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Without going into great details for the reasons behind it, people in The City travel everywhere by bicycle.

There are no stairs or lifts (elevators) in high rise buildings and no safe parking spaces for bikes at ground level.

To reach their home or office in a high-rise building, cyclists must cycle up the vertical face of the building and enter through a window.

I'm looking for a realistic way to implement this. Whatever the solution, it must not involve outside help, either human or mechanical. The bike rider must use only pedal-power and stay on the bike at all times while it is moving.

Here's what I have so far. The bike is only slightly modified. It has a spool mounted on the rear wheel that uses friction to climb the rope. It also has 'spikes' sticking out of the hubs of each wheel (these are described below).

The building has a rope hanging down and the cyclist winds it once around the spool. The rider then slots the spikes which are extensions of front and rear axles into two vertical slotted rails that extend up the whole building.

The cyclist then rides up the side of the building to the required height.

Question

Are there any theoretical or engineering factors that make this setup impossible? Note: I am not asking whether the idea is sensible.

What, if anything, is bad about my design from an engineering point of view and (without investing in a lot of extra machinery) what could be improved?

From a strictly practical angle, there are two problems I can see.

1: Coming back down. Would you go headfirst?

2: Body weight no longer useful to push against. This is a bigger problem. A bike is meant to support from below and the rider uses his/her own weight to press against. Pushing my leg against the pedal pushes the pedal down and my body up. At this angle. gravity does not pull me back down towards the bike. Tilting the bike 90 degrees means the rider can no longer push down using body weight.

The solution to both issues is to keep the bicycle aligned the same way it is on the ground. This video shows an invention that does exactly this, for much the same purposes you want.

https://www.youtube.com/watch?v=TANb2p-HwlE

Thinking a little further, counterweights (as with an elevator) would be very useful here. They would slow descent and provide gravitation potential energy to aid ascent.

I worry that these prosaic considerations violate the rule of cool. What you want is for a bike rider to zoom up to the building and just keep going straight up. Ropes are fussy too. What you need is a harness clipping you to the seat so you can push down at any angle, and wheels that lock into a track and are held against it.

I think your biggest limitation is the human.

Your setup is meant to lift a cyclist of mass M at a certain velocity V directly against the pull of gravity.

Let's say your cyclist (and their bike) weighs 80 kg, that makes 800 N.

The world best cyclists, properly trained for the task, can produce a peak power of 2500 W for no more than 10 seconds, while during a climb on the mountains a more accurate power output is about 450 W.

This means that the climb velocity could be at best around 3 m/s for about 10 seconds, or 0.5 m/s for sustained effort. Not bad, you might think.

But we are talking about trained (and possibly doped) athletes. If we take a more normal person, the power output is lower. Let's take myself, not an athlete but at least used to cycle on long distances, I can produce about 120 W (extrapolated by timing a climb on a road of known length and slope). This means I would climb the building at 0.1 m/s. I can climb normal stairs at higher velocity and with less struggle.

If I had to choose, I would take the bike on my back and go for the stairs.

Reality Check:

FAIL

Rationale: Your scenario makes two competing and altercancelling claims. First, you state that people must ride their bikes up the side of a building in such a way that it must not involve outside help, either human or mechanical. Second, you depict an assistive mechanism constructed of simple machines. Your rails act as stationary levers keeping the bicycle in alignment. Your rope and friction spool act as a pulley system. Machines (apart from the human and the bicycle) count as outside help. Therefore, I'd say your premise fails the reality check.

If it weren't for your competing claims, I'd say the exact opposite. Bicycle powered elevators are a thing:

And while I find it odd that people would build high rise dwellings without stairs of any kind, that I'd chalk up to cultural oddity. There are primary world buildings (often monasteries) that can only be accessed by climbing up or being hoisted up the outside. And of course, Rapunzel's posh downtown Amsterdam flat could only be accessed in this fashion as well.

Rescue: You will need to figure out which basic element of your premise is more important: bicycles or no outside help. I believe that if you sacrificed the no outside help element, these people could easily construct elevators that accommodate and interface with a resident's bicycle.

I don't know what will happen in a busy office building where dozens go either up or down in one minute. All is without distinguishing which rail is currently being used to go up or to go down. There must be a central control system to avoid vertical traffic jams, as well as avoiding someone from sliding down at full speed regardless of whether there is someone along the way.

You need:

1. The bike seat must ba adjusted so you may lean to while going either way.




2. Separate tracks for up and down.




3. Built-in clamping device which connects the red cable.




4. Good timing: exit the window when nobody passes by it




5. Safety device: what if few people are on the same track and the cable snaps?




6. Children climbing walls? Wheelchairs? Mothers with babies? A crippled grandmother? Can you help them?




7. Black glasses (so you won't look down)




8. Find a way to move in and out of the vertical position to your floor or street. That's too awkward.

Solutions:

1. Paddle-powered platform. Has few seats so that each one paddles, not just one. A paddle wheel is mounted at each level so that you can bring the platform to you. The same platform must therefore move either way. The platform's weight is counteracted with counterweights. The cable below may be of differnt color than the one above it, so by looking at the cable, you know if the platform is above you or below you. Still, no central security control. You want to use it and someone else tries to get it at the same time. What to do?




2. Stairs. Always worked, be it under fires or earthquakes or blackouts.