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Originally Posted by autozen
Larry,
I've pretty much always agreed with you on most posts, because you are a professional and know your stuff, but I'm going have to disagree with this one. I too was tought during my apprenticeship that a loose front end component could allow shimmy but not cause it. I've had a couple of times and a 91 4matic wagon in particular where I couldn't find anything wrong. The steering shock on the wagon wasn't too yippy skippy, but I couldn't see how that could cause the intermittent shimmy. In desperation I changed it, and the problem disapeeared. I know, Larry, just when we think we know something, they change the rules. 
Randy,
High speed tires are rated at higher speeds, because they are designed to control expansion at higher speeds. A tire will balance fine on any old balancer, but when the tire starts rotating at speeds that make the tire want to fly apart, an area of a defective tire will actually go out of round causing a deformity in the tire at high speeds. That special Hunter balancer you mentioned can detect the defect. It is funny you mentioned Goodyear, because that is one tire company that has had a problem in this area. For normal everyday balancing almot any balancer will work fine unless you encounter this problem. Then you need to seek out the Hunter. In fact my wheel balancer is a Snap-On that doesn't even spin the tire. You reach down and spin the tire a few revolutions by hand and wait till the LEDs tell you where to put the weights. I also have a Sun high speed balancer, and I don't see any difference between the two. Hope this helps. |
Autozen,
I have seen something similar to what you describe in the case of the dampener correcting the vibration. This is a very unusual thing to see happen. In the case where I saw it, there was a combination of alignment anomalies that were causing it. If I remember correctly it was a previously crashed car that was way out in camber and a little toed out. The combination seemed to put the front wheel in a bind while going down the road straight and was causing the wheel to shimmy in and out.
Such an odd situation can cause all sorts of weird things to occur, but typically if the wheels and tires are properly balanced, no excessive RFV or lateral run out, you can take the dampener off and throw it away and not be able to tell the difference. That's just what I've found.
As with anything, there are almost always rare exceptions to the rule.
As far as todays Goodyear tires go, I would run wheels off of a covered wagon before I would spend my hard earned money for Goodyear tires. If I were going to sell Goodyear tires I would make DARN SURE that I had a GSP9700 in the shop with a maintenance contract on it because I would probably wear it out in short order.
BTW autozen, I know the Snap On manually turned balancer that you are talking about and I think that it is an OUTSTANDING unit. It does the very same thing as most any other spin balancer and does it in the same way. The difference is that you don't have an expensive drive motor to repair/replace/rebuild. The computer balancers don't need to spin the wheel fast to resolve the balance. I expect that they will work as good or better than any computer spin balancer. I have an old Coates 1001 and love it, mainly because I have learned how to fudge the settings for different situations such as using tape weights behind the spokes for balance of the outer plane. I would like to have found a Snap On like yours because not only does it do a great job, but I love the simplicity of these units.
My $0.02,