True.


Not true, in any meaningful way. Your center of gravity remains the same.

Like I said, I may be wrong about this but if it works for high jumpers why wouldn't it work for this application? If you are weighting the pedals vs weighting the saddle wouldn't that move your center of gravity downward?

I throw that one out to the chart and graph set. Prove me right or prove me wrong.

Center of gravity is a geometrical thing. For high jumpers, in dynamic motion, the arc their body makes centers their gravity below the pole. You, on your bike, are not in dynamic motion, at least not to that extreme. If you don't move your body, you don't change your center of gravity. Simply pushing on the pedals changes where you are putting the input into the bike, but does not changing your physical center of gravity.

Weighting the outside pedal in a turn isn't about shifting center of gravity. It's about leveraging the bike upright to maintain contact patch between tire and road surface. This should be done in conjunction with leveraging the handlebars.

Sliding off the bike or shifting your weight towards the inside to offset centrifugal forces does shift center of gravity because it shifts weight.

High jumpers contort their body substantially. When you weight the pedal, the mass of your body hasn't moved appreciably.




Which part of the body is bearing the pressure doesn't matter, it's the position of your body.

Your lower legs have small mass, and moving one down means the other moves up. To have an appreciable change in CG, you'd have to start kissing your front tire.

I understood Bob as saying he was leaning his torso off the bike, which would move the CM out of line with the frame.

I agree on the pedal weighting not changing the CM though.

Actually, no, I didn't claim that. If you can set a line that lets you continue to pedal, that's definitely faster. But in a sharp, high-speed corner, the most important thing is banking the bicycle as appropriate, set a line through the corner that lets you resume pedaling as soon as possible and coast through the part of the turn that requires it, depending upon your bank angle. It's not just about speed; you can't unweight the saddle while pedaling unless you're standing through the corner, which is incredibly unstable and will make it necessary to take a crappy line, thus slowing you down a lot more than just accepting the need to coast through turns. Either way, it's not a good idea except in a sweeping turn like you're talking about.

A better criticism for me to make would have been that too much of the "advice" the OP HAD been getting was way too generalized (and, uh, basically wrong). The right technique depends upon the situation, which is what CDR and Bob Dopolina are getting at, here. For example, I will also swerve the bike and not my body to avoid a hole in the pavement. But if I'm taking a turn in a crit, that's not the technique I use! Moving the bike is a good way to dodge holes or rocks while still holding your line. It's not a good idea in corners because it's very difficult to hold a steady line this way (see what CDR said about maintaining even turning arcs and its importance for best cornering).

As for Racer Ex and others claiming that leaning the body more than the bike makes for a faster corner and better technique, well, that's just plain not true. Moto GP is NOT a valid comparison. The handling dynamics are fundamentally the same, but the weight balance is completely different (moto: heavy bike, light rider, cycling: heavy rider, very light bike) and the CG is much lower on the motorbike. Not to mention the enormously greater traction available to the motorcyclist. This is all very important. Leaning the body might not HURT, but it just isn't going to provide any real benefit, and it may unbalance you in the wrong situation. Likewise, sticking your knee out on a bicycle probably doesn't do anything but make the rider feel better. And yes, I do it, too.

The point is, there are a lot of different things you can do, and it's very easy to get away with poor technique - plenty of racing cyclists do it all the time. I'm not claiming mastery of cornering technique, but if I did a lot of the things described early in the thread, I would be cornering a lot worse than I already do. I want to get better at this, doesn't anyone else?

I suspect that the OP was in the hoods b/c his bars are too low.... so that's the old geezer advice - raise your bars a bit so you're comfy in the drops for long periods, like, say an hour crit. Then when cornering hard, crouch even lower, to get more weight on the front and generally lower your CG.

Well, much thanks guys. CDR, I will definitely be harassing you at Bethel in the new year (if you don't mind).

See you there!

This

heh, pics, yellow is me, gent in black in photo 2 is the guy I followed through the fatal time.

