Dave
I am not claiming to be a tire expert, far from it. The point I am
addressing is what I have seen on the salt the last 20 years.
I agree with you about the lack of tire loading and ratings not being
available, but in our specialized type of racing there are not a lot of
people beating down our doors to make us racing tires. The M/T's and
Goodyear's are what we have. As I stated yesterday the salt conditions dry
or wet are a factor in partly how the tire works.
As far as loading and down forces there are vehicles with high loading. The
Firebird of Lindsleys & Leggitt had heavy loading and the ground effects
along with the body (front) was almost self destructing. I am glad it didn't
go over 333mph as I think the vehicle would have had a different ending.
Earl Woodens tire failure was delaminating down the center of the tire
resulting in it exploding. The other factor in the coupe was the engine /
drive train was on the right side of the vehicle and in turn had more load
on the right rear tire. Like I said I am just passing on lessons learned
from the past. I wish we had more experts in the tire world to take an
interest in our needs and give us safe 500 mph tires.
----- Original Message -----
From: "Dave Dahlgren" <ddahlgren@snet.net>
To: "glen barrett" <speedtimer@charter.net>
Cc: "Bryan A. Savage Jr" <basavage@earthlink.net>; "Grib"
<rgribble@carolina.rr.com>; "List Land Speed" <land-speed@autox.team.net>
Sent: Saturday, August 25, 2001 4:30 AM
Subject: Re: Everybody Knows That Won't Work
> Interesting things to think about here!
> My 2 cents worth from looking around the last 10 years tells me there are
very
> few wings at B'ville that make that much down force. KT would have told
you
> about how the car settles down during a run from down force, well i
instrumented
> it this year and the car moved very little probably on the order of 1/8
inch.
> From what I can see of the rules for the most part real wings are not
allowed in
> most classes and a spoiler is for cleaning up air flow and is not a foil
that
> can generate large amounts of down force. personally i think tire
failures have
> more to do with the the weight of the car. Most tires that I am aware of
all
> have both a load rating and a speed rating. I would also have to think
that an
> overloaded tire will have less strength and therefore a lower speed rating
than
> one that is not overloaded. I have looked through the rule book and did
not find
> anywhere so far a place that discusses the load rating of a tire. Does
anyone
> think that i could run a Goodyear land speed tire on a Ford Expedition or
a GMC
> Yukon at 200 mph and be ok with handling? or that the tires would not be
> overloaded? yet i have heard all about 5000 lb doorslamers with tires like
these
> on them. If you really want to get a handle on tires and failures you
might want
> to ask some one how much the car weighs and if the tires are rated for
that
> weight and speed that they are planing on running. If they have a 5000 lb
car
> and small front tires and have 55% front weight you have a failure waiting
to
> happen!! I would bet most are severely overloaded.
> The front runners have no load rating at all listed on Goodyears site and
many
> of the land speed tires are rated for 1200 lbs others at 1700 lbs with one
> listed at 3000 lbs. I looked at M/T site and there was nothing listed
about LSR
> tires there ...
> If you really want to put any tire issues behind yourself you have to have
a
> tire from a company that will give the recommended load and speed rating
and
> check cars for compliance as part of a safety inspection. If you look at
this
> link http://www.goodyear.com/us/tires/racing/products/racect19.html
>
> You will see that all these tires are rated at 300 mph or less at the
rated load
> or less load..
> So if you have a car that goes over 300 on these tires you have an issue
to
> begin with and like i said the front runners don't even have a rated load
or
> speed that I saw so what is safe for those?
> The other side of this that I would have to ask is the age of the tires.
But
> maybe that is another issue How do cars with visible checking on the side
walls
> even get through inspection? They are there and i have seen them many
times!
> What is the speed load rating after 4 years with a side wall that is
checked and
> how do you separate cosmetic damage from structural damage?
>
> Dave Dahlgren
> Who personally would not buy a tire without a load and a speed rating and
would
> believe it!
