235_85_16 Broncos on a disco ? advice please

On or around Sat, 16 Oct 2004 17:44:17 GMT, "Shayne" enlightened us thusly:

no but they're large enough to foul the bodywork unless you lift the suspension as well.

valid for getting more diff clearance in a serious offroader, and they will cause a slight raise in the gearing leading to a speedo inaccuracy (the arithmetical solution is left as an exercise for the reader)

but bodywork will be your main worry, AIUI.

as i suspected. im aware of the bodywork mods (already done) ;) they make the speedo read 35 when doing a gps verified 40. it just seems to be a lot slower off the mark and i seem to need more loud pedal to maintain speed on inclines than i would] have expected.

Yes....

It's not too bad in a manual but can make it hard work in an auto where you have to keep kicking it down all the time. I had this problem with my Range Rover and, latterly, the 100 inch Defender that shared the same drive train. Fitting a 1.4 transfer box (or converting it) instead of the 1.2 compensates well. The 1.6 transfer box, I found, was too low geared making motorway speeds uncomfortable but the 1.4 is just about spot on with 235/85.

A lot of Defender TD5 owners seem to be upgrading their standard 1.4 ratio xfer boxes to 1.2 as the 1.4 is a bit low geared for the engine and this has generated a fairly steady supply of second hand 1.4 ratio gears at reasonable prices. You do have to be in the right place at the right time though.

cheers

Dave W.

ah superb thats just what i wanted to know thanks :)

now where did i leave those gears......

OK, so I'm bored.

Old tyres have a nominal radius of 368mm. New tyres have a nominal radius of 403mm.

Therefore gearing is buggered up (not down) by 9.5%. So when your speedo says 70 you are doing 77. In fact my Disco used to say 77 when I was doing 70 on standard tyres, so you might find it is now bang on!

Dave - thinking of taking Martyns Lead on the 101 and Auto front , what typically would I find a 4 speed ZF and 1.2 (1.192??) ratio transfer box in? Only ask as I haven't a clue. How would I spot the difference assuming I get down and dirty.

Lee D

The 1.2 (actually 1.222 IIRC) is easy to find. It's standard fitting on Discoveries and Classic Range Rovers with the ZF 4-speed and most of the manual boxes. If you want to change the ratios at some time without changing the xfer box then you need to look for the LT230 xfer box. This rules out the later RRC (89 on) with the BW xfer box. They are easy to spot as they have no diff lcck position on the lever - just hi and lo.

The 1.0192 (or whatever it was) was used on the back of the 3 speed auto in RRCs. They are really useful for big diesel engines (like the v8 GMs) when used with the ZF 4 speed but are over geared for most other engines.

Spotting the difference comes down to two options - look for the sticker on the back of the xfer box or count the turns. For the latter just turn the output shaft through 1 full revolution and see how far the input shaft/gear turns. 1.2 turns and it's a 1.2, 1.4 turns and it's a 1.4 etc... The sticker is usually somewhere around the filler/level hole.

1.4 ratio boxes are found on modern Defenders of all types. Older ones with LT230s can have either 1.4 or 1.6 ratios depending on engine, use and wheelbase.

Don't rule the BW box out if you can cope with the 1.222 ratio. The viscous diff and the chain drive make for a much quieter transmission than the LT230 does. I'd guess that this would also be easier to fit to a 101 as you just need a single linkage that travels along the gearbox so you could mount the lever on the engine cover ?

If you get a ZF that was originally bolted to a BW xfer box you may need to get a replacement output shaft to use with the LT230. The LT230 shaft has splines almost it's full length whereas the shaft fitted to the BW xfer box MAY only have splines cut half way along it.

cheers

Dave W

A Range Rover? Warren simply called a breaker in Worksop (Phil, are you here yet?) and it arrived a day or so later...

How is Worksop and environs nowadays? That's the general area of my forebears - I haven't been there for almost 2 decades but last time I did it was in a new 110.

Very green, lots of regeneration, some good pubs, nice people...

Shame it's in Notts, but hey, at least it isn't in Lancs ;-)

Given the prospect of breaking a Rangie or purchasing individual bits... choices choices.

I have a want for (note not a need!)

Leather seats for Alfie.

3.5 / 3.9 and Auto for Morph Power steering set up for Morph.. I assume a rangie one will go just the same?? Replacement better condition top tailgate for Alfie. Replacement rear wings for Alfie as the arches rot has introduced ally rot in a nice arch type shape.

The remains would then be ebayed away with the help of my chopper :-)

I could of course just manage to scrape by with none of the above... but whats the fun in that.

Lee D

Dunno what you mean (whistles aimlessly...)