nonojoe66

what is the hight of a 275/40zr17 tire? (inches) i just bought a z and I need to program the speedo for gears

96flame

25.7" rings a bell. Try the proper section of the forum next time this is for LT1/LT4 engine questions.

nonojoe66

yea sorry wasnt realy payin attention to the forum... too excited for my new car lol

Injuneer

The following sizes have pretty much the same outside nominal diameter of 25.66" +/- .02":

245/50-16
275/40-17
315/35-17

Your question is answered in the "FAQ" stickied at the top of the "Wheels and Tires" forum.

97formulakid

you shouldnt need to reprogram your computer. stock it came with 245/50/16 and if you are going 275/40/17 they are almost identical in size.

Injuneer

Not all V8 4th Gens came with 245/50-16 tires stock. The base cars, Z28, Formula and T/A had 235/55-16 tires as standard. You only got the 245/50's if the car was ordered with the Z-rated tire option (RPO QLC) or one of the other options that included the Z-rated tires. The 235/55-16 is larger diameter (approx 26.18").

97formulakid

but still the 235/55/16 are pretty close to the same size as the 245/50

Injuneer

Last I checked, 25.65" (245/50-16) does not equal 26.18 (235/55-16). Its a small speedo error.... only about 2%, but why have your odometer rack up 1,020 miles for every 1,000 miles you drive, particularly when you have the ability to program the correct diameter, as nonojoe66 apparently has.

97formulakid

sorry your right and im wrong my bad

Will84

nonojoe66 FYI...

275/40zr17

• Your tire has 275mm tread width...(converted to inches: 275/25.4 = 10.83")
• The sidewall height is 40% of the tread width: 10.83" x 0.4 = 4.33" (top and bottom)
• Height: (4.33" x 2) + 17" = 25.66" Dia.

Good to know.