From Newsgroup: rec.bicycles.tech
On 1/7/2026 5:57 AM, zen cycle wrote:
What Twain actually wrote was "The report of my death is an
exaggeration." in response to newspaper reports that
confused him with the his cousin James Ross Clemens who died
in London in 1897.
But this post is actually about bike tech.
Some cycling media outlets are predicting the death of the
derailleur now that Sram has patented an enclosed automatic
transmission, initially for the ebike market.
https://www.pinkbike.com/news/sram-patent-reveals-design- for-an-integrated-12-speed-motor-gearbox-unit.html?
"Altogether, these developments signal that the reign of the
derailleur could soon end, at least in the e-bike space
anyway."
I'm questioning though why 12 speeds are needed with an e-
bike, since the RPM range of an electric motor with the
relatively flat torque curve would seem to make gearing
superfluous. The following statement from the website
doesn't seem to make much sense in that context
"The e-bike is the natural and logical home for gearbox
technology, where the increased torque and mileage expedites
wear on traditional drivetrain parts, and the e-assist
steamrolls any drag-associated downsides."
Do e-bikes _really_ have expedited drive train wear, or is
it a function of most e-bike users not maintaining their
drive train (generally not _real_ cyclists)?
Comments welcome.
Nice observation about gearing. In the postwar years, four
speed derailleurs fought for market share with Sturmey 3 and
4 speed gearboxes and lost. This began to change with better
derailleur systems at the end of the 1950s and the very
marketable 'ten speed' magic phrase.
Yes electric systems have a wide torque band (not infinite
but adequate). Compare small IC mopeds:
https://www.vespamag.com/en/24277/simple-design-reliable-function-vespa-gearboxes
versus electric:
https://www.bosch-mobility.com/en/solutions/powertrain/battery-electric/electric-powertrain-2w/
explicitly here:
https://www.savicmotorcycles.com/blogs/blogs/do-electric-motorcycles-have-gears
"no need for a clutch, because we can produce enough torque
at 0 RPM to propel the vehicle, and there is also no need
for a gearbox, as werCOre able to produce this constant,
blistering amount of torque up until about 4000 RPM. "
And just like any other engineering problem, the wear rate
of the drive train centers as much on weight, space and cost
as on longevity. That is, its useful life is whatever
management decided was adequate.
We were very much enamored of the German Sachs Super Seven
and sold many complete bicycles so equipped and even more
aftermarket setups. Great product for the urban or short
distance recreational rider.
http://www.yellowjersey.org/suprsevn.html
from my page, "Derailleur trouble may also be described as
'death by normal commuting' ".
All that said, previous 14 speed gearboxes never sold well
at all. The Sevens have failed in the world market and
Shimano's Eight has waned to insignificance. This may be
more parallel to the demise of bowties vs long ties or even
the lack of proper menswear generally in favor pf pajamas in
public. There's no 'why'. It just is.
--
Andrew Muzi
am@yellowjersey.org
Open every day since 1 April, 1971
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