[bone]

hey guys, more stoopid questions. but what offset rims are you running?? keen to increase the track (stability) of my car a little, just a 99 jim 2inch lift, most probably gunna end up with 215 75 15 muddies on there... thanks crew!

[Benz]

haha your jimny will never have much stability!
mine has scared the shit out of me a few times on dirt roads....

[watermouse]

Its kind of complicated to explain but the ideal rim offset for a given tyre size is one where the kingpin axis line meets the ground ahead of and on the centerline of the tyre.

While this is not entirley necessary it does help with steering stability. e.g. If you dont increase the negative offset for a larger than stock tyre the kingpin axis will fall outside the centerline of the tyre this means that at any forward speed and due to friction/drag etc there is a moment (or force if you like) acting around the kingpin axis trying to turn the steering wheel. On flat, nice road this is balanced by the wheel on the other side of the car so you might not notice it until one wheel drops into a pot hole or loses grip in which case with large tyres you will get a big force into the steering system causing juddering or swerving.

I run the common 215 size on the stock rims. The size increase is small so the effect is not so pronounced but I do get some measure of juddering and weird steering effects on uneven road surfaces. Ideally it would be good to push the rim centerline outboard (negative offset) 10-15mm to correct this

So while this doesnt really answer your question you should realise that not only do you get a more stable vehicle with wider track offset rims and bigger tyres but you also improve your steering stabilty too.

The only question left to ask is how you get your bigger tyres and offset to fit the cramped Jimny wheel arches.

[Benz]

215's on a 40mm lift. he will fit them no probs =]

[Birdman1985]

They say on a stock jimny the most you would want to go in wheel size before needing a body lift to prevent guard scraping too much is a 225. So 215 aint gonna be a drama at all.

[bone]

watermouse, your just talking about the effects of bump steer right. i know in the past weve tinkered with roll centre adjusters etc to nullify the effects of the increased track... benz dirt roads = tail popping out a few times already. one puckerd a-hole hahaha.... birdman just talking about rim offset, not tyre size thanks though

[bone]

watermouse wrote:

... Ideally it would be good to push the rim centerline outboard (negative offset) 10-15mm to correct this...

woooord, this is pretty well what im chasing what offset have people run on a 15x7 rim

[Benz]

first weekend i had my car. went camping. drove along a gravel road with a long sweeping bend. was going like 50 Kph. decided to put a bit more power on and the tail slid out. not yet use to power steering (old car was a heap of shit) i over corrected and hit the brakes a bit too. tail then swung the other way and ended up facing the wrong way on the side of the road.... missing a fence by about half a meter.

had another big big sideways moment but going allot faster a while ago. glad i knew how to handle it a bit better that time.

4wd on dirt roads in nice =]

[zukenutter]

A bit of sideways action is always fun. My 7" rims are almost perfectly centred compared to the standard rims. About .7 of an inch wider inboard and .8 of an inch outboard. They tuck into the guards really well when articulated fully. 7 inch rims would bit an inch too wide though for 215s.