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post #1 of 9 (permalink) Old 06-27-2000, 12:14 PM Thread Starter
 
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i found this on the r6 board i go too.. i saw it a few months ago (either here or there) & thought it would be good to post because of recent tire questions.....

********************************************

This letter was posted by Erik Astrup on a news group not long ago, it is a letter sent to him from a guy at Dunlop Race Tire Service...


Steve is well known in the racing world, and you've likely seen him in the
background shots in the winner circle. Steve is really hard to miss!

Anyway, Steve is President of Race Tire Service and is "Da Man"
for Dunlop on the East coast. He used to be out in the West coast
which is where I first met him at AFM races. Good guy.

Anyway, here's Steve's input -

=======================
Dear Erik,

Here is something you can post with regards to DOT racing tires on the
street.
-------------------------------------------------------------
Erik Astrup has asked me to post regarding running DOT racing tires on the
street.

First thing I must mention that I work exclusively with Dunlop product and
can only speak about product that I have first hand knowledge and
experience with.

SAFETY. There is not a safety issue in running DOT racing tires on the
street. By SAFETY, I mean the tire will not have a failure or come apart
from normal aggressive street use. Excluding road hazard. (Falling down
on oil, gravel or excessive throttle is not a tire failure)

DIFFERENCE: The biggest difference in the racing tire and the street tire
is in the construction. Street tires have JLB construction and race tires
have a Cut Breaker or Cut Belt construction.

JLB is when the main tread belt (the ply just underneath the tread rubber)
has all of it plies running in the same direction. All the fibres are in
the same direction, pointing the way the tire rotates.

Cut Breaker construction is when there is 2 belts, both have the plies
running at an angle to the rotation.

Take one hand and hold it in front of you, point your finger to the
ceiling and keep you fingers side by side. This is what direction the
fibres run on a JLB breaker. Now take both hands with the fingers side by
side, lay one set of fingers on top of the other set at a 45 degree
angle. This is what a Cut Breaker looks like. (a picture is worth 1000
words, wish I had a picture to describe it better).

Whether you understanding the direction of the plies or not, the basic
difference in feel and performance is that the JLB construction is very
good for stability over bumps and feedback on odd surfaces. It also give a
much more smooth ride. This is better for a street ride and over the
things that one runs over when riding in street conditions.

The Cut Breaker is better at overall side grip. The basic word here is
SIDE GRIP. Cut Breakers give much more side grip and a bit of a stiffer
ride.

TEMPERATURES: What does tire temperature have to do with performance? Lets
first understand an old falsehood "Race tires won't stick till you warm
them up" this is untrue and is a falsehood. Here are the facts. If you
took a race tire and a street tire and ran them side by side, the race
tire would provide more grip than the street tire in every temperature
range. So if both tires are at 60F the race tire works better. If both at
160F, the race tire still works better. Now will a cold race tire work as
well as a hot street tire? I don't know, it would depend upon the
tires. (But I am sure that someone did this and fell down, then started
the rumor. ) The big difference comes in the cold verses hot
performance. A race tire get much better when hot. A street tire gets a
little bit better when hot.

WARM UP TIME: Dunlops generally come in, in 1 lap (the warm up lap). A
street tire gets a little bit better when hot, but not as much as a race
tire. The harder one rides the quicker and hotter the tire gets. These
are basics datums. The rider has to gain experience with tires and how
they work by riding on them many times. There are not hard numbers to
describe degrees of traction for every increase in temperature. Experience
is the key here.

Why would you use a RACE TIRE for the STREET?
Plus points - More grip.
Minus points - Harsher over bumps, less feedback, cost more, tend to wear
quicker.

Why would you use a STREET TIRE for the STREET?
Plus points - sufficient grip, smooth ride, more stable over bumps, last
longer, cost less
Minus points - Don't look as cool as my friend with race tires.

