Twitchier handling with shorter stems? Interesting. Maybe I'm thinking about it the wrong way because I've always thought and felt the opposite.
A long stem means that wheel feedback (say a side impact from a rock on your wheel that we are trying to resist in a rock garden say) will have greater leverage on your hands will it not? Imagine mounting a handlebar to a manhole cover, right in the centre with no stem and then trying to twist with both hands. Now imagine trying to do the same thing (again twisting motion as we use on the bike - opposing forces with each hand) by mounting the bar on the outside rim of the cover, furtherest from the centre.
You can also imagine someone grabbing the front wheel of your bike while you try to resist a rotational force they are applying. If we were talking about our hands working in concert ie. applying a force that was in direct opposition to the rotational forces then the longer stem would supply more leverage but we can't apply a force like that. Vectors at work and all that.
The power you can generate with no stem is going to be much higher assuming a bar of equal length it seems to me. I also find that those who have issues with switchbacks on slack bikes often have longer stems. I don't have these issues. Interesting physics question and it's entirely possible I'm thinking about this the wrong way.
Physics nerds, please help!
Aug. 24, 2017, 11:53 a.m. - Cam McRae
Twitchier handling with shorter stems? Interesting. Maybe I'm thinking about it the wrong way because I've always thought and felt the opposite. A long stem means that wheel feedback (say a side impact from a rock on your wheel that we are trying to resist in a rock garden say) will have greater leverage on your hands will it not? Imagine mounting a handlebar to a manhole cover, right in the centre with no stem and then trying to twist with both hands. Now imagine trying to do the same thing (again twisting motion as we use on the bike - opposing forces with each hand) by mounting the bar on the outside rim of the cover, furtherest from the centre. You can also imagine someone grabbing the front wheel of your bike while you try to resist a rotational force they are applying. If we were talking about our hands working in concert ie. applying a force that was in direct opposition to the rotational forces then the longer stem would supply more leverage but we can't apply a force like that. Vectors at work and all that. The power you can generate with no stem is going to be much higher assuming a bar of equal length it seems to me. I also find that those who have issues with switchbacks on slack bikes often have longer stems. I don't have these issues. Interesting physics question and it's entirely possible I'm thinking about this the wrong way. Physics nerds, please help!