Wheel Sizes for Future Classes

[Ron Earp]

I've just a general question on wheels sizes for classes, how is it determined? take the average stock wheel size for cars in class? Use the largest stock wheel for cars in class? Smallest? Base the size on tires available?

Reason I ask is in putting together a list of cars for a ITU (or R) class it is painfully apparent that cars over the last 10 years, and in some cases even older, flat out have large wheels and tires in comparison to accepted IT wheel diameters for C through S.

I find that sixteen inch wheel sizes is pretty much the bare minimum for these cars, with seventeen inch being fairly common. I've not investigated race tire availability for these wheels yet but will take a look.

Any comments or suggestions?

Ron

[Matt Rowe]

Ron,

Maybe I'm just misreading the intent of the title, but I think you may be mis-stating the problem. It's not that 15" wheels are hard to get, at least not at this time. It's that a car made for 17" wheels may not be able to fit 15" wheels over the stock brakes. That's the area on wheel sizes I would focus on in putting together a list of IT(U/R/Q/Alpha) cars. You might also take into account common wheel widths in those sizes and looking into race tire availability is a good thought, although somewhat hard to predict what the future may hold.

[dickita15]

Ron,
why are you specing a wheel size. up untill last year IT ran the stock diameter. (well except for 12" coulds use 13") the up to 15" was a responce to a percieved shortage of 13s and 14s.

just stick with the stock diameter

[Ron Earp]

Originally posted by dickita15@Dec 30 2005, 04:19 PM
Ron,
why are you specing a wheel size. up untill last year IT ran the stock diameter. (well except for 12" coulds use 13") the up to 15" was a responce to a percieved shortage of 13s and 14s.

just stick with the stock diameter

69612


Both of you are correct in what you say - the 15" is hard to get was in response to the fact that it is hard to get a car with small wheels. Sorry if that is confusing.

As for specing a wheel size I was under the impression a class had to have a tire/wheel size that everyone could use if the wanted to in order to "level" the playing field. Remember, I started last year, so for me, a speced wheel size was normal.

It might be sort of necessary for a ITU class too - some of the cars can be had with some really large wheels. Some BMWs had performance packages and optional wheels sizes from the factory that were 1" larger than stock in most cases. I assume these are allowed?

Let me re-phrase the question and title of the post:

*Does an IT class need to have a specified maximum wheel size? Does this help level the field somewhat? If we do need a maximum, what would be a good size for ITU?

So far I've not run across any cars as cadidates that have 18" stock, but lots of 16" and 17" wheels for certain.

Ron

[Andy Bettencourt]

Ron,

Factory diameter is what you want, the maximum width is what the question should be. I would say 8" or 9"...would make sense to have it be in line with the other classes...

AB

[Bill Miller]

Ron,

I agree w/ Andy, either stock, or possibly a max. of 17".

Andy,

I would think 8" would be plenty. Of the cars that have been floated for ITR, how many came w/ tires larger than 8" wide?

[Knestis]

Philosophically, I have difficulty with the idea that any car should be listed with a wheel smaller than the smallest one that it came with, in terms of either diameter or width. It just doesn't seem OK that someone would be illegal running the stock wheels. Note here that I'm not talking about any optional larger wheel that might have been available (a la the Ford Focus, that is listed in IT on 15's, even though many came with 16's.

K

[Hotshoe]

Originally posted by Bill Miller@Dec 30 2005, 10:23 PM

I would think 8" would be plenty. Of the cars that have been floated for ITR, how many came w/ tires larger than 8" wide?

69625



Bill & Andy,

..... I agree on the 8" wide wheels. I work on a lot of higher end sports cars and they have 8' or wider rims. And the sizes range from 16" to 18". I hardly see any 15" wheels anymore.


... Rick

[Ron Earp]

Originally posted by Hotshoe@Dec 30 2005, 06:37 PM
Bill & Andy,

..... I agree on the 8" wide wheels. I work on a lot of higher end sports cars and they have 8' or wider rims. And the sizes range from 16" to 18". I hardly see any 15" wheels anymore.
... Rick

69627


I'm trying to collect data on this, and I *think* 8" would cover it but it might not - there might be a couple on the list that have slightly wider widths.

I agree with you Kirk on the stock wheels sizes, but, what if one car fits into the class and has huge wheels/width, should the others be allowed to use that size or no?

