We've kicked off our Coupe project this week starting at the bottom by rebuilding a 1275gt gearbox.
It was fitted with a 3.44 diff and I have a 3.7 available.
As it's a 13" wheel model, what ratio would you guys recommend?
Also, what tyre size do you run on the 13" wheels?

Andy

It's a question of what your using it for?
And your personal driving style.

Myself I would go for the 3.76.

I was wondering this for a race car using Cooper s C/R gearbox, I was thinking more like 3:44 but mine is going to be 10" wheels, so probably work out the same!

That's how I worked it out

But I have run the 3.9 in the Cox
That was Scary!

Your not what you call driving, your more holding on, using the force. JUST.

I've run the 3.76, too, but obviously I'm not running the high revs of normally aspirated, due to the turbo.

Back in the day I ran 2.95 on a mg metro engine suited my intention, it ment 60 in second was achievable

Neil

On my old Cox with 1430 engine I used 3.44 with 10" wheels on the road and also used to sprint it using 13" wheel fitted with P7 (50% I think) these were the lowest profile available back then.
My twinny mini was built here in Kano using 3.9 diffs in both engines and one of them is in the back of my GTm on 13" wheels i doubt I will use less than 60% aspect ratio tyres when its time to buy
John