Since the time change my evening commute is getting close to complete darkness. In hopes of making myself slightly less invisible, I've added some reflective tape to my helmet. In preparation for doing this I read up a bit on the subject. Here's what I learned and what I did.
There is reflective tape, and there is reflective tape. There's a lot of difference between the cheapest or most flexible vs the most reflective. Different colors return different amounts of light. The best single internet source I found for technical info on reflective tape is at
http://dr650.zenseeker.net/ReflectiveTape.htm. A good source for many of the materials discussed is at
www.identi-tape.com.
A key tradeoff is between reflective efficiency and the flexibility you need for compound curves like helmets. Most of the tapes will flex in one direction, like when you wrap a cylinder. Only the thinner/stretchier ones will follow more complex curves.
After reading descriptions of the various materials I decided to try white Reflexite V92. It's one of the more efficient tapes - not quite the best, but supposedly flexible enough for helmets. I wanted the 2" width so I could make a pattern that still showed up as a pattern from a distance. This increases the flexibility requirement since 2" squares have to deform more to follow a helmet than smaller ones.
I found that 1) The tape REALLY shows up well in headlights, and 2) The 2" Reflexite is either "just barely" or "not quite" flexible enough for helmets, depending on your standards. I got it to lie completely flat on the gentle curves of the helmet's sides, but there were a few small wrinkles I couldn't quite get out on the ones on the back. I expect the 1" width would be easier to get smooth, but I really like the pattern of 2" squares.
