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20" Factory Wheels from an XC90. Fit and Good Idea?
So I have been trying to buy a set of factory 19x8.5" wheels as summer shoes for my 2017 S90 for some time now, but this has turned out to be a more difficult task than I had imagined. Turns out sales volumes of S and V 90's are smaller than other models, and the smaller sedan and wagon models which do come with 19" wheels use 19x8" instead.
My desire had been to use the factory 255/40R19, but these won't fit on an 8" wide wheel, which is why I need the factory 8.5" wide.
I really don't want to go with aftermarket wheels because I prefer the factory look, but I had almost given up and ordered a set of 19x8.5 BBS wheels, when a set of 20x9" wheels in perfect condition from an XC90 became available locally.
First question: Will these fit well?
Stock 20" size on the S90 is 20x8.5 with a 47.5mm offset. These XC90 wheels are 20x9 with a 38mm offset.
My first thought was that they would rub, but then I saw that the offset was much lower, meaning the center would move outwards.
So according to my calculations, the 38mm offset puts the center line of these wheels 9.5mm further out than the stock configuration. They are a half an inch wider which means a quarter inch on the inside, and a quarter inch on the outside, converted to millimeters, this actually means the inside will actually be 2.65mm further out than stock, so no rubbing concerns. The outside will sit 15.35mm further out which according to visual approximations on my car, still means the wheel will fit inside the fender flare.
So, from a fit perspective, I think it will work. The only difference will be that the center contact patch will be 9mm further out on each side, so an 18mm wider track. I know that if you go too wide it can have stability impacts. The thing is, being a novice to this, I don't know how much wider, too wide is. Would each wheel sitting 9mm further out be a problem in this regard?
Second Question: Is this a bad idea for other reasons?
I have dedicated snow tires on dedicated rims, so these will never see winter use, but even so, 20" on this car would be very low profile, and that makes me nervous about road damage like bends and cracks to the wheels should I see a bad pothole I cant avoid.
Volvo sold (sells?) the S90 with two 20" tire sizes, 255/35R20 which winds up with a 3.5" thick sidewall and 245/40R20 which is a 3.9" sidewall. My rule of thumb has always been to avoid going under 4". Does that still hold true here? My car is equipped with air suspension and active 4C suspension. Does its adaptive nature help mitigate wheel damage over bumps at all? What about road harshness? How bad is it in these cars with 20" wheels?
I'd appreciate any thoughts on this. I'd really like to go with the 19x8.5s, but they have just been impossible to find, and I'd really prefer not having to go with aftermarket wheels.
Will these fit well?
Yes. Perfectly. If you use the 20X9 ET38 wheels from the XC90 instead of the 20X8.5 ET47, the rims will poke out 15.4 mm (kinda like using a 15 mm spacer) and will be 2.5mm away from the strut (so definitely not gonna rub on the inside). With 245/40R20 tires, you will also not rub along the circumference (as they are standard S90 tires).
Find the attached screenshot to see the calculations. Also, find web link attached to do your own combinations.
Is this a bad idea for other reasons?
No. I don't think so. I have 245/45R20s on my V90CC with rear air suspension and 4C. I live in Michigan which (officially) has the worst roads in the USA and my Vehicle floats everywhere and I have never required any wheel balancing/alignment/pothole damage repair, in the 60k miles I have driven. The 20s with Air suspension will do just fine unless you wanna be traditional and go for a big-a$$ sidewall. The 245/40R20 tires should work perfectly in your case.
The 20s also fill the Vehicle much better, IMO.
Appreciate your input.
Originally Posted by Volvolic
It is interesting to me that 245/40R20 is a factory size, as the diameter is 3.7% larger than the 245/45R18's mine came with, and going beyond a 3% diameter increase is generally a negative according tot he wheel size rule of thumb...
By the chart below it looks like 255/35R20 is another factory size, but now the sidewall is only 3.5", which is a bit scary.
It is much closer in diameter to my 245/45R18's though, at 1.1% larger.
Did your car come with those 20's or did you add them after the fact?
Did you feel the Polestar upgrade was worth it?
$1,295 seems a bit hefty for ~14hp, and a 0.1s improvement in 0-60 times.
Unless there is something I am missing?
My car came with the 20s. 20X8 ET49, if I remember correctly.
The Polestar upgrade is much more than just the numbers. It changes the overall driving/shifting characteristic of the Vehicle and, IMO, after driving multiple non-polestar'd Volvos (as loaner vehicles), the Polestar tune is worth it, and I wouldn't own a Volvo without it. See if your dealership has an S90 T6 with a tune, take an extended test drive and decide for yourself. Also, if you get the tune and don't like it, they have a 30-day moneyback policy.
Although I got the tune installed and baked into the buying cost of the Vehicle, it technically cost me around $5-700. You can pair discount coupons from Volvo/Dealership and bring the price down to about $1000, IMO, or maybe even shop around your other local dealerships and see if anyone can offer a good deal.
I run Niche Essen in 20x9 with 38mm offset and it is fine. I am currently running stock tires on my V90CC and since the sidewall is 45 it does not look stretched. Once my OEM wear out I am going to upsize to 275/40/20 which will match the stock diameter of my 245/45/20.
Right now I am back to my stock 20" wheels with winter tires and they look so tucked under the fender. Can't wait to get my summers back on.
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