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From: Roger Merriman <roger@sarlet.com>
Newsgroups: rec.bicycles.tech
Subject: Re: Dual-Chain drive train
Date: 30 Dec 2024 13:15:34 GMT
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Catrike Ryder <Soloman@old.bikers.org> wrote:
> On 30 Dec 2024 11:49:01 GMT, Roger Merriman <roger@sarlet.com> wrote:
> 
>> Catrike Ryder <Soloman@old.bikers.org> wrote:
>>> On Sun, 29 Dec 2024 12:04:34 -0600, AMuzi <am@yellowjersey.org> wrote:
>>> 
>>>> On 12/29/2024 9:39 AM, bp@www.zefox.net wrote:
>>>>> Zen Cycle <funkmaster@hotmail.com> wrote:
>>>>>> https://www.bikeradar.com/news/buffalo-utility-s2
>>>>>> 
>>>>>> Made for developing countries to allow for easier transportation on
>>>>>> cargo bikes, without the exposure and complexity of an external
>>>>>> derailleur or hand-operated shifting (for an internally geared hub). It
>>>>>> was developed and patented with the help of SRAM.
>>>>> 
>>>>> Are derailleurs really that bad? A whole new bike for the sake of a granny
>>>>> gear seems slightly extreme. Internal pawls at small radius are going to
>>>>> be more stressed  and harder to build than a rear sprocket of larger radius.
>>>>> 
>>>>> I'll admit that the narrower flange of a multispeed rear hub impairs the
>>>>> lateral strength of the rear wheel, but a hub with flanges spaced to leave
>>>>> room for a two-cog stack would be vastly stronger. What is the "exposure"
>>>>> alluded to above?
>>>>> 
>>>>> Thanks for reading,
>>>>> 
>>>>> bob prohaska
>>>> 
>>>> 
>>>>> " Are derailleurs really that bad?"
>>>> 
>>>> Yes.
>>>> 
>>>> They last a long while for many competitive events (except 
>>>> criteriums where concrete abrades right through them). 
>>>> Derailleurs are the overwhelming choice for tourists, even 
>>>> of great distances, on roads whether paved or not. 
>>>> Derailleurs are also usually suitable to commuters although 
>>>> in salted areas that vulnerability is a factor.  Offroad is 
>>>> sorta sketchy in that failures are regular but alternates 
>>>> have some serious tradeoffs so the derailleurs just get bent 
>>>> back or replaced.
>>>> 
>>>> [note most offroad is recreation, by riders who can well 
>>>> afford replacement gear. Among the MTB riders, "I broke that 
>>>> too!" is not always a complaint, it's often a boast.]
>>>> 
>>>> Extreme use, where unsupported durability is critical, would 
>>>> lead one to a not-derailleur design of some type.
>>> 
>>> I've long marvelled at the rear deraileur mechanisms and how well they
>>> function when properly set up. I've never had one fail, but I did
>>> replace one a few years back because the idler sprokets were worn
>>> down. Now, granted, I don't go offroad, and I can see potenial
>>> problems there.
>> 
>> I’ve had 4 failures over 40ish years one from rock strike, as a teen with a
>> new MTB early 90’s managed to to wrap the rear mech around the cassette
>> with both the gravel and MTB in filthy conditions ie muddy with lots of
>> vegetation matter, both a few years ago COVID ish times.
>> 
>> And this year the old ish and probably quite cheap rear mech on the commute
>> bike spring snapped separating from ie so the cage and parallelogram were
>> separated made for an interesting commute home! 
>> 
>> That rear mech was an upgrade? In that the original had become sluggish
>> even with new cables etc. so a cheap rear mech ie £20 ish solved that, the
>> gravel bike had a upgrade last winter with a GRX rear mech as that has what
>> shimano call a clutch ie keeps the chain off the chainstay etc.
>> 
>> I believe that SRAM UDH 
>> 
>> <https://www.sram.com/en/sram/mountain/products/udh> is supposed to be more
>> robust and some of the more modern rear mech’s are chunky boys and
>> apparently are more durable.
>> 
>> I only have Cues though I have no UDH compatible frame, nor likely to any
>> time soon, nor do I tend to bash rear mech’s on rocks!
>>> 
>>> --
>>> C'est bon
>>> Soloman
>>> 
>> Roger Merriman
>> 
> 
> I didn't keep track of my bike components back when I rode two
> wheelers, but I put 36000 miles on the Catrike's original derailleur.
> One advantage of the trike is that I don't often lay it on it's side
> and it's also less likely to contact something from the side.

I’d assume that a road or commute type bike the rear mech would last
decades and many miles, indeed the MTB commute bike the cheap rear mech
lasted 9 years and 19,000 miles before separation! 

Previous rear mech a Deore so mid ish end lasted 8 years before I replaced
it, though it had a much harder life being used for the majority of its
existence as a MTB only last two years on the commute.

The full suspension rear mech had been fine until it wrapped its self
around the cassette and was 8 years old though low miles as well MTB rides
tend to be 20ish miles so you don’t clock up the miles.
> --
> C'est bon
> Soloman
> 
Roger Merriman