Chain Guard

I’ve build the MVP of chain guards for my bike today. I suffered the same problems as many beginning a new project. I hacked because it was fun without really thinking through what I was doing. I failed to recognise that I’m building an MVP and it doesn’t need to be perfect first time. It doesn’t have to be good. It doesn’t have to be pretty. It don’t even have to work well. All only needs to be an improvement and hopefully extendable.

Attempt 1

I battered a piece of corrugated iron flat and folded it into a shape somewhat like half a chain case. It kind of worked. I got the shape I wanted. The iron flattened out and with some dollies was worked into the shape I needed.

After chopping, cutting, measuring, hammering, bending and what-not it became clear that this idea would never work.

  • It was too flimsy. I slight knock would have it rubbing against the chain and/or sprocket.
  • It had some dangerously sharp edges.
  • I couldn’t work out how to mount it solid to the bike.

Time spent before giving up: 3 hours

Attempt 2

Instead of trying to mould something around the chain, I would try to just run a parallel bar along the top of the chain. My jeans would be pushed aside without touching it and the job would be done.

I found some c-channel. I found a bolt that I could use to mount to the chain-guard hole in the frame. I made a piece to connect the c-channel to the frame and screwed it down. It worked. It kind of sat in the right spot but one small knock would have it bent right out of shape. Again like my first attempt, I still couldn’t find a way to mount it solid to the bike.

I tried to over-engineer it by cutting slots so it could be bent to follow the curve of the sprocket. I quickly gave up on that idea because if got a knock from below it would easily bend and quickly break.

  • Too flimsy still.
  • Still couldn’t mount it to the bike.

Time spent before giving up: 1.5 hours

Attempt 3

My third attempt is one of my more nasty hacks. It closely resembles the good enough principle. I had an off-cut from another job I’ve been working on that I thought could work as a minimal chain guard. I ran into the same problem as in my previous attempt when I couldn’t find a way to mount it. It had a series of holes which I decided to lace it on with some rope. Yep, it’s a really nasty hack but I think it’s good enough.

Bike Front Back Inside

  • It may not offer enough coverage to protect my jeans from chain oil.
  • It may get knocked out of place easily.
  • The knot may not hold.

Time spent: 30 minutes