Tire Rules/Limitations

Started by Kelly, July 03, 2002, 11:07:25 AM

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Does anyone REALLY think that in the extreme heat of summer-it makes any sense to have tire rules attached to the race groups.  In 90+ heat, a slick and a DOT stick just the same! At this level of racing (Exp-CCS), the compounds of the tires are identical!!  Does anyone else think that this is just a silly rule left over from some point in time when it mattered because tire specs were different-or do we think this rule was designed by the proverbial non-racers we have running this ship???

Super Dave

Well, I'm not a tire engineer, but a slick tire still has more contact patch compared to a DOT.  Yes, in this day and age, the DOT's are pretty good, and they are directly related to the slicks.  Back in 1990, there were DOT tires that were the same construction and compound as the slick tires, but they were put in different molds.

The tire companies want to sell tires that street bike riders use.  Makes their tires seem better to the general public.  

Even then, there are so few "superbikes" at the club level, why do we still have "superbike"?  Sure more races, but why not longer races for a cash purse.  Would make the whole program a little more interesting, right?

Super Dave


I have a question....  If the slicks and the DOT's are made of the same compound - what advantage does a slick have over a DOT?     ???


Paul and Dawn Buxton



Ignore my last post....

Super Dave was quicker than I was - but then again he always is   ;D

Paul and Dawn Buxton



If they stick just the same, why are you even asking this?  Just run DOT's and you are legal for everything.  The slicks have the potential to stick better because they don't have the grooves but it's probably a very minute difference.  The slicks tend to last a bit longer too due to the lack of grooves (notice the rubber rolling off of the edge of the grooves).

Super Dave

Compound is only a part of it.  How it is constructed can be different too.  Sometimes, a tire will have a different contour to it.  It might be more flat, triangular, or what ever.  There might be a little more consistency in a DOT from that point, where a Slick type tire might offer more opportunities.  

How a tire works is a combination of all of those things.  Change the construction of the belts and use the same compound, and one might find that the tire works way better, or maybe worse.  You don't know until it is tested.  That is what tire testing is all about.
Super Dave


I'm planning on going with some perelli(sp) slicks next time I get tire which will probly be in 2 weeks,I just want to try them out I only race superbike legal classes anyway.


 I've run slicks and DOT's, Pirelli and Dunlop, the best tires are NEW. Maybe the Goberts can tell the difference but New anything will beat last weekends anything. It's a shame it's so expensive to go 1/2 second faster. I don't know anybody that has tried Pirelli against Dunlop with a fresh set then go right back out with a fresh set. Anybody done this? Ive been told suspension adjustments have to be made because of the carcass structure. So I'm thinking this would be an expensive expirement. Maybe Roadracing World could do it and save us all a ton of money.

Super Dave

It would be an expensive experiment.  RRW did it a couple of years ago.

The trick is that tire manufacturers make tires the way that they want to.  So, the heights and contours of each tire manufacturers 120/70ZR17 can be different.  So, just slapping on a different tire can dramatically change a motorcycle's geometry.  

And geometry is important.  Just ask GMD Computrack;  they make a bundle setting up geometry on bikes.

Yes, anything new is better.  For me running at Blackhawk on a 600, it means running near the lap record, or two seconds away from it.
Super Dave


I can't comment on the difference in compound or geometry between slick and DOT's.  It does occur to me, however,  that when looking at the part of the DOT tire that is most crucial; i.e. the contact area at maximum lean angle, you're pretty much looking at a slick anyway.  I run Pirelli DOT's and love them, but rarely show significant wear to the section of the tire that has tread.