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When you are riding down a straight line (such as on the rode) on a bike, and you turn right, must the rear tire of the bike cross the line to its left, or does it never veer to the left? Thanks.

There is no reason why the rear tire should veer to the left, but it can if you are making a hard right turn and want to get started on the turn from further out into the road (tighter turns are harder).

Arthur Smith

I would have to reply that the rear tire must move left -- but probably not enough to measure very well. When riding in a straight line you are(presumably) balanced over the tires. If you turn your front tire to the right to turn to the right you are immediately thrown off-balance and off of the bike. In order to make a right turn you must adjust your center of mass to be to the right of the wheels by turning slightly to the left and then back to the right. The tightness of the turn must be matched to how far you lean the bike. Any time you are turning a bike you are essentially falling. Turning your handlebars into the direction of the fall causes the net force on you center of mass to change from downward to be toward where your wheels contact the road. Experienced cyclists (and not much experience is needed!) do not notice that they are actually turning to the left just before a right turn because they are continually adjusting their wheels to correct their balance. When they want to make a right turn they just stop correcting (for falls to the right) until they have started turning.

gregory r bradburn

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