Rear alignment - shim kit numbers
#1
Rear alignment - shim kit numbers
Hi,
After installation of new tires, my left rear wheel alignment was off, 0.30 degrees, but Toyota who sold the tires and installed them, said, "Fo' getta' 'bout it." So when I had the first tire rotation, although not bad, there was a slight, asymmetry wear, 0.77-0.78.
I bought the Firestone "life-time" warranty and decided to fix the problem with a shim kit. A shim kit consists of a set of metal tabs:
1/128
1/64
1/32
1/16
1/8
The problem is there are no guidelines on how much correction each set of tabs provides. Installing the shims is about as difficult as changing a tire with four bolts on the wheel assembly to loosen and torque-tighten. I have an NHW11, 2001-2003 Prius and after multiple visits, this is what I found:
Toe (horizontal adjustment):
1/32 ~= 0.60 degree (0.30 -> 0.90)
1/64 ~= 0.30 degree (0.30 -> 0.01)
Camber (vertical adjustment):
1/16 ~= 1.7 degree (2.0 -> 0.3)
1/32 ~= 1 degree (2.0 -> 1.0)
The Firestone alignment systems, two separate shops, agree that the car is right in spec. However, I'll be doing some high-speed, temperature profile tests to further tweak the numbers.
My goal is to have an even temperature profile across all five treads for all four wheels. This should minimize local stress for longer tire wear and hopefully, the lowest possible drag. I'll then take the car back for one more "baseline" measurement and be done with it.
Bob Wilson
After installation of new tires, my left rear wheel alignment was off, 0.30 degrees, but Toyota who sold the tires and installed them, said, "Fo' getta' 'bout it." So when I had the first tire rotation, although not bad, there was a slight, asymmetry wear, 0.77-0.78.
I bought the Firestone "life-time" warranty and decided to fix the problem with a shim kit. A shim kit consists of a set of metal tabs:
1/128
1/64
1/32
1/16
1/8
The problem is there are no guidelines on how much correction each set of tabs provides. Installing the shims is about as difficult as changing a tire with four bolts on the wheel assembly to loosen and torque-tighten. I have an NHW11, 2001-2003 Prius and after multiple visits, this is what I found:
Toe (horizontal adjustment):
1/32 ~= 0.60 degree (0.30 -> 0.90)
1/64 ~= 0.30 degree (0.30 -> 0.01)
Camber (vertical adjustment):
1/16 ~= 1.7 degree (2.0 -> 0.3)
1/32 ~= 1 degree (2.0 -> 1.0)
The Firestone alignment systems, two separate shops, agree that the car is right in spec. However, I'll be doing some high-speed, temperature profile tests to further tweak the numbers.
My goal is to have an even temperature profile across all five treads for all four wheels. This should minimize local stress for longer tire wear and hopefully, the lowest possible drag. I'll then take the car back for one more "baseline" measurement and be done with it.
Bob Wilson
Last edited by bwilson4web; 06-16-2007 at 06:01 AM.
#3
Re: Rear alignment - shim kit numbers
Bob Wilson
#4
Re: Rear alignment - shim kit numbers
Maybe the 1/128 and 1/64. My rear is currently;
camber(degrees) -.9 left / -2.1 right
toe(degrees) .17 left / .21 right
I'm trying to get the camber to -1.5 and the toe in the range .05 to .09 (straighter the better).
The alignment at the Toyota dealer today was perfect in the front; -.6 camber, .02 toe. Once I can get the rear done I'll be a gliding fool.
Wayne
camber(degrees) -.9 left / -2.1 right
toe(degrees) .17 left / .21 right
I'm trying to get the camber to -1.5 and the toe in the range .05 to .09 (straighter the better).
The alignment at the Toyota dealer today was perfect in the front; -.6 camber, .02 toe. Once I can get the rear done I'll be a gliding fool.
Wayne
#5
Re: Rear alignment - shim kit numbers
Maybe the 1/128 and 1/64. My rear is currently;
camber(degrees) -.9 left / -2.1 right
toe(degrees) .17 left / .21 right
I'm trying to get the camber to -1.5 and the toe in the range .05 to .09 (straighter the better).
The alignment at the Toyota dealer today was perfect in the front; -.6 camber, .02 toe. Once I can get the rear done I'll be a gliding fool.
camber(degrees) -.9 left / -2.1 right
toe(degrees) .17 left / .21 right
I'm trying to get the camber to -1.5 and the toe in the range .05 to .09 (straighter the better).
The alignment at the Toyota dealer today was perfect in the front; -.6 camber, .02 toe. Once I can get the rear done I'll be a gliding fool.
Bob Wilson
Last edited by bwilson4web; 06-13-2007 at 06:25 PM.
#6
Re: Rear alignment - shim kit numbers
Bob,
I PM'ed you via PriusChat.com....I'll gladly send you a couple of $$ for the shims you think I need. Trying to correct my right rear on a 2002, which is currently .24 toe (.02 above high-end spec). The camber is good, at -1.4
Thanks,
Randy
I PM'ed you via PriusChat.com....I'll gladly send you a couple of $$ for the shims you think I need. Trying to correct my right rear on a 2002, which is currently .24 toe (.02 above high-end spec). The camber is good, at -1.4
Thanks,
Randy
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