Gear Ratio question
Thread Starter
Pro
Joined: Oct 2000
Posts: 629
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Gear Ratio question
Ok, I got the original specs on my '79 'Vette from GM and it was built with a 3:55 ratio rear end. I sorta suspected that my car seemed to have a bit of waump when pulling away. And it sorta didn't like to go on highway drives. Both are signs that it may have some stiffer gears back there then it originally came with. So tonight I found a gear ratio calculator. I entered the numbers as follows : speed = 60 mph tire diameter = 25.75 inches and RPM= 3100
and the ratio calculated comes out to 3:96 . How accurate is this method of calculating the rear end ratio and what gears could be back there right now? Thanks again for the words of wisdom!
Indy
and the ratio calculated comes out to 3:96 . How accurate is this method of calculating the rear end ratio and what gears could be back there right now? Thanks again for the words of wisdom!
Indy
Safety Car
Joined: Apr 2001
Posts: 4,795
Likes: 1
From: Regina Saskatchewan, Canada.
Re: Gear Ratio question (Indynut)
You more than likely have a 3.90 ratio or 4.11. The only real method to figure out what ratio you have is to rotate the tire one full turn and count the number of times the driveshaft turns. Or crack the cover and have a look :yesnod:
Race Director
Joined: Dec 1999
Posts: 19,610
Likes: 778
From: Forked River NJ
Re: Gear Ratio question (Stingy74)
If you have an auto trans you might be getting some converter slippage which puts you at a higher rpm. The best way is what Stingy said to do. This is very accurate.
[Modified by Gordonm, 8:49 AM 3/9/2002]
[Modified by Gordonm, 8:49 AM 3/9/2002]
