Re-gearing without going up in tire size
Thread Starter
JK Newbie
Joined: Jun 2011
Posts: 75
Likes: 0
From: Starkville, MS
Re-gearing without going up in tire size
I want to go up to 33 maybe 35's eventually. Unfortunately I only have enough to re-gear at the moment. If I change gears and prolong the addition of new wheels and tires will this cause any technical problems?
JK Jedi Master
Joined: Jan 2008
Posts: 11,463
Likes: 165
From: Austin <--> Colorado Springs
Your sig says 3.8 auto with 3.21's ? You're fine, regear the hell out of it... 
Next time you are out driving, reach down and press the OD Off button. This will give a decent idea of how the higher rpm's will feel.
To look at the numbers - Measure your tires (actual measured height, not mfg spec) and plug it into the chart in the FAQ's. Once you get the rpm with the new gears, go back and find your current rpm, then divide that number by .69 (this gives the OD/Off rpm) and compare the two.
As an example, with these 'measured' tire heights plugged into the chart:
29" tires = 1800 rpm, OD/Off = 2600 rpm, w/5.13's = 2870 rpm (od/off 1800 / .69 = 2600)
31" tires = 1681 rpm, OD/Off = 2440 rpm, w/5.13's = 2690 rpm
So OD/Off right now will get you in the ballpark of where you will be with the new gears. 4.88's will obviously be lower rpms and closer to your current od/off.
Next time you are out driving, reach down and press the OD Off button. This will give a decent idea of how the higher rpm's will feel.
To look at the numbers - Measure your tires (actual measured height, not mfg spec) and plug it into the chart in the FAQ's. Once you get the rpm with the new gears, go back and find your current rpm, then divide that number by .69 (this gives the OD/Off rpm) and compare the two.
As an example, with these 'measured' tire heights plugged into the chart:
29" tires = 1800 rpm, OD/Off = 2600 rpm, w/5.13's = 2870 rpm (od/off 1800 / .69 = 2600)
31" tires = 1681 rpm, OD/Off = 2440 rpm, w/5.13's = 2690 rpm
So OD/Off right now will get you in the ballpark of where you will be with the new gears. 4.88's will obviously be lower rpms and closer to your current od/off.