Questions tagged [physics]

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17
votes
3answers
3k views

What is the effect of adding weight to a wheel vs adding it to the frame?

There are claims often made that, eg, "An ounce of weight at the rims is like adding 7 ounces of frame weight." This is "common knowledge", but a few of us are skeptical, and our crude attempts at ...
11
votes
6answers
12k views

Is it possible to estimate road grade while riding?

It would be nice to be able to estimate the grade of a road while riding, even if the estimate is not completely accurate. With a GPS, in theory it should be possible in theory to ride a short ...
23
votes
10answers
21k views

What makes a bike stay upright when moving?

What makes a bike stay upright when it is in motion? What is the relationship between speed and stability? Is it a linear relationship? I could ask this on the physics site however I am hoping ...
4
votes
4answers
586 views

Maximum Descending Speed

This is a hypothetical question but I'm curious. Assuming an endless, freshly paved road with no turns, what would be my maximum speed? EDIT My question is too general so to help I'm adding some ...
10
votes
5answers
34k views

How do I calculate the power required to climb a hill at a given cadence?

Suppose I ride at a cadence of 50RPM for 10 minutes with a 39x23 gear ratio on a hill with 10% grade. Is there a simple formula to calculate the power output required?
7
votes
3answers
3k views

What bicycle design factors affect stopping power?

I've been under the impression that bikes and motorcycles cannot stop as quickly as cars. I'm curious what factors have the largest impact on bike stopping distance. What comes to my mind are: Tire ...
2
votes
1answer
251 views

why does the lemond revolution turbo trainer quote its volume of air resistance in meter^2 and not per second cubed?

The Lemond revolution states that it creates consistent aero resistance with its fan power from 0 newtons to 40 newtons along one axis and 0 to 160 meters/second^2 on the other axis. Since air flow is ...
-1
votes
5answers
3k views

If I attached a "pointy" pool noodle to my bike, would it make me safer even from sadistic drivers?

A few sources suggest that mounting a foam pool noodle on the back of your bike can help stop drivers from passing too closely. Such noodles are available at my dollar store, unlike spring-loaded bike ...
6
votes
5answers
2k views

Riding into a headwind faster than my top speed - how is it possible?

Recently we've had some pretty strong winds here -- today the weather forecast said 20mph gusting to 30mph, but a few weeks ago the gusts were supposedly over 40mph. The forecast direction was within ...
5
votes
2answers
597 views

CdA of a bike without rider

This question at aviation.se got me calculating the acceleration of a bike strapped to the outside of a plane if the straps broke. As you do. I couldn't find a figure for CdA of a bike without rider ...
5
votes
3answers
4k views

What does a cyclocomputer actually measure for calculating the speed of the bike?

What does a cyclocomputer actually measure for calculating the speed of the bike? Is it the time for one revolution $T$ or is it the number of revolutions $n$ per given time $t_0$? If the radius of ...