Garmin Varia Rearview Radar Tail Light

This is a great device!!!Why buy it:- You connect wireless to your Garmin GPS and you can "see" cars coming from behind on your GPS. It is like a blind spot detector in your car.- It provides a clear display by displaying a red bar on both sides of the GPS- A white dot will be shown in the red bar for a car that starts on the bottom of your GPS and moves up your GPS as the car approaches- If there are multiple cars it will show multiple white dots- When all cars are gone the red bar turns to green then goes away.- It also provides a decent tail light to help make you visible- I found it to give me more confidence and less of that uptight feel not knowing what is coming at you.Limitations:- I have used it for a hundred miles or so- User learning'so You get accustomed to watching the progression of the white dots and get a feel for when a car is coming. Depending on car speeds itshowed a car 10 to 14 seconds out. Be careful not to count on that because a car may make a turn into the road you are on and thusapproach much quicker since it is not coming from clear behind. Thus be mindful of cars at cross streets that may turn onto your roadand approach sooner.o The audible beep is very low so use the visual on the GPS- Device learning'so IT IS NOT PERFECT - YOU STILL NEED TO LOOKo I found that when you come to a traffic light with stopped cars behind you and then when the light turns green it does not quickly pick up thecars behind you.o On a rolling hill road it can not see the car behind the crest of the hill. Thus, cars may suddenly appear that it does not show or shows carswith little notice.o When making a turn that you bank hard it does not pick up cars for a few minutes. I think this is because the unit is not parallel to the road.Not a big deal as it soon picks them up but something to be aware of.Install- Yes this works with an EDGE 810 - that is the set up i am using- When installing first upgrade the software on your GPS and the Varia unit. It is very important to do both. i updated just the software on myGPS and it would not work. Once I updated the software on the Varia it worked.- Remove all other wireless units (heart rate monitor, speed sensor, cadence sensor, etc) from near your bike (40 feet away worked for me). Thisis important as i could not get them to connect until I did this. I then had to resync my hear rate monitor and sensors. it took a few tries thenworked.- Only issue I had was physical install. If you do not have a bag under your seat the physical install is great. However, i do have a bag andattaching it to the seat post stem was an issue as the bag blocked it to much. I used a bunch of zip ties and attached the base to the back ofthe bag that is under my seat. While not pretty I was able to get it secure and the unit (which nicely twists on and off the base) perpendicular tothe road when attached. They need to provide a mount that can attach to under seat bags as most cyclist have one. You may have more roomon your bike if your seat post is higher and your bag is small (mine hangs down a bit) so this may not be an issue.- Thus set up is easy if you follow the instructions and above tips. After set up it just works and all my wireless devices (hear rate monitor, speedsensor, cadence sensor and Varia automatically connect when I turn them on for a ride.- There is a setting that allows you to show the white dots for cars on either the left or right bar on the GPS unit. It would be nice if the unit wouldshow you which side the cars are on by showing the dots on the side that the car is on. While typically cars are on my left there are times whenyou are in a lane and cars can be to your right. Not a big deal just a nice to have - perhaps a future software revision could do this?Bottom Line:A great safety addition to your bike, additional peace of mind and increased my cycling enjoyment (oh and it is very cool to have radar on your bike). Remember it is not perfect so still look before going into a lane of traffic or making a turn.

Lot of money for what it purports to be. I thought. But I've recently had to start riding some short segments on busy fast major main roads to get to my regular routes. I have no problem about wearing good bright apparel and riding aggressively to assert myself on these roads - but a couple of left turns at speed means that checking behind to be sure you are clear can have its "moments". So after reading other reviews - I sprung for this to pair to my Edge 1000.It picks up cars at about 600ft, can discriminate up to 5 cars in that 600ft segment (maybe more - just the most I have seen so far) - gently bleeps to let you know someone is on your 6 and then shows how fast they are approaching. It will NOT replace a final glance behind to check you are really clear - but it definitely detects cars farther out than I can hear them approaching and that is a good thing. Also catches someone trying to draft on you if they manage to sneak in silently! :-)I can't attest to what the cars think of the increasing flashing directed at them as they get closer - but they certainly seem to take wider berths than normal when passing.There is one circumstance in which the unit is fooled and that is when making left turns when there are distinct trees or lamp posts at the side of the road. You then get a warning about the tree (!). But at least it is a false positive and now I understand what is going on. I have not yet had a situation where it failed to detect a car - though if a car turns out a side road on your tail RIGHT as you pass - it may not pick it up till it is about 200ft behind you. But then you saw the car on the side road as you passed - right?Major contribution to safety on busy roads.--Follow up after a couple of weeks use:I'm assuming this uses some form of Doppler radar (detects a shift in phase from the returned signal ) because - traffic on the other side of the road moving AWAY from you is never detected (or rejected). Traffic moving up on you is detected - including bikes moving up on you. But once the bike is drafting you at the same speed it disappears. And that means a car that hangs on your hip waiting for a moment to pick a time to overtake and is travelling at the same speed as you ALSO DISSAPEARS from the screen and then is redetected when it accelerates to overtake. So a little situational awareness on your part is important.A large panel truck of semi WILL mask cars behind it. Obvious really - the radar can't see THROUGH the big trick or panel. so you can get caught by a truck overtaking you and then suddenly a lot of cars also appear on screen - closer than you might expect.But this doesn't detract from the unit - you just need to be aware of these operational limitations and work with them.