Cyclocross - pedal through the corners?

last year, on a twisty downhill grassy, leafy section, there was this dude sitting watch us roadies go through the turn with our outside pedal nailed down and saying calmly each lap "pedal though the turns". Last weekend, I was in a group of three and followed this dude who pedaled all the turns while I coasted them. Is this a mtn bike thing, you get more traction?

You always get more traction when you are driving rather than coasting.

If you're pedaling you pretty well assure that the back tire will skid before the front tire. You'll probably be able to save a back tire skid - if the front goes out first you'll be picking it up and remounting.

You always get more traction when you are driving rather than coasting.

not disagreeing, but i can't think of a physical reason why this would be. any ideas?

making the rear wheel skid before the front makes a lot of sense.

i forgot to put my freewheel back on my flip flop before this weekend's race so i had to pedal through the turns. i figured that i'd have to worry about pedal strike but the speeds going through corners were low enough that it wasn't an issue. mostly i was trying to plan my corners so that i came out of them with as much momentum as possible. so for that, pedaling through would make sense.

You always get more traction when you are driving rather than coasting.

I think the dynamics behind this statement are incorrect. You may be "more stable" when pedaling, but I can't say you get more traction. If a tire is near its traction limit when coasting, adding another force in the mix will cause it to loose traction. This is very different on a car because of weight transfer, but on a bicycle I just can't see how it is.

Maybe someone else will let us know...

Take a book, put it on the table, and move it. Now apply a downward force, and the static friction force that must be overcome to move the book increases.

The parallel is what happens on the faces of the lugs, provided you don't overpower the wheel and spin it out, (which puts things into the realm of kinetic friction rather than static friction). With some power on the wheel, the knobs/tread are actually engaged in the plane that is ~90 degrees to the surface of the tire. It's slight, but it is there. As soon as you apply more power than the tire can apply to the ground (i.e. spin/slide) the friction at that interface is kinetic.

The bigger benefit to pedaling through the corners is stability and the time integral of force, i.e. getting more power though to the wheels for a given time, i.e. a high average speed.

You've gotta be real smooth in your pedal stroke, though. I'm guessing that there are very few people around who are smooth enough pedalers to actually corner better while pedaling (except maybe in nasty mud/sand where you have to pedal to keep speed up).

If you have a significant vertical motion in your pedaling, you'll slide as you 'unweight'...the extreme case is when you're super unsmooth pedaling at really high RPM - you just can't keep a constant downforce on the tires to keep traction consistent.