Wheel diameter rule change Poll

[eh_tony!!!]

Even though I can use 13's or 14's, I still use the 13's for the gearing effects.

However, I do think this is a change who's time has come.

********* One question .. I assume the only proposal on the table is wheel DIAMETER.. I saw some notes about allowing 14x7's and 13x7's (Jake), and 7.5's later...

Any change in width is something that I could NOT support.

[924Guy]

And 924's (ITA) came with 16's... :b

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Vaughan Scott
Detroit Region #280052
'79 924 #77 ITA/GTS1
www.vaughanscott.com

[Joe Harlan]

Eh-Tony,

I mentioned the .5 sizes because a lot of aftermarket wheel makers are only going up in .5 sizes. The problem with getting all fixated on wheel widths is the tires available are what dictate the wheel width along with the fender restriction... fixed rim width was fine when everybody was able to get 60 series tires but it looks like tire makers are trending away from them 50's 55's 45's all require different stuff.

[tderonne]

Couple quick thoughts.
On diameter. What next? 14x7 and big tires barely fit on a CRX, are they going to be asking for flared fenders next? Just one thought that pops to mind.

On width. I'm still waiting for the ITB Mustang crowd to ask for the wheels that the car came with, 15x7. Allow only the OEM 15x7 and any aftermarket 15x6 if you like. There are so many other references in the GCR to stuff that isn't allowed unless it came that way, why not 7" wide wheels, or whatever width wheels for cars that came with them? (Actually we discussed this once before in a different thread, I don't think there were any cars that it would apply to except the Mustang, at least in cars that are currently classed in IT.)

[This message has been edited by tderonne (edited July 18, 2003).]

[ITA_CRX]

I don't see a need for allowing larger diameter wheels.

You don't have to run a 7 inch rim.

Running the larger diameter rim may help handling on the cars with smaller rims. (Hey, my CRX could be faster, why don't I want this?)

As far as final drive, I don't think the overall dimensions of the tire are that much different to alter the gearing any significant amount. From Hoosier's website, 14s have a 23 inch diameter and 15s are 23 or 24 inches. 16s and 17s are 26.6 inches in diameter.

Jamie

[Banzai240]

Originally posted by ITA_CRX:
From Hoosier's website, 14s have a 23 inch diameter and 15s are 23 or 24 inches. 16s and 17s are 26.6 inches in diameter.

Jamie,
You might want to look at those dimensions again... Perhaps also look at what Kuhmo is offering...

The 225-50ZR16 BFGs on my car are 25" in diameter, and a 245-40ZR17 is 24.5".

The whole purpose of going to larger diameter WHEELS, is to shorten the sidewall WITHOUT altering the overall diameter of the tire... Moving from 15" wheels to 16" wheels or even from 13" to 15" should have NO or little effect on gear ratios if the proper tire is selected...

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Darin E. Jordan
SCCA #273080, OR/NW Regions
Auburn, WA
ITS '97 240SX


<Edited due to FAT Fingers!! >

[This message has been edited by Banzai240 (edited July 18, 2003).]

[Geo]

Originally posted by Banzai240:
The whole purpose of going to larger diameter WHEELS, is to shorten the sidewall WITHOUT altering the overall diameter of the tire...

Actually, in the context of any rule proposal, we want to open up the availability of wheels. I wouldn't push this if 13x7 and 14x7 wheels were readily available like they were when IT was created. But now they are truly a specialty item and priced accordingly. I would argue that is not within the philosophy of IT.


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George Roffe
Houston, TX
84 944 ITS car under construction
92 ITS Sentra SE-R occasionally borrowed
http://www.nissport.com

[Banzai240]

Originally posted by Geo:
Actually, in the context of any rule proposal, we want to open up the availability of wheels.

I know that... I was referring to the technical aspects of increasing the wheel diameters, not the philisophical questions involved with allowing it... One has to consider both, because there WILL be an effective performance change if +1/+2 type allowances are granted... (doesn't mean necessarily POSITIVE performance changes, just changes in general...)



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Darin E. Jordan
SCCA #273080, OR/NW Regions
Auburn, WA
ITS '97 240SX

[Geo]

Originally posted by Banzai240:
I know that...

I know. That was not for your benefit, but the benefit of others who may miss the point.

Originally posted by Banzai240:
I was referring to the technical aspects of increasing the wheel diameters, not the philisophical questions involved with allowing it... One has to consider both, because there WILL be an effective performance change if +1/+2 type allowances are granted... (doesn't mean necessarily POSITIVE performance changes, just changes in general...)

That's all open for argument. I've seen different controlleds tests that yeilded different data. I'm sure it depends a lot on how long the straights are and how sharp the corners are.


