Suggestions on a bike radar for my commuter e-bike that doesn’t require a head unit to provide audible alerts? It would be helpful to get alerts while commuting. I’m so used to the Varia on my other bikes.
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I don’t know of any that have their own built-in speaker, but there are apps that will use your cell phone to broadcast the “beeps”. Maybe if your volume is up, you can still hear the beeps if your phone is in your pocket?
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Not being funny, but I don’t understand the use case. Can’t you hear the vehicles?
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No, sometimes I don’t because of wind noise.
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I especially can’t hear the cars on the ebike because of the constant high speed wind noise and the added hum of the motor. Easier to hear on my pedal bikes and I still find the radar extremely helpful.
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I use a Varia and the corresponding app on my iPhone. My commuter has a mount for my phone, so I can see the usual map with cars. But if I have my phone in my pocket, I use my AirPods and the app gives audible alerts.
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Aha. That does make sense.
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I honestly don’t want to come across as condescending, but have you ever used a radar? Pretty universally, the feedback I have heard and experienced myself, once you get used to riding with a radar, you never want to go back, you feel naked without it. IMHO a radar is one of the best bike purchases of the last 10 years, no joke.
Here are a few things that ears, mirrors and such can miss:
- Electric vehicles are super silent and I can’t hear them, at least not until it is too late.
- Wind noise makes it hard to hear.
- Semi quiet and quiet roads with few cars can be dangerous in that you tune out and focus on the scenery.
- If several vehicles are in close succession, a radar will pick up on them and show me e. g. two vehicles when I can only audibly hear one.
- It warns you if the overtaking vehicles are very fast (high speed differential).
- When you are riding in fog (which was a regular occurrence where I used to live), you can’t always see cars, but the radar will pick them up.
- Radar is a great addition, but not substitution for looking over your shoulder and keeping your ears engaged.
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Thanks Kevin. This seems the closest to what would work best for my use-case. I don’t really want to put my phone on my handlebars or have a head-unit on there, but a light is almost always useful. Thanks – I didn’t know about this product. I’ll look into it some more. I do wish the attachment wasn’t just a rubber band – I prefer permanent mounting options like the quarter turn or the Trek Flare ones. Maybe I can MacGyver a work around.
I’ll add that some places are noisy, and hearing something doesn’t necessarily tell you anything about how far away that thing is or how fast it’s approaching. There a number of factors that affect how loud the approaching vehicle is.
Hearing approaching vehicles aside, there’s one thing that a radar can do that humans can’t: it’s always looking for vehicles behind you. It doesn’t get distracted, and it doesn’t forget to look behind you.
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I’ve never used one, but assumed all the goodness you’ve described here, or most of it, is through visual communication with the head unit.
Yes - I did this for my eBike a short while ago! The key was making use of the Cannondale Smartsense system, specifically the one intended for ebikes. You can get a radar and a small radar-specific display (both by Garmin), do a bit of connector hacking, and power it directly from your 12V light port. No Cannondale bike is required.
Some details:
- The non-ebike radar and radar display components assume a central Smartsense battery, so doesn’t work without it. Don’t get these.
- You can also combine it with non-ebike front and rear Smartsense lights, which IMHO gives a pretty slick integration. These work just fine without the Smartsense battery.
- I’m not able to have audible alerts. However, I do get some bright leds right on my handlebars that make notifications hard to miss.
If desired, LMK and I can share more details.
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There are also audio alerts. But seeing how many cars are behind you is a big deal.
The ARadar app for Apple Watch works pretty well with a Varia radar unit. If there is a lot of traffic it can be hard to keep track of the alerts but overall I’ve been happy with it.
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Please share more details on this, I would love to know…..
There is an audible and tactile alert when the radar senses an object. There is a display but I don’t look at it because it is on my wrist. If a single car overtakes you, then it is very helpful because the alert is distinct. When riding in traffic there are lots of alerts so it is hard to keep track all of the alerts.
It also tends to drain the watch’s battery. This isn’t a big deal when commuting (at least for me,) but on longer (>4 hour) rides the watch will die.
Thanks, that’s good to know. I’ve been considering switching from a computer to just Apple Watch, and radar was one of the factors. Appreciate the overview.
So, from experimenting and hacking a bit, here’s what I learned about the Smartsense system…
First, an overview:
- The components work well being powered off of +12V, which means most ebikes can drive them with their light circuit.
- The system is wired, not wireless. So, there are a total of 4 signals in the cables: Power, Ground, CAN-H, CAN-L.
- Of relevance for ebikes, you can get a front light, rear light, radar, and radar display. The radar and display are made my Garmin, and the lights are by Lezyne.
- The lights don’t make use of CAN - they simply pass the signal through the various wires. The radar and radar display, of course, do.
There are two similar but different Smartsense systems:
- The “normal” one, the one Cannondale sells on their website, is intended for non-ebikes. The radar and radar display require the core Smartsense battery, which has some intelligence in it. All of the components use 6-pin connectors to link together.
- The “ebike” one, which does not require the Smartsense battery (or its intelligence). All of the components use 4-pin connectors to link together.
- AFAIK, lights only exist for the “normal” system. But, you can use them anyway.
You’ll need to splice some cables to hack the system onto your ebike. For the 6-pin connectors, there are 2 Power and Ground wires. The wire colors correspond to:
- Power: 4-pin red, 6-pin orange & white
- Ground: 4-pin black, 6-pin black & green
- CAN-H: 4-pin yellow, 6-pin brown
- CAN-L: 4-pin blue, 6-pin pink
For my bike, I decided to use all four components, and to make them interconnect using 6-pin connectors. So, my shopping list looked like:
- Radar (must be ebike-specific, i.e. have 4-pin connector)
- Radar display (must be ebike-specific, i.e. have 4-pin connector)
- Front “foresite” light (6-pin)
- Rear “hindsite” light (6-pin)
- Radar display mount
- Wire kit (comes with two male-female 6-pin extension cables, which I use for splicing)
- Pigtail to connect to your ebike motor’s +12V light port
All but the first two can be found on Cannondale’s website (SmartSense Wire Kit | Equipment | Cannondale). The first two you can sometimes find on ebay (make sure they have 4-pin connectors!) or you can order them as replacement parts at a Cannondale dealership (e.g. I ordered the display for a Cannondale Adventure Neo 1 EQ at REI). Then, I spliced to make the following components:
- Radar display + male 6-pin connector. Splice these together, and keep the wire short since it just connects to the front light.
- Radar + male 6-pin connector. Splice these together, and keep the wire short since it just connects to the rear light.
- Front light. No modifications.
- Rear light. No modifications.
- Motor pigtail + female 6-pin connector + female 6-pin connector. Splice these together with longer wires. Obviously, the motor pigtail doesn’t have the CAN connections - just connect the two female 6-pin connectors together so the radar and radar display can communicate. This becomes the main harness for your new system, and likely gets installed inside your frame.
Of course, ensure splices are clean and robust (good soldering, good heat-shrink with adhesive for weatherproofing, etc.).
That’s it! I’d recommend doing some bench tests as you go along to make sure things are working before you install the harness in your bike for the final assembly.
Hope that helps!
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Forgot to mention the answer to a key question: “why did I bother figuring out this hack?!”
My ebike is Bosch, and requires a Bosch head unit to function. There is no way to integrate any radar with the Bosch head unit. My only alternative was to have a second head unit, or my smartphone, attached to my handlebar… which I thought to be a terrible solution.
Voila - the hack was born 