>
> glen barrett wrote:
> >
> > OK, I sent a reply earlier today and it got lost in cyberspace along the
> > way. I will try and remember what I stated.Regarding tires on the salt,
from
> > my vantage point in the timing stand we see it all. First, this meet the
> > salt was HARD & DRY. This can be a big factor with any tire one runs. It
is
> > also abrasive in this condition.
> >
> > In the past about every kind of tire one can think of has been tried
> > including aircraft 727 main gear type. Over the years I have seen the
> > Daytona's and Taladaga's, front runners, wide ovals etc. tried. At
around
> > 240 mph this seems to be the point where the wide tire seems to start
> > having problems.
> >
> > This is more so in the shorter wheel base sports type vehicles. A lot of
> > roadsters tend to spin because there's a lot of weight on the front axle
and
> > once the vehicle has reached max acceleration the rear starts to move
around
> > and can get away from the driver pretty quick. The same for other
vehicles.
> >
> > So, on to the wide Vs narrow and salt conditions. Tires with grooves
tend to
> > pack salt in the grooves when the salt is wet and get into a hydroplane
> > condition, as do the wide slick tires with more surface area under them.
The
> > narrow Bonneville tires like the Lakesters and Streamliners run still
seem
> > to work best. Please don't miss read what I am saying because I am only
> > going by what has worked best in the past.
> >
> > Some years back racers were still using tubes in the tires and found
the
> > higher speeds caused the tubes to be forced to the outer part of the
tire
> > and pull off the valve stem. High pressure 90 - 100 psi rear and 80 in
the
> > fronts for tubeless type tires seems about the norm. Sealing can be a
> > problem but Keith Turk and others found ways on this great thread on how
to
> > solve that.
> >
> > Another problem is age and down force loading of the tires. The grooved
tire
> > that is running a lower air pressure can start to separate along the
grove
> > and chunk off or split along the groove. I don't claim to be an expert
on
> > tires, but I have been on the investigation of every accident with SCTA
/BNI
> > since 1983. We look at everything that could be probable cause and try
to
> > determine it. It's not easy as in our sport nothing is contained between
> > crash ways etc.
> >
> > Example, Earl Woodens incident from the first indication of a problem to
the
> > last piece of the vehicle was some 3100 feet.
> > In this case, once again the safety rules worked. I think what my
message is
> > approach every venue with extreme caution. Any landspeed racer will
answer
> > your questions regarding tires or just about anything else you are
seeking
> > help on.
> >
> > Brian, Grib, keith Dave,Skip and all of the rest, Once I am only going
by
> > what I have seen from the Best seat in the House. You guy's and Gals put
on
> > one hell of a show in 2001.
> > Thanks, and keep up the landspeed information thread.
> > Glen ( I timed the worlds fastest wheel driven car to date, what a
thrill
> > for me)
> >
> > ----- Original Message -----
> > From: "Bryan A. Savage Jr" <basavage@earthlink.net>
> > To: "Grib" <rgribble@carolina.rr.com>
> > Cc: "List Land Speed" <land-speed@autox.team.net>
> > Sent: Thursday, August 23, 2001 11:33 PM
> > Subject: Everybody Knows That Won't Work
> >
> > > Grib,
> > > I love it when someone like you proves, again, that "What Everyone
Knows"
> > is
> > > sometimes (frequently) totally wrong.
> > > You have made a true breakthrough by running rain tires. I have
watched
> > > several teams try the NASCAR slicks with mixed results (the best was
just
> > OK).
> > > Your comment:
> > > "..there's plenty of open space in the tread designed to expel water
(and
> > air)"
> > > must describe what is happening.
> > >
> > > Now if someone could get Goodyear to do a CDF study ........ this
> > principal
> > > my be adaptable to ultra high speed (500+) tires.
> > >
> > > I didn't think your tires would work. I failed to even consider the
rain
> > > tire design.
> > > Thanks for proving completely wrong Grib.
> > >
> > > When will we have tires designed to aerodynamically increase grip?
> > >
> > > Bryan
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