Author Topic: Road links and derailleur capacity  (Read 7186 times)

Kim

  • Timelord
    • Fediverse
Re: Road links and derailleur capacity
« Reply #50 on: 12 October, 2018, 04:22:28 pm »
FWIW the rat's nest of wiring on the bike I mentioned earlier was worst around the handlebars. Again there is a conflict; keep it all accessible so that it can be fettled/repaired or hide it all so that it is less easily damaged (but more difficult to repair/maintain, obviously). There are always wires somewhere that get flexed/vibrated and even well specified ones can still fail.  I think that you are doomed to have exposed wires somewhere and these can get snagged. 

 One idea for mitigation of the snagging risk is to bind a reinforcement (eg braided nylon shot cord; in ~2mm form it has a breaking strength of something like 150lbs) to the crucial exposed wires using tape, and then tape the ends of the  cord to the frame/handlebars so that in the event of the wires getting tugged, the cord takes the load, not the wires. Some wires are (modestly) internally reinforced with strands of cord anyway, but there is little harm in adding more reinforcement this way.

I'll agree with this principle.  Having made my mistakes on other bikes, on my tourer (which has convoluted dynamo wiring for lighting with an inline switch, output for a charging device[1], and wired computer with speed and cadence sensors) I've ensured that all electrical cables are securely attached to either a rigid part of the frame or luggage carriers, or tied to bowden cables for the run between frame and handlebars.  The short loops where the cable has to flex to allow for steering or suspension travel are arranged to be in places where they're protected from being snagged on things.  No problems with any of the wiring after several years, though I did damage a brake cable outer during a game of train-tetris once.

The most important thing is strain relief:  Any appropriately-specced cable[2] will withstand a decent amount of random abuse mid-span, but repeated flexing at connectors (or worse, absences-of-connectors) with tight bend radii will quickly lead to failure.  The standard wired computer bracket with a cable emerging from the bracket at the handlebars and wandering off towards the forks is a prime example of what not to do.


Quote
Re 'staying in one position';  I have never found this a really good scheme. Once every few minutes I stretch, change position, ride out of the saddle or similar anyway, just to keep good circulation in every part of my body. Changing gear is just another  excuse to move around a bit, so I don't begrudge it.  BTW I don't find STIs especially comfortable to use (maybe back to the wrist thing?) and in many ways prefer a standard gear lever mounted somewhere handy.

Recumbent riders are the experts on this:  Given a sufficiently comfortable position that isn't messing with your nerves or circulation, you can easily stay in it for a couple of hours.  But at some point you're eventually going to want to move around.  If I'm riding continuously (bike with no stopping at junctions, or trike) I'll usually stop for a minute or two once an hour just to be able to bear weight on locked-out knees (which you don't get to do on a recumbent) and flex my back a bit.  Usually that's combined with an opportunity to eat something.

On uprights this isn't a problem.  You can ride out of the saddle for a bit to give the knees something different to do, and since you're continually shuffling around to try to balance hand/wrist/neck/arse/genital pressure, you don't get the same stiffness.

Anyway, none of that changes the obvious advantage of easy-to-get-at controls.




[1] On the basis that the best place for delicate things like battery packs and USB connectors is safely inside an Ortlieb with a single robust connector (on an easily-replaced cable) to quickly disconnect from the bike's wiring loom, rather than strapped to the bike where they can get wet/bashed/nicked.  I accept that endurance racers will have a different set of priorities to tourists here; if nothing else they want things where they can see that they're working.
[2] I reckon Schmidt have the right idea in favouring coax over figure-of-8 bell-wire, even if termination is more of a faff to do neatly.  Where you have a choice, highly flexible rubber or silicone cables (think multi-meter probes) are going to be a lot more resilient than standard PVC coated wire.

JennyB

  • Old enough to know better
Re: Road links and derailleur capacity
« Reply #51 on: 12 October, 2018, 05:25:09 pm »
Recumbent riders are the experts on this:  Given a sufficiently comfortable position that isn't messing with your nerves or circulation, you can easily stay in it for a couple of hours.  But at some point you're eventually going to want to move around.  If I'm riding continuously (bike with no stopping at junctions, or trike) I'll usually stop for a minute or two once an hour just to be able to bear weight on locked-out knees (which you don't get to do on a recumbent) and flex my back a bit.  Usually that's combined with an opportunity to eat something.

On uprights this isn't a problem.  You can ride out of the saddle for a bit to give the knees something different to do, and since you're continually shuffling around to try to balance hand/wrist/neck/arse/genital pressure, you don't get the same stiffness.


