doing the math. tire size vs speedo error correction
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.... uuummmmmm...Ok...if you say so...
(math= green-me=on the ground)
03-16-2010, 07:14 PM
#21
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This following does not make sense... you said...
31's with 3.55 gearing @ 100 miles distance = 111.926
31's with 4:10 gearing @ 100 miles distance = 96.91
The gearing has nothing to do with distance. It will change your RPM's while driving but not the actual distance. The distance error comes from the tire diameter only...
Mike
31's with 3.55 gearing @ 100 miles distance = 111.926
31's with 4:10 gearing @ 100 miles distance = 96.91
The gearing has nothing to do with distance. It will change your RPM's while driving but not the actual distance. The distance error comes from the tire diameter only...
Mike
03-16-2010, 08:07 PM
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Year: 1999
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higher gear ratio makes transmission make more turns per tire revolution.
in 3.55 the transmission makes so many turns to make the tires travel 111.9 miles.
now if 4.10 gears were used the same amount of turns of the transmission only makes tires travel 96.91 miles.
hence the reduction gears give you less mileage.
in 3.55 the transmission makes so many turns to make the tires travel 111.9 miles.
now if 4.10 gears were used the same amount of turns of the transmission only makes tires travel 96.91 miles.
hence the reduction gears give you less mileage.
03-16-2010, 11:28 PM
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Year: 1996 Limited
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Ok so Im trying to fallow all this. But have 1 question. So would 30x9.5x15 inch tires be correct with 3.73 gears?
03-16-2010, 11:31 PM
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Year: 1998, 1999
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Yea, I guess I can see it now that I think about it more. For every one revolution of the tires with 31's and 3.55's as opposed to 4:10's the driveshaft spins more to go the same distance with the 4:10's in my mind. Or I guess it's the opposite... Got it maybe! Good post... made me think! Maybe I need to think some more!!!
Mike
Doesn't a 4:10 mean the driveshaft spins 4.1 times for every rotation of the tire?
Mike
Doesn't a 4:10 mean the driveshaft spins 4.1 times for every rotation of the tire?
Last edited by Mike1998XJ; 03-16-2010 at 11:36 PM.
03-18-2010, 11:15 PM
#26
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yupp. i think some people think tha 4.10 is a ratio. but it's actually the number of revolutions of the driveshaft per tire rotation.
03-18-2010, 11:19 PM
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03-18-2010, 11:42 PM
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Im not doubting you. lol Im just asking because I alway thought it was. So with your math 30 inch tires and 3.73 gears is somewhere in the right ballpark
03-18-2010, 11:47 PM
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let's do it the short way, as it was brought to my attention.
30/27.7=1.083
3.55*1.083=3.84
so, 3.73 is about as close as you can get it.
that's if your stock gearing was 3.55 and your factory tire size was 215/75-15
30/27.7=1.083
3.55*1.083=3.84
so, 3.73 is about as close as you can get it.
that's if your stock gearing was 3.55 and your factory tire size was 215/75-15