Outer Limits 4x4 Board

hi just wondering if its normal for jinmies to sit on 4000 rpm around 100- 110 on the high way, ive never driven a car that revs that hard on high way , if so is there common ratio changes or a way to drop a few revs, ie change tyre size with out it struggling

cheers luke

yes, that's normal.

bigger tyres will lower revs, but, basically suzki has it revving at that speed for a reason. If it could have pulled 100 comfortably at lower revs they would have set it up. No manufacturer gears a car shorter than necessary.

you'd need to go to 29" tyres to lower the revs usefully (that would take about 10% out - so 3600rpm) but you'll probably find you'll be downshifting to 4th if there's any sort of hill or a headwind.

There's no ratios to lower revs - the jimny transfer is already as tall as it gets and there's no taller diff gears for the front diff, although if you never used it in 4WD you could put a 3.7:1 in the rear diff, which would drop revs about 10%

My ex girlfriend owns a 2008 Jimny with 235/75/15 tyres and it's about the perfect amount of revs for it IMHO, it doesn't sturggle at all on the highway and still sits on 110-120km/h easy. THat said it's lifted and had the bumper trimmed just to fit those tyres.

thanks for that guys i can understand gearing that way from factory as its gotta match the torque n power curve , so its due 4 some tyres soon so i think going slightly bigger rubber is good as long as it doesnt start to labour the engine to much so what is the std tyre size in inches are they 28''s,

cheers luke

If you're referring to the stock 205/70/15s, i reckon they're closer to 26" than 28".

235/75/15s are ~ 29" and are a good size for them without messing up the gearing too much.

I run 235's, which puts your Jimny speedo out at exactly 10.2%. Sitting on a 'real' 110km/h puts 'Stumpy' @ 4000rpm.

'Stimpy' ran 32's (speedo out 14%) on a RockHopper III and sat @ 5000rpm on a 'real' 110km/h quite happily. DO change your gear/transfer/block oils every 5000k on your Jimny if run gearing though... the little blokes really do appreciate it.

Even stocker Jimny's give a smoother upchange at higher revs... It's a Zook thing