wiring to rear lamp

[nez]

How do you extend your wiring to the rear lamp? I use bands of self amalgamating tape on the frame, but I notice some people just wind the wire around whatever is available. There's a good example in this Pilgrim cycles picture here http://pilgrim-cycles.co.uk/wp-content/uploads/2018/03/20180307_093227.jpg. I'm quite surprised winding the electric cable around the brake cable is secure, but don't doubt Pilgrim bikes is more reliable on this than my prejudice. Has anyone done it? Does it interfere with braking, even theoretically? By the way you'll notice that very nice looking bike has v brakes. That's also tempting, though I don't suppose my brifters would have enough pull to operate them. Always something... a bike is an invitation to fettle

[Brucey]

it is as well to look at how wires are liable to fail before deciding how best to route them. They fail by

- being repeatedly flexed (esp near joints and connections)
- by corrosion (at the ends)
- by abrasion (where they rub)
- by getting snagged and pulled hard.

Often your choice or wiring route is a compromise, a choice between these various failure modes becoming more likely or not.

FWIW the added flexing of the wires when they are lashed to (say) a brake cable is unlikely to cause so much flexing that the wires will fail internally (although it might if the cables wobble when you go over bumps).

With a standard hub generator setup the part of the cable that is most likely to get snagged /flexed to death is the part that is near the front light; the connections to the light are vulnerable (and should be strain-relieved) and the wires themselves are subject to heavy flexing as the steering turns. Winding a 'pig's tail' into a longer length of wire at this point alleviates the flexing but possibly increases the likelihood of snagging.

Having excess wire somewhere in a long run is always a good idea; this gives you something to work with if a repair is required. A simple away of achieving this is to double it up several times and to lash the wiring to the frame/fork with tape; if the wire is pulled hard, all that happens is that the doubled up tape comes out from beneath the tape. If you expect to have to do a roadside repair, ever, then simple figure 8 cable is easier to work with than coax, but otherwise the right coax is possibly a better cable to start with.

cheers

[PT1029]

I've done dyno wires round the forks as per pilgrim-cycles photo, and round brake wires (variously exposed inner/enclosed inner with outer).
Around the brake cable is tidier in my view (artisitic intepretation, so no "right" answer). Just ensure enough spare dyno wire to allow for brake flex/steering (including bars flopping round fully when parking etc).
Winding the dyno wire round the brake cable as per photo is fine until you want to fit a new brake cable (then it is more of a fiddle). I usually run the dyno wire straight along the brake cable with some small cable ties attaching the dyno wire to the brake cable. Ideally you want the cable ties tightish, or they gradualy slide up and/or along the brake cable, leaving slack bits of dyno wire.
On the rear (or even front) rack, you need to allow for panniers/hooks and clips, and probably at some point luggage elastics.

I'm sure someione will soon bring out a blue tooth microwave power link for rear lights......
Am I correct in that " self amalgamating tape" is er sticky/insulation tape?(!)

[nez]

Am I correct in that " self amalgamating tape" is er sticky/insulation tape?(!)

Yes it is sticky tape but it does sort of 'amalgamate' into one thing given the chance, so is more reliable than electrical tape. More robust too. I'm a sailor as well as a cyclist and it is much beloved of radio hams and sailors. I have arranged the wires from my dynamo (actually alternator, but hey!) as described by Brucey above, and since I consider him the Oracle I suppose that's not a fail.

Maybe I'd wind the wire round a cable casing, but I (literally) didn't know about bare brake cable inner. That provoked my question.

[Brucey]

on bare steel inner cable, an electrical wire may well chafe through over time. If you are going to route an electrical wire this way, it makes sense to use a sleeve (eg a transfil kit) on the steel inner cable, and wind the electrical wire around that.

The self amalgamating tape I have used is brilliant at sticking to itself, but not so good at sticking to other surfaces.

cheers

[mercalia]

Yes breaking by flexing is the issue. I have a number of loose windings around the head tube before it goes down to the forks or along the top tube. I use cable ties or velcro strips to secure them along the tubes. I dont think sticky tape is any good as after a time the stickness turns into a goo and stops working

[Brucey]

self-adhesive tape ('insulation tape') varies quite a lot; some tapes stay nicely sticky for years, in others the adhesive turns to goo or turns hard and brittle. In any case if the tape itself is PVC (as it usually is) then it will go hard and brittle eventually (sooner outdoors of course) even if the adhesive does something different to that.

What often saves it is that you can apply several turns, under tension, and even if the tape starts to go bad, it usually carries on working for longer than you might expect.

If you want to find out how tightly many turns of tape will hold something, try wrapping the tape (under tension) around a finger or something; you will quite easily cut the blood supply off (don't leave it like that of course... ). On bikes, you can often generate enough tension/pressure beneath many turns of such tape to slow/prevent corrosion from spreading further beneath paintwork.

cheers

[nez]

Slightly tangential - why is that bit of wire in the middle of the cross bar bare at all? I don’t suppose anyone wants to save 20grammes on a 14kilo bike. My Dawes (10 years old) is bare, my Major Nichols (40odd years old) is covered

[fausto99]

Ivy Grip Tape is very very good. Not as expensive as it might seem at first, as you can cut it into quite small strips. It sticks, double sided, to anything. You can wash and re-use it too. I’ve used it to route the satnav power cable up and along the dash. I’ve also used it to hold a small preamp onto the side of my double bass. The grip is strong.

[alexnharvey]

Slightly tangential - why is that bit of wire in the middle of the cross bar bare at all? I don’t suppose anyone wants to save 20grammes on a 14kilo bike. My Dawes (10 years old) is bare, my Major Nichols (40odd years old) is covered

I think primarily for lower friction, possibly also for weight.

[PH]

Up the fork I keep the wire out of sight on the inside of the fork, bit of clear tape and maybe a zip tie or two. From front to rear along the top tube - On one bike I have a full length outer and cable is heat shrinked to that. On the other with an exposed inner, I've used clear tape at each end and blobs of super glue between, it's likely to pull some paint off if it ever needs removing, but as it's good quality co-axial cable and I've left enough slack at the ends, I'm expecting it to last between re-sprays anyway.

[nez]

By coaxial you mean the stuff we usually use for antennas?

[PH]

By coaxial you mean the stuff we usually use for antennas?

No, this stuff
https://www.sjscycles.co.uk/dynamos/sch ... 2-x-05-mm/

[nez]

Thanks. That looks nicer than the b+m Twin stuff I used

[Valbrona]

Putting wiring to a rear light is stupid when there are top quality LED rear lights like this that run forever (almost) on regular batteries ...

[img]https://images.internetstores.de/products/4994/02/f07025/4D-Toplight_permanent[570x304].jpg?forceSize=true&forceAspectRatio=[570x304]true?forceSize=true&forceAspectRatio=true[/img]