3M Reflective tape

[kiwiaudio]

My buddy says that the 3M tape on my side bags is hardly visible at night anymore. Do you suppose it diminishes over time?

[Mr_Ed]

Is the top layer of material scratched up at all? Marring the tap layer is the only thing I can think of that would make it less reflective than it was originally.

Also.... how has your friend determined that it's less reflective? Under what conditions? Is it possible that either the source of light or his eyes are positioned differently relative to the 3M material?

[kiwiaudio]

Ed, I'm wondering myself just how visible it is and what conditions my friend is using as judgement. I just shot a picture in my garage in the pitch dark with a flash camera, and the tape appears very bright. Every pic I've seen of this 3M tape looks like the one I took, but i think it is unrealistic. I don't think it simulates a motor vehicles low beam headlights from 50 feet behind me!

 

oops - snowblower got in the way !

[flat_twin]

I've seen this happen with the left saddle bag. Exposure to the exhaust dirties up the reflective film.

[Eckhard Grohe]

I used to use a similar material as part of a high precision measurement system where I work. The tape is what is known as a retro-reflective material. The tape reflects light back to the source. The strength of the reflection diminishes the further the observer gets away from the light source. This reduction can be dramatic once you exceed a certain angle which is dependent on the type of material. The retro-reflective material contains prisms which return the light back to the source. Reduction in the reflectivity can be caused by scratching, dust or degradation of the optical properties of the material overlaying the prisms.

[GoGo Gadget]

Ed, I'm wondering myself just how visible it is and what conditions my friend is using as judgement.

 

I wonder if the back was just dirty the day your friend saw it and made that judgement? Throw a layer of dust across it and it definitely does not reflect as well. I know the back end of my bike is the first place to collect dirt since I ride through 2 miles of gravel roads everyday. The rest of the bike looks clean, but the back end will be filthy.

[Joel]

I don't think it simulates a motor vehicles low beam headlights from 50 feet behind me!

 

Seems like it would be easy enough to try that out for yourself, if you could park your bike on a quiet street or in a parking lot and drive up behind it in your car.

 

In any case, a new tape kit isn't that expensive, especially if you're concerned about visibility.

[Mike]

I never noticed any loss of reflectivity, but it certainly seems logical that you could scrub it enough that it would, over the years, lose some reflectivity. The black reflective tape kits are a nice addition, in the sense that they do not screw up the daytime aesthetics of your bike, but offer a fair degree of reflectivity. However, they're not the most reflective stuff available. In my mind, though, they do make a difference--it's not like a following vehicle is hit with a high-power beacon, but they do present a pretty clearly visible profile that's much more noticeable than the single point of light offered by a tail light.

 

If you want to really light up the night, the SOLAS grade tapes offer higher reflectivity and do so at greater angles. However, using them makes you look like more of a goof.