Rim Offset

Submitted: Wednesday, Apr 15, 2009 at 21:38
ThreadID: 67879 Views:2341 Replies:7 FollowUps:1
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Hi folks, my first entry on forum- please excuse any errors.
My 4WD is a 100series, IFS, Auto, TD and running on Coopers S/T 285x75x16.
I want to decrease/alter the offset to (increase track) improve stability. I know my current offset is +60mm. Can any one please advise me what is the maximum offset, largest tyre and rim size I can go to without major hassels. All advice/help is appreciated. Thank you
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Reply By: Member - Graham H (QLD) - Wednesday, Apr 15, 2009 at 21:54

Wednesday, Apr 15, 2009 at 21:54
Try and get a set of rims off a 2000 solid front end.

They should do the trick

AnswerID: 359746

Reply By: Horacehighroller - Wednesday, Apr 15, 2009 at 22:23

Wednesday, Apr 15, 2009 at 22:23
If my memory serves me correctly you are only allowed to increase the rear track (rigid axle) by 50mm and the front by 25mm (Independent)

Wheels from a rigid front end landcruiser will cause too much increase in track even for the rear.

AnswerID: 359754

Follow Up By: Boobook2 - Thursday, Apr 16, 2009 at 07:23

Thursday, Apr 16, 2009 at 07:23
If Marcus is in Victoria, then 25mm is the legal maximum increase. ( 12.5mm per wheel). That would equates to Positive 47.5 offset. In practice there are a few positive 30mm offset steel rims. There is a Positive 48 rim on the 5 x 150 pattern from CSA.
FollowupID: 627738

Reply By: Member - Mark E (VIC) - Thursday, Apr 16, 2009 at 02:12

Thursday, Apr 16, 2009 at 02:12
Don't fprget the increased work that the steering gear and wheel bearings will be subjected to.

I think you will find this a difficult road to travel..........

Just my .02 +GST


AnswerID: 359769

Reply By: Member - Alastair D (NSW) - Thursday, Apr 16, 2009 at 15:20

Thursday, Apr 16, 2009 at 15:20
What stability are you trying to improve? I have the same vehicle and do not have a problem. If you have a roof rack or other weight loaded high in then that will contribute in a big way.

Changing the track via different wheels will do very little since you can only change it by a few cm. As a proportion of the existing track the % change will be v small.

The wheel offset is designed to make the forces at the bearings such that there is no twisting effect. To change this a lot can lead to major problems and potential breakage.

AnswerID: 359820

Reply By: MarcusT - Thursday, Apr 16, 2009 at 17:49

Thursday, Apr 16, 2009 at 17:49
Thanks for your advice and suggestions.
The stability concern is due to 4yrs ago being led down a closed track (that had recently being bulldozed) by an irresponsible trip leader (and club). The outcome was that we (family of 5) rolled off the mountain! Many lessons were learnt from that episode. The 4WD is also fitted with ARB roofrack, steel drawers, 2" lift, front and rear ARB with 12000lb winch etc etc. Anyway, I feel that there is too much body roll. I figured that if I widen the track, that will improve the overall stability. I know the the rims of a rigid axle have a zero offset and therefore protrude too much. The solution must be in something between the zero and 60mm. Or am I barking up the wrong tree???
Should I be looking at poly airbags?. But would they be any good on the tracks? The 100 series might with a roof rack is still top heavy, or not?
AnswerID: 359838

Reply By: APN - Thursday, Apr 16, 2009 at 19:48

Thursday, Apr 16, 2009 at 19:48
Hi Marcus

I had a 100series IFS

I had the suspension upgraded with a lift of around 2in (without the nose being down), ran the same size tyres you are running (and ran others during the period I owned the vehicle), had a steel bull bar, cargo barrier, full length Rhino rack and all the usual camping gear.

I also had poly air bags - all these do is allow you to play with the rear end ride height (hence airing up pre packing your vehicle).

We always camped (never towed) so carriied everything oi and on the car.

Was always very conscious of weight (the roof bag was packed with two lightweight tents, tarps, 4 chairs, pegs etc etc) - also carried recovery gear on the roof plus a pole carrier - was careful to ensure all was below max. reecomended weight

Last trip before being sold was through the Simpson and as it was a V8 carried an additional 60litres of fuel on the roof (which was emptied as the fuel in tanks was consumed)

Was always very aware of the weight on the roof when cresting dunes and veering right as you do west to east - the negative cambers gives you the heeby geebes, but I have no doubt the reason it did not end up on its back or side was the quality of the coil springs, and not the air bags/

So in summary, I believe it is not the wheel track, not the poly air bags but the quality of the aftermarket springs and front end suspension upgrade (and the spread of load on the roof).

Rollover was and is still something I am extremely concious of so I feel for you and your family.

If you have not already, invest in some very good quality rear coil springs and front end suspension mod's.

Best of luck
AnswerID: 359855

Reply By: MarcusT - Thursday, Apr 16, 2009 at 20:00

Thursday, Apr 16, 2009 at 20:00

Sounds like we have similar vehicle set up with the exception of the ARB v Rhino rack.

From personal experience can anyone advise/suggest, what is a good quality coil springs and front end suspension, what brands should I be looking at?

Who can I speak to re these?

AnswerID: 359859

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