What would happen if I ride my bike onto a moving conveyor?

Factual Questions
1

You know the type. The ones you see at Disney World or Denver International Airport. The kind that are flat, at ground level, and travel at approximately walking speed (maybe 5 miles per hour or so).

Anyway, what happens if I`m riding a bicycle through the airport peddeling at the same speed as the conveyor (5 MPH) and I ride onto the conveyor.

If the conveyor is traveling at 5 miles per hour towards me would I stop instantly?

Likewise, if I ride onto the conveyor as it travels 5 miles per hour away from me would I suddenly accelerate to 10 miles per hour?

I`m having a hard time picturing what happens to the tires at initial contact with the conveyor and how that physically affects the travel of the bike.

Play around with different speeds if you wish.

2

Riding the bike onto a conveyor moving toward you would feel a little like hitting a sudden incline; what is essentially happening is that you’re travelling at a certain speed relative to the ground and suddenly the ground wants to move more quickly underneath you, but in order to maintain your forward speed (relative to the world, not the conveyor) you have to work harder.

If you try it on foot, you’ll probably go head over heels; you start off running at 5mph, so the ground is coming at you at 5mph, you hit the conveyor and you’re still moving at 5mph, but the ground is now coming at you at 10mph, your footsteps aren’t adequately forceful or fast to keep you upright and you fall forwards.

3

I can only comment about what happens when you ride on static rollers, which I have also done on board ship during my navy days.

If you ride toward the conveyor at some speed, your forward momentum will try to remain the same, however, the rate of rotation of the wheels will want to suddenly alter.

As your front wheel hits, it will try suddenly to adjust speed, and since its mass is fairly small compared to your total moving mass, it will probably do this easily enough, there will be some change to your balance and this might need some adjustment on your part.

When the back wheel hits, it would be better if you were not pedalling at the time as you would find this wheel spins up a bit faster, which would mean your effort on the pedals would reduce suddenly. Your leggs would then speed up suddenly for a moment and that might be enough to cause you to wobble somewhat.
You will slow down a little and quite suddenly as the tyre grips and the wheels have to change their speed of rotation.

The trick is to build up enough speed to roll fairly quickly onto the conveyor, your own forward momentum will keep you going onwards for a time during which you can get your pedalling going again after the transition from fixed surface to conveyor.

On static rollers sometimes you get the reverse, sometimes you are pedalling so hard that you wobble a bit too much and drop off the side of the rollers.
The only moving parts are the rollers themselve and the transmission, including the wheels, and your body and bike mass are far greater than thse, so whathappend is tha the wheels spin up rapidly as it drops off the roller, and stops very suddenly as it hits the ground.
There is not enough energy to drive you forward, though the side of the tyres might kick on the side of the rollers, which kick backwards at a lick.
The sudden transitions usually causes one to fall sideways, which is why it is not a bad idea for the inexperienced static roller rider to be inches close to a wall to prop up in such and event.

When at sea on board a ship it demands huge concentration, the slightest movement needs adjustment, the worst its when you are pitched forward and backwards on the rollers as it transfers body weight backward and forward onto one or th ether wheel which makes keeping a regular cadence difficult.

4

Short answer: Your bicycle will be jostled momentarily–unless you’re a klutz–and then your relative speed to the ground will increase by 5 mph.

5

But if Im going 5 MPH in one direction and the conveyor is going 5 MPH towrds me wouldnt the first tire to touch the conveyor just stop? Would the rider feel the same effect as if he had just hit the front brakes?

I know, once your on the conveyor your speed becomes relative to the conveyor and not the surrounding environment. At 5 MPH you would not be making any net progress. I still can`t get my brain around the initial transition.
I have the same trouble picturing a car driving up onto a moving ramp (like one hanging out the back of a truck trailor).

6

I think Im seeing it now. Wouldnt the more abrupt change occur when the conveyor is moving AWAY from the bike at speed.
With the conveyor moving towards the bike the initial interaction is like two meshing gears. With the conveyor moving away from the bike the tire rotation suddently changes to the opposite direction.

7

I think you’re right actually

8

If you attempt to ride onto a conveyor belt your wheels would stop relative to the belt. Gyroscopic forces of the wheels would cease and you would basically be attempting to balance on a bike standing still.

9

For a split second maybe. Which direction are you referring to?

If the conveyor is moving towards you then the tires would NOT stop relative to the conveyor. You would stop moving relative to your surroundings, not the conveyor.

10

I’m fairly certain that it’s your momentum that is the important thing.

If you are freewheeling, it is greatly simplified:

Say you are moving at 10mph towards a conveyor which is going at 5mph in the same direction as you are. You will continue at more or less the same speed relative to the ground, ie 5mph relative to the conveyor. The wheels will now be rotating more slowly. The reason for this is that the conveyor will not transfer its momentum to you - the wheels can rotate freely (if you ignore friction) so all the conveyor will be doing is rapidly slowing the rotation of the wheels.

If the conveyor is going 5mph towards you, again, your speed relative to the ground will not change a great deal, but now you will be moving 15mph relative to the conveyor. In this case your momentum will cause the wheels to spin faster while you maintain the same velocity (again ignoring friction).

If the conveyor is going in the same direction as you but faster, say 20mph when you are going 10mph, you will end up going backwards relative to the conveyor, and your wheels will start spinning backwards as they go onto it. As long as you are freewheeling, this won’t be a problem… if you are pedalling it might be nasty!

11

Just to clarify, I certainly disagree with this. Just because you are now on a conveyor, your forward momentum (relative to the ground) isn’t suddenly going to disappear. Think about it - the conveyor is only pushing on your tyres, which are free to spin. There’s nothing that would stop you moving forwards, other than a little bit of friction due to the increased speed of rotation at the wheel bearings.

12

Right, you would still be travelling at five miles per hour in contrast to your surroundings and 10 miles per hour in relation to the conveyor. That is until you lost your momentum. At that point you would have to begin pedaling at a 10 mile per hour clip to continue at the five MPH in relation to the surroundings.

13

I saw a stunt on TV where a motorcyclist drove onto a moving car carrier with the ramp down and jumped off the front. There was a definite lurch as the motorcycle entered the ramp, partly from the sudden change of relative speed, and partly because the motorcycle had to accelerate quickly to clear the front of the car carrier.