Speed ratings for "tubed" tubeless tires.

[Eldo]

Hi all, I am running a bike in the M750PG class this year, and I have a question regarding my tires; The class record is 137.8MPH, requiring tires in the class to have a "V" rating. The tires I have are Avon AM23 (rear) and Avon AM22 (front) tubeless tires. I will be running them tubed on (spoked) Excel rims. On the sidewall of the tire it states: "If running with tube max speed 210KPH (130.9MPH)" In the rulebook, it states that shaving a tire will bump the tire "up" one speed class. If I shave these tires, will they be "within regulation" to run in my speed class?

[tallguy]

Please remember that the rulebook indicates "minimum" safety requirements.  You are
not prohibited from being safer than the required "minimum" . . .

If you don't cooperate with the tire manufacturer's recommended limits, you are being
irresponsible and a danger to yourself (and possibly, others).

Please stay within prudent guidelines, such as those of the tire manufacturer.

Be safe.  Go fast.  Stay safe.

[Stainless1]

So I'm going to guess probably not, but contact MC tech in the book for the real answer. 
Shaving reduces the tire weight and reduces the chance of pulling the tire off the bead.  Not sure that applies to tubed tires.

[Eldo]

I have emailed the Tech guys, currently awaiting an answer...

[**RP**]

I went through this a decade ago with the old SCTA tech people.  I had to get a letter from Avon stating the rating would not be any lower with tubes, they had no problem giving me a letter to show to the tech people.  The new Avon racing tech person is actually at M/T Tires and she will be very helpful.  New SCTA head M/C tech would be the first person to contact to see what you need for approval.

[Eldo]

Thanks RP, that's great to know. I'll put a call in tomorrow and see what they say!

[Stainless1]

RP, Avon raised it's speed limit 50 MPH for a tubeless tire with a tube if you shaved it??

That's the question....

[**RP**]

No....... 10 years ago Avon stated running a tube in their 149 mph V rated tubeless tire would not lower the speed rating.   SCTA said shaving would raise the speed rating.   I don't remember if Avon gave their blessing on shaving.  Just saying what I went through in a similar situation and that it is best to talk to the tire company people and the SCTA tech people.

[wobblywalrus]

My bike has spoked wheels and tubes are run in tubeless tires.  Bridgestone has special inner tubes for radial tires and I use them inside the radial at the rear.  IRC makes various grades of heavy duty tubes and I use the moderately heavy duty one in the front.  Periodic inspections show no problems.  The tubes get changed out every three years.

There are other makers of high quality tubes that should work fine.  There is a big difference between a good name brand tube and the Funkmaster ones that are readily available at most bike shops.  It pays to use the good ones.

Never ran in an SCTA event so I cannot tell about any experience with their tech system. 

[**RP**]

Eldo

Some Avon AM23 and AM22 are non-DOT Racing tires.  If that is the case they might to good for 199 mph.   How fast do you think you are going to run?