Fitting 33" big boys

[makeitfit]

Just been looking at fitting some 33 x 12.5 x 15s and seen on another site a confusing thread on gear/diff ratios!
I'm on petrol and would like to know in idiot speak what the consequences maybe without any gear/diff changes?
I thank you :wink:

 

[Thomas-the-Terrano2]

ok after finding room and enjoying lift, truck will be overdriven
by around 10% so speedo will be true at last.

imagine loss of engine braking off road, more brakes needed.

possibly slipping of clutch to get truck moving in hi ratio.

that said others have done it, ie blue bull, and hummingbird
has 32s in mind and more.

if was a lr and had rangie 3.54 ratios then some would either
leave as is or go to 4.7:1s to increase final drive ratio and
improve crawling ability.

my concern is whilst would love to concerned at effectively
decreasing 1st gear depth which will certainly impact when
towing. be nice if could get an underdrive to offset tall tyres.

 

[makeitfit]

I'm not sure about the engine braking bit as I've found that a problem off road already on 31s,but I thought that was because its a 2.4 petrol and not diesel.
As I only do towing of boat to and on the beach I'm not bothered about that either.
So overall for offroad ground clearance will be main advantage?

 

[nejones]

I think ground clearance will be the biggest benefit but its a lot of money to spend not just on wheels and tyres but on getting the body lifted also to get an extra 1" under the mechanicals.
On a car fitted with standard size tyres the difference would be 2".

 

[Deleted Member D]

Big wheels

Dont know if this helps but, I went from 30inch tyres to 35inch tyres and in my opinion I can only feel benefit especially off roading.
Ive been on 35's since February and to date havnt experienced any side affects. -dance-

 

[davemud]

HI dadba
did you do any other mods to get the 35 sizes on at all

thanks Davemud

 

[Terranosaurus]

It's over a 14% increase in gearing. Having drive a petrol on std, 30s and 31s, I'm not sure how much more would really be practical. I found myself need ing 1st gear more often in low box the bigger the tyres got and you'd just run out of low gears if you go too big with the tyres. On the motorway 5th became something you could only use on the dead flat or down hill - bt that was with muds, spring and body lift and a roof rack so lots of drag.

With my current TDi on 32" tyres its got a more torque from low down and pulls away a lot better, not really used it off road but I suspect it will be better. It also held a true 75mph all the way up and over saddleworth moor on the M62 without having to change down and without pushing my foot to the floor

The option is to re-gear a petrol to lower the overall ratios. I've looked into this and the only option seems to be to change the diff gears. May be possible to source the rear cwp in the UK from a patrol or even a nissan cabstar but the front diff looks like import from the USA and with current strength of the dollar against the pound thats geting more expensive by the day. There are lower transfere gears available but these only effect low box and are for rock crawlers etc, so don't effect road performance and are horrendously expensive too.

 

[Deleted Member D]

Mods

Yes, Had to cut/grind a small corner off inner wheel well for when full lock was on. I then found some plastic board to cover over the cut, but if your careful taking original plastic off you may be able to use that.
Also Before putting 35's on I'd had a 2-3inch OME lift by using a 4.2LWB suspension upgrade. Ive down sized wheels to 15inch steel 8-spokes plus 30mm spacers.

 

[Thomas-the-Terrano2]

hb, is there any scope to change the high ratio in the transfer box.

i imagine it will be a 1:1 ratio like most none landrovers. i recall in
the rangey it had a high ratio of something like 1.1 :1 and 3.21 :1 lo.
think some folked had inverted the high ratio to effectively overdrive
it probably in conjuction with fitting a low reving diesel such as a perkins.

just thinking if could change hi ratio then would be cheaper? than swapping
both axle ratios.

btw have you heard of marlin in the states, they offer crawler conversions
to hiluxs by adding another low box. wonder if our trucks, atleast the lwbs
could be so modded..mind it does then need the props shortening and
lengthening. so modded trucks can end up with a crawl ratio greater than
100:1 including diffs.

 

[Terranosaurus]

The standard transfere ratios are 1:1 and 2:1 (approx). I have only seen (and I've looked for em) drop gears for low ratio, calmini do them and theres a slightly cheape version from someone else they're both around 4:1. Calmini's are $1300, the others $1050.

Ring and Pinion (or crownwheel and pinion as we call em) are $450 per set.

So its cheaper to change the diff ratios I'd say - thats if you could find a different high box ratio.

 

[makeitfit]

Well I'm after ground clearance especially. Body work doesnt matter as its only a £200 ebay truck. Body lift is cheap(well materials anyway)
I've got some wide wheels and will have some 30mm spacers any day so only worry was gearing off road :?
Hardly go on the motorway with it since the 31s anyway. Main roads sound like machine guns sometimes as it is :x
Does anyone think the loss of engine braking is that bad?
The brakes are sound as its got new calipers on it :wink:

 

[BlueBull]

hiya guys,

Pete you have mail lol.

I had the 33/13.50/16 US pitbull rockers and I found them heavy, they were over 25 kg each tyre and were a nightmare to handle. I took the T2 off roading into very deep mud and found she struggled to lift the weight off each tyre, engine braking was ok but you could feel her wanting to over run each time if you eased off. Over taking was alot to be desired but I just headed straight for the oncoming traffic which did move out of the way.lol. Everybody heard me coming and stopped to look round lol, in the sand the tyres were ok they didn't sink, gearing was ok but going up hill you had to drop a gear and never in 5th lol. Braking was ok as long as you eased into it, but if you did want to stop in a hurry they would move on a little more than usual. I have now fitted BFG MT's 305/70/16 and they are great, got my speed back and gearing is ok as well, now I have fitted a chip I can't stop her and have beaten boy racers in pulling away from traffic lights lol. Not sure what the 2.4 will be like with the 33's but the 2.7 was ok, I suppose if you air down on off road sections they should be ok.