[Wulfspade]

Hi Everyone,

I was considering getting a set of wheels for autocross and maybe a few track days a year. I have seen a bit of a mix between 15x7 / 16x8 and 16x7 and 17x8 wheels used here on the forums. Typically I would want the smallest wheels that can clear my brakes due to weight, in that case I would lead towards the 15’’ 16’’ setup. I see a lot of companies offering more 16/17 setups as opposed to 15/16, are they more concerned about sidewall flex rather than weight, or is it more based off of aesthetics?

I was planning on putting on a set of Regamasters, as I already have a full set of 15x7 wheels. Ideally I can just order a two 16s and be ready to roll, as opposed to buying a full set for the 16/17 setup and selling my current set.

I have also seen some people using a 15/17 setup, but that seems to be mostly for tire sizing?

 

[jds62f]

I know autocross has rules so I'd probably start with any limitations there if they apply to you. If they don't your next best bet is to consider what tires you want to run. Generally speaking 15 or 17 will give you the widest range of possible tires, but it depends on what you want to run. Some people even run 15" wheels front and rear. Color me skeptical on how much of a difference smaller wheels make in lap times unless you consider yourself a top shelf driver.

 

[MarkR171]

With any autocross rule set, 15/16 and 16/17 will be legal - width for AS/SS will be the only limitation (has to be OEM width).

Otherwise, you're good to go. If you have 15s, go ahead and grab the 16s to match. You'll be fine. Personally, my car has 16x7 in front and 16x8 in the back.

 

[waLIEN]

I've always loved the Regamasters. In terms of weight, I'd imagine they weight quite a bit more than the LSS wheels?

 

[Wulfspade]

I've always loved the Regamasters. In terms of weight, I'd imagine they weight quite a bit more than the LSS wheels?

if you get real Regamasters they are fully forged and are actually a bit lighter than the LSS wheels. if you get knock offs like the rota slips you are going to be taking a weight penalty.

Values for the weights were taken from IBC motorsport which should be accurate

.

 

[elise/europa]

I am using 15 front and 17 rear. And since my car is wide body, I am using 225 front and 275 rear. Big choice on 15 and 17. In the past, I tried 16 rear, it was tight with the parking brake cable and lower wishbone.

Look wise, it look great too.

On the picture, it is 225/45-15 fr, and 255/40-17 R1R tires.

 

[Node]

You have quite a bit more tire selection in 15" than 16" since the 15 is a common spec racing size.

FWIW I run 15" on my MRS. The two reasons are tire selection and weight. Clearly cost is no object and if I could have purchased carbon fiber wheels I would have. But, alas 15" seems to have a great selection in R comps compared to 16" so that is where I landed. I think a 15F-17R combination is too much of a difference in behavior to be a good match on the S2 chassis. No matter what you will always end up with the tire acting different on the front vs the back.

My main challenge on the Elise for autocross was always trying to get heat in the front tires when I didn't have back to back runs. With 15" you would have quite a lot of selection and could maybe get something that will work when a little cooler.

 

[atmh]

You're not the first to consider this setup, and as far as I know you're correct: The best performing wheel+tire combo will always be using the smallest possible rim diameter, with all else being equal. That's why Formula 1 for many years ran 13" rims and only recently switch to 18" I believe. As far as I understand it the drivers hated the new wheel/rim combo, which was a change only made for aesthetic reasons due to pressure from the tire industry. (I'm not a reliable source here, so feel free to tell me I'm wrong).

With that said, the searching I did in the past proved that all else is not equal: it can be difficult to find matching wheels in both sizes (but it sounds like you might have that covered) and the tire selection will be different: Perhaps better, perhaps not, just different. FWIW: Konig Heliums are a good choice for the front, but don't exist in the correct size for the rear.

If I had the same selection for wheels and tires, I would always run the smaller diameter wheel.

 

[Catsailr27]

I usually run 15/17 but 15/16 at track and also have LSS with DWS-06. Turbo Phil ran 15/15 for track

 

[thenumberoned]

The 15/15 is probably the best for tire options for the track, but something just looks wrong...

Form over function I guess!

 

[elise/europa]

As per I know, Turbo Phil use a widebody, and maybe the rear wheels are installed more outward. I suppose that 15 rear wheels are really tight with the lower wishbone.

For track car, like mine, it is welcome to use a different design of rear upright like those sold at Eliseparts.com, and custom like mine. I have a bearing offset of 15mm, and bump steer adjustment. I am pretty certain that 15 wheels are too small for those improvement.

About the tire construction, and here I dont really know, but small tire are probably more design oriented for light car, and bigger tire for heavier car. Here I am talking about the sidewall construction. Since the Elige are a lot lighter in the front, tire for ligther car are welcome in the front I guess. Anyway, my car react really well with R7 track and R1R street tire with the 15/17 combo. Still hard to heat the front tire, the pressure needs to be low.

About the 13 wheels on Formula 1, it was mandatory, and maybe not because it was better. And now about the new bigger wheel, with the new areo regulation of last year, it was many issues about the vibration at high speed, and not caused by the wheels size. But I dont know the reality of it.

 

[ScottH83]

I use Volk TE37 Sonics, 16x8 and 15x7.
I actually like the look better with the smaller wheels.

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