Outer Limits 4x4 Board

I have 6.5:1's in my tranny and would like to get some diff gears to share the load, i am running 31s everyday but will be running 33's 34's offroad and was just wondering what gear set people would surgest or if it is even needed?
any info would be great

If you want to keep running the 31's on road, don't touch the diffs. With (hard to find) 4.1's, you'd be at 3800rpm @ 100, and they make stuff all difference to your crawl ratio off road.

Here's the list based on an actual tyre height of 30.5"

Ratio/revs@100/Crawl
3.7/3469/87.78
3.9/3657/92.53
4.1/3844/97.27
4.3/4032/102.02
4.6/4313/109.14
4.88/4576/115.78
5.12/4801/121.47

you could get away with maybe 4.3 at a pinch, but they are hard to find and IMHO the difference between 87.78 and 102.02 crawl is not that significant - in fact, 87:1 might be a better ratio for most use.

Steve.

just wondering what you do to work out revs there steve?? i only ask because i have 31s which measure 30-30.5 and at 100 off 2 different gps i sit on 3600 to 3650ish rpm.this is with WT,3.7s and 6.5s.
have been thinking a bit lately of going to 3.9s to allow for slightly bigger tyres but for some terrain i drive it would be awesome still on 31s with them.

it would be fairly noticeable wouldnt it?87 to the 104 you speak of

There's some small variations based on 5th gear ratio, whose crawler gears you use and tyre rolling radius.

The calculator is based on 0.83 5th, 1.65:1 high range for 6.5 gears.

I just built and excel sheet to do the calcs. It's pretty close.

Yes, you'd notice 87 to 104:1, but if 87:1 is doing the job (which it should) there's no good reason to break open both diffs... but putting 3.9 diffs in will only give you 92:1, which I bet you wouldn't pick.

to get over 100:1 you'd need 4.3:1, taking cruise revs to over 4K with my calc.

Steve.

thanks.im too lazy and stupid to add it all up lol
for rock driving around here the 6.5s are great but in general forest tracks i find myself in high all day so going lower at the stage the zuks at now would be painful i think