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George Roffe
Houston, TX
84 944 ITS car under construction
92 ITS Sentra SE-R occasionally borrowed
http://www.nissport.com

[ITANorm]

Well, FWIW, the precedent exists. All the cars that came with "Ford & Michelin's great failure in marketing" - metric wheels - are allowed to substitute inch wheels. The reasoning behind that is the same as this proposal. It makes sense because of availability.

However - in order to completely validate the availability argument, the proposal would have to be worded such that: "Cars shown with 13" or 14" wheels may substitute 15" wheels of no greater rim width than is currently specified in the ITCS."

Not 13 to 14, or 14 to 13, or 15 to 16. That becomes "performance enhancing" and would not fit under the guise of rising expenses from limited availability of product.

Just my .02, as one who used to be a professional rules guru, on the inside.

[Geo]

Originally posted by ITANorm:
Not 13 to 14, or 14 to 13, or 15 to 16. That becomes "performance enhancing" and would not fit under the guise of rising expenses from limited availability of product.

Again, this is dubious.

Controlled tests yeild inconsistent results. Low profile tires will react a bit faster, but the heavier wheels will slow acceleration.


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George Roffe
Houston, TX
84 944 ITS car under construction
92 ITS Sentra SE-R occasionally borrowed
http://www.nissport.com

[jc836]

Count me in and keep the fingers crossed that we get enough people. I already proposed this to the CB. I genuinely believe that a +1 is not a real competitive advantage if the rest of the equation is kept as you suggest.

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Grandpa's toys-modded suspensions and a few other tweaks
'89 CRX Si-SCCA ITA #99
'99 Prelude=a sweet song
'03 Dodge Dakota Club Cab V8-Patriot Blue gonna tow

[dyoungre]

Is the issue tire availability, wheel availability, or both? If just wheel, then what about requiring the stock wheel be used?
As someone who currently needs to replace a couple of wheels, I would surely support by writing to the CB...Is there an easy way to submit (IE email, or only the old fashion, lick the stamp method?)

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[RFloyd]

Originally posted by Geo:
Again, this is dubious.

Controlled tests yeild inconsistent results. Low profile tires will react a bit faster, but the heavier wheels will slow acceleration.

Why would it matter, anyway? Even if it is for the purposes of changing gearing, allowing the use of any wheel diameter within a maximum width is no more against the "spirit" of low-cost than allowing $1600 custom machined final drives. Sure, alternate F/D sets aren't that expensive for many cars, where they might be available as factory options or borrowed from other models, but in allowing their use in those cars the rules have almost mandated that folks like me pay big $$$ for a custom one for my car since no alternate F/D is available for my car. If I had the option of using any size wheel I want, as long as it's 7" or less wide, how is this any different than changing from a stock F/D to an alternate F/D, as already allowed by the rules. If you don't want this kind of performance enhancing option for fear of escalating costs (I guess you envision a different set of wheels/tires being necessary for each different track you run, to optimise gearing to the nth degree, in order to stay competitive), then we need to outlaw ALL alternate F/D rations and make everyone run the stock ring and pinion. Ooooh weeee, that's be popular.

Admit it, there are VERY FEW RATIONAL ARGUMENTS against allowing open wheel diameter, as long as all other factors stay as they are, when you consider that F/D's are already open making the "violates the spirit of low cost" argument invalid.

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Richard Floyd
'86 Acura Integra LS #90
SCCA ITA / NASA ECHC H5

[This message has been edited by RFloyd (edited July 21, 2003).]

[This message has been edited by RFloyd (edited July 21, 2003).]

[Banzai240]

Originally posted by RFloyd:
Admit it, there is NO RATIONAL ARGUMENT against allowing open wheel diameter, as long as all other factors stay as they are.

Before I respond to this, let me re-itterate that I am very open minded about changing the rules concerning wheel sizes in IT, and wish to "advise" based what the general membership desires to that effect...

NOW, I'm not sure I completely understand where you are coming from on this (addressed to Mr. Floyd) but there is a HECK of a lot more effects to a car when changing wheel diameter, even on an IT car, than just gearing changes... You don't need different wheels to change gearing, just go to a taller tire. Oh, but why wouldn't you want to do that??? For the opposite reason why you WOULD want to go to a lower profile tire... SIDEWALL height...

I don't agree that there isn't a performance improvement, even if some magazine decided to publish a test to show otherwise... But regardless, there are other factors that can be effected as well.

For instance, larger wheels unshroud the brakes a bit, allowing for better air circulation and therefore, better cooling.

One can also run tighter tire-to-strut/spring clearances, since the tires shorter sidewall isn't going to flex as much, which means a wider tire can be fitted.

Spring rate changes should have more effect, because the tire is doing less as a "spring" itself as you go shorter in sidewall height...

I'm sure there are others...

