Work associated with different wheel sizes on bicycles

  • Thread starter cbwieczorek
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In summary, changing the wheel size from 26" to 29" on a bicycle can impact the amount of effort required by a rider on an incline. This is due to the larger radius giving more angular momentum, which makes it harder to turn but also allows for higher velocity. However, there is no free energy gained from this change and the ride may be smoother but also slightly heavier. The larger wheel size may be beneficial for downhill mountain biking due to the increased angular momentum.
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cbwieczorek
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Hello, I'm wondering if someone can help with a little question I have regarding bicycle wheel size and the work associated with keeping it moving. I'm trying to understand how changing the wheel size (effective circumfrance) from 26" to 29" may impact the ammont of effort required by a bicycle racer while on an incline. Assuming the wheel weight is constant and disregarding exterior forces other than gravity how might one go about comparing the two? What I mean is does the simple physics of size play a role in work? I assume it does because a large protion of a bicycle wheel's weight is in the rim and tire, which is near the outer edge of the wheel and should affect rotational inertia, right?

Thanks,

C
 
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Having a larger radius gives you more angular momentum which will make it a bit harder to turn with better stability r x p = L

The larger wheel gives you a longer circumference. Which means your bike moves further across the ground with each petal rotation, and it takes more work, but you go further in less time (higher velocity). You will not get any free energy out of it though, it is no different than changing gears. This is why the original bikes had huge wheels, before gears where in place.

The ride is smoother due to longer spokes which bend more and absorb shock. For road racing this may not be a good thing as there is a slight transfer of momentum to heat.

The bike will be a bit heavier overall, gravity is a conservative force though.

I ride with a guy who switched to 29ers about a year ago and that's all he talks about now. The extra angular momentum can be helpful in downhill mt biking. He is going to build another one and let me try it out soon.
 
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1. How does wheel size affect the speed of a bicycle?

Wheel size can affect the speed of a bicycle in a few ways. Smaller wheels have a shorter circumference, meaning they will make fewer rotations for the same distance traveled compared to larger wheels. This can result in a lower top speed. However, smaller wheels also have a lower rotational inertia, making them easier to accelerate and maintain speed. Additionally, larger wheels have a larger contact patch with the ground, providing more stability and grip, which can also impact speed.

2. Does using a larger wheel size require more effort to pedal?

Yes, using a larger wheel size will require more effort to pedal compared to a smaller wheel size. This is because the larger wheel has a greater rotational inertia, meaning it will take more energy to get it moving and to maintain its speed. However, once the larger wheel is in motion, it will maintain its speed more easily due to its larger contact patch with the ground.

3. Can changing the wheel size affect the handling and maneuverability of a bicycle?

Yes, changing the wheel size can significantly impact the handling and maneuverability of a bicycle. Smaller wheels are more agile and responsive, making it easier to turn and maneuver quickly. On the other hand, larger wheels have a more stable and smoother ride, making them better for long distances and rough terrain.

4. Are there any other factors to consider when choosing a wheel size for a bicycle?

Yes, there are a few other factors to consider when choosing a wheel size for a bicycle. These include the terrain you will be riding on, the type of riding you will be doing (e.g. racing, commuting, mountain biking), and your personal preferences. For example, smaller wheels are better for off-road and technical terrain, while larger wheels are more suitable for road and smoother surfaces.

5. Can changing the wheel size affect the overall performance of a bicycle?

Yes, changing the wheel size can have a significant impact on the overall performance of a bicycle. As mentioned before, different wheel sizes can affect speed, effort required to pedal, and handling/ maneuverability. It's essential to choose a wheel size that aligns with your riding goals and preferences to achieve the best performance on your bicycle.

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