Reduction Gears

[dhula Member Find all posts View Profile Close dhula]

Re: Reduction Gears

Sorry I don't know much about the numbers we're talking.

Am I correct in assuming the Higher the diff ratio (currently at 4.3 as you said), the slower it will crawl down a hill? Yes. Bit of trivia, as the number gets higher, it's called a lower ratio - weird I know

Am I also correct in assuming that the bigger the tyres you run, the faster you crawl down a hill? Yes if the number referred to above is higher you can counteract this

And one final question :P

If the diff ratios were changed to a higher ratio (I think you mean a lower ratio - see above), would this impact on the installation of diff lockers? No

[Whitey1 Advanced Member Find all posts View Profile Close Whitey1]

Re: Reduction Gears

Sorry I don't know much about the numbers we're talking.

Am I correct in assuming the Higher the diff ratio (currently at 4.3 as you said), the slower it will crawl down a hill? Yes. Bit of trivia, as the number gets higher, it's called a lower ratio - weird I know

Am I also correct in assuming that the bigger the tyres you run, the faster you crawl down a hill? Yes if the number referred to above is higher you can counteract this

And one final question :P

If the diff ratios were changed to a higher ratio (I think you mean a lower ratio - see above), would this impact on the installation of diff lockers? No

I'm afraid your wrong, the higher the number the higher the ratio(but the lower the speed). It just means the tailshaft turns say 4.3 times for every 1 turn of the axle. If you put in a higher ratio diff(say 5:1) then the tailshaft turns 5 times to the axles 1. So you need more revs to do the same speed.
Higher ratio lower speed gets people confused. Just think higher ratio higher revs.

[xlr8_87 Advanced Member Find all posts View Profile Close xlr8_87]

Re: Reduction Gears

Excellent!
Thanks for confirming that guys.


Might look into getting some higher ones from US. Should both diffs be done?

[Kalex Junior Member Find all posts View Profile Close Kalex]

Re: Reduction Gears

Yes you have to do both diffs at the same time or you will destroy stuff really fast. :shock:

[dhula Member Find all posts View Profile Close dhula]

Re: Reduction Gears

maybe i should have used the word 'gear' instead of 'ratio' and it would have made more sense
I was taught low ratio/gear = higher numbers, high ratio/gear = lower numbers.
this came from low ratio/gear = low road speed, high ratio/gear = high road speed
this kinda goes with how the t/case on 4wds is talked about (high and low range) and some autos that have 'L' as the 1st gear on the shifter

either way you look at it, if you put a diff center in the car with numerically higher numbers (eg 4.3 as opposed to 3.9) it will be slower down hills and better off road, it will also account for larger diameter tyres.

One thing to remember that I don't think has been discussed here is that when changing diff ratios, there is a need to alter the way the speedo reads/captures actual road speed as it will now be incorrect.

[xlr8_87 Advanced Member Find all posts View Profile Close xlr8_87]

Re: Reduction Gears

Will something like these be the way to go?

http://cgi.ebay.com/ebaymotors/96-02-To ... ccessories

5.29 seems a decent jump though, would it be too much to deal with on a day to day basis?

[dhula Member Find all posts View Profile Close dhula]

Re: Reduction Gears

5.29 - meh.

The daihatsu F10 I had years ago had a final drive of 5.571:1 as standard

But agree, I recon 5.29:1 would be a bit overkill - unless you had 44's or something - Hmmmmmmm :twisted:

[xlr8_87 Advanced Member Find all posts View Profile Close xlr8_87]

Re: Reduction Gears

They've got plenty of different ratio's available. Would something around the likes of 4.8 be the go?

[Kalex Junior Member Find all posts View Profile Close Kalex]

Re: Reduction Gears

Remember that changing diff gears is different to 'reduction gears'.
You normally change the R&P when you change tyre size to bring the gearing back to standard.
If you put lower ratio's in and don't put bigger tyres on, it will lower the gearing in 'ALL' gears and you will loose your highway cruising and economy.

4.56 may suit 33" tyres.
There are plenty of tyre calculators on the web to help you out.

I looked into doing it and found that the gears are cheap, but the labour is a killer.

[StormyKnight Advanced Member Find all posts View Profile Close StormyKnight]

Re: Reduction Gears

Its a pity that someone doesn't make a modified transfer shaft. The low range is chain driven so a change in the chain length & a change of the sprocket ratio could result in a lower crawl ratio for low range only.........

[xlr8_87 Advanced Member Find all posts View Profile Close xlr8_87]

Re: Reduction Gears

Kalex - yeh I realise that, will be paying for it more on road. But it's crazy how bad the low range is on the auto petrol, I need to use the brakes way too much which could potentially cause a lot of damage (brakes locking on a steep hill wouldn't be good)


It's just annoying how little aftermarket gear there is out there for prado's! A modified transfer case or reduction gears would be perfect.

[Kalex Junior Member Find all posts View Profile Close Kalex]

Re: Reduction Gears

Has anyone thought of a transfer case swap with something like a hilux and put reduction gears in that?