33" tyres at rear, 31" at front???

[BlakeNZ]

Well guys, here is my question, as no one has addressed or attempted this style of set up before (that i can find on the WEB at least).
Will it be OK to run 33" tyres at the rear, and 31" tires at the front?
1st, the "how".
The Nissan Mistral (and many terranos) runs a 4.375 ratio diff. So to compensate for a 33" rear tyre vs. a 31" front tyre (33/31 =1.0645) we need a rear diff that is geared approx 6 % lower(numerically higher) than the factory 4.375.
4.375 x 1.0645 is 4.65 ratio diff. Fortunately, H233B diffs commonly feature a 4.625 ratio., which is about spot on.( less than 1% difference) I doubt it has to be perfect, as you only use the 4WD on loose surfaces.
2nd, the "why?"
Simple. Two reasons. The H233B is a big pumpkin (9.25" ), and as such, has quite poor ground clearance when running 31" or smaller tyres. The 33 inch tyres will give an extra inch of diff head ground clearance, with no engineering at all. Also, because the front end is IFS, and is not massively strong(steering/diff/axles) it will mean that many of those weaknesses that would be exposed if going to a front 33" tyre, will live quite comfortably with a 31" tyre.
The only down side i see is (possibly) needing to carry two different size spare tyres. But this is not a biggy, given the low occurrence of punctures, and you would likely only carry a spare 33", and if you needed to fit it on the front axles, fine, no issue. Off road, the loose surface will accommodate the different wheel size. On road, the switch to Rear wheel drive will negate any problems for the drive home.
Any thoughts???

[TJ]

Borrow someone's 33 or 31s and try it out in 2wd and see how it looks and feels. I am having flashbacks of 70s stanced muscle cars and dragsters.

[mudlva]

technically no different to a tractor ah. get the gears right and it should be sweet

personally i would use an old 32 as a spare, as driving with a 1" height difference i would suspect it would chew the treads out on tarseal when on the front. and it would steer like a drunken sailor on his way home after a heavy night
you will get a little bit of lsd cherping but as its only a spare pump it up to 45pd and there will not be much in it. and drop it down to 26-28pd when on the front. a little bit heavier on the steering but nothing major

off no no real issue as ive run a 33s/s as a spare on 35simexs and adjusted the pressure to suit the environment, bit softer in the crud and quite hard when on the hard. worked well

[fh2014]

dont some guys running terranos run 33x10.5s with alloy rims no trouble anyway?

maybe even 33x9.5 on the front if you wanted to keep the weight off?

but sounds an interesting little experiment, and upload photos

[BlakeNZ]

The R20 is considered by many to be an ugly duckling, I imagine one with staggered tires would further emphasize its shape ! (No one wants to see that)
Whilst i like the idea of Lax2wigs 33 by 9.5" application, the 33x 9.5" is actually REALLY hard to source. Not many options out there.
This staggered set up isn't something I can rush into, as financial considerations(Fonterra payout) and practical ones(makes sense to wear out what i have first) will combine to delay it. Taking the idea to the forum is a bit of a feasibility study. Thanks for all and any input.

[lax2wlg]

Yeah unfortunately the 33x9.5 BFGoodrich KM is discontinued.

Its the width that will tear the front end to pieces, diameter is not such an issue.

You shouldnt have problems with the diff and CVs if you are running the 5 bolt double off set CV joints. The R180 front diff that you have isnt entirely bulletproof but it takes a lot of abuse/lunacy to break one.

Steering another story, as you know there are pretty simple solutions.

The thing I have found with wide tyres is that they dont actually work very well on a vehicle that weighs under 2 tonne. They give too much flotation, which if you have a big heavy Safari is a good idea, but I have found that with lighter vehicles you really want the tyres to dig in to find traction.

The wide tyres also add a lot of extra unsprung weight which affects handling, and also pulling force which will accelerate wear on ball joints, wheel bearings etc.

The 33x10.5 BFGoodrich seems to be a really good size/weight for the whole hub assembly on these vehicles. Although they are expensive.

[NJV6]

Maxis also do a 33x10, called a 255/85R16

[fh2014]

From the sounds of it the reason they stopped the tall and skinny 33x9.5 was the fact they couldn't be aired down much before wobbling all over the show riding on the sidewalls

Imagine mum driving down the motorway with a slow leak and the car decides to start driving itself...

Terrano owners know what I'm talking about

[Crash bandicoot]

you mean the 5 second delay in steering inputs? lol.