Final drive ratio?

[Steve_D]

Haynes says my 3.5efi 1987 RR Classic 4-speed auto has a final drive ratio of 3.54:1.

When its transformation to a Dakar is complete it will be on 33x12.5x15 Hankook MT tyres so the ratio will most likely be way too high.

• What ratio should I be looking for and which vehicle does it come from?
• Should I bother looking for a (standard strength) diff of the new ratio or should I be looking for something stronger. When complete it should weigh about 2200LBS.

Many thanks
Steve

[russell_ram]

You've chamged your rolling radius by about 12% from standard so you're obviously looking to recover that difference.

If you've done the change to go off road then going a bit shorter than standard would do no harm really. However if it's just for 'show' then as you have an auto it'll probably be fine as it is.

You'll struggle to find 'cheap' alternate axle ratios. You easiest and cheapest option would be to change your standard 1.2 ratio t/box to a 1.4 ratio one from a Defender - you'll recover the difference plus a bit - ideal. It'll probably whine a bit at higher speeds though but you'll not notice over the increased tyre noise!

Russ

[Steve_D]

Like the transfer box idea.
Will try it on road first and see if I can live with it.
Thanks

Steve