bigdogdazza - I don't suppose you added any width when you went from 225 to 31's though, did you? Imagine how stable it would be with 33's and hilux diffs if it was stock height?
Copied across form the tyre dribble thread. Kimtown wrote:
thanks very helpful, didn't realize the mp's came in such a narrow yet tall tyre. these could be the go. how would they sit under a 3" lift on stock guards?
3" with 32" tyres would raise the centre of gravity greatly though I'm thinking...
and what kind of price range would you be looking at for a larger aftermarket tranny cooler? I will consider it. my original thoughts were if it ever did go, heavens forbid, I'd just install a m16b with a manual gearbox instead of fixing the ridiculously priced gearbox.
edit: I should have just brought a sierra
Thank goodness you're in Victoria so I can talk about what works without people chiming in that what I'm saying isn't relevant.
I don't think "avoiding side angles" is an option for us. The tracks out in the forests dictate the side angles we're going to see. In fact, more cars flop from trying to avoid deep ruts or vehicle damage rather than due to the track itself, if you see what I mean.
I don't think I've never seen any situation where I've thought a car is too low (as in lift height) , but I've seen lots of situations where I've thought a car had too small tyres. In fact, almost every time I go out there's some situation where a slightly larger (diameter) tyre would be an advantage.
I've also seen plenty of situations where I thought a car was too tall. Sometimes that's been my car, and I don't care if I flop my car, but if the car has nice bodywork and is worth money all the more - a tall car is hard to trust.
Because our terrain isn't all crawlable, sometimes it's just necessary to bump the car up something, or get into 3rd low and build momentum. That's where tall cars get spooky.
Lifting a car to fit a tyre is false. The clearance to run a tyre is at full compression, when the axle is on the bumpstop. That has nothing to do with suspension lift, which is the static height the suspension sits when the car is in motion.
I'll describe it using these photos. Please don't take offence Kimtown if you already understand this, but the whole suspension lift to run tyres thing comes up so often it's worth rehashing.
These photos aren't of a Jimny, (It's aactually of the Hall Bros Racing class 8 patrol, with is awesome, even for a patrol,) but it doesn't matter.
Here's the car at ride height.

Here's the car at full droop

and here's the car (or very near) full compression

The amount of suspension travel is fixed by design constraints. In the case of this modified car, it's around 300mm (which is impressive) In a Jimny, it might be around 180mm before custom fabrication is required.
Normally, a car might be set up with 50% compression and 50% droop, and that looks to the case with this patrol, give or take, so that's 6" up an 6" down.
Lets assume that that car was at standard height, as it sits in those photos, with 12" of travel and 6" up and 6" down.
If you added 3" of lift, all that will happen is that the suspension will have 9" of up travel and 3" down. When it lands the jump, there's still nothing stopping the tyres getting as close to the guards as they did before the 3" lift, because how far the axle can move is a design consideration, it's not a reflection of where the suspension sits in that travel.
My own car has about 2" of compression travel and the balance in droop. That's because I don't drive fast and want my car low.
I can swap springs in minutes to raise and lower it - but how close the tyre goes to the guard doesn't change when I lift the car, only the "rest" or "static" position of the axles relative to the car.
I hope that makes sense.
So, with that discussed... you can see why I say that suspension lift cannot, and does not, fit a larger tyre.
There are three things that can fit a larger tyre to a car:
Body lift - this spaces the body away from the chassis, so even when the axles are fully compressed against the bumpstops, there is more room between the tyre and the guard
Bumpstop spacing - this limits how far the axle can move upwards. If you had 8" of travel, 4" up and 4" down, and added a 2" bumpstop spacer, the effect is exactly the same (from a tyre clearance perspective) as adding a 2" body lift, but the car doesn't get any taller. However, you will loose 2" of wheel travel, so the result is 2" up and 4" down, 6 total.
Guard cutting - leave the suspension alone and cut the body away to make room for the tyres.
Obviously, only guard cutting has no negative effect on the behaviour of the car, the other two have some effect.
In reality, the solution to running a big tyre is usually some combination of all three.
Lift springs might be useful to retain compression travel if bumpstop spacing is used.
In the example above, if I have 8" of travel, 4" up and 4" down, and add a 2" bumpstop spacer, I would have 2" compression travel after the spacers are installed. That might not be enough to retain a good ride, so if I fit 2" lift springs, I would have 4" of compression, the same as before the spacers went in, but only 2" of droop.
However, this is where things get interesting.
Once 2" bumpstop spacing goes in, a shock can be fitted that's almost 4" longer, extended, than stock, so it's possible to get that "lost travel" back, so, depending on your use, it's possible to have a very low car - even stock height, if you are willing to give up the compression travel, but have more overall wheel travel than stock.
So, a combination of guard cutting, bumpstop spacing, and longer shocks is what allowed this car to run a 235/85/16 (32X9") with only about 1" of suspension lift.

This car was very stable, very subtle, and quite capable. It suffered from the normal Jimny weaknesses (CV's, rear diff) but there are workarounds available, or coming, for these that wern't available when Mitch built this.
I will add that Mitch had 3" springs in this car with 30" tyres and hated it at that height. It was MUCH better once dropped down.
Mud_Muncher is another vic member who has been dropping his Jimny since he bought it. He bought it in full NSW hektic style, (5"springs and 3" body lift to clear 32" tyres) it's now not
too tall and runs 34" swampers.

It would be nice if it was a bit lower, but it's a pretty good compromise. It wouldn't need to be even that tall if it ran, say, 32" tyres. His build thread is pretty good reading for a Vic driven M engined Jimny
viewtopic.php?f=4&t=22944Gearing:
Whilst it's possible to play with chains and planetaries (APIO and Trial Jimny) and they can be combined, it's an expensive process. A Sierra case is really the answer. even 4:1 gears in a sierra case would be quite useable.
Lockers:
Lockers are the #1 capability upgrade you can do to your car. it doesn't matter how much tyre you have, if it's in the air and you have open diffs, you're stuck (Which is why I suggested lockers first). Lockers let you slow right down, choose better lines, and make better decisions about when to use momentum, for example. I couldn't imagine driving a car that wasn't locked. You'll rarely have the perfect tyre for the job, but lockers are always a huge advantage.
That auto:
There's nothing wrong with the jimny auto, but it's very small and gains heat very quickly. On the same track on the same day, my AW-4 vitara auto was running 50˚ cooler than the jimny auto in gregc's car. He stopped to cool it down when it reached 130˚ or something

but without a temp gauge, he would never have known he was cooking it. He runs a very large PWR cooler in front of the radiator (10X12") and has just ordered a fan cooled cooler pack to be mounted elsewhere (like this) along with the existing cooler.

Don't get it hot and you won't break it. Greg runs his into a 4:1 case (shortly to be a 6.5:1 case) and 5.12 diffs with 35" tyres and the auto has been perfectly fine in over 6 years of very hard off road use. He's a habitual crawler, so he's always slipping the converter, which is where the heat comes from.
A generic water temp gauge tapped into a tee on the cooler flow line is all that's required to monitor temp - the range of a water temp gauge is fine. It's what I use. In my opinion, it's not a consideration, it's 100% a must.
Manuals suck offroad compared to autos, so don't even consider a manual swap. If you broke the auto, I'd be looking at a J20/AW-4 swap long before I put a manual in. If you gear the car correctly and learn to work with the auto, you'll never go back to a manual.
Anyways, there's some thoughts to consider.
Steve.