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RE: Question 1 - tires (tyres!)

To: "Lorcan Parnell" <lorcan@750turbo.com>,
Subject: RE: Question 1 - tires (tyres!)
From: "Russel Mack" <rtmack@concentric.net>
Date: Thu, 11 Sep 2003 06:08:34 -0500
Lorcan:
welcome from me, too.

We beat this topic to death last year sometime.  Can't say exactly when.

The Rulebook allows treaded tires to run up to the manufacturer's rating,
and allows you to run faster if you shave the tread off-- the theory being
that the most likely failure cause on lsr tires is the centrifugal force
operating on the outer perimeter.  If you shave them, it reduces the mass in
this critical area, so there is less force generated to pull the tire apart
(or to break the bead loose).

That said, I have yet to find an American "sit-on" biker who shaves his
tires (although some use racing slicks on the fronts).  The modern Z-rated
radials have very strong resistance to the centrifugal force, and are so
good that most people seem to think it's not worth the effort to shave them.
SCTA allows us to run them WAY past the manufacturer's ratings, just because
there is nothing better available.

I don't know of any of "street radials" failing during a run (although tire
valves and stems have ocasionally given lsr bikers some nasty surprises--
use steel stems & caps).
Russ, #1226B

-----Original Message-----
From: owner-land-speed@autox.team.net
[mailto:owner-land-speed@autox.team.net]On Behalf Of Lorcan Parnell
Sent: Thursday, September 11, 2003 1:13 PM
To: LSR List
Subject: Question 1 - tires (tyres!)


Ok, I've read back through a couple of months archives and as I am grey
enough already I apologise for not reading further and would like to ask
this question (possibly for the 100th time).

I've read in the SCTA rulebook about shaved tyres for motorcycles running
above 200mph. I've run over 200mph several times on unshaved (road) tyres
and others in the UK have gone around 220mph, albeit for short distances
like a timed quarter mile with 1.5 miles run up, without a problem.

If I was to aim for, say, 240mph, would I be advised to use shaved road
tyres, or slicks (I currently use MT slicks on my dragbike)? Is a slick
better or worse than a shaved treaded tyre for high speed use?

I'm talking about running on asphalt here by the way. Think I'd better learn
to walk before I run!

Thanks

Lorcan


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