If you are riding on the street and really need a race tire, you should
not be riding on the street.
Street tires give very good grip, enough to have a very fun time in the
canyons. A street tire on the track will run about 1.5 seconds slower than
a race tire. Compared to 15 seconds slower for the average street rider
that goes to the track, it is easy to see that experience and practice
makes a much bigger difference than just tire choice.

Ride and have fun.

--
Steve Brubaker, President, Race Tire Service Inc.
Dunlop Motorcycle Roadrace Tire Distributor Eastern US
Order 800-772-TIRE, Tech Info 615-641-2234, Fax 615-641-8959
mailto:[email protected], http://www.dunlopracing.com/
---------------------------------------------


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post #2 of 9 (permalink) Old 06-27-2000, 01:20 PM
 
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Excellent! Great Info. that all sounds very reasonable.

------------------
Kyle J.-
email:[email protected]
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post #3 of 9 (permalink) Old 06-28-2000, 03:25 AM
 
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That about sums it up. Thanks for the info.

------------------
Dan F4 Red/Black
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post #4 of 9 (permalink) Old 06-30-2000, 02:58 PM
 
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That is good info, but I think a lot of times when people are asking if it is ok to use race tires on the street they are looking at buying race take-offs. A friend of mine told me I could have his old race take-offs for $25.00 a set. These are one race only tires. A lot of life left in them, but not for him. I have had a lot of people tell me that it is not a good idea. I just got new tires so haven't taken him up on it yet.

------------------
That don't fix it? Get a bigger Hammer
1993 GSXR 1100
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post #5 of 9 (permalink) Old 07-03-2000, 04:15 AM Thread Starter
 
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true hammer... but some people i ride w/buy new race tires for the street & never see track action (one moron even uses a superbike slick). i am guessing here.. but i would think that you would not be able to generate enough heat on the street to make a tire go through a heat cycle so u loose less performance over a longer period of time. as far as a 1 time take off, if what i guess is true, i would think that that 1 time race tire would be fine according to what the above report stated. but you should also remember the pro's & con's the report made to each compound & also the comment on street tires being 1.5sec slower & the avg street rider being 15sec slower.

------------------
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post #6 of 9 (permalink) Old 07-03-2000, 02:54 PM
 
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Wink

I can't imagine wasting all that money on new race compound tires for the street. I have a hard enough time keeping tires on my bike the way it is. Metz MEZ3's only lasted a few months. The set I am putting on now are 205's. I probably don't ride hard enough to get a street compound tire to fail, so give me the extra miles and I'll pocket the cash.

------------------
That don't fix it? Get a bigger Hammer
1993 GSXR 1100
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post #7 of 9 (permalink) Old 07-03-2000, 03:32 PM
 
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That is very good information. Best explaination of this topic that I have ever heard. I knew the info. but had never been able to explain it properly. Also keep in mind that Steve is talking about the DOT race tires, not the slicks.

FYI, If you want to know who Steve Brubaker is, just watch the AMA superbike podium footage. He is the big hefty bearded guy in the Dulop uniform that is normally standing behind the winner.

Just a little point on Steve. He helped us(Grigg Racing) out at Road Atlanta. If it hadn't been for Steve B. we would not have made the Formula Xtreme grid. They had some problems with a mounted tire that wouldn't resonably ballance and he put us ahead of several people to allow us time to get the tires on warmers. There is more to the story but it isn't important. The point is, I asked him nicely for a favor and he never hesitated he took it right to the top of the pile. We had the tire mounted and balanced within just a few minutes. He runs a good crew that works their butts off and have always been very polite in my dealings with them, and they don't know me from Adam.

------------------
Ride Hard!

John
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post #8 of 9 (permalink) Old 07-03-2000, 03:52 PM
 
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Oops, I should have read SpeedPhreaks initial words a little closer. He told about Brubaker being in the background during the Winner's Circle footage.

------------------
Ride Hard!

John
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post #9 of 9 (permalink) Old 07-11-2000, 06:27 AM Thread Starter
 
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i have a dream...

someday everyone will learn to use the search function to find info.

bringing this back to the top cause some people missed it.

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