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Author Topic: Rim offset  (Read 3136 times)

Offline David Mac

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Rim offset
« on: January 02, 2006, 01:56:30 pm »
Can you run a front wheel drive rim on a rear wheel
drive truck?I know the wheel will stick out a bit,I can live with that,any reasons not to.
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Offline tpl

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Re: Rim offset
« Reply #1 on: January 02, 2006, 06:46:36 pm »
If you are talking about running the rim on the REAR of the truck then not recommended for reasons of strenght of rim, loads and forces acting between the tire tread and the wheel bearings... but it would work

If you are talking about the FRONT then dont do it.

In a nutshell:  the tread of the tire will be misplaced relative to the steering angles designed in by the manufacturer. This will cause the tire to scrub sideways when it should be rolling cleanly.  Two effects of this. 1) tire wear and suspension wear   2) Loss of steering grip which may be ok in summer in the dry but you need every bit you can get in the winter.

Now if the difference in offset is only a couple of mm then these effects will be so small as to not notice.... but say, a 0mm offset to a 35 mm offset , thats  a lot of forces for a poor old tire to absorb
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Offline David Mac

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Re: Rim offset
« Reply #2 on: January 02, 2006, 11:51:36 pm »
How do you read the off set?
My rim has
15x6JJ 2.898/7/6kg022
stamped on it.
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Offline tpl

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Re: Rim offset
« Reply #3 on: January 03, 2006, 06:21:50 am »
you measure the distance between the back of the rim and the surface that mates with the hub.  The difference between that distance and 1/2 the width of the rim is the offset.
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Offline morty

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Re: Rim offset
« Reply #4 on: January 05, 2006, 02:58:53 am »
tpl is correct. If you are using FWD wheels they generally have a higher offset, which will cause the wheels to be sucked in rather stick out.
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Offline tpl

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Re: Rim offset
« Reply #5 on: January 05, 2006, 06:29:31 am »
either way   the tire contact patch is not centred where the suspension designer intended it to be.

I have often wondered why the makers of aftermarket wheels dot stamp the oiffset on the rim somewhere
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Offline articsteve

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Re: Rim offset
« Reply #6 on: January 05, 2006, 10:34:55 am »
Quote from: tpl on January 05, 2006, 06:29:31 am
I have often wondered why the makers of aftermarket wheels dot stamp the oiffset on the rim somewhere

Wouldn't be good for sales.  :)


« Last Edit: January 05, 2006, 12:56:52 pm by morty »
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Offline David Mac

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Re: Rim offset
« Reply #7 on: January 05, 2006, 12:05:37 pm »
Yep they are sucked in.I think Ill make up some spacers.
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Offline tpl

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Re: Rim offset
« Reply #8 on: January 06, 2006, 06:48:16 am »
Nooooooooooooooooooooo   unless you are going to buy new bolts or install new studs.

Are these wheels hub centric on the other vehicle?  probably not. So unless you have a good machine shop to make hub centric spacers  yoy will be leaning the whole weight of the car on a few (4 or 5 usually) 17mm bolts or studs.
If you are talking about making spacers then you do presumably have a metal lathe and have the tools required to replace the mounting studs....usually a press of some sort.

And lastly are the seats in the wheels the same as the current bolts or nuts  I am talking the shape of the mating surfaces here? There are two shapes in common use
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Offline David Mac

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Re: Rim offset
« Reply #9 on: January 10, 2006, 08:25:14 pm »
I thought Id just make them out of some 13mm thickish
metal or aluminum.Just cut out some big O shapes
and drill some holes for the studs.The wheel nut dosnt
make contact with the whole stud anyway and 5 bolts are carrying the
wieght on each wheel so I dont really understand what you are saying.
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Offline capriracer

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Re: Rim offset
« Reply #10 on: January 11, 2006, 05:48:40 am »
David Mac,

What everyone is trying to say is don't mix and match rims from FWD and RWD.

But 13mm doesn't sound like the difference between FWD and RWD, so maybe you should tell us what vehicles we're discussing so we can give you better advice.
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Offline tpl

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Re: Rim offset
« Reply #11 on: January 11, 2006, 06:24:30 am »
Quote from: David Mac on January 10, 2006, 08:25:14 pm
I thought Id just make them out of some 13mm thickish
metal or aluminum.Just cut out some big O shapes
and drill some holes for the studs.The wheel nut dosnt
make contact with the whole stud anyway and 5 bolts are carrying the
wieght on each wheel so I dont really understand what you are saying.

So.  You can make these spacers balanced... not a problem with a lathe.
So. The studs are long enough that 1/2 " ( 13mm) sticks out of the nut now?  That is you will have as many threads on the nut and stud in contact as you have now?

My comment about the mating surface where the nut touches the wheel was because that surface,  times 5, is what is holding the wheel centred on the axle as you will have no "hub centering" when you have spacers.  If the surface of the wheel, the depression into which the nut fits, is not the same shape as the bevel on the nut, you will not get a correct fit.  NOw having said that, if you can use the nuts that came with the WHEEL the surfaces should match.

Its a minor thing but you are already adding stress to this assembly  anyway unless you are adjusting the offest correctly with the spacers...but even with that you are generating a couple across an extra 13mm of stud which under extreme conditions can have 1/2 the weight of the vehicle leaning on it.
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Offline David Mac

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Re: Rim offset
« Reply #12 on: January 11, 2006, 03:16:57 pm »
Im doing it to gain offset because the steel winter
rim doesnt have enough offset.No problem
with stud lenth.
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Offline tpl

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Re: Rim offset
« Reply #13 on: January 12, 2006, 06:17:34 am »
Stell rims tend not to have problems with nut profile either.

Ok it should work well enough with spacers to get the offset close.
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Offline David Mac

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Re: Rim offset
« Reply #14 on: January 12, 2006, 07:38:05 pm »
Looked into buying some today ,no luck
at tire shop.Trying on the WWW.
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Offline David Mac

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Re: Rim offset
« Reply #15 on: January 12, 2006, 07:56:55 pm »
Tons on Ebay.
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Offline morty

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Re: Rim offset
« Reply #16 on: January 13, 2006, 10:30:13 pm »
Quote
I thought Id just make them out of some 13mm thickish
metal or aluminum.Just cut out some big O shapes
and drill some holes for the studs.The wheel nut dosnt
make contact with the whole stud anyway and 5 bolts are carrying the
wieght on each wheel so I dont really understand what you are saying..

Sounds scary to me. Not a big fan of spacers to begin with and making your own is a recipe for disaster. If you are going to all the effort, why not just buy wheels that fit properly?
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Offline David Mac

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Re: Rim offset
« Reply #17 on: January 14, 2006, 09:46:30 am »
Price was right,Getting spacers from E bay.
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Offline 84im

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Re: Rim offset
« Reply #18 on: January 14, 2006, 06:22:48 pm »
I'm also in the 'no spacers' camp.  Consider the safety aspect (double the nuts to tighten) and possible balancing problems.   A penny saved and a pound foolish?
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