Thread: Available Ratios

Standard Rover you can get KAM 4.75 diffs I believe.

If you do Toy centers, you can get up to 4.5 easily in Australia, then possible 5.29 if you start buying HP R&P's from the states.

In HR you can only buy whats available standard from RR/Disco?Defender if we are talking LT230, but Maxi and Ash croft both make lower LR kits of which some reduce HR as well.

Dave.

Google KAM & Ashcroft. They will give you a good idea but both are in the UK.

The two common ratios are 3.54 (Rangerover, Disco, 90/110/120/Defender except 6x6, and S3 Stage 1 V8 and Isuzu) and 4.7, not 4.75, (all Series except Stage 1 and very early Series1 + 110 6x6) As far as I know, except for the Series 1 up to late 1948, no other ratios have been fitted by the factory - changes in transfer ratios seem to have been preferred.

John

Yes Series rovers are 4.7 but KAM sell 4.75's as an after market center.

Going from 3.54's to standard rover 4.7's is going backwards in strength.

Dave.

http://www.expeditionlandrover.info/gear_ratio.htm

That'll take a day or two to digest

Regards
Max P

As mentioned - LRs came with 3.54:1 and 4.7:1
Some rover cars had 4.1:1 (or 4.11) I believe. The aftermarket 4.11s are copies of this, but I believe some are reverse cut for extra strength???

The series 4.7 is 47 crownwheel teeth and 10 pinion teeth. The pinion head is small and the teeth thin, which makes this a weak ratio (compared to 3.54). For this reason there are some aftermarket places that make 38/8 tooth centres = 4.75:1, which are much stronger, but probably only about the same as a stock 3.54 (or maybe not even that).

The Perentie 6x6 is fitted with a "special" 4.7:1 ratio. AFAIK it still has 47/10 teeth, but is reverse cut and beefed up (because early perenties kept breaking the series 4.7 centre). It only bolts to a coiller centre, and when I priced it was $1700 for 1 ring and pinion!!!


As for t-case ratios - I assume you mean LT230?
Stock low range is 3.32:1 That's it. Maxi Drive make 2 lower ratios - 4.5:1 is the lowest (I think) anyone know the other?
High range - stock ratios are: 1.003:1 (county 3.9 and some rangies), 1.2:1 (Disco?), 1.4:1 (Defender), 1.57:1 (NA diesel ninety/one-ten - i.e. not in OZ)

Originally Posted by isuzurover

...........
As for t-case ratios - I assume you mean LT230?
Stock low range is 3.32:1 That's it. Maxi Drive make 2 lower ratios - 4.5:1 is the lowest (I think) anyone know the other?
High range - stock ratios are: 1.003:1 (county 3.9 and some rangies), 1.2:1 (Disco?), 1.4:1 (Defender), 1.57:1 (NA diesel ninety/one-ten - i.e. not in OZ)

My 110 (LT95 not LT230) is 0.996:1. I don't know whether the gears are the same as in the LT230.

John

Originally Posted by JDNSW

My 110 (LT95 not LT230) is 0.996:1. I don't know whether the gears are the same as in the LT230.

John

The gears are different, that is why the equivalent LT230 ratio is 1.003:1

Hi Ben,
A bit OT and Just a quick one, but my ex 110 4BD1 county LT230 had 1.211:1 High range, and this was factory as delivered. I have had it said in the past that some late 110 Isuzus had the 1.2:1 case due to lack of 1.003:1 Gear availability. have you heard this?
After fitting my 33's, and having 1.113:1 gears in the LT95, I reckon I can still run .996's and get good road and offroad manners.
JC