It gives the option of no sound or variable degrees of volume and timbre, controlled from the handlebar.
At the push of a thumb you can instantly create the motorbike effect and at the pull of a finger you can stop it instantly.
It is great for grown ups who want to be silly but don't want to be seen being so, or for your children so that they don't drive you crazy with continual noise.
It's an idea that I couldn't get out of my head until I constructed it.
I made it for my friend's son but first Katarina and I had fun test riding it on my bike.
( As you can see in the video, Katarina turns off the sound when she is passing a group of people; be warned, it is a bit noisy ).
It also works like a bell, a blip on the throttle and the pedestrians will move out of your way.
It's an entirely original idea, for obvious reasons; This is a very niche item.
Step 1: The Start.
I had an idea that a gear lever could some how push a card in and out of the spokes.
I thought about complex helical screws, or maybe using a single brake arm bolted onto the forks . . . but then the idea hit me; a rear de-railer from a bike has the perfect linear movement that is necessary for this project.
This became my starting point and everything that you read is the process of trial and error that led to the finished project.
The gear lever became the ' throttle '; giving a variable amount volume by pushing the card, held by the de-railer into the spokes.
Step 2: Dismantling the De-railer.
The de-railer has been in my spares box for about 15 years and now it has a chance to shine.
It's just an old 5 speed; any speed will do; in fact a front de-railer could also work.
The first move was to remove the guide wheel assembly.
This one was held on with a circlip and was easy to remove.
I also cut the housing inside so that I could use a short bolt.
I was going to use metal brackets but realised that I could re-use the guide wheel plates and bolt.
I bent the bracket at a right angle; this is where the card will sit.
Step 3: Attaching the Mechanism to the Bike.
This is my beater bike; made to look as tatty as possible.
I attached the mechanism to the front forks using the QR axle.
Step 4: Fixing the Card On
I placed the card in various positions but there was not enough overhang and the sound was too tinny and blunt.
I moved the the bracket around and bent the angle back to face the other way and eventually got the card where I wanted it.
I drilled it and bolted it on.
Step 5: The Throttle.
I found this in my box of bike bits; an old indexed gear lever.
I fitted it to the handlebars
It will be push to engage; pull to stop.
Using an old cable I fitted it using the method that you would use for a normal rear de-railer, except that the cable went along the front forks and connected to the de-railer.
The taughter the cable gets the more the card is pushed into the spokes.
The limit screws ( pictured) will stop the card going too far into the wheel.
Step 6: Tweaking.
I realised that the spring in the hanger of the de-railer allowed the whole assembly to move back slightly from the impact of the spokes.
I remedied this by putting the assembly on the other side of my forks and adjusting the card accordingly.
It still needed a bit of oomph; I added a cut down can for resonance and used the same bolt hole that holds the card on, (longer bolt and nut).
The credit card was a bit flimsy, not giving me the right sound; I hunted around for plastic to beef it up.
Milk carton was too soft.
I settled on CD plastic with the credit card in front to protect it; After some riding the cd broke.
I scoured the house finally remembering a notepad cover that I had kept because it was too good to throw away.
It was perfect.
I also cut a slit in the side of the can so that the card could actually slide inside it, to increase resonance.
After re-assembly the sound was much better and felt a lot more durable.
We had fun with it.
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