Sorry for the trouble.

Billman to the rescue.

I did the wheel measure trick, I have 4:57's

Make sure you hold the other wheel steady when turning the other. Otherwise you get some differential action.

I am very Sorry for the trouble Jeff.

The Gearing caculator threw me off.

 

It's easiest to turn the wheels both at the same time, bringing them both around to the matchmarks.

 

Another way to do it --

You can go to a dyno and have it calibrated there. Just put your cruise control on, and adjust the YJ. That's what I did -- looks like my tires are a lot smaller b/c I'm turning 70mph @ 4800RPMs

 

Dyno time ................ 100 bucks?
Being paced by another car .................... free.

 

It helps to be a mechanic at a shop

There's no denying that it is the most accurate way though...and it's not like I can get paced by a cop car

 

yeh good stuff Wyatt has the gears now I miss mine

 

what RPM should a the stock diff be at for 70 mph

 

Just as you are a mechanic and have free dyno access. I have lots of cop friends.

but actually, unless you want dead on accuracy in your speedo, it's not necessary to do either. Getting paced by another S2000 will put your speedo right back to the same error it had before the gears - about 1% to 3%. Going to a dyno or being paced by a certified speedo like in a cop car would zero out your speedo error. Then, you would be unique and atypical of other S2000s. I've done this myself, so I guess you might say my car is atypical.

 

Use this:

http://www.turnzero.com/technical_resource...gear_calculator

Not knowing if you have an AP1 or AP2, you're best to look it up yourself.

 

This thread is about finding the gear ratio.

Nothing works better than a crayon.