need advise on 33" tyres and gearing

[steveb12]

hi steve here this is my first post. i have a 93 nh paj 3 l v6 i have lifted the back 50 mm above standard with new ironman coils and wound the front up and i have good clearence. i have been reading some of the other post as i wnat to put 33 '' tyres on it but i am a bit confused with the gearing if i have these size tyres . on the plate it has transaxle v5mti 4625 at the moment i have 31x10-15 , what happens to the vehicle it i put 33s on gearing wise do i need to change diffs if so do you do front and back or just the back. also what happens when in low range gearing many thanks steve ect:)

[xagtho]

going from 31 to 33 inch tyres with lengthen your overall gearing by about 5%, that's 5% higher or faster at any given rev in any gear, high or low ratio.

If you can live with that then you'll be fine, if you want to gear it down you can possibly get lower ratio diffs, you'll need both front and rear, or you could get a crawler gear for your transfer case which will drop your low ratio only.

[mhgill]

My 91 NH SWB has a pissy little 2.6 4 cyl, and with the 33's it actaully drives better unloaded, ie. goes faster in each gear, less gear changes.

Bigger tyres = lower rpm at any given speed
Less power (marginal)
Incorrect speedo (10km at 100km/hr)
Less braking ability (marginal)
better MPG on highway (technically)
MUCH better offroad
less crawling ability

as said, you can change the diffs or transfer case gears, but that's only required if your REALLY serious.

The pro's far outweigh the con's

Just do it!

[Drujba]

If you want to go to 33's, and keep the original behavior of your rig, the best way would be to go for 4,875 diff gears.
And you HAVE to change both front and rear, otherwise in 4X4 you will brake your transmission.

[steveb12]

many thanks to you all for your help