June 2011 Fastrack

[quadzjr]

There are small advantages to be had by running a 15" wheel with lower profile tire over a 14", if your ratio you are lookinng for is available, but more often than not the biggest advantage of 15" wheels is the number of take-offs available. However I have done pretty good with finding new or good take-offs for cheap for 14" on this site.

If the diamter rule goes into affect I would investigate the use of 13" wheels for the MR2. swapping wheels and tires is alot cheaper than a final drive, and can be swapped per the track. 15" wheel for Daytona, 14" for robeling, 13" for CMP. but talk aobut an additional expense. having to have at minimum 3 sets of tires on different wheels for one car for a dry setup, then there are spares...

I am against the width issue, too big of a can of worms, that help some and not others.. If a rule is written IMHO it should affect all (or as close as possible to it) and not for additional performance.

[GTIspirit]

Guys so we are all clear this is not a competition adjustment. This car got a 50 lb deduct for a beam axle it should not have when it was processed and weighted.

This is simply a correction.

The Golf III doesn't have a twist beam rear axle?

[Chip42]

The Golf III doesn't have a twist beam rear axle?

it does. I think that he meant it recieved a weight break for it that it should not have, and that that has been fixed.

[Knestis]

The Golf III doesn't have a twist beam rear axle?

The mythology was that it received a 50# break for "bad rear suspension." We clarified that's silly on a fwd car. Frankly, i think it just got a weight thrown at it when it was listed, since it was the era of the "soft" process.

K

[shwah]

The Golf III doesn't have a twist beam rear axle?

Yep. Just like the Rabbit/Scirocco and Golf/Jetta 2 and others.
No one gets a weight break for it.

[GTIspirit]

Cars may not fit wheel diameters larger than those listed on their spec line. All ITS/ITA/ITB/ITC cars currently listed in the ITCS with a wheel size less than 15 inches would be changed to 15 inches.

Interesting, this rule turned out a bit different than I imagined. It actually opens the door for cars which currently can't run smaller diameter wheels to run them if they fit over the brakes. e.g. None of the Mk2 VW's listed in ITA can currently run 13" rims, under this new rule they could......

This is contrary to the letter I wrote to the CRB where I stated that larger wheels should be allowed because it follows current market trends and offer no performance advantage, to the contrary larger wheels are usually heavier and so would make a performance disadvantage. But allowing smaller wheels than are currently allowed would allow for a performance advantage if someone could say get their hands on a set of 13x7 rims that fit their car and could find appropriate tires.

[tnord]

i don't think running smaller than max allowable diameter wheels is an advantage at all.

[preparedcivic]

i don't think running smaller than max allowable diameter wheels is an advantage at all.

And shorter gearing isn't an advantage sometimes? There seems to be a cottage industry in numerically higher final drives.

[tnord]

And shorter gearing isn't an advantage sometimes?

irrelevant because of the already open allowance for FD ratio in IT.

[erlrich]

irrelevant because of the already open allowance for FD ratio in IT.

Yeah, but there are still a limited number of ratios available for most cars. Having the option to run a shorter tire might give some guys a final ratio they might not otherwise have available. I don't think this will be an advantage to any one car over another, but I do see it giving some cars options they might not otherwise have had.

[GTIspirit]

i don't think running smaller than max allowable diameter wheels is an advantage at all.

Lighter wheels aren't an advantage?

[tnord]

you can (and always could) have a ratio you wanted custom built. all it takes is a check.

lighter&smaller wheels = larger&heavier tires

[preparedcivic]

Yeah, but there are still a limited number of ratios available for most cars. Having the option to run a shorter tire might give some guys a final ratio they might not otherwise have available. I don't think this will be an advantage to any one car over another, but I do see it giving some cars options they might not otherwise have had.

Given the minutia being discussed on motor mount matters apparently, this comes across as a pretty big horse to let out of the barn. A 225/45-13 has in round numbers a circumference, and resulting shorter gearing 10% less than a 225/45-15. It's not the the little wheeled cars going up in size, but the big wheels going down.

[tnord]

letting the big wheeled cars go down is exactly the intent. ie....OEM 19'' being able to run more reasonable sizes.

there are plenty of cars out there that COULD run a 14'' wheel instead of a 15'' wheel if they wanted to today (miata being one, crx another). it doesn't seem to be a problem, but theorize and get lost in the weeds all you want.

initially, it sounds like a bigger deal than it is. we already have open rules regarding FD ratios. we already have minimum ride height rules. listings already exist with multiple sizes as an option.

the request for input was out there for months, i don't think we received a single letter against it.

[shwah]

i don't think running smaller than max allowable diameter wheels is an advantage at all.

Other than lowering the cg without doing bad things in the suspension geometry, effectively increasing the brake diameter, allowing use of the lightest DOT tire Hoosier makes and moving the rotating mass closer to the hub, they are not.

[tnord]

Other than lowering the cg without doing bad things in the suspension geometry, effectively increasing the brake diameter, allowing use of the lightest DOT tire Hoosier makes and moving the rotating mass closer to the hub, they are not.

and again....all theoretical advantages that exist TODAY, and have not posed a problem.

[shwah]

and again....all theoretical advantages that exist TODAY, and have not posed a problem.

I was not addressing that, just the statement that they offer no advantage. IMO they offer significant advantages beyond gearing, which could be achieved via allowed gear changes.

There is an element of warts and all to this class. I race against guys with much bigger brakes than me. This has not "posed a problem" for the class that I have heard. Does this mean I should be allowed to go put big brakes on?

Same for electronic vs. mechanical injection vs. carbs.

There is a line there somewhere. I don't think we should go moving it.

[R2 Racing]

I run 13" wheels on the ITB car. Combining the Hoosier 225/45 13" R6 with a readily available and cheap 4.9FD makes the grocery-getting, highway-geared transmission not suck, and those little sidewalls let me legally run the splitter/air-dam about two inches off the ground.

But that beind said, I've also been looking to sell all of the 13" wheels I have (because it's four completely different sets, in weight, brand, and offset), and buy three sets of identical 13" wheels. But finding 13x6" wheels at all anymore is freaking impossible, and what you do find will cost you two arms and at least one leg, or is complete crap.

[Russ Myers]

Kevin,
Diamond, bart, aero. Steel wheels from the world of mini-stock. and not real heavy. AND cheap.

Russ

[Andy Bettencourt]

But that beind said, I've also been looking to sell all of the 13" wheels I have (because it's four completely different sets, in weight, brand, and offset), and buy three sets of identical 13" wheels. But finding 13x6" wheels at all anymore is freaking impossible, and what you do find will cost you two arms and at least one leg, or is complete crap.

So I look at this in a couple ways:

1. You have wheels and no rule should be changed because you want your stuff to 'match'.

2. We need to consider barriers to entry of newbies building cars. They don't have wheels. It would be nice that they could actually get some parts to build. I don't think this is on the level of Volvo windshields or XXX fenders etc. This is a class-wide issue.

3. Diameter was opened up because of availability but it had far less of a performance impact than this width issue will. Everyone will need to upgrade to keep up.

4. Josh was way ahead of his time a couple years ago when he proposed opening up width and diameter for all classes...no limits except fitting the inside fenders.

This is a classis benefits vs. costs issue. Not sure where I stand.