which diff is best in 1098 2 door

[oldmod1968]

Hi, I have a std 1098 2 door saloon and was wondering if there is any improvent I can make to top end cruising by changing the diff? Any thoughts.

[mike.perry]

For a standard 1098 I would stick with the 4.22 diff as the best compromise between cruising and acceleration.
Roy is about to disagree

[mmjosh]

i have been told that the mg 3.9 diff isnt to bad

[bmcecosse]

If it's an absolutely standard 1098 Minor I don't disagree - the 4.22 is probably the best option. Yes - a 3.9 could be fitted and will ease the revs slightly - but will it make a worthwhile difference ? I rather doubt it. But if you live in a flat area with few hills - could well be worth it. The 3.7 final drive is excellent in my car - but my engine has been 'improved' and so can pull it (as would a standard 1275) - I suspect a standard 1098 Minor would be down in 3rd gear quite a lot - on even slight gradients.

[MarkyB]

Around town and on A roads the standard diff is fine.
If you want to travel on motorways for any great distance then changing the ratio is a good plan.
Maybe if production had continued another gear would have been added to the box or the gearing adjusted to take account of the "new" phenomena?
A quick Google suggests 1958 as the date for the first one so they probably though that they wouldn't catch on.