[Author Prev][Author Next][Thread Prev][Thread Next][Author Index][Thread Index]

Re: Wheelspin

>What your trying to say is right, eric.  You're just using the wrong
>terminology.  In case you don't believe me (which is obviously the case), 
>I'll quote directly from the Milliken and Milliken book, "Race Car 
>Vehicle Dynamics".

Sorry but what I am SAYING IS right.......

>"Tractive force FT and braking force FB are a function of slip ratio.  As
>slip ratio increases (numerically)from zero, the forces rise rapidly to a
>maximum which usually occurs in the range of 0.10 to 0.15 slip ratio, after
>which the forces fall off."
>This is what you're saying.  And quite honestly, I'm impressed with your
>accuracy on the 10% slip ratio.  But in the next paragraph:

Well long conversations with and testing for tire companys will get you 
the correct info....

>"For the traction case, note that the force falls off rapidly after the 
>onset of spinning.", and "Once a tire exceeds the slip ratio for peak 
>force in either traction or braking, it becomes unstable and the 
>wheel tends to either spin-up (traction) or lock (braking)."

Meaning that they were spin to start with.............

>Thus my point - "slip" IS NOT THE SAME AS "wheelspin".  It should be clear 
>from these quotes (from an 890 page SAE publication no less) that 
>maximum tractive force occurs at ~0.10 to 0.15 "slip ratio", but falls 
>off dramatically with the onset of "wheelspin."

Is the tire turning faster than Road speed? Yes it is, and that my friend 
IS Spin......... And I have made it clear that you need to keep the tire 
at a delta V of 10% for max traction otherwise it goes up in smoke.... 
Looks like it's time to go back to class Jeremy.....


Eric Fletcher
St. Louis, MO