https://www.youtube.com/embed/5zy1BhjqIp4
What are the benefits of downsizing to 17-inch wheels on our E46 BMW M3?
In addition to saving money on tires for track days, we also got more sidewall compliance for a smoother ride on the street.
Presented by CRC Industries.
For a specific late-model car, it's fairly straightforward because wheels and tires are fairly (okay, nearly ridiculously) large, so backing down a bit is typically doable and there is currently a good selection. Though the article isn't addressing all cars, it is very much a situation biased toward newish cars. Someone with a Datsun 1200, which came with 12" wheels, is going to see the video title and just turn the page. The over-riding issue is tire availability. Start with a car using 15" OEM tires. Is going smaller a good idea? Given that 14" tires are almost extinct, do you go to 13"? Then it's back to availability - if there's no suitable tires in the size being considered, it doesn't matter if the wheel is lighter or cheaper.
Oh and then there's whether the smaller wheel will clear the brake calipers. There is no one go-to answer (other than for a specific case - as the video is for). I avoided the issue somewhat with Midlana, giving builders recommend tire diameters. This leaves them more freedom in choosing wheels and tires. As long as the OD is somewhat close, they're good to go. I realize this video is about a specific car, so feel free to ignore my diatribe.
I decided to move up to 18s on the E36 M3 (I love talking about my car here, it always sounds like I'm swearing) because of one thing and one thing only: tire selection. I don't really like large wheels and I'm not happy about the extra size or weight, and I don't like the look, but at least they aren't 19s or something.
Just looking at numbers alone, Tire Rack shows 109 different tires in 225/40R18, but 43 tires in 225/45R17. That's more than twice as many options. Or, in a size I might more realistically use on the front, 245/40R18, there are 118 different tires available, vs 61 in 245/45R17.
It sucks but there it is. Those of us running 15s have even less selection. I feel really lucky when I get to choose between two or three different brands and compounds in the size I want.
It's not a GRM sort of car but my '61 Pontiac has 14" wheels, it was a thing for a while on many full size cars in the late 50s / early 60s. The correct size tire just isn't available anymore on the general market, the only choice is to get expensive reproductions from Coker.
I did exactly this with my mazdaspeed3. I went from a 215/45/18 on an 18x7 down to a 17x9. with a little offset shenaniganizing, I was able to get a 245/40/17 under it, and I *think* I could have gotten a 255 under it. I sold the wheels since then, but I remember the size, and it's actually a really common subaru offset so they'll be easy to replace.
stuart in mn said:It's not a GRM sort of car but my '61 Pontiac has 14" wheels, it was a thing for a while on many full size cars in the late 50s / early 60s. The correct size tire just isn't available anymore on the general market, the only choice is to get expensive reproductions from Coker.
Or go with the same overall diameter in a more available size, such as 15 or 16".
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