Bad Cornering

Good Cornering

You look like you're running clinchers. Is it possible that the contact patch of the tire was different in each case leading to your loss of contact? Possibly contributed something. You could also have been lighter than the guy, which decreased the amount of friction you had, but you kept the same centripetal acceleration leading to a wipeout?

Hey wait a minute!
I did that race!

(In the 4/5 anyway. I came in last, I think. yay!)

Me and my friends in Wesleyan Kit were shouting cheers of encouragement at you guys

It's a very valid comparison actually. Weight traction, and CG are just amplifiers or deamplifiers to the same fundamental machine. Two inline wheels, front wheel steered with a fork controlled by a handlebar. Leans when you turn. They respond identically to the same inputs. Your primary concerns are weight bias, angle of attack of the tire, and available traction between the tire and road surface.

Leaning the body in does the same thing it does on a Moto GP bike, it brings the bike to a more upright position which as I mentioned gives you more pedal clearance and addition contact patch area on the tire should you start to slide, where otherwise you would run off the tread edge. By uprighting the bike you're also increasing traction by putting a better angle of attack on the tire. There's also enhanced ability to brake in the corner. Knee out moves the CG to the inside, doing some of the same things that leaning the body does. The downside to this isn't some undefined "unbalance", but is some loss of aerodynamics.

Excellent video of Botero, who was a noted descender. Had been looking for Il Falco and his Giro descent, he employs the same basic style as Botero.

https://www.youtube.com/watch?v=1KELC...eature=related

The left hand hairpin is particularly telling.

I'm Ripley's at this point. "Believe it or not". Stay upright Pinkster. Out.

in the drops
weight on the outside pedal so you're "floating" just above the saddle
light grip on the bars
weight on inside hand
be confident

I'm not leaning out of the plane that the bike is traveling. I'm scrunching down and lowering my body as much as is feasible - rotating my hips and getting my torso parallel to the top tube.

To be honest, I use this more during descending and only during regular cornering if it is really fast and I have to stop pedaling. If I can pedal through that is always my preferred line.

Funny story Racer Ex; that's MY favorite YouTube video for demonstrating how wrong another cornering piece of "advice" is: that pedaling out of a corner is what allows a rider to take the most possible speed out of corners. It's obviously important, but good cornering technique is the key. But I digress.

I'll concede this point. Botero does seem to be hanging off to the inside, albeit only slightly. This is something that I do pretty much automatically, and I didn't consider it worth speaking of, since it's only a slight movement that doesn't make a significant change in the way the bike handles. The folks writing about this describe what sounds like a rather large, deliberate movement, which isn't a great idea. I'm still not convinced that this is particularly important to good cornering - I think Botero's chosen line through corners is much more significant than his body English (Spanish?) - but it might be marginally helpful, at worst a harmless gesture. There are great descenders who don't do these things. I'm so-so myself. Anyway, great video.

There's theoretical and there's actual reality at work here. There's a theoretical limit on adhesion given by physics that's the absolute maximum you can go around a corner if all else is optimized, such as carving a perfectly circular line, perfect weight-distribution, etc.

However, in the real-world, there are other variables that come into play that lowers the actual grip achieved below the theoretical level. As already discussed, the line you take and pedal-strikes can cause a loss of traction at speeds below the theoretical max.

What Grolby doens't get is what thousands of racers with years of experience have discovered. That keeping the bike more upright gives you higher cornering speeds. That's NOT debatable, it's born out to be true way too many times to disregard. What IS debatable is WHY you get faster cornering with a more upright bike. Note that this is only faster at the steady-state cornering mode. The turn-in may be a little slower since you have to move the body rather than just throwing the bike down.

