Descending - Cornering - the geometry?

[lemon cheese cake]

If you have more than one corner coming up ahead, dont just plan for the first corner. Take the best line for all of the corners. If its just one corner, hit the apex just as you are leaving the it. Also have more speed coming out than going in. Hope that helps.

 

[escheator]

If you have more than one corner coming up ahead, dont just plan for the first corner. Take the best line for all of the corners. If its just one corner, hit the apex just as you are leaving the it. Also have more speed coming out than going in. Hope that helps.

This is not what I had in my mind, but thanks!

My question pertains to the road surface patchings and their effect on the best trajectory through the corners. Especially longitudinal patchings where their edges can have effect on control.

 

[DirtyWorks]

This is not what I had in my mind, but thanks!

My question pertains to the road surface patchings and their effect on the best trajectory through the corners. Especially longitudinal patchings where their edges can have effect on control.

There's no good answer except if you are practiced at counter steering, having the wheels slide under you can happen and it doesn't mean you are going to fall. I practiced on smooth dirt or grass and regular shoes. You don't have to be fully kitted-up for it.

Being able to slip and slide a bit counter steering is imperative in cyclocross and mountain biking. It definitely works for road bikes too.

 

[hmronnow]

Steering "resonance" descending cold

Interesting thread to read. I have an of topic question, but people on this thread are likely apt to answer.

Recently I experienced something I hadn't tried before. Descending a mountain pass in cold weather (probably 0-10 degrees with fog and rain) at high speed (probably ~70kmh) I was freezing a lot, out of sugar etc. Suddenly my handle-bars started wobbling and the more I tried to hold them straight the larger the amplitude of the wobbling became. I eventually managed to brake to a halt (wasn't easy as fingers almost numb). When I started again, the wobbling came back as soon as I went over ~50 kmh

This is the same bike I have descended on many times before and after the incident. The only difference being that I was very cold and tired. So I am convinced the wobbling came from my counter-steering (or whatever mirco-movement it should be called) somehow being out of phase, thereby causing amplification rather than damping.

Questions:
1) is this a common well known phenomenon?
2) are there any tricks to stop it (other than do not descend when very cold)?

Thanks

 

[Hawkwood]

a better thread would be how to teach a Brit to cook a steak

Lol I'm a `Brit', here's my method, get steak, wave it near frying pan, put it on plate.

On topic, I'm quite a good descender and have got up to 80kmph+ on short, 400 meter long, local descents (the speed limit is 50kmph). Others have commented that my cornering is good, however I was never anywhere near as good as a mate of mine. He had been a first cat roadman, and for a few years when I trained with him he rode a cyclo cross bike with big clearances and cantilever brakes, he went down fast twisting descents as if he was on rails.

 

[DirtyWorks]

Questions:
1) is this a common well known phenomenon?
2) are there any tricks to stop it (other than do not descend when very cold)?

Thanks

Yes.

The short answer is, it is most likely a geometry problem.

http://sheldonbrown.com/brandt/shimmy.html

If you are one of the few riding an alloy bike, it's possibly a fatigue issue in combination with a geometry problem. But, not too many alloy bikes sold these days.

 

[hmronnow]

Thanks a lot.
The last paragraph in that link exactly explains it.

It's an aluminium frame (Cervelo soloist), but don't think it is a frame issue as it never happened before or after. Must have come from my body shivering at the right/wrong frequency.

 

[Rapido]

Re:

[

"Dude! First, no one brought up what I mentioned in my last post about balance and why a bike doesn't fall over once in motion.
Cheers[/quote]"

A vertical bike, rolling in smooth motion, doesn't fall over as long as the two wheels are in an exact straight line. Yes?