high-speed cornering

[Orange Fish]

How much does equipment play into your ability to corner at high speeds?

Last night I was on our local sprint ride where we have 9 sprint lines with 600, 400, and 200 meter markers set up and after this one scary sprint, it got me thinking about this.

I came around a tight turn after a sharp, quick descent, and entered the corner at around 43mph(I was doing the leadout down the hill). However, I felt my rear wheel start to slip and ended up drifting way across to the other side of the road. Definitely not where I wanted to be, but I felt like if I didn't let myself drift, I would have certainly slid right out. I have a high-performance bike, but I wasn't sure if it was something about my bike (i.e. something that i can upgrade to make it more responsive - like wheels or something), etc. or if it was just that I need to keep training to better develop my technique for coming into and out of a corner like that at high speeds. My chainstay length is about 420mm, so it's not the shortest chainstay length made, but is that enough of a difference to make high-speed cornering a little squirrely like that?

 

[AussieRob]

Road surface is the big question when cornering. Beyond that, its up to tyres and confidence. What you need is nice soft, new tyres. The problem with soft tyres is that they don’t last long and are expensive.

 

[Orange Fish]

good point. the road surface was asphalt with a very very small amount of scattered gravel (barely noticeable, but there), and my tires are the training-type of tire...so they have a puncture resistant bead, and are probably stiffer i'm guessing?

the second guy, who was right on my wheel came off and took the turn like it was nothing, but then again, he used to ride for the Navigators, so i guess that probably has something to do with it...me being a cat 5 and him being an ex-pro. lol.

 

[topcat]

good point. the road surface was asphalt with a very very small amount of scattered gravel (barely noticeable, but there), and my tires are the training-type of tire...so they have a puncture resistant bead, and are probably stiffer i'm guessing?

the second guy, who was right on my wheel came off and took the turn like it was nothing, but then again, he used to ride for the Navigators, so i guess that probably has something to do with it...me being a cat 5 and him being an ex-pro. lol.

I no expert on this but as you go round a fast speed bend, push down on da the outside pedal as much as you can and the front wheel slightly away from the corner so that get a beter grip on the front tyre, hopefully the back tyre should stick a lot more with more pressure on it anyway.

 

[Spider1977]

43mph - that's pretty fast for a corner, or is it just a gentle bend? Were you seated or standing? The Wendels in Bike Racing 101 suggest to get slightly out of the saddle and put weight on outside pedal - I assume this lowers the centre of gravity. They also suggest leaning the bike rather than steering. The latter is used when the road is wet or slippery. At 43 mph (over 70 kph) I wouldn't have the balls to corner severely at that speed, so you are in a league beyond my comprehension.

 

[Orange Fish]

43mph - that's pretty fast for a corner, or is it just a gentle bend? Were you seated or standing? The Wendels in Bike Racing 101 suggest to get slightly out of the saddle and put weight on outside pedal - I assume this lowers the centre of gravity. They also suggest leaning the bike rather than steering. The latter is used when the road is wet or slippery. At 43 mph (over 70 kph) I wouldn't have the balls to corner severely at that speed, so you are in a league beyond my comprehension.

It was a steep, short downhill banking turn - pretty close to 90 degrees, but on a bank (probably around 75-80 degrees), so that helped a little bit as far as not having to scrubb off as much speed. I was seated the whole time trying to hang on for dear life . I usually don't have the sack to corner at that speed, but an ex-pro was with us that night and I was trying to give him a good leadout, so I didn't want to look like a wuss in front of him. lol.

You're right about the weight on the outside pedal, and support the other comments on that. I completely forgot about that issue...probably the wind in my face was making it hard to think at the time. lol. But as for the slightly getting out of the saddle to lower center of gravity, I've never heard that before, but it's interesting and I'm going to think about it for a while to figure that one out.

 

[dhk]

It was a steep, short downhill banking turn - pretty close to 90 degrees, but on a bank (probably around 75-80 degrees), so that helped a little bit as far as not having to scrubb off as much speed. I was seated the whole time trying to hang on for dear life . I usually don't have the sack to corner at that speed, but an ex-pro was with us that night and I was trying to give him a good leadout, so I didn't want to look like a wuss in front of him. lol.

You're right about the weight on the outside pedal, and support the other comments on that. I completely forgot about that issue...probably the wind in my face was making it hard to think at the time. lol. But as for the slightly getting out of the saddle to lower center of gravity, I've never heard that before, but it's interesting and I'm going to think about it for a while to figure that one out.

Good tires and correct tire pressures are obviously important for road grip. Don't worry about saving money on tires; get the good stuff if you're going to be leaning on 'em. Also, best grip isn't going to be at the max-rated sidewall pressure for the tire, unless you're a heavyweight.

On fast descents, believe staying in the saddle, low and centered in the drops with some weight on the handlebars works best. My theory is you want a good weight distribution on both tires, plus minimal steering input to the front wheel when in the corner. And inside pedal up for big lean angles...one less thing to worry about.

 

[frenchyge]

But as for the slightly getting out of the saddle to lower center of gravity, I've never heard that before, but it's interesting and I'm going to think about it for a while to figure that one out.

It doesn't technically lower the center of gravity. Using the legs to give a little bit of dampening effect for any bumps will add a lot of stability and ensure the tires maintain maximum contact with the road. Hovering slightly on the saddle is like adding suspension to your bike.

 

[Orange Fish]

Ok, I gotcha. Now I know what ya mean.

