Taller 4th gear and/or final drive.

Taller 4th gear and/or final drive.

Author
Discussion

TAHodgson

Original Poster:

875 posts

178 months

Friday 5th August 2011
quotequote all
Just about to take the keys to my new mini, having driven one before I know that they're not exactly at home doing 70mph ish, and seeing as a lot of my miles are dual carriageways and motorways, what can I do to make it live a bit longer and be a bit less of a screamer?
I've been told the 5 speed 'boxes are very expensive and quite weak, but I have heard of taller final drive's etc, but I don't have a clue about gearboxes. So where can I get hold of this sort of thing, and how much money are we talking?

Cheers guys!

guru_1071

2,768 posts

241 months

Saturday 6th August 2011
quotequote all
the taller the final drive (so the faster the car is for a given rpm) will make the car slower to accelerate, so its always a trade off.

things like wheel size etc will also affect the gearing, so also need to be taken into account.

my car runs 10" wheels and a 3.1 final drive, so whilst accerleration isnt exciting, it cruises at 70mph at 4000rpm, which is smooth, (fairly) quite and stress free.

road going five speeds, although expensive are not really 'weak', they are based (often) on the std gearbox, so by design are no stronger or weaker than a normal box - just like a std 4 speed, the 'nut behind the wheel' decides how many miles a gearbox will do!

as ive said before on here - i know of a minispares five speed that did 80,000 miles (in a 1380 daily driver) before it needed a small rebuild.

the use of a five speed obviously allows the decent crusing speed, but making use of four gears to spread the acceleration rather than the standard three.

if i was willing to blow the cash, a five speed is the only thing that i feel my car lacks

TAHodgson

Original Poster:

875 posts

178 months

Saturday 6th August 2011
quotequote all
I did realise you make a 'choice' really over acceleration or speed, my car is/will be running 12 inch wheels, but I have no idea what the fina drive is, i'm guessing standard...

guru_1071

2,768 posts

241 months

Saturday 6th August 2011
quotequote all
if its a late model car with factory 12" wheels it will be a 3.1:1

you can work out gearing and what not using this

http://www.guess-works.com/Tech/ratio.htm