Re: Getting old is not for sissies

On 3/3/2025 7:47 PM, Roger Merriman wrote:

Zen Cycle <funkmaster@hotmail.com> wrote:

On 3/3/2025 2:07 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.

>
Specifically for UCI races, yes, but the vast majority of national
sanctioning bodies follow UCI rules even in races that aren't UCI
sanctioned. In the US, the sanctioning body is USACycling (USAC) If a
race is however a UCI race, it must follow UCI rules and UCI rules will
take precedence even if the race is being administered by USAC.
>
For non-UCI races sanctioned by USAC, there is no weight limit for any
kind of bike. In fact the actual equipment requirements for regular
bicycle types are surprisingly sparse, only covering just over two pages.
>
https://assets.usacycling.org/prod/documents/USACycling_RuleBook_7_2024.pdf
>
Pages 28 - 31

 Uk hill climb competition is definitely non UCI with bikes being few KG
lighter 6ish they do now require helmets and lights though they just have
to exist, the lights at least! And do still get some very weight focused
bits of kit, ie ridiculous light disk rotas etc that like the bling rim
brakes previously worked but not well but where light and reassuring
expensive and well fun bits of kit.

And similarly here in the northeast US we have the BUMPS series.
https://bumpshillclimb.com/
There is no weight limit but the bike must be "road legal".

>
I have seen situations where someone raises an issue referring to UCI
rules, and the answer from the official is "this isn't a UCI race".
>

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.

>
I probably should have clarified, the 6.8 Kg weight limit for UCI is a
_minimum_ weight. If one felt the need to ride a 30 pound walmart bike
in a UCI race, there wouldn't be any rule against it as long as all the
other mechanical requirements are met.
>

 Roger Merriman
 

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