Ah, that would explain why the Gossamer Albatross that flew the Channel was an upright though its predecessor the Condor was a recumbent.
Jennifer - Walker of hills

Kim

  • Timelord
    • Fediverse
Re: Road links and derailleur capacity
« Reply #52 on: 12 October, 2018, 05:37:02 pm »
Recumbent riders are the experts on this:  Given a sufficiently comfortable position that isn't messing with your nerves or circulation, you can easily stay in it for a couple of hours.  But at some point you're eventually going to want to move around.  If I'm riding continuously (bike with no stopping at junctions, or trike) I'll usually stop for a minute or two once an hour just to be able to bear weight on locked-out knees (which you don't get to do on a recumbent) and flex my back a bit.  Usually that's combined with an opportunity to eat something.

On uprights this isn't a problem.  You can ride out of the saddle for a bit to give the knees something different to do, and since you're continually shuffling around to try to balance hand/wrist/neck/arse/genital pressure, you don't get the same stiffness.


Ah, that would explain why the Gossamer Albatross that flew the Channel was an upright though its predecessor the Condor was a recumbent.

It possibly also enabled the, erm, pilot, to put out a higher peak power, which I can see being useful for takeoff.  Or was just a better match for the type of training they'd been doing.  Fit upright cyclists don't perform well on recumbents if they aren't trained for them.

Actually, looking it up, the Gossamer Albatross flight time was 2 hours and 49 minutes.  Like most of the serious[1] riders who didn't have a mechanical or whatever, I rode the Red Baron continuously for 3 hours at the WHPVA championships, and suffered 'mild discomfort' in the neck and shoulders[2] (plus normal fatigue and digestive issues), so I don't think that's a limiting factor if you're doing something important like not having to ditch your plane.


[1] FCVO serious.  But many of the non-serious riders sensibly stopped for a break to get out of the sun and rehydrate mid-race.
[2] Like a DF road bike, the neck angle is compromised for aerodynamic gains - just in the other direction.  I could go for longer in my tourer's more neutral position without that problem.

LittleWheelsandBig

  • Whimsy Rider
Re: Road links and derailleur capacity
« Reply #53 on: 12 October, 2018, 06:40:32 pm »
I suspect that an upright flying pedalist allows a shorter fuselage than a recumbent pedalist does, which might be better aerodynamically at slow flying speeds.
Wheel meet again, don't know where, don't know when...

Re: Road links and derailleur capacity
« Reply #54 on: 12 October, 2018, 07:37:33 pm »
Recumbent riders are the experts on this:  Given a sufficiently comfortable position that isn't messing with your nerves or circulation, you can easily stay in it for a couple of hours.  But at some point you're eventually going to want to move around.  If I'm riding continuously (bike with no stopping at junctions, or trike) I'll usually stop for a minute or two once an hour just to be able to bear weight on locked-out knees (which you don't get to do on a recumbent) and flex my back a bit.  Usually that's combined with an opportunity to eat something.

On uprights this isn't a problem.  You can ride out of the saddle for a bit to give the knees something different to do, and since you're continually shuffling around to try to balance hand/wrist/neck/arse/genital pressure, you don't get the same stiffness.


Ah, that would explain why the Gossamer Albatross that flew the Channel was an upright though its predecessor the Condor was a recumbent.

It possibly also enabled the, erm, pilot, to put out a higher peak power, which I can see being useful for takeoff.  Or was just a better match for the type of training they'd been doing.  Fit upright cyclists don't perform well on recumbents if they aren't trained for them.

Actually, looking it up, the Gossamer Albatross flight time was 2 hours and 49 minutes.  Like most of the serious[1] riders who didn't have a mechanical or whatever, I rode the Red Baron continuously for 3 hours at the WHPVA championships, and suffered 'mild discomfort' in the neck and shoulders[2] (plus normal fatigue and digestive issues), so I don't think that's a limiting factor if you're doing something important like not having to ditch your plane.


[1] FCVO serious.  But many of the non-serious riders sensibly stopped for a break to get out of the sun and rehydrate mid-race.
[2] Like a DF road bike, the neck angle is compromised for aerodynamic gains - just in the other direction.  I could go for longer in my tourer's more neutral position without that problem.



Your reference to the Gossamer Albatross reminded me of watching it all the first time around! I wonder, and didn’t manage to find out from a quick google search, what Bryan Allen’s sustained power output was, as well as the short term bursts. He sustained a cadence of 75rpm if the online literature is correct.

A marvelous project, as was Gossamer Condor before.

Re: Road links and derailleur capacity
« Reply #55 on: 13 October, 2018, 09:35:46 am »

....A marvelous project, as was Gossamer Condor before.

too right; a considerable athletic feat, a technical tour de force, and an utterly compelling theme; man's primal desire for flight, almost the dreams of Daedalus and Icarus made real....

cheers

JennyB

  • Old enough to know better
Re: Road links and derailleur capacity
« Reply #56 on: 13 October, 2018, 10:02:43 am »

....A marvelous project, as was Gossamer Condor before.

too right; a considerable athletic feat, a technical tour de force, and an utterly compelling theme; man's primal desire for flight, almost the dreams of Daedalus and Icarus made real....

cheers

Funny you should say that. THIS is almost forgotten now.

Apologies for derailing the thread.
Jennifer - Walker of hills