Sunday, August 5, 2012

NiteRider MuNewt: long-term use report

In 2010 I did the Mt Tam Double Century, borrowing friend John's NiteRider Newt light for the pre-dawn start. My first time doing the double, I'd gone without lights, thinking I could rely on the pace car for guidance. That was a big mistake. The pace car was driven at a constant speed, which on the steeper slopes of Lucas Valley Road, the first climb, put me deeply into the red. With John's light, I was able to ride my own pace on the climb, and it contributed to the ride turning into one of my strongest doubles ever.

Afterwards, I decided I wanted one for myself, and I was happy Cara got me one as a birthday gift. But instead of the Newt with its frame-mounted battery and sloppy cables connecting these to the handlebar-mounted LEDs, I went with the newer MiNewt, which has rechargable batteries and LEDs in an encapsulated package. The light was important for my commute from my then-new job in Mountain View on a heavily trafficked road.

I got the brighter 250 lumin model. Even through MTBR tested these lights and determined the light is a bit less than claimed, 250 lumins was plenty for any riding I do. In fact I rarely run it on high power: of the three illumination levels available, even the lowest is sufficient for my commute. With advances in LEDs, 250 lumins isn't even sold any more: now options are 350 and 600 claimed. So there's plenty of light (beam pattern is another issue I won't discuss, however, lacking sufficient comparison).

Unfortunately, though, the MiNewt is a classic issue of the hidden details. I still use 26 mm handlebars, preferring them to the heavier and (theoretically) stiffer 31.8 mm bars which are now the de facto standard (despite still being called "over-sized"). Bar-mounted products typically in some way accommodate both sizes, and these lights were no different. For use on the smaller, 26 mm bars, a rubber pad is inserted between the clamp and the bar to make up for the radius difference.

This extra pad requires a substantial clamping force to inhibit the light from rotating. This wouldn't be a problem if there was some mechanical advantage offered for tightening the clamp. Unfortunately, there is none. A ratchet must be closed by hand. Overcoming the resistance of the ratchet thus requires applying more than the static clamping force with fingers alone. My fingers aren't up to the task, so have begun to use an adjustable pipe wrench, but this risks breaking the relatively fragile plastic. Then I can get three clicks on the ratchet. I can get four, but the ratchet can't handle it, and retreats back to three. Every other light I've used, indeed every clamping part on a bicycle, offers some mechanical advantage for tightening. Not multiplying the force available from puny cyclist arms was a big design flaw.

There is a moment (M) created by the displacement of the light center-of-mass (COM) from the vertical plane of the handlebars. The light would be more stable if it was positioned further back.

But it wouldn't be so bad if the clamp had been better placed. When the bike rolls over a bump, the wheels accelerate upward, which since the bike is rigid, accelerates the handlebars up as well. This applies an accelerating force to the light clamped on the bars. If the center-of-mass of the light is above the clamp, this force is direct, and no torque is exerted. However, if the light center-of-mass is not positioned above the clamp, there is a torque equal to the force multipled by the offset of the center-of-mass relative to the clamp.

It appears that no consideration was given to this in the clamp placement. Every time I hit one of the ubiquitous San Francisco pot-holes, unless I can attain those elusive 3 clicks of the ratchet, the light rotates downward. After a few of these events, the I have a nice view of my front tire and little else. Obviously descending Lucas Valley Road in the dark this is a major safety concern. If I was Jan Heine I'd surely have machined a new clamp out of Aluminum: the Cateye-specific portion which attaches to the light body is attached to the main clamp with a screw, and it could easily be transferred.

Then this year the light started randomly failing. It would go dim or go completely out without warning. Banging it with my hand seems to generally bring it back to full illumination, but that requires that I notice first and that I have the luxury of removing a hand from the handlebars, Finally on Friday I removed the battery and wiped down the contacts, which seemed to have been scummed somehow, perhaps when the light got wet. This seemed to fix it: I had no problems during the Mt. Tam Double yesterday (report to follow). And to be fare I should complement Cateye on how the unit is constructed: solid, with screws which are easily removed for disassembly, a nod towards maintenance for a product where the pace of technology often leads to an unfortunately short usage life.

So the light itself is excellent, but watch for water penetration. The USB recharger and battery is excellent. But the devil's in the details, and the clamp design, in particular for 26 mm bars, is a big issue.

3 comments:

Rich said...

Dan, NiteRider makes a bolt on mount that is much more secure. I complained shortly after buying my light (having already read complaints about the mount) and they sent me one. I think they now sell them for about $10.

djconnel said...

Cool!

djconnel said...

Follow-up: they swapped my mount for free, and the light is much better now.