Spacers vs. Offset

[Indvdl M]

Is there a difference in terms of tire clearance between the following 2 hypothetical situations:

18x9 wheel, 245/35/18, and 40mm offset, 10mm spacer

18x9 wheel, 245/35/18, and 30mm offset, no spacer
(Same wheel and tore combo, just different offsets)

I know spacers are sometimes used to allow a wheel to clear brake calipers, but froma stand point of tire clearance is there any difference between using a spacer and a different offset wheel? Thanks for the help.

[The HACK]

Yeah. There's 20mm of difference in clearance. The second wheel will be pushed out towards the fender by 20mm. That's almost a whole inch.

[Indvdl M]

Yeah. There's 20mm of difference in clearance. The second wheel will be pushed out towards the fender by 20mm. That's almost a whole inch.

I'm sorry I had the spacer on the wrong wheel the first time. Post has been edited to reflect my actual question.

[KarlSpackler]

I'm sorry I had the spacer on the wrong wheel the first time. Post has been edited to reflect my actual question.

No, the same.

Although the second set of wheels would look better because of a more recessed face. It looks more agressive

[Critter7r]

If you had a wheel with 40mm offset and a 10mm spacer, it would equal a wheel with 50mm offset, not 30mm. The 10mm space would have to go onto your hypothetical 30mm offset wheel to equal your hypothetical 40mm offset wheel. But then you'd need 10mm longer studs too, to compensate for the spacer, and as mentioned, the face of the wheel would be deeper on the wheel without the spacer.

[KarlSpackler]

If you had a wheel with 40mm offset and a 10mm spacer, it would equal a wheel with 50mm offset, not 30mm. The 10mm space would have to go onto your hypothetical 30mm offset wheel to equal your hypothetical 40mm offset wheel. But then you'd need 10mm longer studs too, to compensate for the spacer, and as mentioned, the face of the wheel would be deeper on the wheel without the spacer.

You are wrong, please dont argue. (Except on the part about the face being deeper on the 30mm wheels)

KThx

[Indvdl M]

If you had a wheel with 40mm offset and a 10mm spacer, it would equal a wheel with 50mm offset, not 30mm. The 10mm space would have to go onto your hypothetical 30mm offset wheel to equal your hypothetical 40mm offset wheel. But then you'd need 10mm longer studs too, to compensate for the spacer, and as mentioned, the face of the wheel would be deeper on the wheel without the spacer.

I don't agree. A wheel with 40mm offset (meaning the mounting face is 40mm outside of the center of the wheel), plus a 10mm spacer would push the mounting face 10mm closer to the center of the wheel, then creating a 30mm offset. If my thinking is correct.

[KarlSpackler]

I don't agree. A wheel with 40mm offset (meaning the mounting face is 40mm outside of the center of the wheel), plus a 10mm spacer would push the mounting face 10mm closer to the center of the wheel, then creating a 30mm offset. If my thinking is correct.

See above, he is mistaken u and I are correct

[Indvdl M]

Thanks

[Ty Vil]

If you had a wheel with 40mm offset and a 10mm spacer, it would equal a wheel with 50mm offset, not 30mm. The 10mm space would have to go onto your hypothetical 30mm offset wheel to equal your hypothetical 40mm offset wheel. But then you'd need 10mm longer studs too, to compensate for the spacer, and as mentioned, the face of the wheel would be deeper on the wheel without the spacer.
wow when you don't know what you're talking about, please don't post.

[Ty Vil]

And to answer the OP's question.

Neither is going to fit on the rear of an E36 M3 with an offset of 30.

[Indvdl M]

And to answer the OP's question.

Neither is going to fit on the rear of an E36 M3 with an offset of 30.

It was just a hypothetical situation.

[KarlSpackler]

wow when you don't know what you're talking about, please don't post.

Ty, you just dont try hard enough buddy :D

[The HACK]

wow when you don't know what you're talking about, please don't post.

He is technically correct. If you have a 40mm offset, adding a 10mm spacer will result in a 50mm offset.

Technically. BMW offsets are NEGATIVE offsets. Therefore the 40mm offset wheel is actually a -40mm offset, and the 30mm offset is actually a -30mm offset. Adding a 10mm spacer will result in a -30mm offset on the -40mm offset rim. Since this is a BMW board, we all assume that the offset numbers given are BMW offsets, therefore assume that the 40mm number is actually a -40mm.

Positive offset wheels would behave exactly as the poster you so elegantly singled out said.

[The HACK]

If you had a wheel with 40mm offset and a 10mm spacer, it would equal a wheel with 50mm offset, not 30mm. The 10mm space would have to go onto your hypothetical 30mm offset wheel to equal your hypothetical 40mm offset wheel. But then you'd need 10mm longer studs too, to compensate for the spacer, and as mentioned, the face of the wheel would be deeper on the wheel without the spacer.

That is correct. I assumed the OP was referring to offset that will fit on BMWs, which is typically negative offset. The situation you are referring to, positive offset numbers, are not commonly found or used on BMWs. I am aware of no BMW in past or current production that accomodates positive offset rims.

[ghambino]

WOW! adding a spacer/adapter only decreases wheel offset. You can't go from 40 to 50 with a spacer. And about BMWs having neg. offsets is crazy. I've test mounted a 17x9 wheel with an offset of +25mm on an E36 and the wheel stock way out. Now imagine a negative offset, you would need serious wide over fenders to fit over a wheel like 17x8 -25mm for example. Typical BMW wheel is about 17x8 +38mm. 17x8 -38mm on a BMW is rediculous.

[ghambino]

Positive offset sinks wheel into fenders. Negative offset pushes the wheel out away from fenders.

[The HACK]

Positive offset sinks wheel into fenders. Negative offset pushes the wheel out away from fenders.

Yeah my terminologies are crossed, BMW wheels are positive offset but in a negative offset situation adding spacers will increase offset.

http://www.tirerack.com/wheels/tech/techpage.jsp?techid=101

Sorry.

[ghambino]

You almost got it. Lets say you have a wheel that is: 17x9 -25mm. If you add a 25mm spacer/adapter to that. The effective offset will be -50mm. Which is pushed even further away from the fenders.

[KarlSpackler]

Yeah my terminologies are crossed, BMW wheels are positive offset but in a negative offset situation adding spacers will increase offset.

http://www.tirerack.com/wheels/tech/techpage.jsp?techid=101

Sorry.

Still off


You almost got it. Lets say you have a wheel that is: 17x9 -25mm. If you add a 25mm spacer/adapter to that. The effective offset will be -50mm. Which is pushed even further away from the fenders.

You got it