[robrox]

[Feldybikes]

Yeah, motorcycles weren't the best example, but it was the first thing I thought of. But, as mentioned above, it works with bikes, too



As for what's going on physically. This awesome crayon-like drawing is supposed to be front end with the tire turning in the direction of the chevrons.



Fg = Force of gravity
FN = Normal force
FNx or y = x or y component of normal force
Fc = centripetal force
Ffr = force of friction

The net force is perpendicular to the direction of motion. This causes circular motion. Top down view:



If the force of friction isn't enough to hold the wheel(s), you drift towards the outside of the corner.

Of course, it's possible to turn by steering and not leaning the bike at all, it's just there are easier ways to do it.

And since I was not at all clear above, Vanilla Ice was there because "Cool as Ice Motorcycle" came up while I was searching for "ice" and "motorcycle." I thought it was too funny not to post, but apparently I'm the only one who thought that. C'mon, there were only like 12 movies that only made it onto laserdisc and this was one of them. WTF?!?

[polemonium]

IMO: At high speed, the turn is initiated by handlebar motion which causes the bike to tip, and the turn is continued by the lean, which provides the inward force throughout the turn. At high speed the lean provides more centripetal acceleration than the relatively small steering angle of the front wheel. This is different at low speeds where you can turn with a high steering angle and almost no lean - here the scrubbing of the front tire makes you turn.

I do believe that countersteer can be used to initiate the lean but that it's near unconscious for anyone moderately practiced at riding a bike. I'm not sure thinking about it really helps turning that much.

It's hard to actually see countersteering in action on a bike most of the time. I have an example, I think. If you ride a bike no-hands around a turn, you have to shift your weight, the handlebars pivot in the countersteer direction, the bike leans in the way you want to go, the front wheel comes back to the turn direction, and you continue around the turn with the bike leaning and the wheel near straight ahead. I tried this today, and I think that's right. Use good pavement for your test track.

[robrox]

[robrox]

[Feldybikes]

Though it looks like the front tire is pointed towards the outside of the turn, I think the front wheel is carving around the turn and the rear wheel is skidding out sideways. It's not turning as quickly as the front wheel, so it falls to the outside of the corner. It's an effect of the velocity of the rear wheel and I don't think it really has anything to do with the rear wheel being accelerated by gravity (bike) or an engine (motorcycle). Said acceleration is required to maintain the skid as friction slows the wheel down. But you can make this effect happen on flat ground, at least temporarily. I used to do this with a sweet Free Spirit 3 speed around the dirt paths on my college campus:

http://g.co/maps/vjzt2

(if anyone knows of a non-tedious way of embedding a map picture -- as in not getting a screen shot, making a .jpg and uploading it somewhere, adding a lin -- please let me know)

[hdiddy]

[robrox]

Putting plus travel rotational speed give the motorcyclist an extra tool in the kit. Adding power (producing wheel spin accelleration) changes the utility of the skidding action from being a drain on speed through the turn or in the case of a downhill turn, maintaining a rate of speed through the turn.

It's the only missing tool in the bicyclst's toolkit. The cyclist simply cannot accellerate the back wheel of leaned over bike because of pedal strike. If the possibility of pedal strike is removed, then the bicyclist can do the turn exactly like a motorcyclist. MTBs are damned fast these days so maybe that's a good thing!

Then again, It did occur to me that stored energy employed while the cranks freewheel and the chainrings are powered on turns might give the MTBer a serious advantage over his vastly heavier and bulkier motorized bretheren.

Think that over for a little bit and recall that if the cranks equate to "offset footpegs" while they freewheel, the lower center of gravity is a huge plus.

Just thinkin out loud....

...What, nobody remembers Shimano's Front Freeweeling cranks? They were very heavy and intended for lazy riders...

...but...brought into the modern era to use for descent specials....hmmmm, the potential for further development does sort of stare one right in the face
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"Moderate is not the new Low" - Chris Joosen, USFS Lead Snow Ranger (Tuckerman Ravine, White Mountains National Forest)

[Mtngrrrl]

How many telemarkers does it take to debate a mtb carve?

Really, it doesn't matter if you're on a big hit bike, on steeps, or in rocks. If you are trying to carve a turn, or keep some speed through a curve, countersteer AND (I haven't seen this mentioned yet), use your HIPS to direct the bike, just like you do in skiing. The bike will naturally follow.

[rsireland3]

Proper hip movement is essential for most worthwhile activities.
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[jfeller]

[twopass]

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DUCKBILLS FOREVER!

"Always remember, a cat looks down on man, a dog looks up to man, but a pig will look man right in the eye and see his equal."

[heyyou]

[Goombay]

[Bob T]

Burke. Lift-served. Opens 16-June. Lower Jester. Without brakes. It's massively bermed and twisty. You either commit and carve or hit a tree after flying ten feet. Compelling.