Wheels, wheels, and more wheels

[ScotMac]

Now 'fess up... I'll bet you wish you'd had that conversation with Jeff before you bought tires, eh?

IMO when it comes to Hoosiers at least, you can plus or minus and wishful think until the cows come home... a 225/50 works best on something a lot wider than a 6" wheel, lip size be damned. For that matter, my money says the same applies to a 205/50. In other words, I'm betting the 205/50 Hoosier will perform better and last longer on a 7 inch rim, all else being equal. I hate to even bring up the category here in IT-land, but I have a hunch (having done zero research on the subject) that it's no accident the Spec Miata bunch is running that very combination... 205/50 on 7 inch wheels.
[/b]

I think the analysis that i just did is correct. ie, that ~8" is optimal for the 225, and that 1" around it is "pretty good" (7" to 9"), and race usable.

I haven't done the same calc's for the 205/50, but my guess is that 7" is probably optimal for it, and that 6" - 8" is probably a good range.

And yes, knowing that Hoosier's "recommended size" isn't even THEIR recommended size (website is basically BS), is useful. I gave him some crap about it, and he took it pretty well, and said that they were thinking about putting YET ANOTHER SIZE on that spec chart for the REAL recommended size. That is obviously not the answer, just makes it even more complex. Since they already made an allowance for the standards organizations by making the "measured size" the DOT standard size, the should thus make the "recommended size" THEIR RECOMMENDED SIZE!!

However, i still don't necessarily think that 205 are better than 225's, on 6" rims. I think it depends on the car, and the track. They are probably pretty close, which is shown by the fact that it appears there is good number of people running each of them, and some running both together.

[lateapex911]

However, i still don't necessarily think that 205 are better than 225's, on 6" rims. I think it depends on the car, and the track. They are probably pretty close, which is shown by the fact that it appears there is good number of people running each of them, and some running both together. [/b]

Maybe, but you clearly have to admit that changing ITB to 7" rims could result in performance increases, due to some folks running 225s on a more optimal rim, correct?
And that there are cars that are rim limited, and that some cars will acheive better results, either fr one lap or 20 while others will not, or can't....

Which is NOT what you purported way back when you said any differences in performance between a 6" and a 7" were insignificant...

[ScotMac]

Maybe, but you clearly have to admit that changing ITB to 7" rims could result in performance increases, due to some folks running 225s on a more optimal rim, correct?
[/b]

We knew all along that 7" was more optimal and thus a performance increase: ~5 deg more optimal from my calculations. The only question was/is how much of a performance increase, which we still don't know. As i have said from the beginning it is a tradeoff: the greater supply of suitable wheels at more reasonable prices for B and C drivers vs. the impact from the improved sidewall angle.

All we have determined is that both 6" and 7" are further from optimal than we thought, the relative distance to each other hasn't changed. The "sidewall performance curve" is likely to be close to linear in the beginning, and more and more exponential as we get further from optimal. So, the question is, are we still in the "close to linear" area or the "exponential" area?

[Andy Bettencourt]

We knew all along that 7" was more optimal and thus a performance increase: ~5 deg more optimal from my calculations. The only question was/is how much of a performance increase, which we still don't know. As i have said from the beginning it is a tradeoff: the greater supply of suitable wheels at more reasonable prices for B and C drivers vs. the impact from the improved sidewall angle.

All we have determined is that both 6" and 7" are further from optimal than we thought, the relative distance to each other hasn't changed. The "sidewall performance curve" is likely to be close to linear in the beginning, and more and more exponential as we get further from optimal. So, the question is, are we still in the "close to linear" area or the "exponential" area? [/b]

Scott,

Here is the point: There IS a real and perceived advantage to a 7" allowance over a 6". Therefore the NEED, both actual and perceived, will be instantly created by a change. It then costs EVERYONE money.

I will say this: I don't think the need is there to make a change - YET. When all available wheels dry up, then a move is warranted. Under 10# wheels are $300+ each for everyone, 7" or 6". Stock up when you can on the most affordable option.

[ScotMac]

Scott,

Here is the point: There IS a real and perceived advantage to a 7" allowance over a 6". Therefore the NEED, both actual and perceived, will be instantly created by a change. It then costs EVERYONE money.

