Transfer case reduction gears
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I hear you can get reduction gears for transfer case that reduce raitios in the high and low range
Does that mean I can have larger wheel diameter without extra strain on the motor?
Does that theory work in real life?
How big can i go in tyre size and i guess i have to do a body lift
Thanks Neil
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Temeraire (2018 quasar grey automatic)
One of the last 200ish of the gen3s, probably.
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sniper
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The maths is fairly simple. Use a website like tiresize.com/calculator/ to calculate in the % increase in tyre circumference and aim to match or exceed this figure with the high range gear reduction. For low range, the lower the better really!
You don't have to go much bigger than standard before you get body clearance issues. The relationship between tyre size and lift required is well documented on this site.
The best approach is to choose a suitable tyre size, then do the sums for the gearing, then look into what sort of lift and trimming you will require. Don't buy stuff until you've done the maths. It soon becomes quite expensive to do it properly!
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Building a fully off-road Jimny, have got 2004 with M16A nonVVT engine and AT box, manual transfer case.
I will be running 31 or 32" tires, so
1) Do I need gear reducers in t-case, why, what real benefit do they give apart from more controlled descending?
2) What gear reduction would you suggest with the 1.6 engine, AT box, 32" tyres?
ps Did a lot of searching in the forum archive but could not find this answered, if it has - you can direct me to the thread please
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Temeraire (2018 quasar grey automatic)
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Btw, would there be an issue with the reduced gearing eg no more top speed or smth?
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Temeraire (2018 quasar grey automatic)
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Fit VVT 4.3 diffs and you would have the same drivetrain as me bar VVT.
1600VVT + R7ME gearbox + Manual (stick) transfer box + 4.3 diffs + 30" tyres...... My shafts are standard.
It goes well for a Jimny, powerband and road speed are well matched and eager in all gears... 70mph @ 4000rpm, could probably handle 31" comfortably......
Start going above 30" tyres and most I know who use them to lane, have needed Longfield shafts and CV's following failures of standard kit. On a road car it might not be such an issue.... but it's why I'm staying at 30" for now. If i go bigger than 30" I will fit H/D shafts and CV's, so £800 before you look at tyres..... Might be on 30" for a while yet lol....
sniper
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Work well, but there is room for 30" I guess. Without them the car was more or less useless offroad but ok on the highway. A bit high rev now on the highway but ok if I had 1,3.
Edit: mine is a 2005 stick shift 5t manual with a push button transfer. All original except for the gears in the transfer box, 1.6 VVT and 235 tires.
Norway 2005 Jimny M16A VVT, 235 BFG MT, 2" Trailmaster, ARB rear lck, 17%/87% high/low gears.
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Temeraire (2018 quasar grey automatic)
One of the last 200ish of the gen3s, probably.
ADOS Attention Deficit Ooooh Shiny!
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I had missed that Lambert, thank you..... VVT diffs would still be of benefit but you would be looking more to 30" tyres....Lambert wrote: Don't forget this refers to an automatic main box which has different ratios.
There may be some benefit from changing to a manual electronic transfer box but I'm too thick to do the math.....
sniper
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