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Vibrations With New 20s AR Piranha


Full Member
May 17, 2003
Worcester, MA
I recently installed a new set of American Racing Piranhas with GY Eagles LS 275-55-20 on my 03 Z71 WBH and have bad vibrations above 60 MPH. I had the wheels balanced twice and also did an alignment and camber adjustment without any improvement. I also tried many tire pressure values from 30 to 44 PSI but it didn't help at all. The Piranhas have a backspace of 5.5 inches and an offset of 19 mm. Did anyone experienced this type of issue or know what may be involved ? I really like the new wheels but I now think the Piranhas may not be compatible with the Avalanche. Is the offset or backspace values acceptable ? I'm running out of options here and would really appreciate any input.

Many thanks.
Your problem my be the way they balanced them. Ask if it was static balanced? I had the same problem as you are having and it was corrected when I had them rebalanced (4th time) with the balancer set on the Alloy setting.

Yes, I have more weight's on the wheels, but none are past the center point, and now no shaking.
Ok, I finally fixed the vibration problem. Just make sure you remove the little tabs from the studs holding the wheel. There are two tabs for each wheel and they look like small washers. Apparently they're used in the assembly process and will not hurt anything with stock wheels but 20" wheels don't like them. This advice is from American Racing and my vibration is now gone :D