The major contributing factor I've found is the better contact-patch when you keep the bike upright. It's flatter due to the profile of most tyres, especially when you've got some wear on it. AND you're not riding on the squared-off sharp corner between the worn and unworn parts of the tyre. I suspect, in the OP's case, if he was riding with his body inline with the bike, that it's actually possible to ride off the rubber close to the skinwall of the tyre. Especially if he tightens up his line mid-corner trying to keep up with the guys ahead. I've learned this lesson the hard way myself trying to keep up with more experienced riders around corners.

I've also raced motorcycles as well and the handling is the same as bicycles. Things are heavier on a motorcycle and it takes more force on the bars to lean over, but that gives you time to analyze the dynamics. And when things starts to slide, it's a lot slower and easier to catch on a heavy motorcycle than on a bike. The main problem with hanging off the side on a bicycle is that you end up catching a lot more air than if you're tucked in on top. And you can't start pedaling as soon coming out of the corners compared to someone who's in the saddle.

BTW - stability and maximum-grip are two completely different things. Sure you can go around at corner at 35mph and be stable. Take it at 40mph and it'll require a lot more attention and corrections, but it's still faster.

Not a problem. Bethel has no turns though (Turn One doesn't count), so if you want to work on turns, I'd go to Plainsville, CT. If the guy holds the series in 2009, he'll do it on Saturdays. That race is flat, 2 real turns, and has a different rhythm from Bethel. I have a helmet cam and post on Plainville. I really enjoy racing there.

Plainville clip:
https://www.youtube.com/watch?v=syun-GZtkYg
Obviously I have a lot of Bethel clips too

Plainville post:
https://sprinterdellacasa.blogspot.co...-in-rough.html

Regardless you're welcome to harass me at Bethel.

cdr

There is one significant difference between motorcycles and bicycles. In a corner, the motorcycle has power and the bicycle does not. On a motorcycle, the rider uses his right hand to keep the bike upright-by twisting the throttle. You are on the throttle through the corner on a motorcycle. Power keeps the bike upright and the rider can focus all his efforts into steering and fighting centrifugal forces.

On a bicycle, the rider loses the power and must replace it with physical efforts to keep the bike upright by using his/her feet, hands, and butt to keep the bike as upright as possible. Obviously, since the rider is not pedaling, all the focus can be on the physical efforts to do this, but since it is counter intuitive, most riders want to see how far they can lean instead of how upright they can stay, this must be practiced, usually on grass with a marked out course.

Seriously, you think that because I know how to turn a bike in a circle that I'm presuming to be an expert on racing? Give me a break. Taking the body seriously out of line with the bike (which I've admitted to be a misreading of what people were saying) doesn't work well.

What I didn't get was that I was reading the "lean your body more" statement as advocating a much more extreme body position than was actually meant. My mistake. Like I said, it's something that I do when cornering hard. I don't know whether or not it's faster - I'll just have to take your word for it - but I do know that it makes me feel better. When I needed to improve my cornering, I worked on getting my weight off the saddle (outside pedal really helps here, though it isn't strictly necessary) and getting back and low.

I think about theory and do lots of thought experiments. It's how I work. I'm not claiming to be some kind of cornering maven. I'm maybe a bit better than mediocre, myself, in the context of a race, just fine otherwise. I'm sorry for stepping on any toes. There's a low signal-to-noise ratio in threads on cornering advice, and I'd prefer not to be the noise. I'd also prefer that others not be making the noise, and I try to call out the crap that seems obvious to li'l ol me. I made a mistake.Yow.

EDIT: it's "grolby," by the way, all lowercase . And skinny, now I don't know what you're getting at at all.

No, mostly I'm trying figure out what the big deal is about some kid with a big mouth. That would be me. Feeling more sanguine about it yet, or do you need to laugh some more?

Thanks all (cept maybe the bickering, but this is BF...).

Cdr, I'll definitely hit Plainville as well as Bethel (I've raced Bethel many times...even beat you in a sprint for 6th once [went early into the hill, your uber throw at the end wasn't quite enough]).

So would I be crazy for putting together a cheap single speed, throwing some padding on, and just throwing myself at turns for a while? Seems kind of entertaining...