CMC 17" Wheel Weight & Welded Spacers

[mach1]

I pushed to remove the welding requirements due to safety. It’s also easy as hell to audit.
If I end up building a fourth GEN I’m going to get a Ford bolt pattern hub and axle so I can easily use and purchase the enkeis

[marshall_mosty]

The real genesis of the rule change was due to an Enkei RPF1 with a steel spacer that was attached to the wheel with screws (drilled the wheel and counterbore in the spacer) then plug welded so the attachment screws can’t back out or the wheel separated from the spacer, making a pseudo custom wheel).

That led to folks saying the heavier spacer “mass” was in the middle of the wheel, hence lowering the rotational inertia which created an advantage. That prompted the rule to be written around an aluminum wheel and aluminum spacer.

I’d still lobby for a permanently attached (screws plus plug weld which is easier with standard billet 6061 spacers).

Since the original steel spacer and alumunimum wheel combo was my idea and Jeremy was clever enough to try it (and McSpadden copied the idea with my CAD file for the spacer and took it to Nationals), blame all this on me... LOL

[Sook]

The real genesis of the rule change was due to an Enkei RPF1 with a steel spacer that was attached to the wheel with screws (drilled the wheel and counterbore in the spacer) then plug welded so the attachment screws can’t back out or the wheel separated from the spacer, making a pseudo custom wheel).

Adding holes to the center bore of the wheel scares me... and then plug welding them will locally destroy the wheel's temper.

That led to folks saying the heavier spacer “mass” was in the middle of the wheel, hence lowering the rotational inertia which created an advantage. That prompted the rule to be written around an aluminum wheel and aluminum spacer.

How does going to aluminum solve remove the inertial advantage? I'd rather go with a steel non-attached spacer. I can make your wheels (thanks for the deal btw) work with steel spacers.

So here's the question, if I show up to COTA with aluminum spacers not welded to my wheels will I be DQ'd? I wouldn't take the risk of showing up with a car that directly goes against the rule book, if we can get clarification ahead of time against welding wheels it'd be awesome.

- Josh

[Suck fumes]

yah sook make sure you get clarification on anything wheel related. I saved all Marshals approval messages on my phone when i took my setup to Utah at miller mot park just to cover my butt cause it created a firestorm online once people realized what i did to the wheels (marshals idea) to make weight. BUT it’s the budget way around spending thousands in fikse or ccw wheels.

[marshall_mosty]

Just to clarify the plug weld would ONLY be on the spacer, not the wheel. The only permanent modification are the tapped holes that the screws which hold the spacer on screw into.

Regarding steel vs aluminum spacers, for a given weight and thickness, the outer diameter of the spacer would be smaller on the steel spacer (advantage)...

[mach1]

Any mod to the wheel compromises safety IMO, I don’t understand the point of it being permanently attached, potential safety issue with no upside that I can see. If someone was protested you would audit the same way in impound, pull the wheel, dismount tire, weigh with with spacer as it came off the track.

[Suck fumes]

exactly!

[DAlgozine]

Any mod to the wheel compromises safety IMO, I don’t understand the point of it being permanently attached, potential safety issue with no upside that I can see. If someone was protested you would audit the same way in impound, pull the wheel, dismount tire, weigh with with spacer as it came off the track.

So in this scenario, a Ford can run a 16lb wheel with a 2lb spacer and get to the 18lb minimum. Great
However, there are no off the shelf, other than custom $$ GM 17 x 9.5 wheels that weigh any where close to 16 lbs or 18lbs with the proper spacer, Or 18lb that have the proper offset. They don't exist. Closest a GM car gets its about 21lbs with a needed spacer.

[BryanL]

yah sook make sure you get clarification on anything wheel related. I saved all Marshals approval messages on my phone when i took my setup to Utah at miller mot park just to cover my butt cause it created a firestorm online once people realized what i did to the wheels (marshals idea) to make weight. BUT it’s the budget way around spending thousands in fikse or ccw wheels.

