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ET-55 Wheels Fit?

4K views 13 replies 8 participants last post by  Zetec2000 
#1 ·
Has anyone put wheels with a ET-55 offset on their S90? Did you have to use spacers?

I'm considering buying a set of wheels for winter tires. Thanks for the help!
 
#3 ·
Has anyone put wheels with a ET-55 offset on their S90? Did you have to use spacers?

I'm considering buying a set of wheels for winter tires. Thanks for the help!
Just keep in mind that wheel offset doesn't mean much without knowing the width of the rim.

Assuming it is the same width as a stock 18" 8" wide rim most S90's came with, it will probably be fine but it might be close to rubbing.

The stock 18's have an offset of 42mm, so a 55mm offset will mean that the center of the wheel will be 13mm further in. There is a chance that might rub at full turns, but it is probably small.

If the offset is 0, exactly half of the width of the rim sits on either side of the wheel hub mounting surface.

With a 55mm offset, this is shifted 55mm inward (it's counter intuitive, you'd think more offset would move it further out, but that's not how it is measured)

For vehicle Dynamics it's generally a good idea to stick as close as possible to the original equipment, but it's not a huge deal as long as it doesn't rub.

Even Volvo themselves have a 5.5mm offset range from smallest (42mm to highest 47.5mm) on the factory wheels so there is a range that is acceptable.
 
#12 ·
the range you are talking about is based on width of the rim,... Playing with ET ...you play with scrub radius
Passenger cars like your Volvo will be set up with at least a little bit of Negative Scrub radius. This consistently pulls the wheels in, which is good for emergency conditions like a blowout or single brake failure.
Moving the tire further inboard by a small amount (<5mm) will usually be imperceptible to the driver. Going more can make steering heavy, but is more often an issue with clearance to hard parts on the suspension, as noted in earlier posts. More negative Scrub won't make the car unsafe.

On the other hand, adding positive scrub can be a problem. As scrub approaches zero, the car will get a bit twitchy, as the pull on the tires switches inside/outside with changes in road surface, etc.. Positive scrub is fun in lightweight race cars, but not for the passenger market.
 
#5 ·
call Nick at Re-Volv in Oxford, MA. I picked up a set of 19” OEM wheels from him for cheap. He gets port take off wheels and sells them for a steal. He’ll ship if it’s too far.
 
#6 ·
call Nick at Re-Volv in Oxford, MA. I picked up a set of 19" OEM wheels from him for cheap. He gets port take off wheels and sells them for a steal. He'll ship if it's too far.
I'll have to check that place out. It's in my neck of the woods (even though Oxford is kind of in the middle of nowhere)
 
#7 ·
For my winters, I used my old set of 19x8 ET55 Bor's, adding 10mm spacers to get them away from the suspension and brakes.
 
#11 ·
I gave him a ring. He put me on his list to call back when he gets more wheels.

On a side note: I used to live in Gales Ferry and worked at EB, but just recently moved to NY.
That's where I work. Been there a little over 11 years.
 
#13 ·
Thanks Zetec and mattlach for the solid information on offsets! That's very timely information for me. I have 20" Rd wheels on my V90 with a published offset of +45 I believe. Many after market wheels seem to have mid 30's to 40 liste3d, so that would mean the wheels edges would be further out toward the fender then? I wouldn't mind that as long as it doesn't tend to rub. The downside would be that spacers wouldn't be able to correct for that..ouch. The various polestar rims also seem to have less offset. Does anyone know if all of those would work with a V90?
Thanks for all of the expertise!
 
#14 ·
In almost all cases the "ET" offset number reflects Negative offset. In the case of your RD 20's that means -55mm. The Numbers you see for most aftermarket wheels are also negative, so a lower offset means further outboard, closer to fender, and pushing toward or into a POSITIVE scrub radius.

I've not seen any alignments threads that might show the stock Scrub, or how much adjustment the V90CC has; maybe other can chime in.
That said, a talented alignment shop may be able to help you adjust to get driving dynamics you like, even with a move in offset. Check with your local SCCA autocrossers, they know the really slick shops that can work magic. Here in SoCal that means WestEnd in Gardena, and I'm sure there's an equivalent near you.
Best of luck.
 
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