Re: Getting old is not for sissies

On 3/3/2025 1:07 PM, Jeff Liebermann wrote:

On Mon, 3 Mar 2025 11:09:15 -0500, Zen Cycle <funkmaster@hotmail.com>
wrote:
 

On 3/1/2025 4:39 PM, Jeff Liebermann wrote:

On Sat, 1 Mar 2025 13:55:50 -0500, Frank Krygowski
<frkrygow@sbcglobal.net> wrote:
>

On 3/1/2025 1:22 PM, Jeff Liebermann wrote:

On Sat, 1 Mar 2025 07:43:22 -0600, AMuzi <am@yellowjersey.org> wrote:
>

On 2/28/2025 5:52 PM, Catrike Ryder wrote:

I was thinking about fixies just the other day on my ride and thought
maybe I could set up a fixie on the Catrike. Then I considered how
often I coast. Keeping my legs moving the whole ride is not something
I want to do.
>

>

I thought about your comment this morning.
>
While almost everything humans can imagine is possible when
time and money have no value, there's no practical
straightforward way to make a Catrike fixed gear.

>
Hardly straightforward, but certainly possible.  Remove the gears,
chain and sprockets and replace them with a hydraulic gear pump, two
hydraulic hoses, and a hydraulic motor on the wheels.  This is nothing
new.  There are motor vehicles and construction equipment that use a
hydraulic pump at the engine, T junction, and a hydraulic motor on
each wheel.

>

IIRC, hydrostatic transmissions are standard features on zero turn
mowers. But as you noted, the mechanical efficiency is lousy. That's not
a concern if you have a big enough engine and low enough use hours. It's
a huge concern for a cyclist.

>
True, but the huge concern is mostly for racing.  If you're using the
bicycle as a moving exercise machine, the added weight and increased
friction might even be considered beneficial.  It's like the weights
on barbells where light weight is not a concern.  For competitive
fixie racing, maybe the governing organization should specify a
minimum allowable bicycle weight, which might inspire technical
innovation instead of shaving grams off the bicycle weight.

>
The UCI weight limit of 6.8 Kg applies to all types of bikes, track
bikes (aka fixies) included

 I assume that applies only to UCI sanctioned bicycle races.
Oddly, I haven't seen any bicycle-like exercise machines being sold on
the basis of them being light weight.  Probably the same for moving
bicycle-like exercise machines (i.e. trainers).
 Note:  The discussion was initially about adapting fixie technology to
a tricycle (Catrike).  Andrew commented:
 "While almost everything humans can imagine is possible when
time and money have no value, there's no practical
straightforward way to make a Catrike fixed gear."
 I then provided a possible solution using hydraulics and mentioned
that weight would be "a huge concern, especially in racing".  From
that point on, the comments assumed that such a hydraulic drive train
would be used on racing bicycles and that it would not be a good idea
because if would be unsuitable for racing.  It might be best if we
simply not consider racing to be a suitable use for a hydraulic fixie
bicycle.
  

Much agreed on that last point.
I still think, especially regarding hydraulic drive, "...there's no practical straightforward way to make a Catrike fixed gear."
Possible? Sure.
--
Andrew Muzi
am@yellowjersey.org
Open every day since 1 April, 1971