This was going to be about vacuum cleaners: The best way to corner a bicycle

[Tommy D]

So, today I was out for my 'daily' loop and I got to thinking about proper body position while cornering a bicycle. Most of my life, I've been on two wheels, and most of that has been on dirt. But none of that time has involved any kind of 'training' or instruction of any type. Just the bike, the trail, a couple friends, and some good times.

While MTB riding, I have a 'technique' that works for me, and is very similar to carving a snowboard: For lower speeds, I actually load the 'nose' and rock my weight back through the turn, almost pulling the front end around. But of course, if my weight goes too far back, I'm screwed. If I'm bombing the single track, I keep all my weight evenly distributed as best I can, but still 'rock' fore/aft very subtly.

Now to the road bike: different geometry, different purpose. I'm sure there's a proper cornering technique out there. Anyone want to offer up suggestions? I've been experimenting, and I know the bike reacts a lot faster the more forward I get. (And is probably more stable too.)

As an aside for all you motorcyclists: I used to subscribe to a motorcycling mag back in the day,(no, I don't ride, and never have ... Someday!) and one article in particular stands out in my mind. Yup, it's an article on cornering technique. The article suggested that upon turn initiation, briefly turn the wheel opposite the way you want to lean. (I'll call it 'opposite twitch' here.) Let's use a left turn in this example... Riding along in a straight line, twitch the bars to the right. This causes the bike to lean left. Here's where it gets foggy; I think the purpose is to make leaning over happen faster, and allows for a tighter, more aggressive line through the turn.

Anyway, I've tried the 'opposite twitch' technique on mountain and road bicycles, and it definitely works. It's a mind bender too. I've also tried opposite twitch in my car, and yes, it works there too (Though for different reasons: think pendulum turn without the lurid slide.)

What are the applications for this? None I can think of for the recreational rider, but it is a lot of fun, and a neat trick to have in the bag.

What do you think?

ps - I can not resist: What's your favorite vacuum cleaner, and why? Mine's a Dyson. It sucks. Really. All the time. Makes the dog hair disappear like magic, and makes a cool whooshing sound too!

[Speedzilla]

So, today I was out for my 'daily' loop and I got to thinking about proper body position while cornering a bicycle. Most of my life, I've been on two wheels, and most of that has been on dirt. But none of that time has involved any kind of 'training' or instruction of any type. Just the bike, the trail, a couple friends, and some good times.

While MTB riding, I have a 'technique' that works for me, and is very similar to carving a snowboard: For lower speeds, I actually load the 'nose' and rock my weight back through the turn, almost pulling the front end around. But of course, if my weight goes too far back, I'm screwed. If I'm bombing the single track, I keep all my weight evenly distributed as best I can, but still 'rock' fore/aft very subtly.

Now to the road bike: different geometry, different purpose. I'm sure there's a proper cornering technique out there. Anyone want to offer up suggestions? I've been experimenting, and I know the bike reacts a lot faster the more forward I get. (And is probably more stable too.)

As an aside for all you motorcyclists: I used to subscribe to a motorcycling mag back in the day,(no, I don't ride, and never have ... Someday!) and one article in particular stands out in my mind. Yup, it's an article on cornering technique. The article suggested that upon turn initiation, briefly turn the wheel opposite the way you want to lean. (I'll call it 'opposite twitch' here.) Let's use a left turn in this example... Riding along in a straight line, twitch the bars to the right. This causes the bike to lean left. Here's where it gets foggy; I think the purpose is to make leaning over happen faster, and allows for a tighter, more aggressive line through the turn.

Anyway, I've tried the 'opposite twitch' technique on mountain and road bicycles, and it definitely works. It's a mind bender too. I've also tried opposite twitch in my car, and yes, it works there too (Though for different reasons: think pendulum turn without the lurid slide.)

What are the applications for this? None I can think of for the recreational rider, but it is a lot of fun, and a neat trick to have in the bag.

What do you think?

ps - I can not resist: What's your favorite vacuum cleaner, and why? Mine's a Dyson. It sucks. Really. All the time. Makes the dog hair disappear like magic, and makes a cool whooshing sound too!

"opposite twitch" is called counter steering and over a certain speed it's the only way a two wheel vehicle will turn. Everyone does it, they just don't realize it.

