Motorcycle tire rule change

[dw230]

At the 5/21 SCTA Board meeting a mid-year rule change regarding tires for motorcycles which run in excess of 200 MPH was passed. The new rule will require all motorcycles competiting in classes with a record of 200 MPH or more to use tires specifically made for racing.

Old wording:
7.B.8   Tire Requirements:

200 MPH +   Experience has shown that using tires
      with hard rubber compounds and
      reducing the tread thickness by 2/3 by
      carefully shaving the tread provides
      the best results.
New wording:
7.B.8   Tire Requirements:

200 MPH +   In excess of 200 MPH Special tires for racing as
                         designated by the manufactacturer.

Reason for change: For speeds over 200 MPH it is mandatory to be on
race tires and not just ZR street rated tires.

The decision for this change was prompted by the speeds now being achieved by the motorcycle competitors.The head tech persons were assisted by the motorcycle advisory committe which is composed of some of the fastest racers now racing. Several tire manufacturers were also consulted.

Please contactt the following for further info:
Van Butler- catherinejuneau3@mac.com

Tom Evans- oileaky2@yahoo.com

Lee Kennedy- lee.kennedy@avmeterics.net

[donpearsall]

What is the problem with ZR tires? To my knowledge, there has never been a tire related problem with the over 200 mph speeds when a ZR rated tire is used. Jason's tire blew at Speedweek 2008 because he hit some FOD. A racing tire would not have prevented that. What is the experience that caused this change?

Also, does this "mid-year" rule change amend the current rule book? Meaning all events in 2010 will be affected?

I am for safe tires, but just don't see where the problem was.
Don

[John Noonan]

Don,

ZR street tires will not be allowed, many of the tire manufactures make racing tires.

Nobody ever went down at Bonneville because they ran over debris on the course.

This change is to take effect at the next SCTA meet.

[wobblywalrus]

My youngest boy will be graduating (hopefully) from high school in a couple of years and we are planning on running in an SCTA event.  This is his graduation present.  Both of our bikes are slow and we will be running for the experience and the chance to meet new people and see roadsters, belly tanks. etc.

My Triumph is a 1000cc modified partial streamliner with a modern engine and the SCTA class record is over 200 mph.  The bike will do 150 mph if I attach a lead weight to it and throw it off of a bridge.  Should I plan on changing wheel sizes and getting racing tires, or is there an exception for the velocity challenged?

No complaints about the new rule.  It is a very good one.  I just need to plan ahead.

[fredvance]

The rule is you must meet the safety requirements for the record in your class.

[donpearsall]

OK, I thought I read right here that Jason's crash was due to hitting an engine part that was on the course. If you know the true cause what was it? Defective tire?
I don't have a problem with buying $500 worth of racing tires (if they are really safer than ZRs), but just want to know what experience caused this new rule.
Don

[donpearsall]

Also, here is a question that I need opinions on. Most M/C racing tires come in slicks and some with a little bit of tread. What is better traction for the salt? Also most racing tires are very round in cross section which results in a small contact patch because of the need for road racers to corner at 180mph. We don't need that. We need a large contact patch in the center of the tire. Anyone have a tire in mind that would be best for the salt?
Can racing tires be shaved?
Don

[ol38y]

I don't have a dog in this hunt, yet. I also thought I read here that Jason ran over something on the track that blew the tire.

[John Noonan]

A narrower tire has more weight per square inch than a wider flatter profile tire, if you were running in turns with traction then a wider tire is better..ever look at how narrow the car streamliner drive tires are..


Don't believe everything you read on the internet..

[Jasontmc]

Please enlighten us on the root cause of my crash John.

To this date I have not read the SCTA crash investigation report from my incident. If you have please forward it to me for review.

To speculate the cause of my incident from here say would be inaccurate but not uncommon.

There was a considerable amount of shrapnel found on the line that I was riding that day and some cuts in the tire itself.  Tires chunk all the time and the bikes don't go down. The strength of a tire is not in the tread but you knew that. There was a rapid loss of air pressure in the tire and that is what caused the crash.

[46champ]

Is this another knee jerk reaction by the SCTA a la all cow racing suits, oh well when I can aford to go again it will be to the Bub meet.  I don't really have a dog in this hunt I run in a class that will never be over 200 mph but I might change classes then I see a problem.

[joea]

scta doesnt do "knee jerk" reactions....

although...participants often do.....

tough to argue with a phenomenal record forl over 60 yrs......

[1212FBGS]

There is absolutely no empirical testing that says ZR motorcycle tires are safe to run substantially more than the manufacturer’s recommendation…. Period… Just because you jump off a bridge and live doesn’t make it safe!…. Just because you take a shower every morning and don’t slip and fall doesn’t make it safe!…. Just because you smoke pot every day doesn’t make it safe…. Hummm maybe not a good example…. But the reality is, just because you put a monkey on a motorcycle and it makes a 200mph+ pass its just damn luck! The only testing done on these tires has been done by the manufacturer and they say their not safe…. Believe me this is not a knee jerk reaction this has been debated and kicked around for quite a while…. Most of those who have run over 200mph have been CC’d and were involved in the decision making process, so this rule change is of no surprise…. Just escalated due to some bikes running over 270mph…
Now before you start off with the traditional “It’s the insurance scare excuse!” well it for damn sure “IS” the reason.!... Most of you don’t realize that the SCTA has had 2 pretty big insurance payouts due to us “Damn bikers” and actually we didn’t have insurance up ‘til a few days before the May El Mo meet! And the insurance policy has tripled!! “Damn bikers!” and the car boys don’t want us to jeopardize their fun just because us “Damn bikers!” want to be stupid… And I personally don’t blame them!
As far as tire failures…. Well hello! “Tire chunking” IS a failure I don’t care what dictionary you’re reading and we’ve had plenty of it…. Jason’s carcass failure happened and he is damn luck to be walking as well as alive… I particularly don’t want to see my friends go out and get hurt just because they want to be cheap and stupid to disregard safety recommendations… Jason, I don’t know who told you that you ran over something maybe you should have requested the piece that could have killed you as a souvenir… I have no knowledge of debris causing your accident… if you ask me I believe your rim failed causing rapid loss of air pressure….Yep if I had my way about it their would be a ruling about rims also…. There is a lot of technical stuff about tires and tire construction I don’t have the time to type but everyone involved in this decision process has been educated…
I personally don’t see the logic in someone spending $10g on a turbo system or $5g on a motec system to go faster and won’t spend $300 on a tire to be safe…
Kent

[fredvance]

Kent, I dont know where to look for tires like we need, I looked at road racing tires and the are all pretty soft. Any suggestions/help would be greatly appreciated.

 Fred

[Seldom Seen Slim]

Fred, I'll be looking forward to hearing where we can get the new tire requirement satisfied.  I've never had to shop for 'em -- and will be happy to list some potential vendors once I learn them.  I guess we could ask Nate Jones, I betcha -- how long has he sold motorcycle racing tires and served the land speed racing group?  Monday I'll call him -- folks, list the sources so we can all start our shopping.  Bitching about the rule won't change it -- so let's all buckle down and start helping one another adhere to it.