Question on 20 style 87

[braves]

Just put a set of 87's with toyo s/t's 275-40-20 and 315-35-20.X5 drives straight and holds road very good but I notice that I have side to side movement in my steering wheel. Just would like to know if anyone else has this. Is it because the tires are so wide? The X drove so smooth before with the stock 17 but it looks so bad and tough with the 20's.

[cruzin420]

could be a balancing issue! I believe that is the stock set up for the 4.6 and 4.8 X5. I dont see why there would be a difference. Just a guess...

[apetrov1x5]

yes, that is because of the width of the tyre, nothing to worry about

[Driver8]

It's hard to tell specifically what type of side to side movement you're experiencing from your post, but it can be one of two things, one easily addressed and the other not addressable.

First, the unaddressable issue: going to wider tires creates the effect called tramlining, where the tires want to follow ruts in the pavement. It is most noticeable where pavement is uneven, often seen near stoplights.

The second possibility is that your wheels and tires were not balanced correctly. There are several ways to balance a wheel and tire depending on several variables like wheel size and weight. Unfortunately, there is not usually a good investment made in the software behind the tire balance procedure, i.e. the guy doing the work, so "quickest and fastest" tends to be the methodology behind the way they're usually done.

With smaller OEM fitments, one can do a "single plane" balance where the weights are attached to the rear plane of the wheel rim and it will work fine. However, with larger fitments (18" and up), you should have a "dual plane" balance, where the wheel is balanced on the front plane of the wheel rim as well as the rear plane. The weights are usually adhesive backed and attached to the cylindrical part of the wheel rim where the spin balancer indicates the weights need to be applied. Almost all spin balancers have the capability to do dual plane balancing (however, unfortunately, not all operators know all the features of the machine they use).

If you feel a gentle pulsing or swaying effect in the steering wheel, then you should have your tires and wheel rebalanced using a dual-plane procedure. Start with the fronts as BMWs tend to be very sensitive to wheel imbalance because of their sophisticated front suspensions. This may fix it, but if you feel it in the seat also, you may need to do the same to your rears as well. This should take care of it.

If this doesn't fix it, and it only became noticeable after installing the 20" wheels, it may also be 1) a wheel or tire being out of round or 2) suspension related (control arm bushings may be worn, for example). Out-of-roundness can be detected on a Hunter Road Force Balance machine (PST9700 I believe). My dealer has one and it found a set of new tires on my '03 530i to be out of tolerance for run-out (vertical up and down motion as the tire is spun). The Tire Rack replaced them upon seeing the printed proof from the Hunter machine.

How do I know all this about wheels and tires? First, I cannot stand a vibrating car regardless of HOW nice it looks! Second, I just installed a set of 20" wheels two weeks ago on my X5 and had the same problem (i.e. wheels were single-plane balanced). Finally, my summer job when I was in college was mounting and balancing tires, so I know my way around wheel and tire balance issues.

Good luck, and let us know how it works out.

Mike

[Driver8]

FURTHER INFO

Wayne - After reading your PM with the description of the condition, your shimmy sounds almost EXACTLY like the textbook example of the need for a dual-plane spin balance. I would check around for a shop that has a Hunter Ground Force balancing machine, or alternatively, a reputable tire shop, and tell them about the symptoms you're experiencing. I firmly believe a good dual plane balance by an experienced tire expert will resolve the issue. Do the fronts first, and see if that fixes it. While the tech is spinning your wheels and tires on the machine, have them look for excessive run-out (vertical motion caused by tire or wheel out-of-roundness). If everything balances okay, and you still have the shimmy after that, check to see if your wheels require a centering ring, which is a plastic or metal ring that fits inside the rear of the wheel bore to center the wheel on the hub center. If it requires one, and if it's missing, it will cause the wheel to not be centered on the hub, and consequently, it will vibrate. This does not, however, sound like what you have going on...it sounds like you just need a good dual-plane balance done on the fronts. Check it out and let me know what you find out. Good luck!

[braves]

Thanks to Driver 8 I had my tires put on a dual plane balance machine and it solved the problem. It is very nice to beable to access info from X5 world that can help out with problems.