Date: Tue, 29 Jun 1999 11:51:57 -0400 From: "Crisler, Jon" To: "'gts-1000@elektro.cmhnet.org'" Subject: Tyres, Tires, so tired.... Message-ID: <2FB4119D5ECDD2119DA20008C7B18F7F210131@EXCHANGEELI1> Well, since I sort of rekindled this topic over the last few weeks, I will let everyone know (or remind them again) of what I have learned. This info was gained by trial and error, finally finding a good bike mechanic, and consulting my brother the mechanical engineer (F/18 E/F fighter design) If you have a wobble or vibration problem on the front wheel, check the following: 1) Air pressure. Easiest to deal with. 2) Make sure the wheel is torqued properly in steps, and in a criss-cross pattern. This prevents the hub area of the front wheel from slightly twisting. The method is the same as is supposed to be done on a car, but make sure to do it in steps of about 20 ft/lbs., up to the required 69 ft/lbs. Although this was not my problem, a Yamaha mechanic that talked to tech support at Yamaha indicated that this is a common problem, and can cause a deformation of the wheel if done incorrectly and left for a long time, which results in a slight out-of-round or excessive runout condition. 3) AS PER THE SHOP MANUAL and Kevin Hawkins, you should only use the Yamaha weights specified in the manual, or weights of similar configuration. They are similar to auto-weights, but not exactly. DO NOT USE tape-on weights, because, and this can be very important: weights only go on the SPOKE SIDE of the wheel. If you study the front wheel, you will see that the weight will mount EXACTLY on the same plane as the front hub surface. Its impossible to put tape-on in the same plane as the wheel hub. If weights go on the wrong side, it will cause a side to side vibration in relation to the front hub, even though the wheel might seem to be balanced fine. There may be a balance technique that can get around this problem, but then again it might be just dumb luck, or an insensitive butt/hands. The shop manual says ONLY PUT WEIGHTS ON THE SPOKE SIDE. This seems to indicate that the wheel cannot be dynamically balanced with a side-to-side compensation, which is what the mechanics were trying to do on my wheel at first. Normally, this would be the optimum method. The Yamaha weights have the following characteristics that might not be found in other weights: A) - available in very small sizes (increments of 5 grams) for more precise balance B) - painted to prevent aluminum corrosion. C) - steel clips long enough to hold the weight, but not so long as to cause air leaks at the tire bead. D) - dimensions to help prevent the weight from migrating around the wheel. Also, some weights including the Yamaha specified part can have the clip bent enough that the weight can fall off or migrate, so watch for that. My weights had been used so much that they started to fit a little loose, and move around the rim. My mechanic called Yamaha tech support 3 times, and on the first two occasions he was told that there was nothing special about balancing a GTS front wheel. But on the third call the guy indicated otherwise..... ------------------------------ From: "Crisler, Jon" To: "'gts-1000@elektro.cmhnet.org'" Subject: RE: Tires revisited Message-ID: <2FB4119D5ECDD2119DA20008C7B18F7F55F281@EXCHANGEELI1> Yes, I had major front tire balancing problems. Exchanged tires, rebalanced 6 times at two different dealers, and always had vibration/wobbles. Out of desperation, I went to a local Goodyear store, and convinced the manager to balance the tire. He did it himself, AND DID NOT EVEN CHARGE ME !! He really had a good laugh when I told him about the Yamaha wheel weights cost $10 each (except for the 5 gram which is about $7.50. They found that a weight of type EN (I forget the maker of the weight) fit ok, its also works on late model Mazda RX-7's and a bunch of Hondas. When I get a chance I am going to write up a FAQ on front tire balancing. This discussing has been raging for many years now....