How to reduce drive ratio?

4.75:1 CWPs although stronger than Rover 4.7s, are still a bit on the undernourished side to drive 35s in any sort of anger. Maybe the 4.8 Hilux diffs in the Rover housing solution is better worth investigating.
Bill.

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Originally Posted by wagoo

4.75:1 CWPs although stronger than Rover 4.7s, are still a bit on the undernourished side to drive 35s in any sort of anger. Maybe the 4.8 Hilux diffs in the Rover housing solution is better worth investigating.
Bill.

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IRC there is also a 4.5:1 bundera diff???

Are you talking about the new Ascroft R&Ps Bill? I didn't think anyone had broken one yet?

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Originally Posted by isuzurover

IRC there is also a 4.5:1 bundera diff???

Are you talking about the new Ascroft R&Ps Bill? I didn't think anyone had broken one yet?

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I wasn't Ben, as I thought the new Ashcroft CWP was only available in the 3.54--4.1 ratios. I must try harder to keep abreast of developments.
bill.

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Originally Posted by wagoo

I wasn't Ben, as I thought the new Ashcroft CWP was only available in the 3.54--4.1 ratios. I must try harder to keep abreast of developments.
bill.

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To do that you might need a bigger internet quota ;)

Ashcroft Transmissions - Heavy Duty 4.75 R & P

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Originally Posted by isuzurover

To do that you might need a bigger internet quota ;)

Ashcroft Transmissions - Heavy Duty 4.75 R & P

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They still look a bit scrawny for 35s though Ben. But there is only so much that can be done within the original design (spiral bevel) and space constraints.
Bill.

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Originally Posted by wagoo

They still look a bit scrawny for 35s though Ben. But there is only so much that can be done within the original design (spiral bevel) and space constraints.
Bill.

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I agree, certainly compared to the 3.5/4.1s However the pics are from the wrong side...

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Originally Posted by Jitterbug

After putting 35s on my 90 I want to bring the final drive ratio back down to standard. It is an lt77 gearbox and lt230 transfer. I think the diffs are 3.54.

Am I better to go for new R&Ps in the diffs or for new ratio in the transfer box?
Any advantages or disadvantages to either of these methods?

Thanks,

Dave

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Hi Dave,
Whats the main reason you want to change ratios?
Is it not enough power to push it at 100kph. If it is what about investing some money in the motor to get it going a bit harder.
I've exprienced this going from standard 29.5 to 33 inch tyres
I find it an advantage with lower rev's at 100kph but you need a bit more torque to push it.

Regards Paul

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Originally Posted by tebone

Hi Dave,
Whats the main reason you want to change ratios?
Is it not enough power to push it at 100kph. If it is what about investing some money in the motor to get it going a bit harder.
I've exprienced this going from standard 29.5 to 33 inch tyres
I find it an advantage with lower rev's at 100kph but you need a bit more torque to push it.

Regards Paul

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The gearing just feels a bit long at the moment. Not had chance to get out and in low range with it with the 35s so cant comment there.

The motor has already had work (not certain exactly as it was in when i bought it) but someone went to the toruble of spending a couple of k on the Wolf 3D engine management install and tune (complete with shift light:twisted:) so i would guess they have done a some other mods.

There is pull at 100kph in 5th, just not at 80 where it used to be. 4.11s might be a better middle ground.

Quote:

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Originally Posted by wagoo

4.75:1 CWPs although stronger than Rover 4.7s, are still a bit on the undernourished side to drive 35s in any sort of anger. Maybe the 4.8 Hilux diffs in the Rover housing solution is better worth investigating.
Bill.

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I am happy to look at non rover options. I intend to go lockers, axles, flanges, CVs and correct the ratios all in one go. Might it be cheaper/stronger to look at hilux or toyota diffs in there?

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Originally Posted by Jitterbug

There is pull at 100kph in 5th, just not at 80 where it used to be. 4.11s might be a better middle ground.

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Thats where I thought you'd be roughly, or 4.3 which would be standard gearing on a Discovery with 35's, although you are probably running a lot lighter so 4.11's may work too.