How important is it to match the oem wheel offset?

[Throckmorton]

I am looking to replace my 18" oem wheels on my 4.6l Genesis with 18" wheels from a Genesis Coupe but doing so means moving from a wheel with 39mm offset to a staggered wheel setup where two wheels would have a 30mm offset and two would have a 33mm offset. Since the tires I am mounting will be winter tires in the oem 235/50-18 size I don't expect I will have issues with fender clearance.

What are the risks of using a wheel with a different offset? Fwiw, all of the wheels recommender by the tirerack appear to be wheels with a 35mm or 40mm offste. Does it matter that much?

 

[901Memphis]

Should only matter if the differences in offset cause the brake caliper to rub.

 

[Olas]

The lower the offset, the further your wheel centreline is from the hub so the staggered pair give you 14mm more poke on the front and 20mmthe on the back (per axle, not per wheel)

Google 'rolling radius calculator' for a a good link
*edit: willtheyfit.com

 

[Throckmorton]

If I understand the meaning of tire offset correctly, wheels with less positive offset will appear to be pushed out toward the fender. Is that correct?

 

[Olas]

Originally Posted By: Throckmorton
If I understand the meaning of tire offset correctly, wheels with less positive offset will appear to be pushed out toward the fender. Is that correct?


You got it positive offset is tuck and negative offset is poke

 

[KitaCam]

Here's a good place to start:

Fitment considers tire size as well as rims...
http://www.rimsntires.com/specspro.jsp

 

[Rand]

as mentioned less offset means the wheel will stick out more.

are they the same width wheels?

 

[ARCOgraphite]

It will affect scrub radius if the replacement tire is same dia. Luckily you have rwd, but the steering return and bump steer can be affected as well as propensity to shimmy if the scrub R is moved near ZERO.

 

[Throckmorton]

Originally Posted By: Rand
as mentioned less offset means the wheel will stick out more.

are they the same width wheels?
Actually they aren't. Two of the wheels are 18x7.5; two are 18x8, whereas the oem wheels are 18x7.5.

 

[OneEyeJack]

Offset is only important if you want your car to handle like the designers set it up. If style and fashion are more important then ignore the handling, tire wear and potential other problems. There's a kid that works at the local parts store and drives a slammed Honda. With the negative offset and negative camber his tires never make it to 10K miles. He said it's okay because it looks "kool". He also said that when he hits the brakes hard it always darts to one side or the other. Evidently looking "kool" is more important than brakes, too.

 

[Throckmorton]

Thanks for the link. Also thank you to olas for willtheyfit.com. This spares me from having to do my own calculations.

 

[901Memphis]

For winter wheels i don't think it should make much of a difference, you will have less handling already with the winter tires, so hopefully you won't be driving it like it has summer tires on it.

 

[Throckmorton]

The thing about handling is that I never approach the limits of my tires' performance envelope in dry or wet conditions. The only time I ever come close to the limits of what a tire can offer in terms of performance is in ice or snow where it is easy to find oneself temporarily going beyond the limits of what a tire is capable of.

As far the offset difference, I don't think it will make much of a difference as I will be using the oem tire size and as I expect the tread width to be slightly narrower on winter tires compared to all-seasons with the identical sidewall width.