Questions tagged [theoretical]

Any questions about calculating numbers, expected results/times or weights.

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How does bike stay balanced when the gear is on the side not in the middle

I wonder why because my road bike has crank and rear gear on right side so I thought they might lean on right side?
• 383
8k views

Why do they not sell bicycles with four wheels?

In the summertime, and Fall/Autumn, and Spring, my normal, two-wheeled bicycle works perfectly well. But then there's Winter. What is normally friendly, non-slippery asphalt and grainy forest paths ...
• 155
5k views

Can I convert a 1x9 speed bicycle to single speed by putting 9 identical cogs into cassette?

As the cogs in cassette seem separable, can it be converted into single speed by just putting the 9 identical cogs of the gear you like and retaining the rest of the gear mechanism as it was? Such a ...
• 7,879
6k views

On a long smooth descent, do brakes really heat less with intermittent hard braking compared to dragging?

It is my impression (both from experience and from online opinions) that braking on a mountain bike is to be done in intermittent hard engagement of one or both brakes. The reasoning being that ...
• 13.8k
1 vote
2k views

How much human-provided power is needed on an e-bike?

If we want to ride 50 miles (80 km) on a 35lb (15.9kg) Class 2 e-bike at an average speed of 20mph (32 km/h), how much power does the human need to provide if e-bike is on light-assist setting?
480 views

Why are disc brake calipers behind the wheel axle?

After reading this (anxiety inducing) question on a disc brake dislodging a front wheel on a brand new bike with a QR axle I wondered why the brake calipers are placed behind the axle in the first ...
• 2,301
244 views

How to model the dynamic tension distribution of a loaded bicycle wheel?

Jobst Brandt has in his book The Bicycle Wheel the results of a computer simulation of the dynamic tension distribution in a loaded bicycle wheel. However, the code of the simulation is not available. ...
• 19.2k
488 views

Wind (nano-/pico-)turbines installed on bicycles for regenerative charging of batteries?

What is the smallest wind turbine available on the market that has been installed on a bicycle? and what about R&D or even conceptual wind turbine? This question is a follow up to question why are ...
• 3,704
1k views

Is it possible to build a bicycle with magnets that somehow will ease required muscle power? [closed]

Sometimes, when I have magnets in my hands, I think - maybe it is possible to integrate this magnets into wheels or chain and move using their passive energy, without muscles at all?
303 views

How to get or build Superman Swimming bicycle? [closed]

Human body front area depending on pose in case it will be possible to ride in horizontal position drag must be way smaller as front area will be at least 5x smaller. Pardo face down HPV design. ...
• 344
380 views

Rolling resistance, comfort or puncture proof? [closed]

Edit: Adding another layer was useless, increased rolling resistance and XPS was squashed. Changed then to slider cut from old narow tyre, but best experience was changing back tyre to 623x23c - worth ...
• 344
6k views

How to decelerate during long downhill rides and avoid brake glazing

I mostly ride touristic style, and its not uncommon descents of few hundred meters or even 1000 meters (vertically, usually average gradient is around 5-10%). What's the best technique to brake to ...
• 111
1 vote
335 views

cogs for front wheel

See this wheel. Can I put two freewheel cogs on it, instead of one freewheel and one fixed? (driving clock and anti clock, so both driving forward) Then get this wheel onto front steel fork, by ...
339 views

Carbon foot print from the manufacture of bikes?

It was said on National Public Radio in the US that in most cases the carbon foot print from the exhaust off your old car would be less in a life time then carbon footprint to manufacture new cleaner ...
• 1
2k views

Would variable crank arm length be beneficial to a rider?

I was thinking it would be cool to have a bike where the crank arms can be adjusted automatically "on the fly", depending on load. If that is not so safe then maybe a manual adjustment that the ...
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