C5 Wagon Wheels
09-17-2016, 04:31 PM
#1
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Location: Tacoma, WA
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C5 Wagon Wheels
I picked up a set of C5 Chrome Wagon wheels. All four wheels are 17x81/2. Two tires are 245/50 ZR17 and two are 255/50 ZR17s. They came with a set of spacers because they were on an older Vet. Will these bolt right on my 2002 SS? Will I have to have my speedometer re-calibrated?
09-17-2016, 08:12 PM
#2
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Re: C5 Wagon Wheels
Since your SS is a ’vert, I think it came stock with 16x8.0' wheels and 245/50-16 tires. I know in earlier years of the 4th Gen, they only put the 17" wheels on the coupes.
If the 255’s are in the back, that's a 27.0" tire. Stock tire diameter on an SS is 25.7". That means your speedo will read 5% lower than actual speed, for example, read 57 MPH at a true 60 MPH. PCM needs to be reprogrammed with the new tire diameter to correct.
If the wheels are all 17x8.5" you have four front C5 wheels, with 56mm offset (vs. 55mm on your stock wheels). Will bolt right on without the spacers, increasing the backspace by 1/4" and increasing the front space 1/4" compared to your stock wheels/tires.
If the 255’s are in the back, that's a 27.0" tire. Stock tire diameter on an SS is 25.7". That means your speedo will read 5% lower than actual speed, for example, read 57 MPH at a true 60 MPH. PCM needs to be reprogrammed with the new tire diameter to correct.
If the wheels are all 17x8.5" you have four front C5 wheels, with 56mm offset (vs. 55mm on your stock wheels). Will bolt right on without the spacers, increasing the backspace by 1/4" and increasing the front space 1/4" compared to your stock wheels/tires.
09-18-2016, 10:52 AM
#3
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Re: C5 Wagon Wheels
Since your SS is a ’vert, I think it came stock with 16x8.0' wheels and 245/50-16 tires. I know in earlier years of the 4th Gen, they only put the 17" wheels on the coupes.
If the 255’s are in the back, that's a 27.0" tire. Stock tire diameter on an SS is 25.7". That means your speedo will read 5% lower than actual speed, for example, read 57 MPH at a true 60 MPH. PCM needs to be reprogrammed with the new tire diameter to correct.
If the wheels are all 17x8.5" you have four front C5 wheels, with 56mm offset (vs. 55mm on your stock wheels). Will bolt right on without the spacers, increasing the backspace by 1/4" and increasing the front space 1/4" compared to your stock wheels/tires.
If the 255’s are in the back, that's a 27.0" tire. Stock tire diameter on an SS is 25.7". That means your speedo will read 5% lower than actual speed, for example, read 57 MPH at a true 60 MPH. PCM needs to be reprogrammed with the new tire diameter to correct.
If the wheels are all 17x8.5" you have four front C5 wheels, with 56mm offset (vs. 55mm on your stock wheels). Will bolt right on without the spacers, increasing the backspace by 1/4" and increasing the front space 1/4" compared to your stock wheels/tires.
Thanks for the reply and info. My car came with the WU8 package which included 17" Wheels (not sure of the width) and P275/40 ZR-17 tires. Unfortunately there is some road rash and the tires are old, that's why I picked up the new ones. Will they still effect my speedometer by 5%? Also I noticed a lot of wandering with my original tires, specially in ruts (I think they call it trammeling?) Will the thicker sidewall and the offset in tire size front to rear help alleviate that? My goal is to eventually pick up another set of SS wheels (hopefully chrome) and keep the vehicle looking stock. I did see a guy selling a set of Magnesium wheels (All 17", so they must be fronts also) that I think looked good and I've heard they weigh less than 10 lbs!
Cheers
Steve
09-18-2016, 04:59 PM
#4
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Re: C5 Wagon Wheels
OK.... guess they eventually decided to put the 17" wheels on the convertibles. The first few years they did not.
Doesn't change the speedo problem. The 275/40-17 is also a 25.7" diameter tire, just like the 245/50-16. I run 315/35-17's in the back, also a 25.7" tire. Keep the tire diameter the same and the speedo is fine. Go with a larger diameter tire like 27.0" and the speedo indicates less than actual speed.
The wider the tires, the more sensitive they will be to tramlining. Switching to a narrower 255 should reduce that. But it varies with the specific tire line. Some designs are just worse than others.
Doesn't change the speedo problem. The 275/40-17 is also a 25.7" diameter tire, just like the 245/50-16. I run 315/35-17's in the back, also a 25.7" tire. Keep the tire diameter the same and the speedo is fine. Go with a larger diameter tire like 27.0" and the speedo indicates less than actual speed.
The wider the tires, the more sensitive they will be to tramlining. Switching to a narrower 255 should reduce that. But it varies with the specific tire line. Some designs are just worse than others.
09-18-2016, 09:25 PM
#5
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Re: C5 Wagon Wheels
I think it's just LT1 SS convertibles that came with the 16" wheels. Every LS1 SS I've ever seen, both coupe and convertible, came with 17x9" wheels. I'm certain that it's true of all 2002 SS cars.
The outer diameter of a 275/40R17 is nearly identical to that of a 245/50R16, so Fred's math still applies.
The outer diameter of a 275/40R17 is nearly identical to that of a 245/50R16, so Fred's math still applies.
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