12 replies to this topic

[Chewy]

Hey all

Does anyone know what final drive is when i am doin 50 it revs really high and i am 10 inch minilites
would it help if i was on 12's
help

My engine number is 12HD24 112523

Edited by Chewy, 08 November 2007 - 10:34 PM.

[minimanclive]

The MG Metro and most Metros had a 3.44:1 final drive. There's not much difference in the rolling radius between 10 and 12 in wheels to make a big difference to your engine RPM. You'd still be looking at over 4000rpm at 70mph. If it's reving higher than that then it could be your clutch slipping.

[Ethel]

Download WinSU - you can play around with different ratios and tyre sizes.

Not sure if the later MG Metty's didn't use 3.2 diffs ???

3.44 diffs were used on 10" wheeled Minis for many years.

[wolfys_mini]

Hey all

Does anyone know what final drive is when i am doin 50 it revs really high and i am 10 inch minilites
would it help if i was on 12's
help

My engine number is 12HD24 112523

you dont say what gear

what do you call really high?

[WiredbyWilson]

mine does 90mph at 5000 rpm and im running a metro lump but had to chance the speedo drive in the box. 90 mph at 5k is right as the guy on the RR said it topped out at 90 and was pulling 5k

[Jammy]

Download WinSU - you can play around with different ratios and tyre sizes.

Not sure if the later MG Metty's didn't use 3.2 diffs ???

3.44 diffs were used on 10" wheeled Minis for many years.

Guessworks has a gear ratio calculator thingy ma bob on his site too.

[Chewy]

ok But it feels a bot low geared could i change the diff from the 1275 a+ from my other engine with out taking to g-box a part

what size wheels were the mg metros

[adam25]

12.5 Metrics

[Chewy]

I have fitted a rev counter 2 day me and a mate drive down to northampton and we were doin 70 Mph @ 5500 RPM this is not a 3.44 diff my mini club mate said that is could be a 4.1 or a 4.7 is this i dont knwo anything about diff ratios

The engine is really screaming when doin 70 mph what diff could i put in it

Edited by Chewy, 02 December 2007 - 07:10 PM.

[Ethel]

It doesn't sound like it has the original diff!
Swapping to 12's won't make more than a few mph difference. Have a look at some of the gear calculator stuff mentioned above. You could run anything down to a 2.7 or 2.95. but you might miss the acceleration

[Chewy]

Hey


When i bought the engine the bloke said that it has a 850 diff in it

i have got a 3.44 from a 998 A+ would this be a worthwile diff change

[Guess-Works.com]

How do you know you were doing 70, and were you in 4th, as I would not be relying on the speedo, 5.5k @ 70 is really short and is not a ratio which is anyway standard to the mini metro or pretty much any stock varient of the A series gearbox...

I believe you'd have difficulty controlling the car in 1st or 2nd without track/slick tyres on.

Get a GPS speedo, and hook a multi meter to the ignition to get an accutate reading of the RPM. I think you'll probably find it's a 3.6 or 3.7 in the end, which means @ 5.5k rpm you'd be cracking 80+ mph, so on a motorway about the same speed as everyone else

[Chewy]

thanks to you all

My old standard 1275 metro engine had a 3.44 which i prefer it would cruise at 60 with the revs not very loud like it is now
my mini club mate said that i have probably got a 4.1 i donnt know what this means

can i change the diff with out splitting the block from the box i have seen this done be4 its very fiddely