices ...

Check to see if they are bent or out of round wheel. If its not too bad, either can be fixed.

First, I'd loosen the lug bolts and properly retorque the wheels onto the car with the cross torque sequence. Shops use high power air tools and when they don't use the cross torque sequence, can bend the wheel. Sometimes loosening and retightening the lug bolts solves the problem

You need to measure the rims to see if they are bent.

You can do this on the car by jacking up one wheel so it doesn't touch the ground and spinning the wheel while measuring the rim movement.

Two possible rim movements. If it's bent from a side hit, face the wheel like you want to remove the lug bolts. Place a dial indicator at the edge of the rim so that the probe of the indicator is parallel to the axle and touching the edge of the rim next to the tire. Spin the wheel. If the rim is bent, the probe of the indicator will move in and out along the axis parallel to the axle.

The other bend to a rim comes from a front impact such as a curb or pothole. In that case, the rim is no longer round and a dial indicator can also tell.

Sometimes you get both.

If the rims are OK, it's probably the tires.

There has been some discussion about Lug-centric and Hub-centric wheels. I am not sure if this is an issue here but maybe this thread could be a start to see if this could be your problem.

hub vs lug centric thread

I have original bbs wheels on my fiero and everytime I get new tires they tell me the wheel is bent and they are, two of them with no apparent damage. It still rides great up to it's max speed of 120mph. Their only bent about .100 and it's two wheels and I rotate them and have yet to notice any problems. The shops notice it when they are balancing the wheels. If the wheel and tire can be balanced on the machine, it's the rotor and hub assy. In the late 70's I had toyota gt's with aluminum wheels and everytime I would replace the factory tires the shops could never get the balance as good as the factory balance. You might need a better tire shop. Two sets of tires is a little suspect.

Not sure about Mahles, but Pedrinis have early and late designs (lates are hub centric) which could make a difference depending on whether you have early or late hubs on your car. If you have a mixture on your car and when the wheels were removed for tires they might have been moved around.

Trying to remember, but as I recall earlys only fit on early hubs (seat correctly), while the lates will fit late or early hubs. Just a thought...

When I was having similar problems (mine was rectified by replacing the tires) I was able to minimize the problem somewhat by identifying the offending the wheels and placing them on the rear axle. This allowed my front-end to be a bit more manageable at the higher speeds.

But what was said in the previous posts is absolutely on target - identify the offending wheel(s) and work from there.

Good luck!

Eric Read

Thank you for your advices ...

I have just lifted the car to check the rim and here is the result !...

V
V
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V
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V
V
V
V
V
V
V

>>>
What a moron !
Now I know the caliper is close to the rim ...

Nice sweater, damn that looks a little sore. It's 90f and about 80% humidity here. I'm trying to get the pool going. I cut two fingers on my only good hand on some ss sheetmetal yesterday carrying it the wrong way.

I've found that having the tires balanced on the car gets rid of the shaking. this is especially true with the low profile tires

At least you still have the finger.

Ken

Yes ! ... it helps, I am comics artist ! ...



Tires balanced on the car ? How can you do that ?

Pull the tire and have them test the balance on the bare wheel.

I think this is your problem
this has happened to me before!

Are the front wheel bearings properly adjusted so there is no slop?

what comic?

I had a high-speed shake when I first bought my car and this is exactly what is was.

Anyone here use balancing beads?? I used these on my wife's minivan and they work incredibly well and the tires are wearing VERY evenly (well as evenly as they can with Ms. Andretti at the wheel). The 914 will get them when I up-grade the tires.

johannes, there are two shops in my area that have a tool that they roll up to the car and they can spin the tire and balance it. I think its called strobe balancing.

This link is not exactly what I was looking for but it is an example of the equipment used: http://www.hunter.com/PUB/PRODUCT/balancer/900T-1/index.htm
can you find this sort of service in France?

the third paragraph of thie lotus article tells about it: http://www.lotuselan.net/publish/care_n_re...el_wheels.shtml

I'll try that as soon as my finger will be OK again



Yes, it has be done, and the front suspension is in good shape. You can't move the weel with your hands. Everything is tight



I haven't seen that before. I'll ask around. Thank you for the advice.



This one ... http://HMSbd.com you can watch the trailer on the top of the webpage

Sorry for the hijack but the beads look interesting. If these work and fit through the valve stem, why wouldn't small steel balls work?

Check to make sure that the mounting surface is free of rust/crud so that the wheel is mounted flush to the rotor. This created a big problem on my miata.

I had the same problem when I bought a set of Mahle wheels. It turned out my front discs were not the "hubcentric" type and the Mahle's really need that in order to mount correctly and not vibrate. Maybe because they are so light.
I corrected by buying new front brake discs that had the hubcentric ring in the center.

