High Range Gearing

[Bush Tucker Man]

Having been (comparatively) spoilt with the Discovery for the past 3years, I'm begining to feel that the 110 is a bit too low geared.

I did a brief motorway run this morning (M62; jct 31 to 27) to meet up with 'Jim-Willy' (superb Gingerbread, J-W. My extreme compliments to your mother =D>  =D> )

I took notice of the tachometer reading, it was 2,000RPM (in 5th) at approximately 45mph.
Having said that, I was out in the Fabia prior to that, & that was also showing 2,000RPM (in 5th) at 45mph (it's not got a lot of torque, so lower geared than the bigger engined examples)

So, I suppose the options are;
1. Replacement high-range gearing (Ian Ashcroft, or similar?)
2. GKN Overdrive (expensive, but flexible, but also read a couple of bad stories)
3. 'Rover-Drive' (Canadian?/American?, not very common over here?)


4. 'Go with the flow & just take it easy, well I usually do, it was extremely rare the Discovery went above 60mph

[H]

this will probably sound like sacralidge to defender fans but .... will a disco gearbox fit on?

H

[Budgie]

It's not the gearbox you would change, it's the transfer box.

The transfer box you have in the TD5 is a 1.4:1 ratio, if you changed it for a 1.22:1 box out of a Disco then that would give you more legs on the Motorway and the low box would stay the same as it is now.
This OK as long as you don't got too large on the tyre dia' as it could go the other way and be too overgeared!!  :?
 
I went the other way cos' of the large dia tyres and fitted a 1.4:1 t-box in the Disco.
So guess what I've got in my garage that could be brought down to the Spring Adventure!!  :mrgreen:

[Xtremeteam]

disco box -no
transfer box-yes gives you an increase from 1.41 to 1.2 ratio i think,although it might already have a higher ratiobox due to it being a td5

[Bush Tucker Man]

Not too sure on the ratio of the transfer-box fitted.

I don't intend going bigger than 235/85's. BUT, I have seen pictures of a 110CSW with Michelin 8.25's fitted
Don't want to lose any steering lock though

An overdrive is the most logical solution, as you still have a good spread of ratios for towing.
The High-range increase is wallet-led, but it will still undoubtedly (allowing for gearing increase) cope with what I want it to tow

[drum]

Fit bigger tyres  :D

[nosnibod]

So, I suppose the options are;
1. Replacement high-range gearing (Ian Ashcroft, or similar?)
2. GKN Overdrive (expensive, but flexible, but also read a couple of bad stories)
3. 'Rover-Drive' (Canadian?/American?, not very common over here?)


4. 'Go with the flow & just take it easy, well I usually do, it was extremely rare the Discovery went above 60mph

Hi,

I have a 2004 110 and found the same as you (lots of revs and noise above 60-ish).

I looked at an overdrive first - the GKN ones were reported by several people to be unreliable so that put me off them altogether. I did have a test drive of a 110 fitted with one, and it did make quite a considerable difference.

I then looked at raising the gearing (your 110 almost certainly has the 1.4:1 transfer box) and although this was a cheaper and more reliable solution it did raise another problem - the fact that the standard tune of Defender TD5 isn't really up to it.

This is especially important if you do any towing of course.

In the end I decided on the 1.2:1 transfer gearing coupled with a remapped ECU and larger intercooler.

The result is superb. It's no rocket-ship, but it simply drives so much better and feels so much more relaxed that it's almost a different vehicle.

Of course the other much cheaper alternative is to simply take it easy, and if I didn't use motorways much then I don't think I'd have bothered changing anything.

[Bush Tucker Man]

Thanks for that insight Dave.
I'd have thought that a bog-stock Td5 would cope with the 1.2:1 box, or is the low gearing masking the standard situation?  

I've been out this morning, but only to Otley & it was a perfectly relaxing drive there (mainly A-roads)

[nosnibod]

Thanks for that insight Dave.
I'd have thought that a bog-stock Td5 would cope with the 1.2:1 box, or is the low gearing masking the standard situation?  

I've been out this morning, but only to Otley & it was a perfectly relaxing drive there (mainly A-roads)

The Defender TD5 is (or was) slightly less tuned than the Discovery, and in my opinion I wouldn't want to try the 15% higher 1st gear like that. It will be fine unladen, but when towing...

What JE have done is take into account the higher gearing when remapping the ECU (they even take into account the type of exhaust fitted). The anti-stall still works beautifully - you can pull away on tickover even when towing as long as you're not too sudden with the clutch.

It seems that re-mapping the ECU across the entire range is the "correct" way to go about these things, rather than just squirting in more fuel at a certain point. JE prepare the TD5s for Bowler and apparently they are perfectly reliable tuned to 250BHP, so my 195BHP should be okay for a while yet. Apparently exhaust gas temperature is the thing to be careful of, and the correct "pattern" of fuel delivery into the cylinder is critical - just dumping fuel in leads to all sorts of problems.

I'm drifting off topic here though...

If the GKN or other overdrives prove to be reliable now then I might well go that route if I was in the same position as you.  The TD5 in the Defender is perfectly capable of handling everything you throw at it with the standard gearing, but raising the gearing, especially in 1st, is asking a bit more than I would feel comfortable with.

The downside of the "cope with everything" low gearing is of course the high revs and noise at motorway speeds. Adding an overdrive will sort that out  :)

[Bush Tucker Man]

The subject is also under discussion on 'LandRovernet.com'


http://www.overdrives.co.uk/landr.htm

[Mace]

BTM  I have the opposite problem with my Disco being overgeared now I've got 32" tyres on. I'd like to do as Budgie has said and do a straight swap, my Disco transfer box for a defender transfer box, this will sort me out and give me scope for upping the tyre size in the future. Not got round to it yet as I'd have to do the exchange with ashcrofts and pay for the privilege.

However, I've a friend with 8.25's on his 90. He find's it cruises very well at 70 mph and it will pull the caravan without much trouble. He's not got a full blown intercooler upgrade either so he's not got as much power as your td5 should have. He says it's certainly quieter and more relaxing (once you get going).

I've got a spreadsheet somewhere that tells me what Transfer Box ratios - tyre sizes give what speeds. If you've got a particular speed / rpm in mind then I can work out what ratio / tyre size combination is best.

[Bush Tucker Man]

Installed Overdrive on My 110SW

Transfer Box Gearing

[Budgie]

Installed Overdrive on My 110SW

Transfer Box Gearing

I forgot that place existed, not been in there for over 18 months!!

So you're still torn between the overdrive & the transfer box then Richard? How do these compare with getting the TD5 re-chipped? That increase in engine power maybe all that's needed.  :-k

I suppose it's what's going to give the best benefits for the money really!!  

[Bush Tucker Man]

I forgot that place existed, not been in there for over 18 months!!

It's still very much there

So you're still torn between the overdrive & the transfer box then Richard? How do these compare with getting the TD5 re-chipped? That increase in engine power maybe all that's needed.  :-k
I suppose it's what's going to give the best benefits for the money really!!  

Not so interested in more power, higher-gearing (less revs for same speed) is the issue for me

[littlepow]

Overdrive gives you the option for higher gears on motorways and flat roads, yet leaves you lower gearing when required for hilly climates or heavy loads.

[LOFTY]

My 130 CSW was just the same, its chipped and cooled by JF, and noisey on the motorway. Its got bags of power, so i got D44 to fit GKN overdrive, so i still have the right gearing to tow, yet can cruise in peace(well not peace as it is a Defender), had no trouble with mine at all.