ratio changes

[uninformed]

G-day all, this is my first post..... i have a 98 defender 110 tray back and am looking at changing the gear ratios (both low and high). Its my daly driver and i tow a 8x5 dual axle tralier for work. I would like to run 900-16's @ about 36.5 inches tall. Currently its on 235/85r16's about 32 inches tall. I find 1st high isn't low enough to start off on a slight hill with the tralier ( revs and clutch slip over come this) and 1st low is not that good for offroad work. This will be compounded by the 900-16's. So i'm thinking of running 4.7's in the diffs and the Maxi-drive 30% low range. This should give me 24.46-1 1st high (org 18.42-1) and 75.44-1 1st low (org 43.38-1). The front axle is stock and the rear has a maxi locker. any thoughts would be great

[suzidisco]

Rangie spare sell the 4.7 cheaper than maxi's but you might want to think about changing your cv's to the stage 1 county, as i dought that they will last very long if you are running 36 rubber
Has maxi drive done the 40% low range yet as i know he has the billet as im waiting for him to machine them

[lowbox]

or consider swapping out your hi range transfer case ratio for a lower geared version. They range from 1.003 through 1.667, more information here:
http://www.ashcroft-transmissions.co.uk/transboxs.htm

[modman]

you gotta do a search on the weaknness of the rover front end.
going to 4.7's will futher weaken the front end.
search and read up on swapping in toyota diff carriers, larger axles,flanges and longfield cv's.
the rear end is stronger being a salisbury, but you will need maxi axles eventually.
maybe even a complete gq or gu front end would be an option.??
good luck and do some reading before you get to excited!!!!

david

[uninformed]

Rangie spare sell the 4.7 cheaper than maxi's but you might want to think about changing your cv's to the stage 1 county, as i dought that they will last very long if you are running 36 rubber
Has maxi drive done the 40% low range yet as i know he has the billet as im waiting for him to machine them

as far as i know mal has a new machine for this but may have to put the 40% on hold as he has some more orders for his drop boxes.

[uninformed]

Thanks for the reply guys and keep them coming. I already have a set of the 1.667-1 transfer gears, this will only compensate the difference in tyre size and will not compound low range so the best i will get will be 30% 57-1 or 40% 60-1(maxi-drive). I was looking at 75-1 as the 101's had this gearing with 900-16's. I'm not too worried about the weakness of the front end as i'll be getting a maxi-locker and the new 4.7's are reverse cut and made from better material which should make them better than the 3.54's. Oh i have a stock tdi with a wopping 195lb/t of torque and a soft right foot.

cheers, serg.

[Strange Rover]

What do you mean the new 4.7s are reverse cut. I didnt think you could get reverse cut unless you went to the toyota hypoid gearset??

Sam

[modman]

maxi locker won't strengthen the r+p and even the strongest lr c.v. is dubious with 36" tyres.
don't forget the torque is multiplied with gearing and with f+r lockers the max. torque can be applied to one wheel.
but you are using the strongest lr parts available so go do it!!
i am jealous about your collection of parts.
does anyone know the price of a toy long front c.v conversion using lr centre and maxi axles???
just to compare this and the "stronger" lr c.v. conversion?
this maybe a good option?????

david

[red90]

1) 9-16s are 35.5" high.

2) The 4.7s will be weaker than the 3.54s. Sorry it is NOT possible to make them stronger.

3) CVs and front R&P will die eventually with this setup. You can help life by limiting use of the front locker. If I were you I'd try the transfer case gear set first and see what you think of the gearing with the larger tyres.

[HSV Rangie]

Toy front conversion.

Toy diff centre: $350.00
JacMac Axles: $550.00
The above optional.


Toy CV Profield/longfield: $80-120 US. pluss frieght.
Bore spindles and fit Bushes: $100.00 each. aprox
JacMac flanges: $150.00

Michael.

[modman]

thanks michael, i allready have an arb locker and am happy with 3.5's
this maybe an option for me if/when i break a c/v.

david.

[uninformed]

What do you mean the new 4.7s are reverse cut. I didnt think you could get reverse cut unless you went to the toyota hypoid gearset??

Sam

Sorry for the dely in relpys i dont have a computer at home and the one i have access to is more unreliable than a p38. As far as i know (very small mechanical knowledge) the standard r+p's are the same directional cut back diff and front so the pinion is being pulled out of its bearing support in the front diff due to its direction of rotation????? the new r=ps mals selling are cut different for the front. Mal would be able to explain this alot better. they are not hypoid. please correct me on anything you pick up. I have read alot of your posts and am very impressed. still trying to get my head around the ideas of mechanical engineering. always learning.