Jimny gearing for 33+ tyres

[stimpy]

Scottie - what tranny box and final drives are you running in your Zook?

[ScottieJ]

Sammy axles or 413 axles are narrower?

The Jimny has a wider track than the Sammy?

Yep wider than sammy

[ScottieJ]

Hehe...

The chap i bought it off has had it 6 years on standard box and axles so he's either been lucky or very careful..

I suspect i will be much harder on it so will find the limit of things

It seems a few folk are using the trail gear 6.5:1 set up. That in itself obviously affects other areas and of course the gearing on the road which frankly one doesn't want to go too quick in it for fear of certain death!!

He was probably ok because without the lower gearing and a stock 1.3 it barely has the torque to move let alone break stuff.

I'm running stock 3.727 diffs and just a 410 tbox behind the doubler (1.580 hi-hi /2.511 hi-lo), but it does have a 1.6 so that helps. Could do with being lower on road with some 4.3 diffs but it'll still motor along well until I get to a steep hill happily cruises along a 60-70mph on road. I have 4.56 in lo-lo box and it's good, used to run a 4.16 on the back of the doubler so had 7.55 lo-lo but that was just too low most of the time so I only really shifted the 4.16 into lo.

Really it's best to spread the reduction between diffs and the tbox but I've not had issues, however I do have a full float rear conversion and chromo shafts and CVs

[stimpy]

Thanks mate.

And yes, with the asthmatic power of the standard 1.3 id imagine it would be tricky to get into a position of trouble in the first place!!!

Going for a play this weekend, don't imagine ill be out of 1st gear low all day.....

Spoke to Rich (RW) earlier today which was insightful as ever. Seems little point swapping thew diffs for little reduction, and it will be a 5:1 box needed...

Cheers

[stimpy]

Just an update to say that i spoke to Rob (RS) and he reckoned a 6:1 was correct for 33s.

I think it will very much be dependant upon true tyre size , with remoulds generally measuring larger than stated and manufacturers being smaller sometimes....

Gutted i missed a 5:1 by days in the classifieds! If anyone has anything stashed away please let me know....

[Anton]

Swapping in a 5:1 or even 6:1 is probably the quickest and cleanest option, sure - but not always the cheapest. If you can get the diffs cheap and have a 4.16 rocklobster lying around (like I do) then that makes the most sense.

But then I have a 413, not a Jimny.

[stimpy]

Swapping in a 5:1 or even 6:1 is probably the quickest and cleanest option, sure - but not always the cheapest. If you can get the diffs cheap and have a 4.16 rocklobster lying around (like I do) then that makes the most sense.

But then I have a 413, not a Jimny.

Haha!! Definitely cheaper mate....

But it would take more time and when doing the diffs you'd end up doing a load of "while you're in there" stuff... And sadly i just don't have time these days else i'd be building a LWB sami :-)

[ScottieJ]

Gutted i missed a 5:1 by days in the classifieds!

sorry

[ScottieJ]

Some food for thought.

Presuming that your jimny has 3.909 diffs at the moment and the Tbox is 1.32 in hi and 2.145 lo (i don't know what year, engine it is so that's a guess??)

As stock they run 205/70 tyres so 26" tall.

This means stock is
hi 5th at 4000rpm= 59.9mph
lo 5th at 4000rpm= 36.9mph

With a true 33" tyre, a 4.16:1 tbox and 4.3 diffs.
hi 5th 4000rpm= 57.8mph
lo 5th 4000rpm= 21.9mph

33s, 4.16:1 tbox with 4.090 diffs.
hi 5th 4000rpm= 60.7mph
lo 5th 4000rpm= 23.1mph

33s, 5.1:1 with 3.909 diffs
hi 5th 4000rpm=58.9mph
lo 5th 4000rpm= 19.7mph

33s, 6:1 with 3.909 diffs
hi 5th 4000rpm=57.7mph
lo 5th 4000rpm= 16.7mph

So There's not really much in it at all. I actually think a 4.16 box and 4.3 diffs would be the best option, it's actually lower in low than my sj.

[stimpy]

Gutted i missed a 5:1 by days in the classifieds!

sorry

You bugger!!

Wanna sell it??