Oh, and the 20 year old Eureka I got at a garage sale for $5 does the job for me.

[Neil Gendzwill]

"Opposite twitch" isn't an option on a motorcycle, it's the way you initiate a turn, they teach it in the beginner's courses. Want to go left? Push the left bar. It's counter-intuitive but that's the way it is. Maybe some of the more motorcycle-y geeks here can explain it. I've got my motorcycle endorsement but have never owned a bike so I don't have a ton of experience.

[Jack M]

"opposite twitch" is called counter steering and over a certain speed it's the only way a two wheel vehicle will turn.

Not true. You can turn a motorcycle at any speed simply by leaning the bike that way. You can actually steer with your knees - without holding on to the handlebars.

What you can NOT do, is initiate a right turn by turning the bars right. (or a left turn by turning the bars left) However, once the turn has been established, the bars are actually turned in the direction of the turn ever so slightly, assuming proper tire inflation.

The same applies to bicycles as well. It's just that on a bicycle countersteering is not as important because it is easier to initiate a turn by leaning, since the rider is heavier than the bike. Most motorcycles are heavier than their riders, so countersteering is needed more.

What I'd like to know is why I don't think I've ever seen a bicyclist "hang off" the bike like a motorcyclist.

[tilledog]

Drop the knee, baby!

Dave

[mirror70]

What I'd like to know is why I don't think I've ever seen a bicyclist "hang off" the bike like a motorcyclist.

Because when you do that, you can't pedal.

[tilledog]

If knee dropping is warrented, pedaling is probably not feasable at that time anyway.

[skatha]

In 20+ years of road riding, I've just leaned into the turn after I pick my line....

Prior to installing aerobars in the early 90's, I could lean into a high speed turn-after picking my line, without holding onto the handlebars. With the aerobars, my front tire is too weighted down to do that-plus, I value NOT loosing my teeth more than I did when I was in my late 20's-early 30's

I do "gunboat" when I take a turn a bit slower, because I still prefer leaning into a turn than turning the handlebars into one. I also "gunboat" more down hills at higher speeds

[terror]

Get the Dyson. Your carpets will love you for it!

[Baka Dasai]

<b><a href="http://www.sheldonbrown.com/brandt/descending.html">Jobst Brandt on cornering</a></b>

Jobst is <i>the</i> cycling guru, although his perspective is very much road-riding rather than mountain-biking.

[Dave*]

See if you can find a book called " a twist of the wrist" by Keith Code, a motorcycle racing guide book I think written back in the 80s should still be in print,

great explanation of the whole countersteering phenomenon,

bunch of other usefull stuff for motor/pedal/and snowboard applications, great section on racing lines that gate bashers might find interesting

Dave*

[Guest Randy S.]

If anyone wants it, I have an abridged video of Twist of the Wrist with Code that I can send you. It came with a magazine I bought recently. Fortunately there's no Scientology crap on the video (Code's pretty into it).

[Slim]

Don't know if you heard this discussion of the science of cycling on NPR's Talk of the Nation Science Friday, but it covers some of the issues you're wondering about (it also discusses Lance's remarkable physiology).

<img src="http://tinypic.com/af8x1j.jpg" alt="KBH, Poison Spider Mesa, Moab, Utah">

[Guest Randy S.]

Oh, BTW, some people would argue that you can drag knee on a bicycle:

:lol:

[Neil Gendzwill]

What I'd like to know is why I don't think I've ever seen a bicyclist "hang off" the bike like a motorcyclist.

Not near enough gyroscopic effect from bike wheels to counter that weight.

[ncermak]

Oh, BTW, some people would argue that you can drag knee on a bicycle:

:lol:

This is what happens to the EC crowd when the snow melts...

[Speedzilla]

Not true. You can turn a motorcycle at any speed simply by leaning the bike that way. You can actually steer with your knees - without holding on to the handlebars.

Not true.

Check out Kieth Code's "No B.S." bike. They mounted a second set of handlebars to the bike, except they were mounted directly to the frame.

