[Land-speed] Contact patch size

[Jon Wennerberg]

On Nov 17, 2008, at 3:46 PM, <neil at dbelltech.com> <neil at dbelltech.com>  
wrote:

That works great for sand rails but on an LSR car it might lead to
catastrophic tire failure. As the tire flexes as it rotates, the carcass
generates heat and it gets worse as the speed increases.

Regards, Neil   Tucson, AZ





	Neil and all the rest of you:

Good - lots of responses.  First of all -- I want a very simple  
contact patch -- one that doesn't include things such as sand or snow  
where the surface material might get up and between bits of the tread  
pattern.  I'm talking about flat rubber contacting flat surface (be  
that pavement or salt or ice).

I'm also disregarding the concept of traction that's available (ice is  
slippery compared to concrete compared to salt, etc).  I'm only  
talking square inches contacting a flat surface.

I hope you understand that I realize that a softer tire will likely  
flex more and thereby will probably generate more heat.  I don't care  
about that in this argument -- I only want to talk about the absolute  
size of the contact patch.

Different tire materials are also irrelevant -- in that it'll take  
just as many square inches of air-inflated rubber as it will air- 
inflated nylon or Kevlar or whatever.  A hard tire (concrete or wood,  
for example) would not flex and therefore isn't of interest here.

I will say that Mayf's comments is good -- that is, a high pressure  
inside the tire will translate to high pressure between the tire and  
the surface, and that can be assumed to offer an opportunity for  
higher traction.  And also -- narrow can be better for traction for  
hydroplaning, of course -- just like it is when driving in snow ("cut  
through the water/snow rather than float over it").

Back to you. . .

       Jon Wennerberg
Tall guy with moustache
and a pair of 2 Club hats