^^^What do you see by turning your head that you don't see in the mirror? I understand this is necessary using a mirror with a limited FOV with resultant significant blind spots, but with something like a Take-a-look on the glasses, the FOV is wide and you can scan behind by turning your head a few degrees.

I've tried them all and I keep cycling between them. I recently went back to the Italian Road Bike Mirror and, for the first time, got it properly and perfectly positioned. This is the best in my opinion. By far. But you need to take the time to set it up properly.

For helmets/glasses, it has to be a helmet mirror. I *hate* glass mount mirrors it just seems and feels awkward. So I use the HubBub Helmet mirror. HubBub Custom Bicycles Online Store - Product Detail

J.

So do you have a preference between a helmet mounted rear view mirror, or one mounted onto the handlebars. Advantages/disadvantages to each?

I've tried the Italian road bike mirrors and wouldn't get them again. On both of my bikes, the glass has fallen out, likely due to me trying to do minor adjustments on them after setup. These mirrors are wrapped with your bar tape, so be prepared to remove your tape to replace or adjust. I bought the Sprintech mirrors a while ago and love them. They fit into a plug that replaces the bar end, sort of like a ball and socket joint. They can be adjusted and can be replaced if needed without unwinding tape. Mine is very positive and I've not needed to adjust at all after initial setup, but I could if I needed to. They came as a pair, one for the left bar end and one for the right. Didn't install the right one, but now that I see how unobtrusive it is, I'll put the right one in as well.

I finally got my Italian Bike Mirror set properly and it works great. Prior to that I'd agree with your assessment. What I did was to set the mirror in place with electrician's tape so that I could see the very edge of my thigh. Then I taped the handlebars and that worked perfectly.

I've used the Sprintech mirrors too, but I keep hitting them with my knee when I'm up out of the saddle. So, they came off. They do protrude farther than the IBM does.

J.

My Mirror Experience
 

I have used eyeglass mirrors for more than 30 years. They have saved me twice on mountain rides (Sierras and Big Bear) with drivers purposely targeting me. I bailed off the road and but for a few scratches did survive to finish the rides. I never used them in crits, RR or TT's but have received my share of insults from other competitive riders in the peloton. But I started my riding career with double centuries in fairly remote areas with drivers who were not used to bikes.
I used the "third Eye mirrors for years and found them hard to adjust and not staying in adjustment. I found as I got older my neck will no longer turn enough to look back so must rely on a mirror if I wish to ride/ drive. I found the TAKE A LOOK mirror from Bike Peddler in Greeley, CO a little over a year ago. It has both horizontal and vertical adjustment, is longer than the third Eye, is easily bent if need be and is EZ to adjust on the bike. Plus it has a wider field of vision. I consider it as important as the helmet!

Mirror preference is a personal choice, but I prefer the bar mount mirror. My wife and I are primarily touring cyclist, although we also ride road bikes. We ride year around for fun or getting ready for a tour. We have mirrors on our touring bikes, but not on our road bikes.

IMO the disadvantages of the helmet mount mirrors are: 1. They are in the way of a helmet cover. We do a lot of riding in the rain, and the helmet covers go on and off regularly; 2. They are relatively fragile. We pack our bikes and gear, including our helmets, for transport on buses, trains and planes; 3. I really don't like them in my field of vision.

Pretty much the same with glasses mounted mirrors with the addition that they do not seem practical when switching from my regular glasses to sun glasses several times a day, or when putting glasses in a case.

We have tried 3 different bar mounted mirrors: Mirrycle, Blackburn, D+D Oberlauda. Mirrycle is the one we prefer. It fits well is sturdy swings out of the way when parking etc, and is easy to mount or install when packing the bike. The mirror is about 3" in diameter, giving a wide field of view without making objects very small. The Blackburn was second, and my daughter uses one on her Long Haul Trucker.

Mirrycle mounted on my wife's touring bike.
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As far as the visual scan- I don't trust the field of vision of any mirror, either driving or riding.

I see the utility of a mirror and have tried most if not all the mirrors mentioned above but cannot find any that work both when riding on the hoods and the drops. The change in head angle seems to require different positioning of all mirrors. I spend about 30% of a ride in the drops, 60% on the hoods and 10% in other positions. Any ideas?

I use 3rd eye mounted on helmet, I have broken three of them by constantly taking on and off eyeglasses. One I was using yesterday broke while riding, I felt blind the rest of the ride. I have arthritis in my neck and find it almost impossible to turn and look behind.
I like 3rd eye but mounts are a weak point.

The Sprintech Drop Bar mirror is what I use. It's a little harder to see in the drops but there is no loss of the field of view when switching from position to position. When in the drops you have to move your arm out and your leg in to catch a quick peek behind you. You get a great sweeping rear view with the two mirrors. The one thing you have to get used to is the convex surface of the mirrors makes objects appear further away than they are. Now that I have gotten used to them they are an indispensable part of my bike. One important factor is they look good and they don't take away from the look of a race bike.

I hated these at first because I couldn't see very well past my knees. Then I figured out that if you turn the bottom out a bit you can see very well.
http://img.photobucket.com/albums/v2...ps2f52df8a.jpg

http://img.photobucket.com/albums/v2...ps9f21b813.jpg

My helmet mounted mirror has probably been cussed at more than any other mirror in the history of mirrodom, BUT I'm starting to get the hang of it and cuss it considerably less now!

I used a Mirrycle with Shimano 105 brifters, but it would not work with my Shimano Ultegra brifters or DI2. That is why I use the Selle Italia Eyelink.

Glad you've had good experiences with them. I stopped using them over 35 years ago. The only close calls I've ever had have been with things ahead of me. Not all of which I've managed to avoid.