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Date: Fri, 3 Dec 93 12:13:46 PST From: "John Coffin"To: bmw@balltown.cma.com Subject: Re: Front End Shimmy .. Original-To: bmw In-Reply-To: WRPYR:bmw-request@balltown.cma.com's message of 12-03-93 11:30 >A note: They only put weights on the inside of the wheels .. > The dealer put's em on BOTH sides ... While putting weights on only one side of the wheels usually works fine I have noticed that in some situations (the reason remains a mystery to me) the only way to get some cars to stop the wobble at some speeds (if it's all speeds the wheels are not balanced correctly) is to put the weights on both sides. This seems especially true if the wheels have any nicks in them. One way I have seen the weights on one side work is to have a strobe balance. A strobe balance is done by spinning the wheel on the car and using a strobe and variable weight set on the wheel to balance it while it's turning. I've haven't seen one in a while (it's an old idea). The last place was the Porsche shop I worked at. ==== John Coffin >From: "Kuzma, Joseph P." To: bmw-request Subject: Re: Front End Shimmy .. Date: Fri, 03 Dec 93 15:28:00 est Encoding: 49 TEXT X-Mailer: Microsoft Mail V3.0 One of my cars had a front-end shimmy when it went 55-60mph. It was very annoying, and the car went in and out of the shop so many times I don't care to remember. This was on a new car, just purchased. It escalated to the point of invoking the local lemon laws on the car, and contacting the manufacturer. The manufacturer contacted me (after I sent out my letter requesting full refund of my vehicle, with copies of all the repair receipts and failed attempts at getting rid of the shimmy) and recommended that I get a full-on-the-car balance. This is a process where they balance the wheels on the car (sounds like your strobe method of balancing). The manufacturer told me that this is something that they are now considering requireing in all their authorized shops due to the way the cars are made. (Something about striking a balance between sporty and luxury ride). Anyhow, they did this to my car and the shimmy went away! But, unfrotunately for me, everytime I do anything with my tires/wheels I need another on-the-car balance which is not cheap and hard to find. BTW: The manufacturer was Honda ---------- Date: 3 Dec 1993 16:08:05 U From: "Kinports Brian" Subject: Re: Front End Shimmy To: "ZBMR List" On the Car Balancing My experience with some cars particularly 320i's is that a 1/4 oz uncertainty in most common balancing equipment can contribute to front-end shimmy. On the car balancers solve this problem because they are sometimes more accurate and the following theory: The rotor and hub assembly can contribute to an unbalance of the rotating assembly including the wheel. To carry this further, the wheel/tire must be mounted in exactly the same position on the hub every time or the balanced assembly will change. Brian From: welty@balltown.cma.com (richard welty) To: bmw@balltown.cma.com In-Reply-To: "Kinports Brian"'s message of 3 Dec 1993 16:08:05 U <9312032104.AA04422@balltown.cma.com> Subject: Front End Shimmy > The rotor and hub assembly can contribute to an >unbalance of the rotating assembly including the wheel. To carry this further, >the wheel/tire must be mounted in exactly the same position on the hub every >time or the balanced assembly will change. speaking as someone who changes tires too damn often every year, this is for me a good reason not to bother with on-hub balancers. a further reason not to bother with them is that i know two people who are good enough with a quality spin balancer that i _never_ have a problem with wheel balance provided that the wheels are round and true, leading me to the conclusion that on car wheel balancing is just a scam. cheers, You raised a good point about wheels being true enough to balance. Tires can also be out of round and cause an inability to balance correctly. I also agree that changing tires too often is a real bother. I run my street car at various driving schools in the southeast (Sebring, Road Atlanta, etc.) and change to race wheels/tires on a very regular basis. I have always lived with the little 45-60 MPH shimmy in my 2002. Happy Motoring, Brian On the Car Balancing My experience with some cars particularly 320i's is that a 1/4 oz uncertainty in most common balancing equipment can contribute to front-end shimmy. On the car balancers solve this problem because they are sometimes more accurate and the following theory: The rotor and hub assembly can contribute to an unbalance of the rotating assembly including the wheel. To carry this further, the wheel/tire must be mounted in exactly the same position on the hub every time or the balanced assembly will change. Brian