On Tue, 30 Jul 2019 09:06:39 -0700 (PDT), Frank Krygowski
wrote:

On Monday, July 29, 2019 at 4:07:59 PM UTC-4, Zen Cycle wrote:
On Thursday, July 18, 2019 at 4:29:43 PM UTC-4, Frank Krygowski wrote:
On Thursday, July 18, 2019 at 1:59:23 PM UTC-4, Chalo wrote:
To my eyes, they don't look as nice as a frame made from tubing, but they look nice enough. Braze-on style front derailleurs are a nuisance, because they limit the sizes of chainrings that can be used. But these days, you can go without a front derailleur anyway.

My one major misgiving is the deletion of the right seatstay on the "Erik" model. If you can put that kind of grievous design blunder into production, what other-- less visible but still serious-- problems might you have made for the end user?

Looks like they forgot the left chainstay, too. Asymmetry must be very fashionable
now.

I know Cannondale's "Lefty" front non-fork hasn't taken the world by storm, but
I gather it works pretty well. Maybe that's the inspiration?

Some motorcycles have a single swing-arm design

https://en.wikipedia.org/wiki/Swinga...e:SprintST.jpg

IT would seem there isn't too much of a problem structurally.

I think BMW was the first modern motorcycle to use a single sided swing arm.
I know it can be done. And IIRC, at the time BMW said the design was stiffer
and lighter than the dual-sided swing arm it replaced.

But that doesn't mean it would have been stiffer and lighter than a more
modern, redesigned dual-sided swing arm. It does, however, ease removal of the
rear wheel in case of a flat. (Interestingly, I've owned four different
motorcycles and never had a flat with any of them.)

On that "Erik" bike, I can sort of see the benefit of omitting the right side
seat stay. If you have one, the belt drive requires it to be separable. Omitting
the seat stay certainly solves that problem. But I don't see an advantage to
omitting the left side chain stay. Except to add a "Look at ME!" feature.

- Frank Krygowski

I somehow have the recollection that the first single swing arm rear
suspension was used on racing motorcycles to allow the rapid changing
of a rear flat. I can't remember for the life of me where I got that
idea but somehow that is what I remember :-)


--
cheers,

John B.