FC/FF maximum width measurement

[Steve Bamford]

Probably a silly question, but why not go back to the two post rule that Steve L referenced and be done with it. make adjustments to the max allowable a needed to compensate for the camber required with radials?

Because someone will spend $125,000.00 or more to build a new FC to take advantage of the rule & enter the Majors & scare the huge fields of currently running FC cars away. Same reason why we run narrow side pods in FF so someone doesn’t build something that isn’t out there & take advantage of the rules. We are being protected from this. I’m sure there is a line up of new FC people waiting in the wings & hoping we go to the two post rule so they can exploit by reengineerinf a new car.

[R. Pare]

If you stick with the 2-post rule and the current width, the scaring of somebody building a new car stuff will never happen.

Either your car fits the box, or it doesn't. If it doesn't, it's up to the car owner to fix it. It is NOT up to the Club to modify the rules for you.

If a new spec tire is mandated that makes all or most of the modern cars too wide, that is a different story - AND the width will need to be spec'd at X amount of negative camber.

[John Robinson II]

This is being way over complicated. The intent is no matter how much camber is run a set dimension is adhered to. Hence, axle centerline for measurements.

Greg,
i guarantee you have the proper tools in your trailer to measure this. I saw you using alignment bars with strings at Sebring. Set those up on car and then pretty simple math, distance between strings minus distance from strings to rims. Simple, accurate and eloquent. Doesn't matter if you run + 5' or -5' measurement is the same.

Question still remains, is wheel interpreted as rim or tire?

John

[R. Pare]

maximum width has always been interpreted as to the tire, regardless of camber or toe settings.

The entire car, which includes the tires, has to fit between two posts.

[problemchild]

How much did SCCA change the value, when they changed the rule measuring location?

I just measured up a Mygale with Hoosier front spec radials mounted on Dixon aluminum forged wheels at 21 psi set at 4 degrees camber. The difference in width measured at the tires maximum and the wheels on centerline ...... was 1.5" PER SIDE.

Again, the style of wheel will affect the differential, but did the SCCA adjust the value by 3 INCHES? And again, the tire style and construction of each tire will affect the value. There may be dozens of different branded wheels in use and at least a dozen different tires (with front and rears) between the classes..

Yes my measuring was crude ..... as expected ..... I used a vertical bar and digital level, and a vernier, so perhaps we can conclude a tolerance of 1/4", but the difference between the tire and wheel at the bottom was over an inch.

A few inches is a whole lot more than the few mms that could have made the original rule work .
I think a whole lot of people will be building new A-arms ..... and axles .....and brake lines .... and trailers .

Does anyone not care that the effective tracks are changing by several inches using the same values in the new rule.?

Unless most of us are going to build new A-arms for our cars by leaving the same values in the new rule ...... we will need to establish new values that will need to accommodate dozens of different wheel and tire combinations. These new variables will far exceed the differences of camber and toe. These new variables will take considerable time and effort to collect, catalog, assess, project, etc.

This new rule is not only stupid but incredibly flawed. Much like the side pod rule, the only reason not to abandon it, will be spite and control. Let's just kill it and return to the original. If there actually is a concern, (which I think is trivial), then change the value of the original rule by a few mms to accommodate rogue VDs.

[DaveW]

Since I don't think the new width rule is practical or will give the hoped-for results, and I don't perceive much support for it, I believe we need to go back to the original rule (width is measured to the widest point on the tires) where there is obvious, incontrovertible, interpretation plus easy measurement and enforcement.

I will write another request to the CRB on this subject today.

[DaveW]

Since I don't think the new width rule is practical or will give the hoped-for results, and I don't perceive much support for it, I believe we need to go back to the original rule (width is measured to the widest point on the tires) where there is obvious, incontrovertible, interpretation plus easy measurement and enforcement.

I will write another request to the CRB on this subject today.

Request submitted:
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Letter ID Number: #24942

Title: FF/FC Maximum width measurement

Class: FC

Request: On further consideration of the complexities of the recently-introduced maximum width definition rule (defining maximum width as between the outside of LH & RH wheel rims), I have concluded that this definition introduces too many unknowns plus difficulties (special tools required) with measurement and rule enforcement.

Therefore, I think the best solution for these issues is to revert to the original rule where maximum width is defined as between the widest points on the car, i.e., the outermost points of the tires at the front and rear of the car.

This interpretation is easily understood and measured both in the shop and at the track.
---------------------------------------------------

[CGOffroad]

Since I don't think the new width rule is practical or will give the hoped-for results, and I don't perceive much support for it,

Ok, I will ask a question that doesn't appear so obvious to me... What is the 'hoped for result?'

As Frog said early on, there has been a rule that has worked for 30 years. What is broken right now that needs to be fixed? Did ONE car show up to an event that for some reason squirmed around the rule a little? If that is the case, deal with the ONE car directly instead of trying to make rules that have a potential negative impact on ALL other cars.

[DaveW]

Ok, I will ask a question that doesn't appear so obvious to me... What is the 'hoped for result?'

As Frog said early on, there has been a rule that has worked for 30 years. What is broken right now that needs to be fixed? Did ONE car show up to an event that for some reason squirmed around the rule a little? If that is the case, deal with the ONE car directly instead of trying to make rules that have a potential negative impact on ALL other cars.

I think the hoped-for result was less width-compliance issues with cars having to run more negative camber in order to use (larger OD) radial tires.

[DaveW]

It appears that the rule will not be changed from what it was announced to be before I started this thread - max width is to be measured at the widest point on the rims on the horizontal centerline.