wheel calculations
6th Gear Member
Joined: Jul 2005
Posts: 5,172
RE: wheel calculations
ORIGINAL: bscottie
anybody got the proper calculations for determing the wheel calcs to make adjustments for different wheel sizes?
anybody got the proper calculations for determing the wheel calcs to make adjustments for different wheel sizes?
MF Moderator
Joined: Mar 2005
Posts: 3,441
From: Missouri
RE: wheel calculations
From the Preditor manual to calculate your revolutions per mile...
Measure your tire diameter in inches and use it in the following formula.
20168 divided by tire diameter = revs per mile
Your Stock 235/55/17 PZeros' are 27.1" in diameter.. soo
20168 / 27.1 = 744.20664 revs per mile...
The stock gear ratios on the 2005 mustang are 3.31:1 for the automatic transmission cars and 3.55:1 for the manual transmission cars. If you have changed your rear differential crown and pinion gears, (select the appropriate ratio using this parameter to correct your speedometer and shift points). Use this parameter to select the appropiate ratio to correct the gear ratio.
Measure your tire diameter in inches and use it in the following formula.
20168 divided by tire diameter = revs per mile
Your Stock 235/55/17 PZeros' are 27.1" in diameter.. soo
20168 / 27.1 = 744.20664 revs per mile...
The stock gear ratios on the 2005 mustang are 3.31:1 for the automatic transmission cars and 3.55:1 for the manual transmission cars. If you have changed your rear differential crown and pinion gears, (select the appropriate ratio using this parameter to correct your speedometer and shift points). Use this parameter to select the appropiate ratio to correct the gear ratio.
2nd Gear Member
Joined: Jun 2005
Posts: 271
From:
RE: wheel calculations
It's a simple ratio. Take the height of the new tire and divide by the height of the old tire and you'll get a ratio. Multiply that by whatever you're trying to convert and you'll have the new number.
For example, if the old one is 27.1" and the new one is 27.6" the ratio is 1.01845. Whatever speed you were going when your speedometer said 60 mph will now be 1.01845 times greater. If you were going exactly 60, now you will be going 61.1.
You only need the one ratio to figure all of the other stuff. You don't need any complex equations.
For example, if the old one is 27.1" and the new one is 27.6" the ratio is 1.01845. Whatever speed you were going when your speedometer said 60 mph will now be 1.01845 times greater. If you were going exactly 60, now you will be going 61.1.
You only need the one ratio to figure all of the other stuff. You don't need any complex equations.
1st Gear Member
Joined: Dec 2005
Posts: 107
From:
RE: wheel calculations
ORIGINAL: bscottie
anybody got the proper calculations for determing the wheel calcs to make adjustments for different wheel sizes?
anybody got the proper calculations for determing the wheel calcs to make adjustments for different wheel sizes?
If you want to find out tire comparaison, go to this site where you can compare your stock size versus any other, you'll find many valuable infos. Have fun
http://www.miata.net/garage/tirecalc.html
GTCS1
Thread Starter
3rd Gear Member
Joined: Feb 2006
Posts: 515
From:
RE: wheel calculations
ORIGINAL: Professor Wizard
From the Preditor manual to calculate your revolutions per mile...
Measure your tire diameter in inches and use it in the following formula.
20168 divided by tire diameter = revs per mile
Your Stock 235/55/17 PZeros' are 27.1" in diameter.. soo
20168 / 27.1 = 744.20664 revs per mile...
The stock gear ratios on the 2005 mustang are 3.31:1 for the automatic transmission cars and 3.55:1 for the manual transmission cars. If you have changed your rear differential crown and pinion gears, (select the appropriate ratio using this parameter to correct your speedometer and shift points). Use this parameter to select the appropiate ratio to correct the gear ratio.
From the Preditor manual to calculate your revolutions per mile...
Measure your tire diameter in inches and use it in the following formula.
20168 divided by tire diameter = revs per mile
Your Stock 235/55/17 PZeros' are 27.1" in diameter.. soo
20168 / 27.1 = 744.20664 revs per mile...
The stock gear ratios on the 2005 mustang are 3.31:1 for the automatic transmission cars and 3.55:1 for the manual transmission cars. If you have changed your rear differential crown and pinion gears, (select the appropriate ratio using this parameter to correct your speedometer and shift points). Use this parameter to select the appropiate ratio to correct the gear ratio.
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