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diff gearing

Posted: Sat Feb 05, 2011 11:21 am
by tezza88
my 79series diesel cruiser runs 35's with standard 4.3 ratio diffs, it copes just fine although driving up a long steep hills on the highway it'l drop to 95 - 100 ks. although this doesnt realy bother me but i'd like to gear it down a litle for offroading. reduction gears for the transfer are in the plans but 4 now money doesnt allow and i have to rebuild my front diff at the moment any way as i broke a tooth on the crown. so while im at it im thinking of changing the diff ratio's......
So my question is, wot diff gearing would be best/ recommended?, (keep in mind i use my car as an every day driver 4 work through the wk and use it 4 play on the wk ends. so, i no its a bit of give and take, but i dont wanna be chewin diesel and revving the crapper out of it tryin to do 110k' s on the high way.
...cheers

Re: diff gearing

Posted: Sat Feb 05, 2011 2:02 pm
by 94lux
Hey mate i run 35's on my everyday driven lux and run 4.56's. Very happy on and offroad.

Re: diff gearing

Posted: Wed Feb 09, 2011 1:18 pm
by tezza88
thanks 94lux. i,ve bn lookin into geting the 4.56 gears.
so by the amount of veiws but lack of replies on this thread can i just asume that nobody bothers regearing their diffs after throwing on a bigger set of tyres... cum on guys, any 1 out their (that owns a cruiser preferably) but 4 the sake of the topic: that has bothered to regear their diff after throwing on a set of bigger tyres... what gear ratio have u gone to, or tryed, and have u bn happy with them, any comments etc?????

Re: diff gearing

Posted: Wed Feb 09, 2011 1:52 pm
by hulsty
I have a different cruiser to you, but I run stock hi range gearing with 35''s and its great. Is yours turbo? Mine is and can easily hold 100km/h up most grades.

Re: diff gearing

Posted: Wed Feb 09, 2011 4:06 pm
by 80's_delirious
35" tyres will raise the gearing by approx 10%, 4.56 gearing wont quite bring you back to the equivelant of standard gearing, 4.8 would be slightly lower than standard.

I think 4.56 would give a good compromise particularly if you think transfer gears are likely addition in the future.
unless you do a lot of steep rock crawling, then go for 4.8s

I have just done the opposite of what you looking at. I have 35" play tyres on my HZJ105 and also recently changed to 4.1 gears, on 35"s it has taken some puff out of it on the highway, I find I need a gear lower for a lot of hills now, so it ends up being revved more anyway. Off road it is still pretty good I find I drive most stuff in Lo 2nd, except for really steep rocky stuff, it is a bit high geared for this.

Re: diff gearing

Posted: Wed Feb 09, 2011 4:48 pm
by dogbreath_48
I run 4.56's and 37" tyres on my HJ75. The gearing is roughly equivalent to that of a standard HJ75 (with 4.11's) if it were running 'small' 35's, which suited me perfectly (with turbo - if it were still n/a 4.88's would probably be the go). I'm not familiar with the later model gearbox/transfer ratios so can't comment on your situation but you're best to do the maths and decide where you want to be - calculate your RPM at cruising speed etc and try to land it back in the meaty bit of the torque range.

Re: diff gearing

Posted: Wed Feb 09, 2011 9:13 pm
by tezza88
thanx guys, i was just curious to see wot others have thought after changing the ratios. yeah transfer reduction gears are in the plans 4 later, n for now my ute's only got the non turbo 1hz, wen it dies i'll be chasing a commy v8 doner engine. as far as the reason 4 me wanting to change the diff gearing, im not really worried bout on road performance as it is, it has plenty off pull, it's just a lil doughy in 5th up hills, but i can live with that. I'd just like it geared down beter 4 off roading including 4wd High range.