Plenty of Bikes

15 04 2012

It’s obvious why any cyclist would be excited with the arrival of warmer weather (though it’s snowing again as I write this, but it’s a warm snow storm). Spring is doubly sweet for me because I finally get to deploy the Sustain SU bikes that I’ve been working on all winter. The Sustain SU Bike Library lends out bikes to U of A students & staff for a month at a time, and nobody ever walks away sad after getting a bike with only a $40 deposit.

The bike library after a crazy busy rental day.

I wanted to get a picture of the whole fleet, but I didn’t have time before half of them went out the door. Oh well, with such a small space I can only pull so many bikes off their hangers at any given time, even after I’ve cleared out all the scrap rubber & metal.

A season's worth of scrap metal & rubber: three bins of rubber, one of metal, a box of cables & housing, and a bunch more wheels, tires & frames on top, all headed off via bicycle power for recycling. I'm a truck. This is what I was up to when I broke my fender stay.

While I’ve been turning wrenches and generating scrap rubber, the Campus Sustainability Volunteers have been working on profiling all the bikes for Plenty of Bikes, our new approach to matching people with bicycles. And now (drumroll please!), I’m proud to share the brand new Plenty of Bikes video!

I cannot understate how giddy this makes me. The volunteers did a fantastic job!

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A Brief Public Service Announcement on Locking Your Bike

27 05 2011

Sometimes I’ll see a poorly locked bike, and I’ll want to leave a note for its rider about how to properly secure it, but I never do because I worry that said note will attract the attention of opportunistic thieves.

Today was a little different though, because the bike in question was an ECOS bike, one of the fleet of bikes I maintain for the the University’s bike library, and guess who recently organized all the spare keys? The bike was locked over the handlebars, with a brake cable being the only thing actually securing the lock to the bike. (I forgot to take a before picture. Sorry.)

So, thanks to a spare key, let me demonstrate how to properly lock your bike:

The U-lock goes through the frame, wheel and bike rack. If this bike had a quick release back wheel, it would also need to be secured with a cable or additional lock.

Locking your wheels as well as your frame may seem like overkill, but this is campus, next to an LRT station, and the entire area is littered with bike carcasses from riders who didn’t bother to lock the wheels they wanted to keep.

In retrospect, I should've included some introductory niceties.

So I wrote the cheeky note. It turns out it wasn’t necessary because the lady who rented the bike came for it as I was leaving. I introduced myself to her and explained what I had done and why. She seemed quite surprised by the whole encounter, and I’m worried I might have scared her, even though we were both smiling by the end. Hopefully I’ll see her again when she returns the bike and we can have a laugh about the whole episode.





Positron-ic!

1 02 2011

In the late 70’s, Shimano introduced its first mass market attempt at indexed derailleur shifting, Positron. There were several versions of it, starting with a dual cable version, and none of them stuck around for very long. The consensus of most of the research I’ve done on it is “good riddance.”

As I’ve been fixing up more bikes to add to the ECOS bike library, I came across one with this evolutionary dead end of a gearing system (version II to be exact). It was a cute little cruiser with a quirky shifter, and in the rush to get it stripped down and painted green, I initially didn’t realize how much of an oddball I had on my hands.

The Positron shifter. Chunky but still pretty cute, eh?

The more I examined it, the stranger it got. My second clue that I wasn’t dealing with anything like I’d ever repaired before came when I saw the “cable,” which technically isn’t a cable but a thick wire. On the derailleur, there is only one limit screw, and no springs. In the shifter, there’s neither friction nor a clicking mechanism to keep it in place. I also found that the freewheel was quite stiff, so I ran a whole bunch of oil through it and let it work through while I hit the books (er, interweb)  to try to figure out how to make it all function.

The Positron II derailleur. Notice the single limit screw and the solid wire instead of cable.

Positron is different than modern derailleurs that use a spring to return the derailleur to “normal” (high gear, except on low-normal derailleurs) when tension is relaxed on the cable. There is no tension on the Positron wire, instead it works by directly pushing and pulling the derailleur back and forth. There are five notches in the derailleur, which hold it in gear instead of springing back into high when the tension is released.

The Positron derailleur from the back. Note the saw toothed indexing mechanism that clicks each gear into place. In modern systems, the indexing action is in the shifter.

And the freewheel? It’s supposed to be stiff (though this bike may now have the loosest one around). If you’ve ever had a stiff freewheel, you know how annoying it can be as it either shifts itself into higher gears as you’re slowing down or just throws off the chain. But this doesn’t seem to be an issue with the Positron because of the lack of derailleur spring.

This springlessness also changes the strategy for adjusting the gears. After making sure the frame and derailleur were properly aligned (and bending both back into shape), I set the wire “tension” by moving the derailleur into the lowest gear and pulling the shifter down as low as it would go and tightening the pinch bolt. Then, I set the limit screw, which corresponds to the highest gear. Once I quit trying to set it up like conventional gearing, the shifter worked beautifully.

ECOS bike #38, ready to roll.

When I first met this bike, it was a sad little rusty brown Venture with a misaligned frame. Now, after a whole lot of elbow grease, it has been reborn as ECOS bike #38, ready to be loaned out and ridden again by a U of A student this spring. I took her for a little test ride in the basement corridors of SUB, and it made me glow inside when two different people randomly came up to me and said “nice bike,” (I wish I had a “before” picture). And it’s such a sweet ride – both peppy and comfortably upright, it reminded me of Marjory.

I’ll worry about it, though. The chances of finding a replacement Positron part, should I ever need one, are slim to none, and it would be easier to replace the shifter, cable, derailleur and freewheel with something more common (an old SunTour friction setup would be nice) in that situation. None of the sources on the net I looked at had any love for Positron, and even though it’s working well now, it will still need to stand up to the (often surprising) rigors of an existence in a bike share program. In the meantime, I hope many people will have the chance to enjoy this authentic 70’s ride, and I hope that Positron won’t live up to its reputation.





The Fleet Hits the Street

21 04 2010

Nestled deep in the bowels of the Student Union Building (SUB) at the U of A, beyond the “No Bicycles in Building” signs, near a lounge hidden at the end of two narrow hallways, is one of the best kept secrets on campus. The Environmental Coordination Office of Students (ECOS) runs a bike library with a fleet of around 30 bikes that members of the U of A community can borrow for a month at a time, and one of the hats I wear is chief wrench, crank, and maintainer of the fleet. I’ve been working with volunteers throughout the winter rejuvenating and overhauling the green bikes and cobbling together fresh bikes to add to the collection. And now that the weather has turned positively summer like, it’s time to find riders for them.

ECOS bikes ready to roll.

We pulled down all the good-to-go bikes from where they’d been hanging all winter, and seeing them all lined up, ready to take to the streets made me so elated and proud. I couldn’t help but giggle as I gave them a final visual inspection and checked the lights and the bells. Brrrinnng brrrinng hooray!

Packed in like a clown car for two wheelers.