Thread: Best Diff Ratio

I run 33s on 4.12 and it revs under 2500 and is geared niced, your lucky to get Ashcroft diffs, locked and pegged as it cost me $6000 landed for both of my diffs last year but it's a killer setup

Went through this agony in choosing diff ratios myself, six tabs of ashcroft ratio calculator open and a whole lot of soul searching so to speak.

Came from the point of view of my D1 300 TDi when this went to 32's and the impact off road on the low range gearing. Where previously could toodle around the VHC in 2nd with the 29's and barely used 1st, the 32's had me constantly changing gear to modulate speed downhill in particular. So in going and changing diff gears in the D2 I wanted or hoped for something that approached the D1 on 29's in low range, cognizant of the fact the auto has different characteristics off road.

So at 10kph in Low Range 1st,

300 TD1 standard 3127 rpm
300 Tdi with 32's 2834
TD5 Standard 2100
TD5 4.37 32's 2350
TD5 4.75 32's 2554


On road at 100kph, well lets face it the 300 TD1 struggled on 32's so does not warrant comparison for this exercise!
TD5 Standard 2249
TD5 4.37 32's 2516 2285 (1.1 TF)
TD5 4.75 32's 2735 2484 (1.1 TF)


What does this show, only that compromises must be made between the off and on road when choosing diffs ratios. Have chosen the 4.37 as my compromise due to the distances travelled to get anywhere to go 4WDing but if I was to do this with no limit to budget would look at the 1.1 ratio in the Transfer box which would give standard cruising gearing or the compromise I am willing to accept with a better low ratio...

Originally Posted by Kaaaiju

I run 33s on 4.12 and it revs under 2500 and is geared niced, your lucky to get Ashcroft diffs, locked and pegged as it cost me $6000 landed for both of my diffs last year but it's a killer setup

I did well then. Mine cost $3000 and included a brand new ARB compressor.