Old 09-23-18, 12:31 AM
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Blasptwenty: Overdone, over-complicated mod build for video rig

First off, all purists be warned before entering! (Can't believe I'm saying that).

With that taken care of, let me preface this build: I've been using my '70 Twenty for shooting work-related Bike to School events. This is usually done with a GoPro mounted front and back, and these have done well enough for now:

But it's not good enough. I usually shoot 2.7K video so I can re-crop the footage, and the bitrate on the GoPros (I'm using 4 Silvers now) with that video size is terrible; worse with motion. As a result, the ride footage always tends to look soft and mushy. Color depth is also a bit iffy.

Since then, I've acquired a gimbal and a Panasonic GH5 to put on it, and I got it in my mind to finally merge gimbal with bicycle. For the meantime, I've designed a 3D printed plate that'll sandwich the Pletscher rack and hold a cheese plate above it. In turn, the plate will hold a camera mount.

It's yet to be printed; I'm hoping I get the word next week that it is done.

But I don't want to modify the '70 Twenty any further than that. I like it original, even though the brakes are absyminal, the wheels are heavy, and the cotters catch my pantleg every second.

Obviously, this is a serious situation of variable "N" in need of "+1." And since I have access to some brazing equipment and other doo-dads over at Mike Terraferma's shop, I figure this was an opportunity to pick up a decidedly bad Twenty so I could do some serious modifications to the frame itself to turn it into a single-purpose vehicle: An all-around gimbal-operated camera bicycle.

I don't have much to share at this point, except that the victim has been acquired. I dug up a suitably ratty Twenty - this one also a '70 - on OfferUp and it is essentially identical with exception to being one of the lone oddballs with brazed-on seattube pinch ears. It's not all that bad, except for an AW hub with pawls that won't engage, and silver paint over most of the brightwork.

With the guardian of the fleet:

Since I really need not much more than frame/fork/handlebar, this Twenty should do nicely, and I won't regret putting the brazing torch to it.

This said, I'm envisioning something along the lines of the following (honestly, posting this list is mostly so I just don't forget:
  • Steel racks designed to accept camera cheese plates brazed directly to the frame, front and back.
  • 26TPI BB threads filled in, tapped to 24tpi, BB faced to 73mm for a square taper or Hollowtech crank, whichever comes first for cheap
  • Sun CR-18 ISO 451 rims with Primo Comet tires (possibly a bad idea for smoothness, even with the gimbal, but I'll be able to check this against the 406's on the other '70.
  • Modern Sturmey AW so I can stand on the pedals if need be - already have this.
  • Drum brake up front - or if possible, convert the fork to disc and shove a set of proper dropouts in the cheap-o Raleigh blades in the process
  • Tektro long-reach dual-pivot in back
  • Removal of the factory kickstand for a kickstand plate; installation of a double kickstand
  • Possible integration of a Pelican case to hold camera/gimbal in stora
  • Braze-ons added for a rear wheel lock (like an Abus Pro Tectic)
  • Planet Bike Cascadia ALX fenders
  • Some other stuff I can't remember at this late a time at night.
Feel free to PM if you happen to be parting with any of these bits I need.

It's decidedly not really a C&V build, but the starting point of the build is. Sure, there are other folders, but I believe in the Twenty and am familiar enough with it that I'd like to start with it as a base.

I've got the rear wheel torn off it in the meantime, but not much else. Cranks come off tomorrow, and I need to touch base with Mike TF to see when I can spend some time modding this thing.

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