The bottom line is that we have to look at the overall effect of the change and decide if it's a good thing for IT. Ultimately, it should be up to all of you to decide. You just have to be sure to let the ITAC/CB know what your decision is! (which means WRITE YOUR LETTERS! )

I do believe it would be nice to give people options, and also think we need to look carefully at what is READILY AVAILABLE. It does no good to allow a 15x6" wheel when they are just as hard to get as a 13/14" wheel... Likewise, if there is a movement toward allowing 16"+ wheels, if the generally available sizes, or the most popular sizes are 7.5" width rather than 7" or ???, then it cost the competitor less in the long run if we go with what is more popular...

Whatever makes the most sense for IT...



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Darin E. Jordan
SCCA #273080, OR/NW Regions
Auburn, WA
ITS '97 240SX

[RFloyd]

NOW, I'm not sure I completely understand where you are coming from on this (addressed to Mr. Floyd) but there is a HECK of a lot more effects to a car when changing wheel diameter, even on an IT car, than just gearing changes... You don't need different wheels to change gearing, just go to a taller tire. Oh, but why wouldn't you want to do that??? For the opposite reason why you WOULD want to go to a lower profile tire... SIDEWALL height...

I don't agree that there isn't a performance improvement, even if some magazine decided to publish a test to show otherwise... But regardless, there are other factors that can be effected as well.

OK, I should clarify - I agree with you, I believe there is a performance enhancement to be had. And yes, I I know there're more variables affected than just gearing when changing wheel diameter, and that gearing can already be affected just as directly by changing sidewall height. But I would add that there is only a certain range of aspect ratios available in any given tire size, and by allowing a driver to choose alternate wheel diameters only seems to open up the window of available tire fitments.

Yes, larger diameter wheels do have the other benefits you mentioned, albeit all with negative side effects such as extra weight and rotational mass. Methinks there are advantages to be had, but they are small. ON THE OTHER HAND, compare the marginal improvements of larger diameter wheels (don't even think about how much easier it will be to get wheels and how much LESS $$$ will have to be dropped on wheels if 15's and up are allowed instead of having to hunt for 13's and 14's...) to the enormous benefit gained from expensive LEGAL modifications such as the use of $1600 custom machined F/D sets, $1000 + custom valved shock sets, LSD's, blueprinting and balancing, etc., etc., etc.

I know the line has to be drawn somewhere, but to say allowing guys who are forced to run 13" wheels the freedom to upsize to a wheel diameter that can actually be bought for a reasonable price from more than 2 manufacturers in the world is somehow gonna give them some insurmountable performance advantage and it violates the "spirit" of low-cost in IT is laughable at best.

OBTW, I've amended my original statement to a little more accurately convey this sentement...

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Richard Floyd
'86 Acura Integra LS #90
SCCA ITA / NASA ECHC H5

[dyoungre]

I absolutely agree that the cost reduction is much more significant than the performance enhancement potential. Don't forget that going from a 13" with 45 series to 15 inch with the same will change ride height adversely; returning to the minimum ride height will most likely hurt already strained geometry, and may limit suspension travel. Not all is rosy....

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Dave Youngren
NER ITA RX7 #69

[ITA_CRX]

I still don't see any need for this change.

Are 6 inch rims hard to find? You can fit a 225 on a 6 inch rim, the ITC guys do it very effectively. You don't have to run a 7 inch rim. It isn't required under the rules. Do you have any data showing how much faster 7 inch rims are?

Are you talking about only allowing cars with 13s and 14s to use larger sizes? I don't like this idea because you get into different cars having different rules as opposed to one rule for everyone.

Jamie

[Tom Donnelly]

This presents quite a cost issue for me.
What if someone, me for example, has spent years, time and money accumulating several sets of legal sized and very light and competitive wheels for the particular type of car being run? And accumulating and heat cycling several sets of legal tires as well to keep a leg up in tire usage and remain competitive. Only to find, within a short time that the investment was wasted. That the 1 inch difference is about a half to one second difference in lap time and the 3-4 sets of former premium 14" wheels are basically junk. And the only reason that 14" wheels were bought was based upon legality?

Cast off used pro tires are a nice concept but there's a dang good reason the pro teams cast them off too.

This all reminds me of the performance coatings/no performance coatings issue and the RR shocks/no RR shocks issue.

You can have your dang 17" wheels if I can have my dang RR shocks! And don't tell me to go to production, don't they allow bigger rims in production?

George, who do I write to and what's the address/email?

Tom

Banished Wadded Boxers Motorsports

[This message has been edited by Tom Donnelly (edited July 22, 2003).]

[racerdave600]

As someone who is now shopping for 14 x 7's, I can tell you they either have to be custom made, or you have to wait for someone like Panasport to make a run. They are NOT easy to get, and they are expensive. I've checked several sources, granted not all, for others, and was told that Borbet and some others had made them until recently, but not anymore.

I could have 15 x 7s delivered the next day for less than half the cost. I've spent quite a bit of money getting my car to this point, it would be nice if I didn't have to drop another one to two thousand on wheels, and then add in the cost of tires.

Dave