Really it's just looks.

 

Size of the wheel doesn’t necessarily translate to weight. lower wheel mass will improve acceleration.

simply as mentioned only benefit is preference in look. Other could be all over meaning you might have litter 20” wheel then 19” or a narrower that would be worse on traction.

 

I should also add that I have not seen any adverse impact to fuel/electric range from running a bigger size wheel on my S60, and I'm using 21". If there is any, its pretty much negligible.

 

Size don’t matter, it’s the total weight wheel plus tire and tire compound = drag coefficient

that’s what matters

 

and again it’s the entire assembly wheel plus tire. Normally bigger rim lighter tire in same size

Really! I just assumed more material meant heavier. That's interesting. So maybe there's negligible difference.

I know another V60 PE owner here, wonder if he has the 20" wheels. Maybe we should drag race. 😜

 

its all all about the material, and manufacturing process, not size. and sure Lets GO LOL

 

An alternate view - I’ve moved from city suburban to country rural this year, my xc60 has 20” cratus low profile, which whilst ‘look good’ are absolutely terrible on poor potholed roads which some are here. They transmit every bump & shake. The side walls on these wheels are magnets for curb rash vs alternatives. I’ll be switching from 20 to probably 18” all terrain as soon as I can find reasonably priced replacements.

 

Agreed I would definitely go to 18” from 19” if possible to get a bigger side wall

 

Effects of Upsized Wheels and Tires Tested

Plus-Size Models: Testing the performance effects of upsizing wheels and tires.

www.caranddriver.com

 

I just went from 19 to 20 inch wheels and apart from losing some sidewall (which I know will come back to bite me) I was surprised that I could avoid affecting the speedometer. 1 extra revolution per mile with 20s. The fact that my new wheels are so much lighter makes my gas mileage theoretically better. I have not tried to compare acceleration before (19) vs after (20).

 

I believe the car can (should?) be programmed to what size wheel is installed - I know I’ve seen it there, just never dug Deeper, so if it’s an ever an issue (Speedo) it can be adjusted / corrected with right software.
i was bitten by these larger tyres, had a puncture, which I didn’t notice (rear wheel) for a few hundred meters on straight road. Pulled over & swapped to spare - was later told that otherwise perfectly good tyre they would not repair as I’d driven on it flat too far & damaged the sidewall 😡. Costly replacement for a damned nail on the road - made me become aware of run flat tyres & their merits.

 

really depends on what you mean by acceleration. more mass to move means slower acceleration response, but wider and bigger tires on road means higher grip/slip limit so you can accelerate harder with higher effective power before spinning

 

As for increasing wheel size affecting weight, you have to factor in tire weight as well. Some tires can vary a LOT, the lower profile, can have thicker sidewalls, and actually be heavier. Also if you want to get real technical, The tire makes the most difference, since the weight is at the outer radius, whatever that angular momentum term is, moment of inertia, something like that.

 

Yes, too many variables in tire and wheel weight to make blanket statements. My S80 came with 18"x8" wheels that weigh 30lbs each. I bought a set of 18"x8"s that weigh 27lbs each, and my winters are also 18"x8" but they weigh only 25lbs each. You can just feel a change of 2-3lbs with the butt dynamometer, but it only equates to about a 0.1sec difference in 0-60 acceleration.

If you were to purchase a high-end forged wheel that comes in about 10-15lbs lighter, you would probably feel like you gained 10HP.

 

Here's a relatively scientific evaluation:

Effects of Upsized Wheels and Tires Tested

 

Here's a relatively scientific evaluation:

Effects of Upsized Wheels and Tires Tested

That is cool, actual real data points.
I wish they broke down wheel weight and tire weight separately though, but 14 pounds per combo from one extreme to the other is significant.
I suspect some of that IS additional tire weight, since they started with 195s and ended with 235s.

 

presuming the rolling radius is the same the difference is comfort.

anyone talking about acceleration needs to run the numbers! I asked a physics friend (phd lecturer who does experiments at CERN) and he worked out the energy stored in my track car wheels (e46 m3) in rotating energy (wrote it as a sybol that looked like a Greek w) vs the kinetic energy in the car.

I can’t remember the exact numbers but the wheel energy was minisucule compared to the weight/kinetic energy at 70mph. Like inconsequential.

unsprung mass is a bit different as the shock absorber does operate in the kHz range At least on a track.
Conclusion my side - comfort vs looks

 

Honestly the only reason you would get bigger wheels is for looks. Larger wheels and tires to match the size almost always means higher total combined weight.

Even if you fork out money to get significantly lighter wheels, you're bound to have more NVH transmitted back as the tire sidewall loses travel for deflection. Smaller sidewalls means less cushion before you potentially damage those now lighter wheels. And the larger the wheel, the more drastic this is.

Often times manufacturers will tune the suspension based on the weight of the standard wheel offered with the car, so if you get larger wheels you change the unsprung mass which affects how the suspension feels (usually harsher).

The argument I've heard is there is better steering response but I think that is so negligible and often offset by having wider tires that come with those upsized wheels.

My Focus came with 19" forged OEM wheels and a winter set of 18". The car rides significantly better on those winter sets that even with the squirm of the tire tread I prefer the feel of the car on 18s. The larger wheel is much more prone to curbing as well. I really wish Ford had just given two sets of 18s and charged extra for those who wanted the look.

 

I’ve got 22 on my xc90
I’m thinking of getting a set of winters in 19 inch and seeing how that feels.

we have air suspension but imo that Can’t make up for the nice big fat sidewall on a smaller alloy. We will see!

 

My guess is the combination of winter tread, and 1.5" more sidewall, come spring you won't want to take them off.
I had 2 Cadillac SRXs (2010 with the very unusual 2.8 Turbo, and a 2013) Then a 2018 XT5. They had 20s on them, but I bought a set of base model SRX 18" wheels and put winter tires on them. They rode SO much nicer both with impacts and general road imperfections, like seams. I think that thick dep dread was part of it, not just the 1" more sidewall.