Dynamo Lights

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  • Di2 stuff or gorilla tape.

  • Di2 channelling sticks very well for me on glossy carbon. It's designed for skinny round cabling though, so I can see it peeling up if you to try to wedge figure 8 cable in.

  • I've found that the wire which supernova use on their lights is too thick to happily stick inside the di2 sheath causing it to come away from the frame.

  • Cable ties and tape. Might look shit but does the job.

  • Does anywhere in London sell a length of ordinary dynamo cable? (for normal B&M lights).

    Can't be bothered to put an order in with SJS for 2m of cable for £1.98 with £3.50 postage.

  • speaker cables work I think

  • For those playing along at home, here is what I've settled on for the moment. M6 bolt, 3x spacers from a mudguard install, some anti rotation washers and a p clip. Spacers were needed to get the light vertical enough to throw a nice beam.

    Think I'm done.

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  • 'Bell wire' should also work; Screwfix or Wickes will sell you 50m for under a fiver, and you should be able to get it in B&Q etc. Or as amey says, see if an audio place will sell you speaker cable - it's all low voltage, so should be fine.

  • Wilko sell it by the metre if you don't fancy a massive reel.

  • Super helpful thanks @amey @Thrustvector @grams

  • I need to figure out a cable routing system for a front light (supernova e3) mounted on the front mudguard. It's for a custom steel fork so I can more or less do what I want in terms of braze-ons etc.
    Also happy to drill / modify the mudguard (PDW Full Metal Fender), which will be mounted to threads under the fork crown.

    It'll be guided in the usual way up the inside of the fork but I'd like to figure out the neatest way of routing it from there to the light on the mudguard. What's the usual way of doing it?

    There won't be a huge amount of room between the guard and the tyre (maybe 9 or 10mm)... And it's for front only so no need to worry about rear light wiring.

    Any suggestions / links to pretty pictures?

  • Up the inside of the fork blade and out at the top, then through the mudguard? Or if there's enough clearance, up the inside of the fork and then just along the edge of the mudguard (do the PDWs have rolled edges?).

  • Thanks : )

    Yes I think under the mudguard is my preferred method.
    The frame builder won't drill the forks for internal routing so we're using little loop-shaped braze-ons to pass it up the inside of the fork blade.

    It's the exact details of how it changes direction at the top of the fork blade and goes under the mudguard that's difficult to find proper info on.

    So far I'm thinking the journey looks like this, with unresolved bits in bold:

    1. Out of the back of the light
    2. Through a little rubber grommet (maybe an angled one like this to get the transition smoother)
    3. Under the mudguard somehow (how do you secure it safely under there?)
    4. How does it get from under the guard to the first loop at the top of the fork blade?
    5. Then down the fork to the connector on the hub.

    Here's a picture of it mocked-up on my (very dirty) other bike:

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  • Trad constructeur solution is to run it along the edge of the metal mudguard - you can crimp it in the rolled edge - but a) the PDWs don't have a rolled edge and b) the Supernova's cable is fairly chunky (is it coax?).

    Securing the cable under the guard can be tricky; I think some people use silicone sealant? Or Gorilla Tape? I guess you want something that's potentially removable. Whether it's better along the mudguard centreline or along the edge may be determined by the clearances.

    With the cutouts in the guard under the crown I'd have thought you could run it straight up the fork blade and then just fix it to the underside of the guard, effectively making a 90° turn.

  • Ah I get it now, thanks.
    Shame about these mudguards... pretty sure they're only ones that will fit easily in the limited space we'll have. Might look into options with crimping.

    By Gorilla tape, do you mean gorilla branded duct tape? Or do they do something more specific for cables?

    Not sure if it's coax wire - it's two thinner wires (with their own outers) running through a fatter outer.

    Thanks for your help, sounds simple enough if I can find a way of securing it to the mudguard.

  • Yeah, the duct tape stuff - apparently it works pretty well if it's applied to a clean mudguard and possibly warmed with a hairdryer on application.

  • Can you put another grommet on the side of the mudguard, and an adjacent eyelet as high up the fork leg as possible? The hard part is going to be keeping it off the tyre.

    Duct tape should protect the cable a little bit from tyre rub. Not likely to be a problem on your front mudguards but can be on rears.

  • Brilliant, thank you! : )

  • Yes that's a good idea... I think I'm gonna try these Di2 grommets and run the wire along the inside of the ridge in the mudguard where there might be a tad more space.

    I'll try and place the exit point just behind the caliper, so it's kind of hidden but the wire has enough space to turn the corner to the fork without adding too much stress on the tape.

    If all else fails I'll just keep it on show and run it over the top of the brake.

    Kind of handy for dynamo light fans that Di2 got invented.

  • I've also seen this stuff (or any of the other Goo Glues, though I guess the marine might stand up to weather best?) recommended for gluing onto mudguards: https://www.ebay.co.uk/itm/193331972727

  • I mean, it has the best name ever.

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  • Goop is what I'm planning to use. Have already used it for a few things. Very "gel" type consistency and takes a while to dry so let it sit at least a day to set up.

    I'd put a hole and grommet, or cut a wee slot in the side for the cable to exit - depending on where you're running it on the fender.

  • I've got a light that I'm fairly sure it's kaput. How do I double check with this thing before I chuck it?

    Also is the iq-x good bang for buck? Any better options for mainly road riding?

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  • Switch to ohms and check that there is a circuit. i.e. it reads some resistance rather than no reading.

    or use the diode test setting, best option

  • I get a reading yes, if I swap the polarity I just get a 1 (does this just mean infinite resistance?) Defo no light in either polarity though (pretty sure that shouldn't matter with a b&m light)

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Dynamo Lights

Posted by Avatar for hugo7 @hugo7