Originally posted by gheba_nsx:
sjs,
here are some lecture about wide tires and improved braking:
http://www.vdat.de/prg17e.htm
http://www.datsuns.com/Tech/tech_tires-2.htm
Well, the first is a nice article about a scientific experiment which for the most part merely proves what we’ve already know for many years, but I didn’t notice any reference to the better cooling qualities of wider tires. In other words a good article but I don’t see anything to support your assertion.
The second is not so much an article as an individual doing his best to explain a few things about braking, and as it says at the end “*While Mark is no tire company engineer, he is a degreed and licensed mechanical engineer, so is probably as qualified as anyone to answer the posed question.“ I’d disagree that a mechanical engineer is inherently qualified on this subject. As even he states, things are more complex than they seem, so applied knowledge from other areas has limitations. But yes, as I said in my prior post there are extreme cases where the rubber gets too hot but beyond that I think his reasoning is flawed if he attributes the braking benefits of wider tires to better “cooling” due to their greater surface area. For example, he seems to completely ignore the added mass and therefore heat absorption capacity of the larger tire. Seems a pretty big omission for an engineer.
I put the word “cooling” in quotes earlier because someone might argue that I’m splitting hairs here since it sounds like I’m saying that the heat is spread out over a greater area and therefore lower at any given point. But there is a big difference between the ability to absorb heat and the tendency to shed it.
So to summarize, wider tires certainly will cool faster than narrow ones, no argument there. The question is whether over heated tires play a significant role in braking limitations, and then whether the added cooling provided by the increased surface area of wider tires can make a significant difference in that situation. I’m not even an engineer, but I’d guess that the answer to the first is “rarely”, and to the second “probably not”.