Tommy

This is what a hubcentric disc looks like
Click to view attachment

This is a non-hubcentric disc:
Click to view attachment

Years ago that's how you got tires balanced , they ( tire shops ) would jack car up , bring a machine designed to spin the wheel , tire , brake drum ( then ) and the whole rotating assembley up to certain speed , shoot with strobe gun , determine where the weights would go , recheck , do all four corners like this , you wound up with a very good balaned set of wheels and tires , the bus comp I worked for took the buses with new tire to these type shops and had it done , this was in the mid to late 70's when I was a bit younger ( ha ha ha ) , there may be some of these type shops around , check for shops that balance big vehicle's wheels and tire , they might fit you in.

Jaxdream

I know a guy who used high density air-soft BBs with equally good results. He just used 3 oz in each wheel (popped the bead on one side and poured them in). He was out the door with perfectly balanced tires for about $7 from WalMart. . . Your tires sweat on the inside as they get cold and hot, so steel BBs will tend to rust and go away over time. 'Course it would likely take a long time and you'd likely need new tires before that happens.

I do balancing on my restoration cars with these since it's cheap and allows you to not have to run ugly weights on restored wheels that can come off and ruin the finish.

[quote]I've found that having the tires balanced on the car gets rid of the shaking. this is especially true with the low profile tires[/quote]

Tires balanced on the car ? How can you do that ?



[/quote]
Years ago that's how you got tires balanced , they ( tire shops ) would jack car up , bring a machine designed to spin the wheel , tire , brake drum ( then ) and the whole rotating assembley up to certain speed , shoot with strobe gun , determine where the weights would go , recheck , do all four corners like this , you wound up with a very good balaned set of wheels and tires ......

Jaxdream
[/quote]


That is how I've had my 914 wheels (Pedrinis) and tires (195/60 15) balanced. 90% of the time, everything is smooth and stable. The other 10%, the small amount of wheel shake that is noticable I attribute to the fact that the car is lowered (w/ a bump steer kit) and the road surface. Since no adverse tire wear is apparent, I am fairly confident that the wheel/tire combination is properly balanced.

Paul

Thanks. Good information

Hijack over

What is air your set at? I had the same problem my low profile 205/55/15 were low on air (could not see it right away hard to see) Went for over a year till i figured it out! 55/65 mph shook like crazy! Wanted at least 35 psi.

Try this. www.allstates.com/tire_truing_machines.htm

If you want a good tire balance, go to your local ford dealer. If they have a (radial force balancer) aka road force balancer, they should be able to take care of your problem. They should be able to measure all of your wheels for excessive run out, and give you a print out of all the wheels.

I'll check that too... Thanx


I live in France ... I don't think Ford dealers in Europe have the same equipement


My 914 is a 75 and the Mahle were adapted to this car. I have hub at the front and no hub at the rear. I think this is stock setup.

Steel looses its roundness quickly, due to rust. Once it stops being round, it stops working. And it also starts wearing the interior of the tire, which could lead to premature failure.

beads don't work if they clump in the wheel. they need to flow to the point of imbalance. 4x4 guys use balance beads all the time, as those big tires are a total bitch to balance.

For my m715 with 38inch tall TSL mudders, the shop would not even try to balance the wheels and told me to get ceramic beads, 10 OZ in each wheel. (my tires are WAY bigger then 914 tires, though....)

Zach

Beads in the tire......

That's got to make a lot of noise...

When my sister got married, we attached cans on chains to drag behind the car, and put marbles in the hubcaps. Made a lot of noise as they drove away after the wedding.

Marbles spinning around in the hubcaps make a really funny noise.

I would imagine beads would do the same....

Hijack over.

Get that finger healed.

Ken

Keep in mind that when you balance the tires on the car, any changes to the tires (i.e. wheel rotating) causes the balance to no longer be valid. This means any time you rotate the tires or make a change to the suspension, you need to re-balance the tires on the car. I rejected this approach on my car because to me it solves the symptom, but doesn't remedy the problem.

IMHO this problem needs to be corrected to safely drive your car at hiway speeds.

Eric Read

Noise? Can't say. In my truck I doubt I will hear much of anyhting over the engine, transfer case whine, and huge knobby tires.

Check this out:
How they work.

Zach

Johannes,

Go to a local toyota or even a porsche dealer.
They have the load force balancer.
Most dealers do.
It wont be cheap, but they measure the rim while balancing to see if its bent.

Rich

Nope. I can't hear them. I imagine if you had a really quiet car and you listen closely, you may hear something just as you come to a stop. But seriously, I never noticed any.

Has anyone considered worn out shocks/struts?

Fixed my 72.

I also have considered the shocks ... But I want to be sure it's not something else before I change them. They aren't cheap and dont forget I already changed the tires and had three ballancings and this had no effect ... I am tired to spend money with no result.

Can you identify which wheel is shaking?

If it's the left front, swap the front wheels to the other side. See if the problem moves to the other side. If it does, it's the wheel..

Another question. Before you got these new wheels, did your old wheels have this problem???


If not, it's probably a bent new wheel...

Ken