Category Archives: Chain

How to tension a chain

Would have liked to wait for the right bike to show up at the recycling centre, but time was slipping by. So I bought a lighter chain wheel to replace the one used to test the concept.

Might be placebo, the power of suggestion, or perhaps I’m getting fitter… but I was able to pedal so hard that the alternator generated 17.9 volts. A new personal best! 🙂

If you want the details, this pic shows the chain wheel specs.

Chain tensioning

Spotting my chain problems, one kind visitor took the trouble to make contact and give me this tip. It’s made a big difference to my confidence while pedaling. So I’m sharing it in case it helps others.

The chainwheel inserted here is from a kid’s bike dumped at the local authority recycling yard. It is a bit heavy and you can see the effect on the chain. Mountain bikes and racers would have lighter pedal sprockets. So I’ll be checking the recycling centre often. Sure, I could probably buy one. But I prefer the idea of rescuing / re-using parts from bikes others think are only worth throwing out.

Meanwhile I can relax while pedalling and make electricity in comfort 🙂

I’m not HEAVY enough-!!

The inspiration can be slow sometimes…

… but my battery weighs a good 20-25kg and seems weighty enough to keep the back-end of the pallet from jumping so much.  Which is great in that the impact vibrations are practically nil on the alternator now.

But now there’s a new problem: I’M NOT HEAVY ENOUGH-!!

I thought my weight would be sufficient to hold the bike stand (& bike) down onto the pallet. That there would be no need to clamp the turbo trainer down onto the pallet.

But last night there were plenty of small lift-offs during a 23-min pedal. Which put me in mind of cycling along a bumpy Irish road (although the bumps in this instance were regular and predictable!).

Hard to tell while pedalling and looking over my shoulder, but the bike jumping up might be due to a combination of

  • the chain between bike and alternator being too taut so the bike now wants to move back toward the alternator (seeing as the alternator can’t move forward now, the bike moves backward toward it);
  • the pallet wood being too soft and so starts to bend up under the tension.

So it looks like a better pallet is definitely on for starters. A ‘euro’ pallet would do nicely. Hopefully that, combined with a less taut chain,* will resolve things. If not then I’ll have to invent a brace from alternator to bike stand.

More tweaking-fun ahead-!!

 * Should just be a matter of moving the chocks holding the turbo trainer in place. Simple job of unscrewing and moving them back slightly.

Video of the turbike!

Sorry!  Forgot to post the video of The Turbike. In time I’ll start putting up some guidelines re how to make it, design considerations etc. But the basics of what’s needed are:

  1. a frame to hold the bike steady
  2. a frame to hold the turbine alternator steady (the forces are quite strong on it)
  3. a turbine alternator (mine is the 3m one from Hugh’s Recipe Book)
  4. all the bits & bobs needed for getting the electricity to (and from) the battery
  5. a bike you won’t be in a hurry to disengage and take out on the road!

Here’s how The Turbike looks and works so far:

I’ll do some posts about the reality of pedaling and regenerating my office’s power as soon as I get more experience of that.