Marshall-will you approve my aluminum rear diff cover? I'm not aware Marshall was ever a CMC director to my knowledge to give "approval"? I'm pointing this out more because I get uneasy about anything that needs an "approval" since it's likely pushing the intent of the rules or possibly worse.

I agree with Tyler and any others that modding a wheel is a potential safety issue.

Wheel weight rule just has a better benefit for the Mustangs with the Enkei wheel option unless there is a wheel under 18 lbs for the F-body that ins't over $2k for a set (though I sure like the looks of the CCW). There are all kinds of advantages/disadvantages for each platform.
Sook-send it in for rule change request in our now non-existant silly season to get it approved to lower the wheel weight since it improves safety, lowers cost, and doesn't impact performance since people were already running the Enkei. Heck maybe you could get the rule changed before hand instead of a nod/wink approval.

I also agree with DAlgozine that it seems to be a goofy loophole that shouldn't really be in CMC. But then I'm checking to see when my custom Ford 9" with aluminum center section is going to be delivered so I can get it installed before nationals because my aluminum diff cover with a drain plug is illegal. Just doesn't make sense to replace it with a stock cover when for $3,800 I can get a stronger diff, better posi, and nearly unlimited gear options. Only downside is I have to order a new pair of CCW's for the different bolt pattern.

[marshall_mosty]

Marshall-will you approve my aluminum rear diff cover? I'm not aware Marshall was ever a CMC director to my knowledge to give "approval"? I'm pointing this out more because I get uneasy about anything that needs an "approval" since it's likely pushing the intent of the rules or possibly worse.

I agree with Tyler and any others that modding a wheel is a potential safety issue.

Wheel weight rule just has a better benefit for the Mustangs with the Enkei wheel option unless there is a wheel under 18 lbs for the F-body that ins't over $2k for a set (though I sure like the looks of the CCW). There are all kinds of advantages/disadvantages for each platform.
Sook-send it in for rule change request in our now non-existant silly season to get it approved to lower the wheel weight since it improves safety, lowers cost, and doesn't impact performance since people were already running the Enkei. Heck maybe you could get the rule changed before hand instead of a nod/wink approval.

I also agree with DAlgozine that it seems to be a goofy loophole that shouldn't really be in CMC. But then I'm checking to see when my custom Ford 9" with aluminum center section is going to be delivered so I can get it installed before nationals because my aluminum diff cover with a drain plug is illegal. Just doesn't make sense to replace it with a stock cover when for $3,800 I can get a stronger diff, better posi, and nearly unlimited gear options. Only downside is I have to order a new pair of CCW's for the different bolt pattern.

Bryan,
When I'm not available to field AI questions, they defer to Michael. The inverse is true for CMC. In this case, I was also discussing with Michael at the same time since we typically talk several times per week anyway. The official "legal or not" doesn't even lie with me or Michael. It ultimately would sit with Al Fernandez and the National Office. Michael and I are simply ambassadors of the series and make the best call we can with the information provided. Obviously my discussions with Aaron were under the pretense that he executed the wheel modification exactly as we had discussed. If he had done anything outside of our documented conversation, the "approval" most likely would have no grounds for being upheld. NASA always has the ability to reach out to the series directors to point out if we are overstepping our authority. In this case, I didn't hear a peep and Aaron didn't have any issues with the wheels at Nationals.


Clarification for pushing the limits of the rules are what continue to grow series, not in inverse. There are many examples of series that don't exist anymore due rulesets that are close ended with regards to future grown and or written with a ruleset that stifles innovation.

I personally don't like it when people talk about the rules and then as a subset the "intent". If it was the intent to allow or not allow a particular modification, it needs to be clearly specified in the rules. For example, if a battery box per intent isn't supposed to be made out of 1/4" steel plate and put behind the roll cage, the rules need to a maximum weight for a battery box.. Looking at a battery box and saying it is illegal because it doesn't meet the intent of the rules is not a solid defense, IMHO. There are so many loopholes that can be closed with clarified rules. If the series is seeing rules creep with a particular item (wheels plus spacers), the rules can be changed to clearly set the allowed parameters for the wheels.