Thread: Helix Update?
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Old 04-15-18, 11:59 AM
  #1032  
funk17
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vello bike, change of hinges

Full disclosure: I've backed vello bike on kickstarter, so might be considered an invested fanboy. But of course,
I'm also not at all thrilled by the delays and silent weight/dimension increases in the vello campaign.

However, the main reason for the increased folding width (from 71 to 79 cms, as far as I can tell), does make sense: The original prototype (and vello bike version 2) folded the rear behind the bottom bracket, thus folding
changed the distance for the chain/belt, which doesn't really work for a belt without a chain tensioner. The current design puts the bottom bracket on the rear rather than on the main frame, and thus folds before the bottom bracket, achieving a constant tension on the chain/belt while folding. At some point they seem to have
considered putting folding hinge and bottom bracket on one axle (can't find the picture anymore), but that probably didn't work out stability wise.

2cms folding hinge behind the bottom bracket, vs. 2 cms before add up to the 8 cms increased folding width of the current design; all doubles up. Some of the reinforcements for this redesign explain part of the increased weight. One can blaim the vello bike creators for never explaining this redesign clearly, but it takes a few words to do so

Apparently, cutting edge folding bike design isn't that easy (look for Andrew Richie's/London Business School talk for the brompton perspective.
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