Automotive

What difference does wheel offset make?

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  • Jul 26th, 2015 11:34 am
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[OP]
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Aug 28, 2005
397 posts
170 upvotes

What difference does wheel offset make?

I'm looking at getting supplementary wheels for my car. I was looking at getting a set from someone on Kijiji - 18x8, with the right bolt pattern for my car. However, the offset (40mm) is different from what the 18x8 OE wheels are (55mm). I currently have 17x7 at 50mm.

From what I think I understand, this means that the wheels will sit further out in comparison to my current wheels? Are there any concerns or issues to be aware of? 1-1.5 cm sounds like a fairly large difference.

The wheels I am considering are from a Volvo XC60; I am looking at using them on an S60 (the tires they have on it currently are probably too big; so I would have to switch those out).

I was also thinking of using these for winter tires for now (since I still have a good amount of life on the tires currently on my 17" wheels). But I had also heard that it's usually better to have a narrower tire for winter? Would 18x8 be a bad idea?
8 replies
Member
Feb 4, 2015
207 posts
99 upvotes
York, ON
Car manufacturers spend millions designing a car for optimum ride and handling and specify the correct specification to achieve that. Incorrect offset shouldn't really affect things too badly, but be aware if you got into a serious accident with a serious insurance claim against you that warrants a closer look, you could be in a lot of trouble running non-spec wheels.

I'm guessing that as you drive a Volvo you're not part of the stance/stretch/camber brigade, so you're not looking to achieve any look, rather save a few $$$. I'd get the right size, personally.

As for winter, yes, narrower is better - thinner tires cut through the snow and have a greater weight per contact patch.
[OP]
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Aug 28, 2005
397 posts
170 upvotes
Thanks the notes. Generally speaking, is there a range of offsets that are acceptable - or is being bang-on fairly important? I notice on TireRack.com, they list offsets ranging from 38mm up to 55mm for my car.

I haven't found any official specs from Volvo about what is acceptable for offset - I didn't see anything in the manual except for recommended tire sizes.

You're right that this is mainly for saving some cash, while also caring a bit about how it looks.. Volvo OE wheels are expensive!
Deal Expert
Jan 15, 2006
19703 posts
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Richmond Hill
Lower the number the closer the wheel will be towards the outside. Obviously going to low an offset will start rubbing and vice versa.
Deal Addict
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Oct 16, 2007
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I am comparing a 17x7 (+55) and a 18x8 (+40). From your current setup the 18x8 rim will be 3mm closer to the strut, and the outside will be 23mm further out. You just need to make sure that with the tire being 23mm further out, that you wont rub on the fender.

if you have friends with spacers, a 25mm spacer will let you test it out on your current setup.

http://www.1010tires.com/Tools/Wheel-Offset-Calculator#
Deal Fanatic
Oct 26, 2008
6868 posts
2666 upvotes
BC
A significant change in offset will affect the steering response in a car that conveys some sense of road feel (such as a Volvo S60).

That is, you may notice that small steering inputs no longer have the same effect that you have been used to.

Whether this will be readily detectable from a relocation outward of 15mm. in the centre of your contact patch is doubtful.

Maybe would be a bigger consideration if talking summer driving conditions as opposed to winter.

The greater concern might be accommodating the 8" wide XC60 wheels with available tire choices.
You will need to go down a step in aspect ratio anyway, but also try and limit how wide a tire you have to get - preferably less wide than your summer tires. Don't know if that is doable.
Deal Expert
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Feb 26, 2004
26998 posts
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Doesn't look good. Might hit the suspension and brakes. Do a test fit before buying.

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