If you're like me, you have no problem finishing the sentence "For my next build, I plan to..."
Well, this is the build thread for my third bike.
The core of the bike is a collaboration on design and build of a "common power module" with ES member 900Steve
. That's the subject of another thread
. I think it will generate a lot of interest. This thread is dedicated to the overall bike that will share that common power module - the story of what I build off a shared/common platform. So here goes:
: The ultimate utility bike. By that I mean a city commuter and grocery getter.
: These are the non negotiable attributes of the build:
1. It will be a folding bike
. Since I moved, I don't use the "folding" capabilities of my Dahon Jetstream "F3" Folding Bike
much anymore. But it's irreplaceable when it's needed. For a little added complexity and weight I gain so much utility. This is a no-brainer.
2. It will be rideable as "pedal only" without too much trouble
. WTF does that mean? I've ridden my A-line ~10 miles pedal only in one sitting. And I've ridden it up "the big hill" I live on (albeit at about 0.5mph, and nearly passed out when I arrived). But its not something one would seriously ride without electric propulsion. In contrast, my folding bike is only slightly heavier and has slightly more friction as pedal-only with electrics installed as it did when it was "just a bike". In this sense, my third bike must be more like the Dahon than the A-Line.
3. It will fit on a bus rack
. Pretty damn specific for a non-negotiable, fundamental User Requirement. But there have been a few occasions where I've needed to load the folder onto a bus rack. The A-Line in contrast literally won't fit (and if it did, it's so heavy I'd be afraid the bike shear the rack right off the front of the bus
). So, there it is - it must fit on a bus rack.
4. I will keep weight and complexity away from the wheels
. My "simple wheels" User Requirement is to keep expensive/heavy/complex things away from the wheels and move them somewhere else (to the middle of the bike). This in turn should mean less expensive wheels - easier to justify having a spare pair on the shelf (for dings, crashes, etc, or for studded snow tires, knobbies, etc.) It will also mean less unsprung mass for better suspension response and less rotational inertia for slightly better acceleration and slightly less wear & tear on the drive chain.
More to follow. If I make changes or additions to these criteria, I will edit them inline but note them below:
7 May 2013: Added link to the build thread for the common power module
in the second paragraph.
9 May 2013: Edited User Requirement #4 above to be more succinct.
15 September 2013: Replaced "Constraint" with "User Requirement", reflecting lingo from a systems engineering class I'm taking.