Trek CarBack Radar Rear Bike Light

[rswagler1]

Lane position is shown on the Trek phone app.

[jn92]

To me this is useless because

a) where I ride there are no two lane roads where cyclists are allowed (that I know of)
b) I don’t have my phone mounted to my handlebars

I hope Trek comes out with a “light” version of what they have here more in the vein of the Garmin Varia in shape, but with their powerful ION RT light, USB-C charging and battery indicator on the side.

[HLaB]

Im not sure how it’ll work, whether or not its sensitive enough to say if a car in your one lane is passing far enough out to give you space or not. If it cant give that info or it only gives that info on the phone app (like you I don’t mount my phone to the bars), I cant see it being much benefit to me over the more streamlined Varia either.

[WindWarrior]

@FlatFylde

What I haven’t heard, and what would be of value, is a radar that identifies a close pass before it occurs. Now that really would be a game changer.

In my mind the game changer would be a live video view of what’s behind me. Make the bike computer an electronic rear view mirror, like what is available on some cars. Depending on price I might upgrade for that.

[Ron]

I have also noted that when the car is approaching fast but is in the further lane from the right most lane (ie 1 lane over in a passing lane or across the center lane) the display is orange and not red. This is some level of indication that it is not as hazardous as a fast approaching right lane pass.

[Neuromancer]

I really like this as I have running headtorches powered by 18650s, and would love to convert to a bike solution but they never seem much cop.

How much does this work out at in terms of weight vs say, a Nitecore NB10000? An 18650 has a max MAh of about 3500ish, so you’d need 3 of them to match it…

The other issue is recharging is never as good as just being able to swap a battery out…

[WindWarrior]

The Nitecore looks nice for $60. I dunno the answer to your questions, I bought the 18650s and case to fix a solar powered patio umbrella.

[Power13]

@WindWarrior

In my mind the game changer would be a live video view of what’s behind me.

Was done 10 years ago by a company called Cerevellum. He was probably ahead of his time and the vision outstripped the technology available.

Cerevellum Hindsight 35 Preview

[WindWarrior]

Yeah, I had to believe it had already been done.

[FlatFylde]

At the right price and with the right battery length that starts to sound Premier League instead of non-league.

[stanion]

I disable the Varia’s light to save power, and use a separate rear light instead. Sometimes the Varia’s light re-enables (connected to a Hammerhead), so I have to occasionally check that it is still off.

[bmcd]

Yeah that’s what I do too (with a Bontrager Flare actually) and also what happens to my Varia. Using mine with a Garmin 530, which is also starting to lose a bit of battery capacity, I think. It’s been excellent though.

[WindWarrior]

@Neuromancer

How much does this work out at in terms of weight vs say, a Nitecore NB10000? An 18650 has a max MAh of about 3500ish, so you’d need 3 of them to match it…

172grams

I’ve got 2 of these $5 batteries: Molicel P28A 18650 2800mAh Battery | High-Performance and Reliable

at 5600mAh (2 x 2800mAh) but could upgrade to 7000mAh (2x3500mAh) for $10.

The Nitecore NB10000 is 150g / 10,000mAh so with my $10 upgrade its still almost 50% more but not sure I would need that much juice for another double century or long day from the valley to South Lake Tahoe.

[huges84]

@Neuromancer

Lithium batteries do not like being run until empty. Unlike, say, a laptop, where keeping it at 50-80% is a reasonable proposition, everyone runs bike lights until they are empty or “one ride left”.

This combined with a small form factor necessitating a small Lion battery means that the only solution to this is SRAMs; aka a removable (and so replaceable, and hopefully I pray recyclable) battery pack - or, better - a standard lion battery like an 18650.

But the electronic device decides what voltage is “empty”. Garmin only needs to set that turn off voltage to a higher value. It would result in a small decrease in as-new battery life yet be a big improvement to years-old battery life.

[mcneese.chad]

TREK CarBack vs GARMIN Varia Radar // The Ultimate Bike Radar Showdown

[huges84]

Anyone considering the CarBack should really watch that video. Based on the range being nothing special, the side detection not being wide enough, and the speed differential being set too high (could be fixed by SW I think), I don’t see it even being on par with a Varia.

[huges84]

Since there was discussion about poor Varia battery life in this thread, I posted what I think might be the cause over here.

[KodiakRider]

Llama mentioned that the light pattern doesn’t change when a car approaches. Honestly, with the Varia that gives me the most security that it flashes more to get the drivers attention.

[mcneese.chad]

Hard to know for sure, but the pattern used by Trek was tested and developed with lots of research to be one that gets attention even if it doesn’t “change” actively.

[BrianSpang]

That was a very good review. What a lot of work. The only thing I didn’t see (and maybe I missed it) was whether the Car Back changes the alert if a car is approaching at a high speed. Varia does this.