Path: ...!weretis.net!feeder8.news.weretis.net!fu-berlin.de!uni-berlin.de!individual.net!not-for-mail
From: Jeff Liebermann <jeffl@cruzio.com>
Newsgroups: rec.bicycles.tech
Subject: Re: Getting old is not for sissies
Date: Mon, 03 Mar 2025 11:07:52 -0800
Lines: 73
Message-ID: <8pubsjt2v5h1u1rksm3gn3jl2c312l3oac@4ax.com>
References: <vpsncj$3o02g$1@dont-email.me> <gjmwP.3138$SZca.1726@fx13.iad> <vpsrss$3om5n$1@dont-email.me> <0jt3sj9iofpo2ru3abmi7ddrt4uk5btc9t@4ax.com> <vpta8s$3rj0t$1@dont-email.me> <j2d4sj1ju5h4qj8l64v92jp2pbfg44podl@4ax.com> <vpthh1$3spru$2@dont-email.me> <eci4sj1ppvglfuut24ahtdg789fkd2v3mj@4ax.com> <vpv2to$848g$1@dont-email.me> <47h6sjdvehovbadru4cv210eha609mospn@4ax.com> <vpvl7m$akr9$11@dont-email.me> <oku6sjpg12tdoqdnp1hlep69c2lj6315i4@4ax.com> <vq4k7b$1bgi1$3@dont-email.me>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
X-Trace: individual.net M+9D8SZ7IM83UTd4R667HQhSpXUMlxceuMeFcD384aaFMcNO+6
Cancel-Lock: sha1:StOoRBaFX8M45LryS0SjmtEu5o8= sha256:X2rvuU2VIsVNjklQO6lfKVAGcOMUbfMKQs0vOSqPfgY=
User-Agent: ForteAgent/8.00.32.1272
Bytes: 4500

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.



-- 
Jeff Liebermann                 jeffl@cruzio.com
PO Box 272      http://www.LearnByDestroying.com
Ben Lomond CA 95005-0272
Skype: JeffLiebermann      AE6KS    831-336-2558