Village Idiot

So how far can you lean off a road bike when taking a corner without toppling over?

I mean, that's how motorcycles turn. Would you be faster in a corner where you wouldn't lose much momentum without pedaling by dropping over and down to lower your center of gravity so you could make it through the turn faster than trying to pedal and leaning like normal?

I'm not talking about putting a knee down, but about getting the butt almost completely off the seat.

kamalster

I think the tread on racing motorbike tires are curved up into the sidewall to support the hard lean. A bicycle tire would probably just slide right out from under you if you leaned that far.

AEO

?

Darth_Firebolt

motorycles turn by turning the handlebars, just like bicycles. the leaning is a side effect.

if you want to know how far you can lean a bicycle over, ask Menshov.

sijray21

leaning off will allow more surface area for the tire during the turn, but i'm much more hesitant to test the limits of the road bike since there could be cars and the dinky helmet plus no gear kind of scares me. i do get my butt off the seat and put my weight on the outside pedal. with a motorcycle background i found that i do carry more speed through the turns than most of the other group riders i ride with. momentum FTW! it really helps on sharper turns that lead up to a hill.

oddly enough i don't have a problem on the race track with the motorcycle though

merlinextraligh

Incorrect. Read the various threads about countersteering. You turn a bicycle (at speeds above a walking pace) by countersteering to induce lean, which in turn, turns the bike.

So yes you turn the handlebars, but you turn the handlebars for the purpose of making the bike lean. The lean is not a side effect; it's what makes the bike turn.

Village Idiot

Leaning has everything to do with turning on a motorcycle when you're starting to push the limits. Leaning yourself off the bike towards the ground lowers your center of gravity and allows the bike to stay more upright, which in turn allows the bike to be able to lean farther while going faster.

AEO

full body suit with kevlar pads and titanium plates versus your skin.

actually with the short wheel bases of road bikes, I wonder what the turning radius is.

Village Idiot

So why don't bicycle racers have suits and helmets that allow balls out without worrying about tearing yourself up too badly? They don't have to be as big and heavy as a full leather suit of course, just enough there to offer some protection.

Darth_Firebolt

i think this pretty much proves everything i was going to say before i even say it.
i've ridden for 14 years, raced for 7, and i'm 19. you aren't explaining anything *correctly* to me.

because the tires won't handle it, and they can't go fast enough to counteract the force of gravity pulling them over when they lean past a certain point.

Village Idiot

I didn't say that you could turn a motorcycle without turning the handlebars, I said that once you start to push the limits, than it has everything to do with the turning. Body position affects CoG which affects how far you can lean. Controlling lean angle lets you go faster by not leaning the bike as far and giving you more ground clearance vs. speed than if you were inline with the bike itself.

Looks like I got 7 years on you if you want to count the little 50cc my dad had me on when we would hit up where he was teaching the MSF course at.

AEO

too hot.
any extra padding gets uncomfortable, sweaty and a source for chafing after a while.

well, there is an event like that. disc brake 29'er with drops or a disc CX bike, equipped with slicks, going as fast as you can downhill on a paved road, with full protection.
I can't remember the name of the event, unfortunately.

Darth_Firebolt

i'm going to do everyone a favor and never reply to any of your posts ever again, because i obviously have zero knowledge of anything with two wheels. at all.

preach on, motorcycling god.

Village Idiot

calamarichris

Two major reasons a motorcycle can almost always take a turn faster than a bicycle:
1) Tire contact patch with asphalt: A motorcycle is riding on two patches almost the size of dollar bills; whereas a typical road bike is riding on two contact patches about the size of nickels. Also the motorcycle contact patches are gooier and more compliant than the comparatively hard, inflexible contact patches on the road bike (which are better at reducing rolling resistance and more aerodynamic.)

2) Motorcycling gear. I passed a motorcycle (admittedly an older guy in jeans on a non-sport bike) and two cars my last time down Palomar on my Felt, but I would never take a hairpin at 50 on my bicycle like I do with my Kawasaki.

rob!

Like already stated, motorcycles have a larger contact with the ground, and are stickier tires.

Motorcycles are heavier, which is more force pushing against the ground.

And you aren't going to lean very much unless you're going very fast on a very tight turn, which would not be very likely on a bicycle. It's simple mechanics.

tribble222

If you watch some of the fast descents on the TDF you'll notice the riders sticking out their knee. I'm sure it helps keep the bike more upright to take the corner a little faster, but like everyone said, the tires just don't allow you to lean over too far.

EventServices

As far as my knowledge takes me, the trouble you'll have is with the constant loss of speed on the bicycle. With the motorcycle, you're accelerating halfway through the turn. Try pedaling the bike when you're butt is off to one side.

calamarichris

In addition to shifting your CoG, sticking your knee out also turns it into an air-brake both to slow for the turn, and to sharpen your turning angle.
For example: if you coast with your hands off the bars and stick out your left hand, your direction of travel will be altered to the left.

prathmann

Motorcycle tires are generally more optimized for traction whereas bicycle tires are more concerned with rolling resistance. But the maximum speed through a downhill turn isn't all that different with the motorcycle only having a slight edge. Both are limited to about 1G of lateral acceleration when on a flat road - i.e. the center-of-gravity will be at a lean angle of 45 degrees from the contact patch of the tires. Here's a picture of Jobst Brandt when he was testing tires for Avocet.

Mose

Because this is an unfortunate part of my nature, I thought I'd pop in to correct some of the arm chair physcis here.

Tire contact patch alone doesn't determine corning ability. The weight of the turning object plays as important a role. Yes, greater weight means greater normal force (to the ground) and greater static frictional force HOWEVER when an object is turning it is accelerating (changing velocity... yes, the velocity changes even if the speed is constant). To change velocity (accelerate) requires force. Newton's second law of motion tells us that a greater mass requires greater force to create the same acceleration.

So a bicycle does not necessary need tires the size of a motorcycle's to corner at the same rate as a motorcycle because it is so much lighter and thus requires less force to turn.

This does not mean I'm implying a bicycle can out corner a motorcycle. I'm just saying there is much more to the whole equation than contact patch size, or even the amount of static frictional force created.

Village Idiot

That ^^

DScott

This much:



Or, this much:



It depends.

big john

There was an event here called the Red Bull Road Rage, downhill only on whatever bike you want, (no fairings or bents). Leathers were optional, and the event was won by Miles Rockwell on a standard road bike.

San Rensho 

Its hard to hang off a bicycle because your inside leg is all the way up and your outside leg is fully extended, so you can't get your center of mass over very far to the inside. With a motorcycle, you have both legs bent quite a bit at the knees, which lets you throw your weight way over the centerline of the bike.