Gear ratio calculator?

[slowgsr]

Hi, Im looking for a gear ratio calculator. Heres what im trying to figure out.

1g awd 5spd, using a evo III 1st gear. I currently have 26" tall tires on it there heavy.. I want to switch to 24.5" tall slicks all around which are much lighter.

Last year I had the stock engine, now I have a built 2L that should rev fairly well, and make power at higher RPM's as well. The problem is my current 26" tires are heavy and I keep poping Tcases. The 1st gear is long I think its hurting my 60's with the tall heavy tire.. I want to switch to a smaller lighter tire, but want to see what my RPM will be at in the gears.

9000rpm in 4th on a 24.5" and the difference between a 24.5" and a 26" in first at 9000rpm (mph difference).

If anyone knows how to calcuate this or can help me out that would be great. Thanks.

 

[turbo addict]

9000rpm with 24.5" tires is 160mph in 4th.
9000rpm with 26" tires is 170 in 4th.

all speeds at 9000rpm
1st with evo first is 48mph
2nd is 79mph
3rd is 119mph
4th is 160mph
5th is 200mph

 

[slowgsr]

hey thanks dude.

any insight on how you figure this out? Im looking to go aprox 150mph in 4th on a 24.5" tire, just wondering how high I will need to rev this thing out to. It would be nice if I could play with the numbers myself.

Plus going from my MT ET streets which are 27lbs a tire to a MT Drag slick @ 17lbs a tire would shave 40lbs off my rotational weight! That would make a big difference I bet.

 

[turbo addict]

GearCalc

Not sure if it the same version that I have, i have had mine for years.
Works great.