At this writing, we have run nearly 100 riders of all experience levels on this double barred bike. It has made believers out of every single one in the actuality of countersteering of course. At 20 to 35 mph, no matter how much you tug or push or pull or jump around on the bike, the best we saw was that the bike wiggled and became somewhat unstable. Did it turn? Not really. Would it turn at higher speed? Absolutely not.

http://www.vf750fd.com/blurbs/countercode.html

[Jack M]

Not near enough gyroscopic effect from bike wheels to counter that weight.

nah, that's not it. and mirror, you know you can't pedal in a serious corner regardless, but I think you were joking.

[Jack M]

Not true.

Check out Kieth Code's "No B.S." bike. They mounted a second set of handlebars to the bike, except they were mounted directly to the frame.

hmm, I guess I was dreaming when I did it the other day then. :rolleyes:

[Speedzilla]

hmm, I guess I was dreaming when I did it the other day then.

You welded some handlebars to the frame? ;)

[Neil Gendzwill]

nah, that's not it.

What would be "it", then? That's what I always thought it was, the wheels make the bike want to stand up straight, you hang off to force it down even more. Have I been wrong all this time?

[Jack M]

What would be "it", then? That's what I always thought it was, the wheels make the bike want to stand up straight, you hang off to force it down even more. Have I been wrong all this time?

Yeah, the gyroscopic effect has nothing to do with it. A bike with good geometry and properly inflated tires will have very "neutral" handling - that is, once you lean it over into a turn, it will stay at that lean angle by itself without any input on the handlebars from the rider. In fact, if you had a throttle lock or cruise control and a big parking lot, you could theoretically ride your moto around in a cirle all day long with no hands.

My understanding is that a motorcyclist hangs off the bike to improve cornering clearance so that hard parts of the bike don't drag on the ground (exhaust, footpegs, etc). Also, to keep the bike from rolling off the edge of the tires. By hanging off, you lower the c.o.g. of the bike/rider unit, and can therefore ride a tighter and/or faster line than the bike/tires would otherwise allow.

[NateW]

"What I'd like to know is why I don't think I've ever seen a bicyclist "hang off" the bike like a motorcyclist."

My guess: not nearly enough traction. I don't know what tire pressure you crotch-rocketeers use, but figure in the weight of the bike and rider and do a little math to find the size of the contact patch (pounds / psi = square inches), and then compare that to a 200-pound rider + bike combo with the tires pumped to 100psi (two square inches of contact patch). I'm guessing that the motorbike has a bunch larger and stickier contact patch, and that makes it possible to stay stuck under much more lateral force.

I guess you have to factor in the increased centripetal force due to the higher mass, but I suspect the bicyclist is still way behind in the traction race. Bicycle tires (street bikes anyhow) are built to minimize rolling friction, which seems rather at odds with pulling Gs.

I wonder what pressure a pedalcyclist would need in order to get a comparable contact patch. My guess is it would be stuggle to get anywhere on it.

So what's typical bike weigh, and what tire pressures are typical? Somebody give me some numbers to play with.... :)

[Derf]

I wonder what pressure a pedalcyclist would need in order to get a comparable contact patch. My guess is it would be stuggle to get anywhere on it.

You can't really lower the pressure to get more traction on a road bike because the tire wouldn't have enough lateral rigidity anymore. Sometimes poeple do this on mountain bike tires to get more traction, but there are more risks of pinch flat this way. What you could do it put on some 2" wide slicks (or wider) on a mountain bike to get more traction on the road.

[Jack M]

So what's typical bike weigh, and what tire pressures are typical? Somebody give me some numbers to play with.... :)

600cc is the most common sportbike size. The 2004 Yamaha YZF-R6 has a claimed dry weight of 357lbs. All the fluids probably bring it to 400lbs. It makes 105 peak hp. Typical tire pressures are about 30psi. I've heard that contact patches are about the size of the palm of an average hand, but that seems big to me. I would guess at speed the contact patch is no bigger than the footprint of a soda can. I've also heard that at 100mph, the contact patch is about the size of a dime, so who knows. Also the contact patch of the rear tire is larger than the front. The R6 uses a 180 series rear and 120 series front.

Consider this: a competitive MotoGP bike makes about 240 hp, weighs 319lbs with all the fluids, breaks 200mph on the longer straights, and costs over a million bucks to build.