A serious dicussion your thoughts

[JackD]

Originally posted by Bob Drury:
  Hmmm, concrete tires...... The center of gravity of the car woould be lowered and the pressure ridges on the salt would be negated.... hmmm......

I knew you theoretical types would like it.
 The use of the kidney belt wouls be determined by the placement of the rocks.
 The ideal would be to match the heavy spots with the power strokes.
 Ya, that's it, match the strokes.
 
  <small>[ March 08, 2005, 05:32 PM: Message edited by: JackD ]</small>

[Glen]

BAH HUM BUG

[jacksoni]

Disney had a cartoon in '50s or '60s with concrete tires and rubber road so has been done.....

[Clay Taylor]

All -
 
 Marvin Rifchin is the Wizard of Watertown, MA, better known as "Mr. M&H Tires" and he was a great guy to shoot the breeze with back in the 70's at NHRA events.  Glad to hear that he is still doing well.
 
 As to Kevlar, I might have an explanation for some of the "bad stories".   Kevlar fibers are extremely strong, and they have virtually zero stretch.   Mountain climbers use Kevlar ropes to haul gear up the cliff faces, because the rope can be very thin and lightweight, and have great resistance to abrasion.  However, they don't EVER use Kevlar for climbing, because if the climber ever fell while attached to a Kevlar rope, when the rope went taut it wouldn't stretch to absorb the shock, and the climber would be dead.
 
 That property of non-stretchiness was explained to me by a designer of climbing gear.   That industry tried using Kevlar to reinforce things like backpack straps and handles on gear bags.  They imbedded the Kevlar inside the Cordura (nylon) webbing and fabric.   However, they discovered that when stress was put on the fabric, the nylon fibers stretched while the Kevlar didn't.  The Kevlar fibers would cut through the nylon fibers like a knife, and the material would fail.
 
 He also related that a few years ago a maker of the big whitewater rafts like they use in the Grand Canyon tried reinforcing the rubber / nylon / rubber construction of the raft body with Kevlar fibers.   The rafts were very lightweight and rugged, but after a while they started getting blowouts.  What they determined was that every time the raft hit a rock and stretched the raft's skin, the Kevlar fibers sliced through the rubber from inside.  Eventually, the hole made it to the outside.
 
 What does this have to do with tires?  
 
 Here's my speculation - if there is a lot of flex in the carcass of the tire (either heavy cornering loads or "growing" at high speed), the rubber of the tire might be sliced up by the Kevlar fibers.  If that happened at 300mph, it would not be a good thing.  Hopefully the makers of the new LSR tires have a solution to that potential problem.
 
 Clay Taylor

[Bob Drury]

Clay, thanks for the imput.  I am not sure how much a current M/T 30" tire grows at 300mph, but as heavy as the constuction is I wouldn't think it would be more than a inch. If any tire was going to flex, I would think it would be the aircraft Tundra Tires, so perhaps he has the potential problem figured out.  One more thing to our advantage, we (LSRacers) normally run at least 90 psi of Nitrogen, so there shouldn't be a whole lot of flex involved.  Just my thoughts.

[wmtsmith]

we had to put 31/3" into our dream chart to get the tach and the timing slip to agree at 270..

[Bob Drury]

Sparky, what was that diameter again?  Are you sure you had no clutch slipage?  Hell, I can't compute anyway, but just curious...........

[ddahlgren]

Sparky. I would not trust the tach to better than 100 to 150 rpm at 8000. You would also have to have the same entry and exit speeds to not be measuring an average speed in the mile. Another thing to be very careful about is to use the tooth count to measure the exact gear ratios if not 1 to 1 especialy with an odd tooth count. They are generally rounded to the nearest 2 decimal places but some of them carry out a long ways after that point and when you multiply them together the error gets larger. If you used the wheel speed senors for checking MPH add some more magnets you might be missing some counts and more magnets will make an occasion miss less important. Just remember to keep the magnets symetrical though.