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Old 09-03-2012, 08:34 AM   #1
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Default Wheel sizing question

I've noticed that you guys over here will go nuts over the 6UL's but they only come in 15"diameter, and many here run 15" wheels regardless of make/type . Is there some specific reason why you prefer 15's over 16-17's? Because I don't think the weight difference would be that great. And running with a lower sidewall would give a more predictable handling.

Anyone want to inform me about the reasoning?
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Old 09-03-2012, 09:52 AM   #2
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Reasoning:
This fine video might shed some light on things.
Pretend Ernie has 16" wheels. You'll need Billy to also have 16" wheels, or you won't be cool.
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Old 09-03-2012, 09:55 AM   #3
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Or you could look at it like "you don't have to pee your pants, but if you don't, don't expect a high five from Ernie." I say, "screw Ernie and his wet pants...I'm rockin 16's!"
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Old 09-04-2012, 12:47 AM   #4
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It's about performance tire choice in appropriate overall diameter. 205/50 is an appropriate size for maitas, there's a goodly selection of tires in that range, and 15x8s are the size of choice for getting the most out of 205/50 tires (15x7.5 for some autox guys limited by class rules on wheel size).

There are several UHP street tires in the 225/45 size, which is again size appropriate for miatas, and those work pretty well on 15x8 but work best on 15x9.

And,there are several R compound tires that fit those size wheels.

Bonus is the 15" tires are significantly less expensive than their larger brethren.
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Old 09-04-2012, 01:09 AM   #5
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Quote:
Originally Posted by G3ML1NGZ View Post
..And running with a lower sidewall would give a more predictable handling.
Please explain your reasoning for this claim. Also please share your direct personal experience testing 15's and 16's under controlled conditions.


Besides 15's just being faster, there are vastly greater choices in performance street and race tires in the preferred 15" sizes. So it costs less too.
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Old 09-04-2012, 01:50 AM   #6
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Having the mass of the wheel further from the center creates greater rotational inertia and requires more energy to start and stop. The rotational mass in a vehicle is more critical to acceleration and deceleration than the static mass by severalfold.

Aside from being slower, why should we look at 16's again? Better tire choices? Nope. Cheaper tires or wheels? Nope. Give me a reason to hang my hat on and we'll talk.
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Old 09-04-2012, 03:16 AM   #7
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Quote:
Originally Posted by emilio700 View Post
Please explain your reasoning for this claim. Also please share your direct personal experience testing 15's and 16's under controlled conditions.


Besides 15's just being faster, there are vastly greater choices in performance street and race tires in the preferred 15" sizes. So it costs less too.
It was a poorly worded sentence. "Wouldn't a smaller sidewall help with handling?" The reasoning I always heard was that the sidewall would flex less. It would give you a harsher ride but it would grip better.

I'm not claiming to be an expert, just came here asking questions and looking for reasons. Not trying to start a flame war.
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Old 09-04-2012, 03:30 AM   #8
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Where the hell are you all shopping? There are 3 choices for a street 15 if you want/need more meat than a 205, and they are all a little bit extreme for a true DAILY driver.

There are quite a few more 16's and they are cheaper.

I'd love to run 15's on my GTI but between Hankook, Toyo, and Nitto I'd be paying hella bucks for a tire that would wear out every year, maybe 2 a year, and I'd have to compete with racers when I needed them. All on a car that will only see an occasional HPDE.

And if any of those companies decides to stop supplying a relatively low volume niche size...

The 16" market has nicer selection for a non-racer.

One thing I think we can agree on, the tire market for old/small wheel cars SUCKS.
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Old 09-04-2012, 04:01 AM   #9
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Quote:
Originally Posted by G3ML1NGZ View Post
It was a poorly worded sentence. "Wouldn't a smaller sidewall help with handling?" The reasoning I always heard was that the sidewall would flex less. It would give you a harsher ride but it would grip better.

I'm not claiming to be an expert, just came here asking questions and looking for reasons. Not trying to start a flame war.
To make best use of a shorter, less flexible sidewall, you need more precise camber control than most production cars offer, including the Miata.

Switching your first post from a statement to a question switches us all from debating/flaming to informing. MT.net is not a place for haphazard post construction if your are thin skinned. Now you know.

So no, 16's don't inherently work better than 15's on a Miata with the tires that are available.
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Old 09-04-2012, 04:08 AM   #10
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In for the 225/30r16 tires.. err wait.
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Old 09-04-2012, 09:07 AM   #11
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Quote:
Originally Posted by thirdgen View Post
Reasoning:
This fine video might shed some light on things.
Pretend Ernie has 16" wheels. You'll need Billy to also have 16" wheels, or you won't be cool.
[YT]dUpaHawFLUk[YT]
Not sure if trolling....or.....
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Old 09-04-2012, 09:09 AM   #12
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Lol!
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Old 09-04-2012, 10:23 AM   #13
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Some sidewall flex is beneficial in allowing the contact patch to better follow surface irregularities and maintain adhesion.
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Old 09-19-2012, 09:03 PM   #14
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Depending on if you have a NA or NB, IMO I run 15's on my NA. Nothing aggressive, just a 15 x 7.5 +25 offset on 205/50/15 Falkens. Good all round daily tire. 16's would look good on a NB since the body looks a little fuller.
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Old 08-31-2013, 02:02 AM   #15
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Tyre size is depend on your car, You should change tyre of your car according to mechanical specification.
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Old 08-31-2013, 02:45 AM   #16
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Oh really? What about dorifto spec?
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