How fast can you take that corner? How quick can you stop? It depends on the road surface, and one riding skill to develop is the ability to judge the road surface as we approach a corner or come through an intersection where we may need to stop quickly. Following are some measurements of coefficients of friction for various surfaces to guide our thoughts. These first friction coefficient estimates are motorcycle-specific from the Master Strategy Group:

Concrete 0.55-1.2
Concrete (wet) 0.44-0.9
Asphalt 0.5-0.9
Asphalt (wet) 0.4-0.7
Gravel 0.4-0.8
Ice 0.1-0.25
Snow 0.1-0.55

Here is another estimate, taken from an engineering text on rubber/asphalt and rubber/concrete coefficients:

Asphalt 0.5 - 0.8
Asphalt (wet) 0.25 - 0.75
Concrete 0.6 - 0.85
Concrete (wet) 0.45 - 0.75
...

Following are the results of my research on whether WD40 is harmful to chains: WD40 consists of 50% Stoddard Solvent (which is just desulferized kerosine with a lower flash point), 25% propellant, 15+% Mineral oil (light lubricating oil) 10-% Inert ingredients. My research on the difference between Stoddard Solvent and kerosene show no difference in their effect on rubber or silicone, and their behavior as a solvent appears to be the same as it would apply to o-rings. This makes sense since they are basically the same thing. It appears that any worries about WD-40 would apply equally to kerosene, which most manufacturers recommend to clean their chains. On a good chain, solvent (wether it is kerosine or WD40) should not get past the O rings, because the O rings do what they are supposed to do, seal the inside of the chain. If WD40 should for some reason get past an ring, kerosine or diesel should just as well. And basically this means the ring is shot and the life of the chain is...

In response to forum threads, or starting my own threads, I'll often gather up my reasearch and make a post. Going back later and finding what I posted is getting to be a pain, so I'm going to start using my blog to gather up stats, studies and other links to things I find useful. I may even throw in a pic or two along the way or a more traditional blog entry.