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Old 08-18-2008, 10:51 PM   #15 (permalink)
johnmyster
EcoModding Lurker
 
Join Date: Aug 2008
Location: Virginia
Posts: 87

Brown Bus - '98 GMC Sonoma X-Cab SLS
90 day: 31.37 mpg (US)
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Wasn't a rant. I agree, poor tire wear indicates a tire being scrubbed. Scrubbing a tire is a waste of energy and an indication that something is causing higher rolling resistance. If you say it pulls hard, I believe you. I tend to wonder why cars go out of alignment over time. I got one airborne one time on a dirt road (dukes of hazard style) and changed my upper mcpherson pivot plate locations once, but that's pretty non typical. It's not like your a-arms or frame are bending, are they?

My theory is that lots of cars will tend to sag on their suspensions over time, which may very well be your case at 19 years. IME, sagging tends to cause excessive wear on inside edges due to camber issues typical of suspension geometry on every car I can imagine, even independent rear suspensions. Short upper arms or McPherson setups tend to go "top in" as they sag. I've seen this on most of the cars I've worked on. I don't know if coil springs tend to sag (I know leafs will) or if it's just the rubber spring seats that compress over time. Sagging will also cause your tie-rod end geometry to change, so toe will be out also.

You'll see in most of my posts - here or elsewhere - I tend to ask more questions or think of other contributors more often than I jump to the typically accepted conclusion. For instance, I know plenty of people say they need an alignment when their steering wheel is off centered. Some people (on s10forums, for instance) confuse this with "pull." While a good alignment tech will fix this, you can be perfectly aligned with a steering wheel off center. If you experience straight tracking on the left crown of the road, then I agree. You needs an alignment. I was simply throwing a word of caution and more factors into the equation before suggesting an alignment. Why? I had to have one recently on my truck and the best price in town $60 for a two wheel only - on one of the easiest to adjust setups ever. It was saw-toothing the inside edges - typically an indication of combined caster/toe issues.

I think we're all on the same page here. The first step in ecomoding is to wisely spend money on maintenance issues - but avoid spending money on things that may not help in reality.
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