PCM has wrong tire size????
PCM has wrong tire size???? Finally managed to grab a file (took 14 min - is that normal?) and started to play with ls1edit. Mainly want to fix the speedo at the moment 'cuz of the 4.11 gears & Nittos. The pcm seems to think the tire is 3.5% smaller than it is - 25.29 instead of 26.18. Is this normal? Is it a fudge for rolling radius being less than diameter / 2?
Re: PCM has wrong tire size???? Yup, that's normal.
Going by the tire diameter calc it comes out to be slightly larger than what the PCM has.
Personally, I measure the rolling distance and back-calculate to the diameter. Seems to give the best results.
Going by the tire diameter calc it comes out to be slightly larger than what the PCM has.
Personally, I measure the rolling distance and back-calculate to the diameter. Seems to give the best results.
Re: PCM has wrong tire size????
Yup, that's normal.
Going by the tire diameter calc it comes out to be slightly larger than what the PCM has.
Going by the tire diameter calc it comes out to be slightly larger than what the PCM has.
Personally, I measure the rolling distance and back-calculate to the diameter. Seems to give the best results.
Re: PCM has wrong tire size???? I can't believe 0.83" of squash.
Re: PCM has wrong tire size???? Squash might mess with your diameter measurement
depending on where you measure, but there's no
getting around the circumference (heh) - it never
changes, or only as much as you burn off. The belt plies don't stretch on street tires. NoGo's
method seems the right way to get the number.
depending on where you measure, but there's no
getting around the circumference (heh) - it never
changes, or only as much as you burn off. The belt plies don't stretch on street tires. NoGo's
method seems the right way to get the number.
Re: PCM has wrong tire size???? I can't believe 0.83" of squash.
I get 25.22" actual vs 25.68" nominal for 315/35/17 Nittos, or 0.46" squash. Short sidewalls perhaps.
