[ChrisN]

Looking for information on differential rations, specifically for the Sierra. Tried a search on "sierra differential ratios" without finding what I'm looking for.

So - I believe my Sierra has a 3.727 diff ratio.

What other ratios are available?

Thanks

[monley]

3.9 1.3 nt sierra
3.7 1.3 wt sierra
4.3 jimny rear (fits sierra)
4.11 jimny rear
3.9 coily sierra rear
Plus a a whole heap of front vitara diffs( lots of ratios there, 4.8, 5.12 etc...)

I assume your sierra is a 89 wide track from your posts in which case it will be 3.7

[ChrisN]

Thanks for that. Yes mine says '89 on the build plate and '90 on the compliance plate.

So the ring & pinion from the Vitara front axle fits into the Sierra axle?

Just for fun I've been playing with a spreadsheet to display speeds for the various combinations. Happy to share that if anyone wants a copy.

Chris

[bibby]

I would love a copy if possible

[Gwagensteve]

I'll just add some context here. Diff gears need to be considered along with transfer gears. Swapping diff gears (alone) to offset bigger tyres will still leave you with inadequate low range reduction. If you subsequently add transfer gears on top of the diff gears to get low range in the right spot you'll then find high range too low for road use.

Therefore if you are looking to to gear, say, a 31 on a sierra, swapping to 4.3 diff gears would make road gearing (and the speedo) read perfect, but low range would still suck at 34:1 waaaay to high for everything except the beach. If you try to then gear the transfer, your road revs go too high- road gearing is now corrected for 34's or similar.

Just something to bear in mind.
I run a g16b, aw-4 auto, 6.4 transfer and 5.12 diffs with 35's and spin 3700 rpm at 100km/h.

[ChrisN]

Good points Steve. I'm trying to bring all the factors into consideration with my spreadsheet.

I like deep ratios in low range, and have an 83% reduction in low range on my GQ (with auto). One of the things I like about the Suzuki design is the separate transfer case and the fact that the reduction gearsets also lower the high-range gearing to compensate for larger tyres on the highway as well as on the tracks.

I'm leaning towards 30 inch tyres and 4.9 (4.869/1.629) in the transfer case, to give me 3,652 rpm at 100km/h.

[Gwagensteve]

That sounds like a good outcome. 3600 on the highway and 66:1 crawl. Sweet.

[ChrisN]

bibby wrote:

I would love a copy if possible

PM sent.