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Two for Three

March 26th, 2013 Comments off

As in Build #2, and three wheels. I’m starting on a recumbent trike…

Tweak List

June 22nd, 2012 Comments off

I’ve done a couple of hundred km and whilst it’s been lots of fun I feel there are a few minor alterations needed. I’ll keep riding and thinking about what could be better until the weather turns crappy in the fall. By then I’ll have a (not too long?) list of tweaks, including:

  • handlebars – when relaxed (which is all the time I’m riding!) my hands naturally fall 4″ or so forward of the brake levers and shifters. I’ll trim the bars to suit my reach.
  • seat  – the glue attaching the foam to the seat isn’t very strong. The layers slowly slide over each other so that at the end of a ride the topmost one needs to be peeled off and repositioned.
  • cargo rack – I adapted an old rack to fit the space available, but it’s flimsy and doesn’t really work. A better solution is needed, including a strong but flexible connection to the back of the seat.

I’ll add any more stuff here as it comes up.

Ride Report #2

October 9th, 2011 Comments off

A slightly longer trip, with over an hour on the move giving me time to focus on how the bike handles and to enjoy the ride. I did 10Km up the Seymour Valley Trailway before I ran out of time and had to turn around and ride back. That 20Km plus the five or so to and from the trailhead made for a decent run.

Overall it was a similar experience to the previous ride – a treat on the flat, exciting downhill, a workout when climbing. The trail is paved but much of it was covered in wet leaves. This made me a little tentative, my top speed being just shy of 50Km/h. I spent a lot of time in the 5-10Km/h range hauling up hill (but balancing reasonably). I didn’t have to get off and walk on any of it, which pleasantly surprised me because last time the climbing was challenging. Mostly I just cruised along having a very nice time.

There’s some bob at low revs but generally everything feels fine. I’ve been thinking about how to adapt my old rack so next time I can take a pack with me. No other tweaks required.

The bike is pretty and unusual so it attracts a lot of attention. Several people asked me where I bought it and how much it cost and seemed surprised when told it’s hand made. That’s a nice feeling.

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.

Build

August 28th, 2011 Comments off

I’ve had quite a bit of practice at putting this machine together, so it didn’t take too long to get from a box of parts to this:

Next I’ll apply the graphics, then restring the chain and add some pedals. Below, closer views of the front and rear.

Paint Job

August 27th, 2011 Comments off

Back in the paint shop – black and yellow topcoats drying in the sun.

The black went on nicely, and looks OK. The yellow – not so much. Getting a decent finish is hard, and demands skills and patience that I don’t have. It looks just passable from a distance, and I’ve no appetite for sanding it down and starting again. Next time I’d take more time, and maybe not go with such a light colour. Perhaps there’s a reason so many home-built bikes are full flat black.

That tiny red dot at the top of the seat tube is a 3 ball. Along with the carefully designed seat it’ll help when manhandling the bike. It adds a little retro chic too.

This picture also shows the ‘fade to black’ effect I attempted on the frame. The curve in the main tube is no optical illusion. I don’t know if it got that way from post-welding contraction (visible here?) or overloading while riding. It’s not getting measurably worse and there’s no cracking so I’m not unduly concerned.

Watching paint dry…

August 3rd, 2011 Comments off

Quintessentially dull, but I’ve been looking forward to reaching this stage for quite some time. Here are some freshly primed parts hanging in the high-tech paint shop:

Beginning of the End

July 31st, 2011 Comments off

Riding then tweaking then more riding. The only addition is some rubber mounts I made to isolate the seat from the frame. That’s it – things are as good as they’re going to get given my limited patience.

So the bike is dismantled and preparation for painting is underway. An angle grinder equipped with a wire-brush demands caution and respect, but makes short work of surface rust and welding scale. It all cleaned up a treat – here’s one of the braze-ons:

The first coat of primer will go on soon: the end is nigh.