After a road ride on Sunday and getting surprised by cars a couple of times, I ordered a Varia and just installed on my bike. Have a couple of questions for those that have ridden with the Varia:
Does is still work well in a paceline of 5 or 10 bikes if you’re on the front? Can it basically see past the cyclists behind me?
Please tell me, “No, you’ll have to sit in at the back of the group for it to work properly”, so I’ll never have to take a pull again!
I’ve ridden with groups up to 5 and it still detects. At worst the detection might not be at the normal 200yds but say 100yds. But that rarely seems to happen. When riding in groups, if you have someone catching you on a downhill going much faster, you might get a false positive there.
So you should sit on the front full time so the rest of group can see when the blinking changes and be aware of a vehicle approaching. 
I would not count on it to pick up cars if you have other riders right behind you. I find it to be hit or miss in those situations.
That said, I’ve found the Varia radar to be one of those rare products that far exceeded my expectations when I bought it. It’s unbelievable how well it tracks multiple vehicles in challenging conditions. It might be the coolest gadget ever, just really impressive technology. It’s not a guarantee you won’t be hit by a car, but it’s a great way to improve situational awareness to minimize your risk.
I’ve had situations where it read other riders as cars which was weird. I had an awkward situation where I thought a car was on my butt and not passing. So I yelled “pass already!” not realizing it was another cyclist behind me. Needless to say, he pulled ahead and did some work :).
Overall though, this device is great piece of mind. It’s like mirrors in your car. It tells you what’s there, but you still need to look over your shoulder before you pull out, just in case.
Thanks everybody for the very helpful replies. I’ll plan to tailgun just to be safe! 
It’ll pick up anything moving towards you at a few km/h faster than you’re going. It’ll also ‘ghost’ things that approach then match your speed. This will happen in slow moving traffic.
Ah makes sense. Guess I’m so damn fast it’s only happened once…or i’m always dropped off the back…
sadly i know the truth
Love the varia and never leave home without it. I ended up getting one for my buddy and he was blown away. This is coming from a guy (my buddy) that has been hit 3 times a few years back.
I’ve been on exactly 1 ride with my new Varia and I can’t stress how much of a game changer it was for me. Before I got it, pretty much every sound made me think a car might be coming and mentally I was expending A TON of energy constantly scanning with my ears for cars. Who knew a rear facing radar would be a device to lower RPE!
I mostly train solo except for Wed night. Memory was refreshed recently… we had 15-20 riders on the last Wed night group ride before COVID-19 shut down the group riding scene. Near the start of the ride we do 4 miles down a county highway with posted speed limit of 55mph. On those types of rides I often hear cars coming before the radar picks them up, due to the length of the paceline and mini echelons that form behind me. Sometimes I hang off the back to get a little extra work (less draft) and serve as the early warning “car back” guy.
Gen 1 Varia owner here and have used it for 3+ years. Best. Purchase. Ever. Using a Garmin headunit and by forming a light network I turn off the Varia lights and get 7+ hours of battery.
Super handy when leading coming to the top of a climb and the rider 20-50m back starts to surge for the line…
I don’t ride in groups that big. Mostly ride solo or up to group of 5. I have both gen1 and gen2. And as good as gen1 is, I like gen2 so much more. Detection is pretty much the same, but gen2 has much longer battery life and it is much brighter.
ya, and like you said groups up to 5 if I’m pulling or rider #2 then detection range is a little reduced. But range is still good in small groups. I’ve noticed decreased range mostly when we are fighting a strong crosswind (April - Sept) as that puts the group into an echelon and creates a larger “barrier” to the radar. In large groups on REALLY windy days the detection range goes back to normal, because the echelon is so wide and we end up with several echelons with large (and increasing) spacing between groups.
I bought the gen 1 and then realized it was too dim as a rear light, so I bought a Bontrager Flare RT. Hard to justify an upgrade at this point.
Varia users…
You’re on a wide shoulder, plenty of room. But a bridge is coming up with 2 narrow lanes and no shoulder.
Look behind you…all clear. Look again…still clear.
Move into the lane and start crossing the bridge.
Then…half way across…you hear the Varia BEEP
Suddenly…
At least you know it is there. Just saying…
It worked flawlessly. I don’t ride without it
Do any of you Varia / Garmin fanatics know how to do this little feature I would love to see?
I have a 530 that manages (records) all of my data while I ride. I also wear a Fenix 5x all the time but if I’m riding with the 530 I don’t also record data with the 5x. But, what I would LOVE to see, or in this case feel, is when the Varia senses a car approaching, is there a way to make the watch vibrate?
A distant second here would be running the sound through my headphones so when the Varia alarm goes off I can actually hear it in the headphones. I have the head unit as well but if the wind is up or there is additional noise around me I won’t hear the alarm and if I’m in a sketchy situation I might not be looking down to see the alarm.
Anyone dealt with this and have a viable solution?
Thank you
I haven’t. But, I know on a Garmin headunit you get the varia notifications even if you haven’t started a ride. If the watch supports varia then i wouldn’t be surprised if it does the same without recording. Worth a try to see if it will pair to your watch.
Good to know I will try that. Thank you!
New units announced today that can connect to mobile phones: