Review of the Garmin Varia RTL-510 Radar

Standard disclaimer:

Being into technology, I’ve accumulated a fair bit of bike tech also.  As such, I’m going to try doing thumbnail reviews of some of the bike tech that I current, or used to, use.

These aren’t going to be super technical reviews.  For that kind of thing I suggest you head over to DCRainmaker‘s blog or GPLama‘s YouTube channel.

These are going to be my impressions of the product … what I like, what I don’t like, what could be better, and some things that should be left just the way they are.

All the items I’m going to review have been purchased outright by me and I don’t get any compensation for the reviews (unless I provide an Amazon link, in which case I get a small commission).

A few years ago I decided I could try bike commuting to work. The office I work in has a bike rack and (lucky for my co-workers) a locker room with showers.

I figured I could leave earlier than I normally would, ride the 20 miles to the office, lock my bike up, shower, and start work about an hour after I normally would. I would leave a change of clothes, toiletries, and fresh cycling kit for the ride home.

A few years ago a 20 mile ride to work would have seemed impossible, but now it’s really not a big deal. Takes about 90 minutes.

The only issue is that I have to ride on somewhat busy streets. This doesn’t bother me, especially when I’m riding in a group, but when I’m riding solo it can be a bit nerve racking. Especially when there isn’t a huge median on the road for me to ride in.

Garmin has had a tail light / radar unit for bikes. When I first saw it advertised I thought it was kind of silly. Now that I’ve been riding on the road more, not so much.

The first radar unit I purchased was the RTL-500. It was good. The only thing I didn’t really like about it was the battery life and the light patterns.

Garmin came out with a new version that’s much better. The Varia RTL-510.

I’m not sure exactly how it works … but it’s able to detect cars behind you and sends alerts to compatible watches, head units (like the Edge 1030), or it’s own display unit. It connects to head units via the ANT+ wireless protocol.

I’m really pleased with it. It’s able to detect most cars that come up behind me and send an alert to my bike computer. The alerts are audio & visual. When it detects one (or more) cars, the head unit chimes, and an indicator shows up on the right hand side of the display (this is configurable). Each car it detects shows up as a dot on the side with their relative distance indicated by how far the dots are from the top. It also indicates their relative speed. If cars are approaching slow, the indicator bar has an orange glow. If the cars are approaching fast, the indicator bar has a red glow. When the cars are no longer there, the indicator bar glows green and then disappears.

When the RTL-510 is connected to a compatible bike computer (currently only Garmin Edge 510, 520, 820, & higher), the light in the unit responds to your speed … so when you slow down, it changes it’s pattern so people behind you (cars & bikes) know you’re slowing down.

What I like about the RTL-510

• It’s very responsive. It detects cars fairly far away.
• Although not a function of the RTL-510, it audio & visual indicators are easy to hear & see.
• It has very good battery life. I’ve done century rides (100 miles) and it still had power left. That said, I do turn it off when I’m stopped for an extended period of time (rest stops & lunch breaks).
• The form factor is much nicer and doesn’t ‘stand out’ on the bike. It looks like a normal tail light.

What I don’t like about the RTL-510

• Sometimes the process to pair the unit with a bike computer is awkward. It takes more time, and more effort, than I think it should.
• When it’s in ‘stand by’ (i.e., the light is off) the radar is still active. I think, when it’s in standby, it none of the functions should be active and it should just be waiting for a signal from a head unit to go active.
• It’s a bit too sensitive sometimes … it frequently picks up cyclists behind me and sends an alert.

Is this something for you?

I would highly recommend this for someone who rides solo a lot on busy roads. It’s NOT a replacement for being aware of your surroundings, but very much an added level of security.

If you primarily ride on side walks, bike trails, or in a large group, it’s probably not necessary.