Friday, December 10, 2004

CHUNK Bike Anatomy: Chopumulator

I'm not going to repeat the sad, sad tale of the great Chopagator, still AWOL for five years running (because a certain someone didn't bother to lock it up at a party one night).

[The one, the original Chopagator]

I think I speak for everyone when I say that part of me still hopes its simply rusting away under some bushes in some backyard, or collecting cobwebs in a garage, not seeing any ride time because its got a flat, or the thief just isn't really interested in riding bikes, despite having gone to the trouble of stealing one. There was a rumor the folks down in the CHUD village had caught a glimpse of it, but investigation yielded no results.

Chopagator's original architect, Megulon-5, missed her so much he built a variation/replication in late '99, Plopulator, the Son of Chopagator.

[Plopulator, Son of Chopagator]

Plopulator was substantially longer than Chopagator, by my reckoning, hence the development of a significant chronic and potentially terminal head-and-steer tube ailment. After one re-build, Megulon-5 ditched the chopagator-fork design, instead bring Ploppy into its current configuration, wherein a chopped mini-motorbike fork is used instead.

I had always had the jones to built a replicant of Chopagator. I actually started this project in late '99, maybe 2000. I got as far as getting that bottom extension of steel tubing welded onto the rear triangle, and set it aside for later. When I next returned to the Lab, someone had welded some handble bars onto the dropouts of the rear triangle(?) and then welded this entire apparatus onto the steertube(!) of a mastadon-esque creation somewhat resembling a tall chopper. This is back when we had many aspiring CHUNKs-in-training around, whom knew very little of bicycle mechanics. I remember wandering into the Lab one afternoon, a bottle of Blitz in hand, and four guys had an entire bicycle grasped in the table-mounted vice by the forks. I was looking for a part or something and sorta watched out of the corner of my eye. They were using wrenches and whatnot to loosen the headset. Which was weird because you didn't need the bike in a vice to do that.
"Wha'cha guys doing?" I asked.

"Trying to get the fork off this frame," they replied.

"Probably help if you took the handlebars off first."

And so on. So I tabled the Chopagator replication project. For, like, five years.

Which brings us to the present. Or, at least, last summer. I'm not sure what spurred me on to actually build a chopper. In the past we tended to keep the entire fleet in one main location, but those days have given way to everyone providing housing for their bike (or bikes, as the case may be) individually. I already had two bikes in an already way-to-small studio apartment. Why did I need a third, heavy, eight-foot-wheelbase chopagator-style bike in there as well?
Whatever the reason, sometime last summer I actually began consstruction of my entry into the Chopagator canon.

Building long choppers resembles building tallbikes, since the trick is getting the new frame to possess a resemblance to straightness. I used a series of jigs (two pieces of wood sandwiched around the frame parts, held tightly in place with zip ties or discarded inner tubes) to keep the frame reasonable straight. The other tricky part was getting the head tube to have an angle that didn’t result into much rake, but at the same time didn’t result in a short fork (gotta have a reasonably long fork, I mean, c’mon).

In the end it all came out surprisingly well, and it only took me four separate weekends to do it! Five if you count the day I fine-tuned *ahem* the shifter and hand brake.

Anyway. Yeah, so here she is… Chopumulator, the Emulator of Chopagator.

Looks nice, if you ask me. I’m very proud of the fact that, like my tallbike, she’s built out of two Chicago Schwinns. Take that, Schwinn collectors! Seriously though, Chicago Schwinns are best bikes for building choppers, tallbikes, etc. That American steel is just so tough and easy to work with, not like that cheap Taiwanese stuff everything’s made out of today.

I had originally planned to put gussets at all the corners of the frame, as well as in the fork, but decided against it based on my experience with my beloved Biscuit. Biscuit is a gazelle-style chopper. However, rather than the traditional “cresent-moon” shape, I did my darnedest to get the front dropouts to line up with the headtube. I did this reasonable success, but the real surprise benefit was (a) the overall lightness of the bike, compared to when you build a mono- or BMX-style chopper, using heavy steel tubing, and (b) the fork ended up having some B-O-U-N-C-E to it. This seemed a little suspect at first, but considering the following: Biscuit is three-years old, going on four, and has competed in three Chunkathalons, including being my bike when I won it all in 2003. Based on this evidence, I felt that gussets were a bad idea, since gussets would make the bike too rigid, and hence more prone to breakage. Chopumulator was finished in early July, and now its December. Choppy’s survived a July 4th ride and burn, a trip to Seattle, and second place at the 2004 Chunkathalon. And there are no cracks in the welds.

The only thing I’m disappointed with is that the mountain bike fork I used for the upper part of the fork must have been tweaked to begin with. The fork pulls to the left on its own slightly. This is no biggie, but is slightly annoying on extended rides. Maybe sometime I’ll jump on the fork a couple times and try to straighten it out.