DOT/Competition Tires for 2012

[Pinarello Rider]

I can't find any of those tires, DOT/competition, or the autox tires listed on Grassroots in a size that will fit on 16's or 17's for the Fofo. 215/55/R16, or 215/50/R17 comes up empty for everything.

[thenorm]

Originally Posted by rangerbay

I don't know about way more 15 than 16. Forged 16 wheels are lighter than cast 15. The shorter tire is like a lower gear. You do need to wind the car out on the straights, tuck it in for the curves, and with the electronic management on the newer cars, the rotational speed of the smaller outside tire may interfere with the traction control. 16 also have a greater contact patch than a 15, giving more grip and braking. 225/50 seems like a lot of sidewall to me for a track tire.. More sidewall, more squirm. Less sidewall, stiffer.

Again, opinions are like tailholes, everybody has one. I have a Porsche 944 S2 that I do track, and use 16 instead of 18 due to price. If they were the same price, I'd go with the 18. No way would I step down to 15's.

and forged 15s are lighter than forged 16s. shorter tires of any wheel size will indeed lower gearing, hence why most small wheel fitments have larger sidewalls. I agree, that in general more sidewall = more squirm, but most competition tires have stiffer sidewalls to compensate.

also, i call BS on 16 vs 15" contact patch. that has nothing to do with the wheel diameter and everything to do with tire width.

to the OP, why get only 215 wide, when 225 will fit and sitll be a close diamter to stock
you can get:
225/50R16
225/45R17
225/50R15 (this one is shorter, but it's still doable)

[rangerbay]

Originally Posted by thenorm

and forged 15s are lighter than forged 16s. shorter tires of any wheel size will indeed lower gearing, hence why most small wheel fitments have larger sidewalls. I agree, that in general more sidewall = more squirm, but most competition tires have stiffer sidewalls to compensate.

also, i call BS on 16 vs 15" contact patch. that has nothing to do with the wheel diameter and everything to do with tire width.

to the OP, why get only 215 wide, when 225 will fit and sitll be a close diamter to stock
you can get:
225/50R16
225/45R17
225/50R15 (this one is shorter, but it's still doable)

Explain to me why in the world you would want a 15 wheel on a track car. The focus st-r has 18's. How many cars at the track do you see with 15's?

[thenorm]

larger diamter wheels are exlusively to clear brakes.

it a car at the track had brakes small enough to run 15s (and still have enough cooling to the rotors), they would. Nascar wheels are all 15", most rally cars run 15". F1 car wheels are ~11"

15" wheels and tires have much lower rotational inertia (which affects accelration and braking, like a flywheel). this benefit, plus lower mass outright, out weighs any sidewall squirm issues.

the ONLY other reason to go to a larger diameter wheel is tire choice. for example. in 15" there is no choice in tire width between 225 and 275, so if you want 235, 245, 255, or 265 wide, you must go to a different wheel size (17" being a convenient size to find all of those).

[wrc_fan]

Originally Posted by rangerbay

Explain to me why in the world you would want a 15 wheel on a track car. The focus st-r has 18's. How many cars at the track do you see with 15's?

My car

Any Miata that's not on 13s
Civics and CRXs
Porsche 914s :P
GC subbies
VW golfs and rabbets
Neons
E30s... not sure on that


Leave the big wheels to the d-bags with E92s, 5th gen ocean liners, any water cooled 911, and vettes and their gold chained wearing owners.

To many stereotypes?

[Geezer]

WRC, I take offense with your statements, I want you to know I'm rolling monstrous 14" tires with porky 11 lbs "stock" wheels on my Miata and love the "LOOK" (smiley here). If I wasn't such a cheapo, I have some 8.5 lb 14" BBS's on it.

[Geezer]

Here are some tire and wheel specs from, arguably, the two most popular racing entities in the world. Draw your own conclusions:

NASCAR

Wheel size: 15x8 (steel wheels)
Tire size: 28x12x15" (Height, width, wheel diameter) Tire size may vary slightly from track to track as does wheel offset.

Formula1

Wheel size: 13" x 12" (F) 13" x 13.7" (R)

Tire size:
Width: 305-355mm (F) 365-380mm (R),
Height: 660mm (25.98") dry tire, 670mm (26.3") wet tire

Note: If you did the math, in both cases the aspect ratio ends up being over 50% (both race series have visibly very tall tire sidewalls). This kind of dispels the myth that taller sidewalls all always more flexible. I've never seen a tire being peeled off a rim as a result of heavy G loads in either of these race series (and both have some pretty high sustained loads). Tire construction, specifically side wall strength, can be built into the tire regardless of it's profile as proven in these race series. A low profile tire does not guarantee a stiffer sidewall just as a taller profile does not guarantee a softer more flexy sidewall. The tire companies that build race tires are not dummies and clearly know the importance of sidewall strength and stability regardless of the profile chosen.

[wrc_fan]

Originally Posted by Geezer

WRC, I take offense with your statements, I want you to know I'm rolling monstrous 14" tires with porky 11 lbs "stock" wheels on my Miata and love the "LOOK" (smiley here). If I wasn't such a cheapo, I have some 8.5 lb 14" BBS's on it.

hahahahaha, forgot about 14" miata guys... not common in autox due to the 255/13 hoosier, but yeah, plenty of track guys running 14s

[Geezer]

The stock class guys are pretty much stuck with wheels the same size as stockers (14x6 and 15X6 for 1st or 2nd gen Miata). Fortunately the stock wheels on a Miata are pretty light compared to other cars. Seems like the most popular tire size is 205/55-14 but some will squeeze a 225/50-14 (Hoosier A6) on them (and yes, both have very stiff sidewalls). More and more people are using the 15's because of the much larger tire selection (and sometimes lower tire prices) and accepting the increased weight. But yep, once in street prepared the guys are cramming huge tires (aka wide) on equally wide but smaller diameter rims. I like to call them cartoon tires as they look like something you'd see drawn in a caricature or the comics.

[rangerbay]

Originally Posted by Geezer

The stock class guys are pretty much stuck with wheels the same size as stockers (14x6 and 15X6 for 1st or 2nd gen Miata). Fortunately the stock wheels on a Miata are pretty light compared to other cars. Seems like the most popular tire size is 205/55-14 but some will squeeze a 225/50-14 (Hoosier A6) on them (and yes, both have very stiff sidewalls). More and more people are using the 15's because of the much larger tire selection (and sometimes lower tire prices) and accepting the increased weight. But yep, once in street prepared the guys are cramming huge tires (aka wide) on equally wide but smaller diameter rims. I like to call them cartoon tires as they look like something you'd see drawn in a caricature or the comics.

Ive got a question for you. What is the contact area for a 16" vs a 15" of the same width and aspect ratio? Do you think its actually the same?