Ron

[dickita15]

ok stock diameter, 8" max width.
next item :rolleyes:

[gran racing]

What wheel size is the easy one to obtain? I have 13" wheels and they are hard to find. I hear the 14" wheel size guy whine. Now 15" wheel? No seriously, what is the easy to find rim size? O.k. I'm only "semi-seriously" here.

[joeg]

Unfortunately, wheel sizes only seem to keep growing, so I would guess pretty much everything 17 inches and under will become obsolete sometime in the future.

Heck, are there any 12" or even 13" OEM wheel new vehicles any more?

[Joe Harlan]

Originally posted by joeg@Dec 31 2005, 08:24 AM
Unfortunately, wheel sizes only seem to keep growing, so I would guess pretty much everything 17 inches and under will become obsolete sometime in the future.

Heck, are there any 12" or even 13" OEM wheel new vehicles any more?

69668



So the thought that this class would be a place for touring cars has left the building I guess. The 350z has 18x10 wheels allowed this year. You gonna make them throw away 400 buck a piece wheels to run your new IT class?

[Bill Miller]

Originally posted by Knestis@Dec 30 2005, 04:32 PM
Philosophically, I have difficulty with the idea that any car should be listed with a wheel smaller than the smallest one that it came with, in terms of either diameter or width. It just doesn't seem OK that someone would be illegal running the stock wheels. Note here that I'm not talking about any optional larger wheel that might have been available (a la the Ford Focus, that is listed in IT on 15's, even though many came with 16's.

K

69626


Which brings us back to the New Bettle in ITC.

As far as 15" wheels ever being hard to find, I seriously doubt it. That's pretty mucb ALL the roundy-round folks use.

[Ron Earp]

Originally posted by Joe Harlan@Jan 1 2006, 01:40 AM
So the thought that this class would be a place for touring cars has left the building I guess. The 350z has 18x10 wheels allowed this year. You gonna make them throw away 400 buck a piece wheels to run your new IT class?

69732


Joe, the class is for much more than just Touring cars. You seized on that statement and it seems to have stuck with you, however, as of this writing touring cars are making up only four or five of the thirty some odd cars that could be included. Anyhow, I'm off topic.

Those are some large wheels (compared to IT) on a 350z, that is for sure! I'm not sure the 350z will even fit into the ITU classification, but thanks for the heads up on them.

As far as wheel sizes, I think I understand. Just simply allow whatever was stock on the cars and move on from there. If something needs to be done to equalize things, like allow all the cars the same size, then it can be done later and itsn't worth worrying about right now for a class that isn't even born.

Best,
Ron

[gran racing]

Ron, also keep in mind the effective gearing changes that occur when moving from one wheel size to another. While it would be much easier and probably cheaper for me now to use 14" rims or larger, it works better for my car to run 13" rims. I realize this also assumes that the same tire dimensions are avail. for each wheel.

[Ron Earp]

Originally posted by gran racing@Jan 1 2006, 11:22 AM
Ron, also keep in mind the effective gearing changes that occur when moving from one wheel size to another. While it would be much easier and probably cheaper for me now to use 14" rims or larger, it works better for my car to run 13" rims. I realize this also assumes that the same tire dimensions are avail. for each wheel.

69753


Very true there! My Jensen, which unfortunately I've not run yet, has 13" wheels stock. But, if I went to 15" wheels the road speeds in gears would really go to crap. I'd have to run a really short rear end gear to recover, which is not available for the rear end.

[RacerBill]

Originally posted by rlearp@Jan 1 2006, 11:33 AM
Very true there! My Jensen, which unfortunately I've not run yet, has 13" wheels stock. But, if I went to 15" wheels the road speeds in gears would really go to crap. I'd have to run a really short rear end gear to recover, which is not available for the rear end.

69754


I agree with Ron, that the wheel issue needs to be looked at in the near future, with long term effects in mind. My 944 has stock 8" rims in the rear (so, right now, I can't run stock size wheels). Take a look at recent adds in Sports Car for performance tires. Some of the latest performance tires (not necessarily for racing but indicative of what is being mounted on these cars) don't even come in 15" size.

I know, here we go with the whole 'rules creep' issue, but that is another thread!

[ITANorm]

Hey - at least you have the choice. I would LOVE to run 13's, but can't - because my car came with 14's.