Electronic Shifting Gboxx2 Prototype DH Bike 12

1 of 11
Autoplay
Autoplay
Gboxx2 Prototype
svg+xml;charset=utf-8,%3Csvg xmlns%3D'http%3A%2F%2Fwww.w3
svg+xml;charset=utf-8,%3Csvg xmlns%3D'http%3A%2F%2Fwww.w3
svg+xml;charset=utf-8,%3Csvg xmlns%3D'http%3A%2F%2Fwww.w3
svg+xml;charset=utf-8,%3Csvg xmlns%3D'http%3A%2F%2Fwww.w3
svg+xml;charset=utf-8,%3Csvg xmlns%3D'http%3A%2F%2Fwww.w3
svg+xml;charset=utf-8,%3Csvg xmlns%3D'http%3A%2F%2Fwww.w3
svg+xml;charset=utf-8,%3Csvg xmlns%3D'http%3A%2F%2Fwww.w3
svg+xml;charset=utf-8,%3Csvg xmlns%3D'http%3A%2F%2Fwww.w3
svg+xml;charset=utf-8,%3Csvg xmlns%3D'http%3A%2F%2Fwww.w3
svg+xml;charset=utf-8,%3Csvg xmlns%3D'http%3A%2F%2Fwww.w3
svg+xml;charset=utf-8,%3Csvg xmlns%3D'http%3A%2F%2Fwww.w3
12 comments

c50 JPC ZEdit MtSnow Finals 2 1543430896.jpg?VersionId=ud0f8F3xANsd6rZ.Gc6TIWwa
sideshow
11 years ago
Wasn't this a Dave Camp Creation?
c50 JPC ZEdit MtSnow Finals 2 1543430896.jpg?VersionId=ud0f8F3xANsd6rZ.Gc6TIWwa
sideshow
11 years ago
Ah! Right on. Forever a fan of garage builds.
c50 88050180 1254804813
CG83
11 years ago
It's still around, though in need of some fork and brake love. Definitely considering using my lessons learned for another gearbox project, but it hasn't happened yet! thanks for the mini-showcase!
c50 Screen Shot 2015 03 09 at 2.10.12 PM 1425936051.jpg?VersionId=RClhlm1GiTEPMPegVFCjJxwA22d
sspomer
11 years ago
awesome! good to know. can you elaborate on your lessons learned? if you don't want to give anything away, no problem, but i think all vital viewers would be stoked to know more about the project.
c50 IMG 20211027 155910 1655061393
Primoz
11 years ago
Would you be using a Pinion now? And put the gearbox higher up to get more anti-squat effect?
c50 88050180 1254804813
CG83
11 years ago
Lessons learned:
1. It was definitely ideal to build multiple frames at once to save on machining and materials costs. We were also able to build alpha and beta protos this way.
2. I underestimated how annoying the chain tensioning would be. I should have designed a really simple roller tensioner onto the swingarm and made a standard thru-hole drop out.
3. The reduced unsprung mass and centralized CG made the bike ride a lot lighter than it actually was at 41.5lbs.
4. The G-boxx II unit was awesome because it was available, nicely made and functioned well, but it is definitely not the right direction for the future. The gear spread was too wide for DH, it was a big hassle to build electronic shifting just for the sake of getting rid of the grip shift, and it was quite heavy with 7 chains inside.
5. I should have run with the momentum and actually tried to make something of the effort. There was some interest, but I could have done a better job of turning that into something actually marketable. I got sidetracked with other projects/promises
6. The pro-squat design of the concentric pivot was nice an active while pedaling, but it would have been nice to have at least a little bit of anti-squat designed in. Next time I will work around it using an idler or alternate output location/gearing setup.
7. 7005 material was tough to get in the shapes and quality that was desired. It was nice because it naturally air-hardened, but that also caused problems with "old" material.
c50 88050180 1254804813
CG83
11 years ago
8. Never underestimate how much you can get done in a few months. I conceived of, designed, built and raced the bike at Sea Otter in 2008, all in a 4 month span. I did the electronic shifting and custom rear hub before the year (08) was up back then.

Some more info: The Genesis of the design and first proto
Ridemonkey part 2
c50 IMG 20211027 155910 1655061393
Primoz
11 years ago
Ooooooooh, nice. Making an electronic shift unit would be EASY today with our Arduinos and a whole lot of batteries available off the shelf. Doing it in 08 was a whole different thing I was thinking in the same direction when thinking about gearboxes, kinda too bad i wasn't the first with the idea, but it is good to see that they do in fact have merit.

Also, where are you from? Please say Europe and tell me where you got the aluminium from :D
c50 IMG 20211027 155910 1655061393
Primoz
11 years ago
Well look at me trying to look all smart before checking any other comments and or stuff written around on te site -_-
c50 88050180 1254804813
CG83
11 years ago
No worries. Sounds like you found out I am from California and got the material from Fairing. The controls back then were a little rough, would definitely be a lot cleaner now!