strain relief

[JimK]

Somehow my dynamo-powered rear light is not working so reliably. Quite a few times the connector at the headlight that runs back to the rear light seems to come loose. Often enough I snug it back in and the rear light turns on. Now I fear that the repeated handling has actually broken the wire where it attaches to the connector. Should be easy enough to put on new connector with a slightly shortened wire, but really this is a symptomatic fix only!

In an attempt to lock the barn door, now that the horse is gone, I have put a simple slip knot in the wire to the rear light, knotting the wire to the headlight support. I am hoping this will provide some strain relief so a tug on the wire won't pull that connector out of the headlight.

I wouldn't mind following that chain of causation a little further. What is tugging on the wire? I do hang the bike from the rear wheel when I store it, and to do that I do lift the bike by holding it at the head tube. So maybe I am tugging the wire then. I try not to, but it is a 40 pound bike and my control is not perfect. Or what else might be tugging that wire?

The headlight is on the forks and the wire to the rear light is on the frame so the wire has to cross that moving boundary so there is a bit of challenge there to manage the movement. Has anybody figured out a smart strategy or observed problems with this little puzzle?

[Danneaux]

Has anybody figured out a smart strategy or observed problems with this little puzzle?

Jim,

By some means, your wire is getting tugged too short; it disconnects as a natural way to relieve the strain.

A strategy that has worked well for me over the last 35 years or so on a number of bikes has been to make a strain relief between the fork and frame for the taillight lead by coiling the wire around a 4-5mm allen wrench. The coil then serves as a strain relief, expanding a little over its coiled length, then contracting again. It is important to make sure there is a little bit of slack at the extremes of movement. My connectors never unplug, whether the bike is lofted to a hanging hook, the 'bars are at full lock either way, or in the event of a crash.

See photo of this setup on my Nomad, below.

This same strategy will also work with wires routed under the top tube (as you have) or below/alongside the downtube, as I have done.

All the best,

Dan.

[JimK]

That's a nifty set-up, Dan! Thanks for the photo! I need to get some extra wire to provide that much slack. These little details!

[John Saxby]

Good luck, Jim -- reckon Dan may have the outlined the way ahead for your Nomad's lighting.

Thanks for this explanation, Dan, of the pigtailed stretch of wire aft of your headlight. I have a big floppy loop on my Raven which serves the same purpose, but doesn't look nearly so, well, purpose-built. I'd looked around various shops & suppliers for something similar to yours (precoiled and springy, maybe), but not finding it, I thought that yours was probably one of those products specific to the Left Coast, inaccessible to the scruffy lot east of the mountains. Now I know that indeed it was, but not a commercial venture  :-)

Good on yer, mate.   

[JimK]

The experts make difficult exercises look easy. Me, on the other hand... can turn the simplest thing into a near disaster! Ah, but the good news: my tail light is back working! Somehow along the way though I managed to ground out the headlight  an impossible number of times! I guess it's like the old measure twice advice... wiring up a tail light, test the connections first before crimping! The worst part of the experience: I disconnected my nice gold plated supernova plugs to verify that yes, I had things connected backwards yet again. Ooops, instead of pulling the plugs apart, I pulled the crimp connection off the wire. That kind of day! Now I have Radioshack banana plug connectors there instead, where the S&S break is.

I used speaker wire - yeah, Radioshack again! Instead of Dan's neat coil, I made a loose coil inside the double flange Nomad fork. Ha! I used a butt crimp connection to hook the speaker wire up to the existing wires back to the tail light, in an attempt to save that supernova gold. Oh well.

Ha, then I took off the Marathon Winter tires and put on the Plus Tours. We have a 70F day forecast for this week!

[mickeg]

My Marathon Winters came off yesterday.

[Danneaux]

So sorry for the tough and difficult day, Jim; we all have those once in awhile. Nothing outright fatal, more like being nibbled to death by ducks. There's days I have "dangerous hands" and dare not go near things lest I mess them up.

The good news is you've corrected the problem and your lights are working again. You've even a bit of spare wiring on board for ready repairs Next Time in case they're needed. Not a bad idea now that Radio Shack is gone.

Real happy to hear you're back up and running and you and mickeg can go back to the non-spiky tires. A sure sign of Spring!

All the best,

Dan.

[JimK]

I have taken some nasty spills on ice, so I am too scared to ride in the winter without spikes. But my little spin today, with real rubber on the road, sure felt great! The next big improvement is when the street cleaners get all the grit swept up. Then the tires can get a serious grip!

[mickeg]

...
Real happy to hear you're back up and running and you and mickeg can go back to the non-spiky tires. A sure sign of Spring!
...

This year it has been so warm in north central part of USA with the strong El Nino that there has been very little snow and ice.  I have put a total of 21 miles on my studded tires this year, hardly worth the trouble to install. 

I finished building up my rando bike a couple months ago.  Even though that does not have studded tires, I have put a lot more miles on that bike this winter than on the bike with studs.  I did not want to use the bike with studded tires when there was absolutely no snow or ice on the ground.

This morning I looked at the ten day forecast, it never dips below freezing.