Monday, 3 November 2025

The mystery of the dormant dynamo

 














Once upon a time, dynamos needed voltage regulators to prevent bulb implosion that was a very common issue when tandems and long descents. I was surprised to discover a pronounced lack of illumination from the long serving Exposure Revo lamp. Thankfully,  the Gaciron Cetus 1700 Gaciron Cetus 1700 Underneath Bike Light | cycling-not-racing was playing backing singer. Most dynamos are very reliable these days, but we only need a snagged cable, or some other issue to plunge us into darkness, possibly many miles from home. For these reasons, I typically have a secondary high power rechargeable torch type along for the ride.

The mount remains permanently attached to the bars, the light typically secreted inside a bar bag, or similar bike mounted luggage. Having returned, I pondered the possibilities. The lamp itself, though thirteen years old and exposed to the worst the lanes and trails could throw at it, very well sealed from the elements and had never been subjected to jet washing, or similar abuse.

The cabling also seemed fine. No obvious signs of wear, or damage.  That left the Shutter Precision SL9 hub. The terminal block, spring contact possibly? The hubs themselves are well sealed and turn on cartridge bearings that in my experience, run for 20,000 miles before getting the grumbles.

Before getting deep in the diagnostics, the easiest thing was to switch back to the Shimano Ultegra unit. I’d already decided that I was using the Sl9 wheel as a second/spare so would not get the hub’s electricals repaired, simply run it as a traditional front wheel. Repair would mean stripping the wheel and returning to Shutter Precision in Taiwan.

I’m fond of these units, but I’ve found Shimano are more cost-effective long term. Not least since basic servicing, such as bearing replacement is within the means of home mechanics and decent shops.  The switch coincided with returning from a mucky ride to discover a slow flat caused by a tiny sharp, most likely a hedge clipping.

Tube switched, pin hole patched and a deep, sudsy bucket clean followed. Switching wheels and giving the wheel a good spin, I was relieved to find the Revo lamp coming to life. While the Weldtite All Weather lube Weldtite All Weather Lube | cycling-not-racing was turning a little filmy, it was holding on, so I decided against topping up, not least since the KMC X10 was coming to the end of its life.

Plan was to run the chain out, switch and either apply some more All Weather, or something similar, should it land on the test bench.  Having washed, waxed and dried Denise, I’ve decided to switch to Muffin, since the weather is progressively wetter. Mudguards and a simple drivetrain being the obvious practicalities, although the geometry and stout buxom rubber makes for engaging, yet predictable handling, not to mention a magic carpet ride. Perfect for general riding, these characteristics come into their own during the darker, slippery months.  The M Part Primo Anti Slip Silicone Gel Bar Tape M Part Primo Anti Slip Silicone Gel Bar | cycling-not-racing is still impressing with its damping and reliable all-weather grip. Then of course, I want to get some more miles in with the Sigma Buster1600 and RL150 lights. Steve’s been impressed with its 800lumen sibling Sigma Buster 800 and RL150 Light Set | cycling-not-racing  

Autumn well underway and another year wiser, I’ve decided to drop Muffin’s gearing slightly, no sense straining the knees, or other joints- another Arundel fixed sprocket since these seem accurately machined, well finished and modestly priced. I’ve gone the electroplated, rather than stainless route on the basis of price, although the latter might repay the investment on salty winter roads.  

I’ve been pondering suitable substitution for the Silca Nastro Piloti Silca Nastro Piloti Bar Tape | cycling-not-racing which performs really well on the tarmac and excellent connection with the bars-a good bet for long steady audax miles, possibly winter training too, although in  my view, a bit pricey for the latter. However, given I like to play in the dirt regularly, damping was also a priority.

Enter this Ergon Orthocell. Apparently, it’s made from a medical grade material that’s also employed in their saddles. This is designed to distribute pressure evenly, thus insulate against intrusive vibration, and ultimately fatigue in the hands, arms and shoulders. In common with others, an anti-slip coating to counteract sweaty hands and torrential rains. Whether these qualities also improve grip and control when the temperatures tank, remains to be seen.