Help with on car wheel balancing?

[mikey]

Go to the end of this thread for the end of the story.
mikey

I just got new tires and wheels and picked up a piece of coat hanger wire in the left rear on the way home last night. The tire is flat.

I am going in to get it fixed but was wondering if anyone can tell me if "on the car balancing" is worth the trouble. I am thinking about getting them rebalanced while I am in for the flat repair.

When orginally mounted they put all the weights on the inside of the wheel to avoid marring the polished deep dish rims. They aren't perfectly balanced so I am looking for alternatives, including of course tape weights on the pretty wheel faces.

thx
mikey

[themadhatter]

if done right, you should have NO off balance problem.

maybe the shop you went to didn't know what they were doing or one of the wheels you picked up is defective.

it's possible if you chose a low quality wheel (not saying that you did) and/or tire.

I have the stick on weights on the inside of my wheels and I have no problems up to about 145mph.

[mikey]

But I have had them balanced twice and they still vibrate at 50. Smooth up to 45, smooth out again at 60 and all the way past 100. The first time the weights were all in line inside the center of the wheels. The second time they were against the back of the face of the wheel and on the inside edge. Different shops. The, second time was at the place I fixed the flat. The tires and wheels are only 3 weeks old.

The wheels are refinished bolted cross spoke off a newer model 528 sport package. The tires are new Yokohamas from tirerack.

The wheels and tires are much heavier than what was on the 740 stock. I also had to use hubcentric rings because the late model 5 series have larger hubs.

Still no answer from anyone about the on car balancing.

[Kos-motate139]

I would say, if you don't feel the need to shell out the big bucks for the on-the-car balancing, then don't. 95% of the cars on the road don't have this, and work just fine. (Course 94% are idiots...but I digress)

Once you get back on the road, if you still find the car not working to your liking, then spend the cash to get it done. On my M3 I had mine done about 7000 miles ago at which time the car was smooth-as-ice perfect. I didn't realize they were off until a recent trip to NV where they acutally do know how to make a nice smooth highway -- roads here suck. My car has a slight flowing shudder around 90-95mph, but goes away above 100.

Conversely, on my '72 2002tii, there's no reason to get the fancy thing done -- it feels fine enough, and hell, over 95 mph the durn thing vibrates so much you can't even see out of the rearview mirror, much less gauge how the wheels are feeling...

[themadhatter]

hmmm, this is new to me.

can somebody explain On Car Balancing. I guess I miss-understood the question.

apparantly not a practice performed over here in Jersey.

-Ron

[Kos-motate139]

Rather than pulling the wheel off and putting it on a machine (the regular way) the whole wheel/hub/everything that rotates can be balanced, but you've got to have the equipment to do that while the wheel is still on the car. A bit more expensive ($110-140?) but definitely worth it to get rid of any little shakes the regular balancing could leave behind.

A little overkill for normal people, but then some of us aren't normal.

[mikey]

$120

They checked the wheels and the tires to make sure everything was round. One of the tires was out just a wee bit.

They spun them up on a "regular" machine and added weights as needed for normal people.

Then they put the front end of the car on special blocks and pushed a cart up to the wheels one at a time. The cart had a steel wheel that turned at high speed against the tires while an optical device measured vibration from low to high speed while a second guy kept a finger on the steering wheel to be sure everything was smooth after minor adjustments were made to the weights.

Then they let the front down and put the rear on blocks, but for some reason used the car engine to spin the rear wheels up to speed, and again added minor adjustments to the weights based on instructions from the computer connected to the optical measuring device.

If the wheels are dismounted they must be put back on the hubs in exactly the same way to align the adjustments made to the balanced wheels with the brake rotors. I guess the weight will have to be adjusted if the wheels are rotated???? They said they did front to rear rotation every 5000 for no extra charge. (uni-directional tread pattern)

Verdict ---- It could be that the two shops that balanced them last week and the week before just weren't very good at it. However, after the "on car balancing", by someone getting paid a premium go to get it right, the tires and wheels are now as smooth as glass from 0 to 110. I seldom drive much over 90 and I don't have enough road to go over 110 anywhere near here anyway.

I see alot of these wheels with tape weights all over the pretty rims. Mine are riding smooth and the weights are out of sight behind the wheel center.

mikey:book:

[GR8 Ride]

I'd suggest that using the 5-series wheels is the original cause of your problems.

Being hub-centric, the BMW wheels (and subsequent ride) are quite fussy about spacing plates and hub centric adapters.

I've run into this several times before, in which people would buy cheap wheels which are not hub-centric, and then complain about vibration at a particular speed (which is generally the resonant frequency of the wheel/tire combo).

The only way to really address this is to pick a set of wheels / tires specifically designed for your car (which does not mean buy only BMW wheels, just don't buy cheap wheels).

Pat