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31's on an LJ80

Posted: Mon Dec 08, 2008 5:26 pm
by meads02
My boss wants to fit some 31's to his lj80. Is it as simple as fitting a body lift, trimming/ hammering guards and big offset? Any help is much appreciated

Posted: Mon Dec 08, 2008 9:21 pm
by want33s
Yes what you've described will allow them to fit but you won't like driving it unless you reduce the gearing.. Not as easy in an LJ as a Sierra.

Jas.

Posted: Tue Dec 09, 2008 6:49 am
by Gwagensteve
fit LJ50 diff gears - these will pretty much correct the tyres.

There should be no need for a BL- 31's should go very close to clearing stock.

Steve.

Posted: Tue Dec 09, 2008 7:12 am
by joeblow
no where near fitting stock. got one in my driveway with 30's....and oh how they rub.

Posted: Tue Dec 09, 2008 5:24 pm
by meads02
thanks guys, looks like i'm helping my boss fit a bodylift soon. i'd say he'll keep the gearing as standard for now. cheers Dan

Posted: Tue Dec 09, 2008 6:57 pm
by Gwagensteve
So don't do it then.

Getting the gearing right is every bit important as getting the clearance right.

Steve.

Posted: Tue Dec 09, 2008 8:48 pm
by meads02
i understand that gearing is crucial. the transfer out of my sierra is being rebuilt with new gears this week. the lj80 is my bosses ride and his main objective for the time being is to get some 31's under it. if he is unhappy with the gearing after the tyres are fitted then i'm sure he'll look at doing something about it.

Posted: Wed Dec 10, 2008 7:13 am
by joeblow
will be too late.....he will break some vey hard to find lj bits i'm sure.

Posted: Wed Dec 10, 2008 5:28 pm
by meads02
are LJ80 cv's, axles and diff centres much weaker than sierra gear? in regards to strength, what do you recommend as the max tyre size for an LJ80 driveline? i know gearing is an issue but if the driveline won't handle 31's then i guess there's no point even getting to that stage.

Posted: Wed Dec 10, 2008 5:37 pm
by cj
Part of the problem is that the gearing will suck which means he will have to try and hit obstacles with more speed which tends to break things easier. Get the LJ50 diff gears. Someone else will know but is the LJ50 t-case geared better too? I had a feeling there maybe a difference but I have never played with LJ's.

Posted: Wed Dec 10, 2008 5:42 pm
by flyinwall
could always put 1.3lt diffs under it with vitara 5.12 centers in them and that should help with strength and gearing

Posted: Wed Dec 10, 2008 5:42 pm
by meads02
i just read that both models had the same tcase gearing.

Posted: Wed Dec 10, 2008 5:46 pm
by meads02
thats a whole new scenario.

Posted: Wed Dec 10, 2008 9:04 pm
by Highway-Star
cj wrote:Get the LJ50 diff gears. Someone else will know but is the LJ50 t-case geared better too? I had a feeling there maybe a difference but I have never played with LJ's.

My assorted notes say the following:
LJ50 transfer:
1.714
3.012
LJ80 Transfer:
1.563
2.571

Thats 10% lower high range, and 17% lower low range. Not enough on its own to compensate for the tyres. But that with the LJ50 diffs would make for a drivable car I'd say. Essentially an LJ50 with an LJ80 motor, body and 31s would be the end result.

Posted: Wed Dec 10, 2008 9:30 pm
by christover1
Don't know much about LJ's.
But I do have LJ50 diff centres (4:9's) in my Sierra, with 31's and a 1300.
Haven't broken anything of significance yet.
So LJ50 centres may cope with 31's, dunno about axles, cv's etc.

christover

Posted: Thu Dec 11, 2008 6:34 am
by Gwagensteve
flyinwall wrote:could always put 1.3lt diffs under it with vitara 5.12 centers in them and that should help with strength and gearing
You could, but then it might be easier to put an LJ body on a sierra chassis.

Both housings would have to be custom as LJ diffs are centred front and rear.

If you wanted an upgrade in axle or CV strength or more width you'd also be up for new axles or resplining.

lots of $$ and hassle.

Steve.