co-axial wiring instructions




Co-Axial Wiring


We sell heavy duty co-axial wire that we get from Schmidt in Germany. Schmidt uses it to connect their headlights to their dynamo hubs, as well as for taillight wiring that they make for us. But we also get this wire in big spools, and we can make up all sorts of wiring for different bikes. We can also sell you this co-axial wire in whatever length you need, up to 500 meters. Probably long enough? For bike shops we stock 100 meter spools. And of course we're happy to spend all day, every day, selling it for $ 1.00per foot.

This wire is 3mm in diameter. There's a center core "power" covered by a clear insulator. Then the "ground" conductor wires are wrapped around that clear insulator and covered by a black outer insulator. The outer insulator is .5mm thick.

The photos below show how to strip, crimp and insulate this wire with various connectors. The connectors shown are the 2.8mm connectors used by Busch & Müller for their headlight to taillight connections as well as their headlight to hub connections on certain headlights. The larger 4.8mm connectors used by Wilfried Schmidt for their hub connections attach in the same fashion. The only difference is that since the connectors are larger, you use a larger (1/4") shrink tubing to protect those 4.8mm connectors.

co-axial wire

No, it's not an advertisement for Phil Wood. It's my spoke ruler shown here so you can easily see the scale. Here the outer insulator has been stripped off. You can see the "ground" wire strands wrapped around the inner core.

stripping the wire

Here I've started to unwrap the "ground" wires. These are all very fine wires, and it's easy to leave a strand or two behind. If you do, you can end up with a short circuit. So be sure to capture them all.


Here I've fully unwrapped the "ground" wire, slid on and heat shrunk a length of 1/16" heat shrink tubing. You can see the inner "power" wire inside the clear inner insulator. To the left you can see another piece of heat shrink tubing (1/8") that I've slid onto the wire to the left of the junction, but have not yet heated. That will cover up the junction once we're done.


And here I've taken another pieece of 1/8" shrink tubing and covered over the first smaller diameter piece. This large piece will add extra protection to the "ground" wire, and since it increases the overall diameter, it makes for a more secure "crimp" to the insulator. So, around the "ground" wire we have two pieces of shrink tubing. The first is 1/16" and the second is 1/8".

another step

Here I've stripped the clear insulation from the end of the "power" or inner conductor, and I've slid the shrink tubing over onto the junction and heat shrunk it.


Here you see how the little crimps have two sets of ears. The set to the left is longer to wrap around the insulator. The set to the right are shorter; they only need to wrap around the conductor. And, this is important: Never solder these connectors. Only crimp them on, and always be sure you crimp to the insulator and to the conductor independantly. That way the insulator takes the stress while the conductor is left to do nothing but "conduct" electrons. All aboard!


And here you see the connector crimped onto the "ground" wire. I use a special crimping tool from Germany which does a great job. We sell two versions of these tools.


And here's the finished product, with both connectors crimped on and heat shrink tubing applied.

To see how to mount headlights and taillights, go to the mounting lights page.

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This page updated: Tuesday, October 25, 2016

Peter White Cycles
24 Hall Rd.
Hillsborough, NH 03244
603 478 0900 Phone
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