# riding a bike on a treadmill **URL:** \ **Category:** Factual Questions\ **Created:** [March 24, 2003, 4:27am UTC](https://boards.straightdope.com/t/riding-a-bike-on-a-treadmill/163706 "2003-03-24T04:27:21Z")\ **Posts on this page:** 4\ **Page:** 2
**Author:** ![douglips](https://avatars.discourse-cdn.com/v4/letter/d/e68b1a/32.png) [@douglips](https://boards.straightdope.com/u/douglips)\ **Post date:** [March 24, 2003, 9:36pm UTC](https://boards.straightdope.com/t/riding-a-bike-on-a-treadmill/163706/21 "2003-03-24T21:36:05Z")
> [@](#): > > \*Originally posted by EasyPhil \* > \*\* > The gyroscopic effect of the wheels has everything to do with keeping the bike stable on a set of rollers or on the ground. The faster the wheels spin, the more stable the bike. \*\* That’s not true. [Hyperphysics - Bicycle Wheel as Gyroscope](http://hyperphysics.phy-astr.gsu.edu/hbase/mechanics/bicycle.html) > [@](#): > > it should be pointed out that experiments indicate that the gyroscopic stability arising from the wheels is not a significant part of the stability of a bicycle. From [Joel Fajans’ homepage](http://ist-socrates.berkeley.edu/~fajans/Teaching/bicycles.html) you can access the 9 MB PDF file of the entire article _The Stability of the Bicycle_ - from Physics Today, 1970 (volume 23, I think.) In it, the authors conduct experiments in which they demonstrate that it is not gyroscopic action but simple fork/steering geometry that makes a bicycle stable or unstable. Sure, the faster the wheels, the more stable the bike - but it is not because of gyroscopic effects but rather because of the increased forces involved in steering inputs and in a greater sensitivity to deflections of the contact patch of the front tire. ---
**Author:** ![EasyPhil](https://avatars.discourse-cdn.com/v4/letter/e/e47c2d/32.png) [@EasyPhil](https://boards.straightdope.com/u/EasyPhil)\ **Post date:** [March 25, 2003, 2:56am UTC](https://boards.straightdope.com/t/riding-a-bike-on-a-treadmill/163706/22 "2003-03-25T02:56:12Z")
> [@](#): > > \*Originally posted by douglips \* > \*\*That’s not true. > Sure, the faster the wheels, the more stable the bike - but it is not because of gyroscopic effects but rather because of the increased forces involved in steering inputs and in a greater sensitivity to deflections of the contact patch of the front tire. \*\* Not really trying to start a debate here, but you can do a simple experiment. Get on a bicycle that’s on a set of rollers and don’t pedal and mark down how long you can balance yourself. Do the same experiment pedaling, you will find that the bike is much more stable when the wheels are spinning. ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [March 25, 2003, 3:37am UTC](https://boards.straightdope.com/t/riding-a-bike-on-a-treadmill/163706/23 "2003-03-25T03:37:39Z")
> [@](#): > > \*Originally posted by EasyPhil \* > \*\*Not really trying to start a debate here, but you can do a simple experiment. Get on a bicycle that’s on a set of rollers and don’t pedal and mark down how long you can balance yourself. Do the same experiment pedaling, you will find that the bike is much more stable when the wheels are spinning. \*\* Read **CurtC** and **douglips** ’ replies more carefully. We all agree that spinning wheels aid balance, but the question is what mechanism is in effect here. As they said, gyroscopic force is not important. What’s important is the sideways movement of the wheel. When you start falling to the right, you turn the handlebar to the right. If (and only if) the wheels are spinning, this moves the front wheel to the right. So the contact patch is now under the center of mass, and balance is regained. It’s easy to test this: just try riding in a narrow slot on the road, like a streetcar rail, so the front wheel cannot move sideways. You will not be able to balance the bike at all. ---
**Author:** ![Mandarax](https://avatars.discourse-cdn.com/v4/letter/m/df705f/32.png) [@Mandarax](https://boards.straightdope.com/u/Mandarax)\ **Post date:** [March 25, 2003, 4:30am UTC](https://boards.straightdope.com/t/riding-a-bike-on-a-treadmill/163706/24 "2003-03-25T04:30:07Z")
[Why is it easier to balance on a moving bike than a non-moving one (revisited)?](http://www.straightdope.com/mailbag/mbicycle.html) [Previous page](https://boards.straightdope.com/t/riding-a-bike-on-a-treadmill/163706.md?page=1)