 

[jagrazor]

pratice corners a lot. I do it on my easy days sometimes. Short ride witha lot of corners. You really figure out what works well if you do that.

obviously getting a basic idea first is good though, might save a lot of wasted time

 

[dhk]

pratice corners a lot. I do it on my easy days sometimes. Short ride witha lot of corners. You really figure out what works well if you do that.

obviously getting a basic idea first is good though, might save a lot of wasted time

Back when I was doing some crits, I practiced on a school playground. Found a well-paved one, with several different curve radii painted on. Was good to learn about limits and build confidence in the tires at low speeds on a traffic-free skidpad.

 

[VeloFlash]

Good tires and correct tire pressures are obviously important for road grip. Don't worry about saving money on tires; get the good stuff if you're going to be leaning on 'em. Also, best grip isn't going to be at the max-rated sidewall pressure for the tire, unless you're a heavyweight.

On fast descents, believe staying in the saddle, low and centered in the drops with some weight on the handlebars works best. My theory is you want a good weight distribution on both tires, plus minimal steering input to the front wheel when in the corner. And inside pedal up for big lean angles...one less thing to worry about.

....with some weight on the handlebars works best

I would disagree, particularly on a downhill corner, where the balance of the weight of the rider and bike has moved forward.

Move weight as far back as possible, weight the outside pedal and feather touch the handlebars.

Unless the rear wheel hits gravel or a slipperier part of the road, it will always be your front wheel that will lose adhesion first, downhill or flat, and bring bike and rider down.

 

[Roadie_scum]

....with some weight on the handlebars works best

I would disagree, particularly on a downhill corner, where the balance of the weight of the rider and bike has moved forward.

Move weight as far back as possible, weight the outside pedal and feather touch the handlebars.

Unless the rear wheel hits gravel or a slipperier part of the road, it will always be your front wheel that will lose adhesion first, downhill or flat, and bring bike and rider down.

If there is no weight on the front wheel, it will be more likely to lose traction rather than less likely. The key is to weight using the outside of the handlebar, not the inside. Fore/aft weighting depends on bike geometry and rider characeristics.

 

[VeloFlash]

If there is no weight on the front wheel, it will be more likely to lose traction rather than less likely. The key is to weight using the outside of the handlebar, not the inside. Fore/aft weighting depends on bike geometry and rider characeristics.

Going into a downhill corner you will have too much weight on the front wheel. The object is to move the excess weight off the front wheel to readjust the balance of the bike.

A heavier weight on the small front wheel contact patch (and smaller whilst leaning into a turn) will not increase adhesion. The bike wants to run straight and the small front wheel contact patch is fighting this force. Either too much speed or too much weight at a lower speed will break this adhesion and the front wheel will slip under. This is the cause of most single rider cornering crashes, not the rear wheel losing adhesion.

You may see a lot of top level riders running wide on corners.
This is because they are experienced enough to feel the bike has too much speed and will lose front wheel adhesion and crash if they continued to corner using the classical line.

Here is a quote from an article about flat land cornering which supports part of my point:

"To corner correctly, you need to have a low center of gravity. Have your body centered on the bike. Lean the bike as opposed to steering it and take a correct line around the apex of the corner. Low center of gravity is achieved by getting your upper body as low as possible while maintaining control. Do not however put too much weight over the front wheel as that will compromise your body being centered on the bike. You want your weight low and between the wheels."

 

[frenchyge]

Unless the rear wheel hits gravel or a slipperier part of the road, it will always be your front wheel that will lose adhesion first, downhill or flat, and bring bike and rider down.

This is mainly because there is less weight on the front wheel. That's probably why the previous advice was to try to balance the weight between the 2 wheels.

 

[frenchyge]

Going into a downhill corner you will have too much weight on the front wheel. The object is to move the excess weight off the front wheel to readjust the balance of the bike.

Under braking conditions I would tend to agree, but on a normal hill the slope of the hill is not great enough to cause a significant forward weight shift.

You want your weight low and between the wheels."

Exactly, and that means trying to balance the amount of weight on each of the 2 wheels.

 

[VeloFlash]

Under braking conditions I would tend to agree, but on a normal hill the slope of the hill is not great enough to cause a significant forward weight shift.

If you can brake in a corner and maintain control you are not going fast enough! If you have to brake - use the rear brake. The rear tyre breaking adhesion has a chance of being controlled. The front - no chance.

Exactly, and that means trying to balance the amount of weight on each of the 2 wheels.

On a downhill, the centre of gravity moves forward. The only way to readjust the balance is to lighten your weight on the handlebar.

 

[frenchyge]

If you can brake in a corner and maintain control you are not going fast enough! If you have to brake - use the rear brake. The rear tyre breaking adhesion has a chance of being controlled. The front - no chance.

The general advice is to brake before entering the corner, not while cornering. I've always read that the front brake is the one to use. Your rear wheel is more likely to lockup when braking because your weight shifts forward (thus lightening the rear wheel).

On a downhill, the centre of gravity moves forward. The only way to readjust the balance is to lighten your weight on the handlebar.

Even a very steep downward grade (say 15%) is only an 8.6 degree drop from the horizontal. That small an angle will change a 50-50 weight distribution to 38-62 split towards the front. That's not a big change, and your typical bike does not normally have a 50-50 split to begin with. The downward slope doesn't necessitate shifting the body weight backwards to offset, and probably helps balance things if the riding position is not adjusted at all.

Now, shifting the butt back in order to lower the torso without shifting the center of gravity is probably a good idea.

 

[Orange Fish]

Well, just got back from a ride today where I got to work on this topic, and I have to say that I realized just how important it is to keep your outside leg solid and to really press on that pedal coming around the corner. Everything felt so "grippy" coming around a few 80-ish degree turns! Good stuff!

 

[Cyclist14]

In one crit I was in there were six corners that were all 90 degree. The fastest three corners were on the downhill side and I can remember coming within a foot of the curb a few times just to complete the turn. It was a good race and I finished fifth.