I will say this: I don't think the need is there to make a change - YET. When all available wheels dry up, then a move is warranted. Under 10# wheels are $300+ each for everyone, 7" or 6". Stock up when you can on the most affordable option.
[/b]

No, under 10lb wheels for $300 are NON-EXISTENT in 6". They are $400+.

This rule (6") is an historical aberration that is only good for protecting the current racers stock of wheels, and hurts all new purchases and new racers. It will have to be changed eventually, and that hit (existing racer's stock of rims) will be same WHENEVER it is changed. So, the sooner the change, the sooner the new purchases can take advantage of the greater supply and cheaper wheels.

[Andy Bettencourt]

So, the sooner the change, the sooner the new purchases can take advantage of the greater supply and cheaper wheels. [/b]

...and the sooner the whole class has to buy new 7" wheels to remain competitive - in reality or perception.

How many people do you see on grid with 9# wheels - regardless of class and availability? It's less than 5% around here.

[ScotMac]

...and the sooner the whole class has to buy new 7" wheels to remain competitive - in reality or perception.
[/b]

Whether sooner or later, that will happen. It is constant. However, the sooner the rule is changed, the sooner people will be able to take advantage of the cheaper and more abundant supply. That amount of people will be greater if the rule is changed sooner...it is time dependent, not constant.

How many people do you see on grid with 9# wheels - regardless of class and availability? It's less than 5% around here.
[/b]

You just made up that number! I'll look around and let you know. But, in general, i believe their are MANY in the 10-13lb range. However, 6" wheels are almost non-existent in that range *also*, not just the 8-10lb range (take a look back at my study in the "Oct fasttrack" thread). 10-13lb are comparably abundant in 7".

[Dave Ebersole]

No, under 10lb wheels for $300 are NON-EXISTENT in 6". They are $400+.

This rule (6") is an historical aberration that is only good for protecting the current racers stock of wheels, and hurts all new purchases and new racers. It will have to be changed eventually, and that hit (existing racer's stock of rims) will be same WHENEVER it is changed. So, the sooner the change, the sooner the new purchases can take advantage of the greater supply and cheaper wheels.
[/b]

I've NEVER had a problem purchasing 6X13 Panasports for my car and none of the guys I race with have ever complained about having trouble purchasing wheels, the Volvo guys, the other BMW guys, the VW guys, so I don't see how the 6" rule hurts US a bit.

[ScotMac]

I've NEVER had a problem purchasing 6X13 Panasports for my car and none of the guys I race with have ever complained about having trouble purchasing wheels, the Volvo guys, the other BMW guys, the VW guys, so I don't see how the 6" rule hurts US a bit.
[/b]

Yes, panasports and spinwerkes are almost the only supply of suitable 6" wheels below $400+ custom kodiaks. And panasports is a partial supply, since they don't support 5 lug rims in their custom stuff. And spinwerkes are 11+lbs. One and a half suppliers is an almost non-existent supply.

[ScotMac]

...AND we are back to the problem being a problem for particular bolt patterns, rather than for "everyone who has to run 6" wheels." PhilsTireService.com just found me 3 more Kosei K1TS wheels (about 10.5#) for about $120 each. I'll now have 18.
[/b]

No, the supply issue is for everyone...it is just a bit more pronounced for 5 bolt or 5x100 wheels. Again, look back at my supply study in the "Oct FT" thread.

Also, my supply study said acceptable wheels were "< 15lbs", even though 15lb wheels are ALMOST DOUBLE the weight of the lightest available.

In terms of spinwerkes, i simply pointed out that they were not the ultra-lw (<10lbs) wheels that Andy was talking about.

Lastly, my supply study didn&#39;t have Kosei in it, because of very limited US presence (japanese company that appears to be just breaking into us market). In fact, i didn&#39;t even find a US based web site (they have an UK one, but doesn&#39;t have all the wheels). The only place i have found that carries them is the TireRack (believe they have an exclusive), and Phil&#39;s (philstireservice.com) is just getting them from TireRack. They quote a 14x6, 38mm offset, 9.3lbs and only a 4x100 bolt pattern at $119. That is a very good deal, and exactly the type of deal of we would have more than one of, w/ more than one bolt pattern, in the 7" width.