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Archive for September, 2011

Ride Report #1

September 14th, 2011 Comments off

I’ve done a few test rides in the course of the build, but now the bike’s finished I can actually go places on it.  I’ve mentioned that it’s quite hilly here; I’m up at the top, so the homeward leg of any trip is going to be an effort.

My first outing was a 6Km round trip and went pretty well. The bike is smooth and stable and predictable. The seat creaks as it flexes which is a little irritating. Braking is reassuringly solid though not up to the performance of the disc brakes on my regular bike. Shifting is vague, but a little tuning should fix that. On the flat and especially downhill it’s great, grinding back up the hill is hard work.

Details

Outbound was 2.5Km steeply downhill, and lots of fun. Due to the (deliberately) low gearing I spin out at around 40Km/h… after that I’m coasting. From what I saw on the speedometer I got to ~53Km/h which feels very fast when you’re low down. Visibility at intersections is a minor problem – sitting so far behind the front wheel means you can’t see very far left and right. Exercising a little caution overcomes this.  The return trip was hard, around 3.5Km with an average grade over 5%, some short sections over 10%. That might not sound like much but as noted here (my emphasis):

  • 2% grade does not seem very steep, but it’s enough to substantially reduce forward speed, and for most riders it will absorb more than half their power output.
  • 6% grade is enough to cut speed to well under half, and absorb more than 80% of a rider’s power output (leaving less than 20% to fight air resistance and rolling friction).
  • 10% grade, and anyone who is not a fit and frequent rider is off their bike walking — and anyone who is not a racer is reaching for all the extra power they’ve got.

The biggest problem isn’t spinning the pedals – it’s balancing. The low centre of gravity makes it difficult to stay on at very low speeds. I expect hope that will improve with practice.

Reckoning

September 11th, 2011 Comments off

Most people eventually ask how much it cost. Of course that depends on how you define it.* Here’s a list of purchases (anything else was salvaged, donated or found in the Craigslist ‘free’ section):

DescriptionCostComments
donor bike$35craigslist
plywood and foam for seat$35about 1/2 remaining
idlers$14
rod ends$24ouch
steel$58
chain and cables$45all new, rather than reused
welding supplies$50
paint and supplies$35

Say around $300 total. When the budget allows I’ll replace those tires with some slicks, maybe another $70.

Approximately comparable commercial machines are available. A local dealer has Rans and Bacchetta and Sun long wheelbase models, all of which are way out of my price range. And even if I had the money, I really can’t see myself on one of these:

This project is over and I have a unique new bike. I’ve acquired some skills and confidence and had some fun. It’s intensely satisfying to start with an idea and see it through to completion. The whole thing took way too long though. I’d guess there’s around 40-60 hours of work, so it’s a little dispiriting that it’s taken me a year to finish it.

Overall I think it’s been worthwhile… but I would say that, wouldn’t I?

The big question is, what’s next?

*I’ve included as costs any materials and components and project specific consumables. I’ve ignored anything I spent on tools because I plausibly needed them anyway and they’ll get plenty more use. I didn’t even try to account for my time.

Done

September 11th, 2011 2 comments

The bike is finished.

I’m quite happy with the result. There’s a bigger picture with more details here.

Over the course of the project I took hundreds of pictures – here’s a selection.