tire size and gear ratio
 

I have 28 inch tall tires and a 4.30 gear and I want to put 29.5 radials on my 318 duster would this affect my e.t. and mph? and what gear should I have in it for the bigger tires?

Re: tire size and gear ratio
 

Just looking at tire size/gear ratios, the closest to what you have now would be a 4.56 gear. As far as the et and mph, you have to look at the power curve of your engine and the rpm you want to cross the finish line.

Re: tire size and gear ratio
 

MPH X Gear ratio X 336 divided by tire height = RPM . you can calculate difference and figure what you need to get rpm you want.

Auto will be slightly higher depending on % of converter slip,can also determine how good converter is working roughly anyway.
Stick will come out just about dead on calculation.
Mike Taylor 3601

Re: tire size and gear ratio
 

Try this formula 26.4/28= ? X your gear = actual ratio.

My wording may not be correct, but whatever.


What is your stroke, vehicle weight and 1st gear ratio?

Re: tire size and gear ratio
 

Don't forget that radials do not grow.

Re: tire size and gear ratio
 

when comparing like size slicks, radials will increase your trap RPM by 200-300.

Re: tire size and gear ratio
 

thanks for the help i want to try the 29.5 radials with a 4.88 gear