Thoughts on a new Cycling App I'm developing?

I’m reaching out because I’m looking for some validation for this idea I’ve been building a proof of concept of.

A little about me to set some context, I, along with my roommates, make free cycling related tools in our spare time, including a routing tool,, a physics simulator tool for cycling, GPX Route Speed Estimator for Cyclists: Multi-Surface, Weather, and Nutrition Strategy, and a GPX activity racer tool GPX Activity Racer - Race Against Past Performances or your competition .

I’ve made a few others as well, but this post isn’t about that, I just wanted to showcase the fact that I can build the upcoming idea, but I’m wondering if it would be worth it to develop it for anyone else.

The idea:

A phone app that lets users import a route GPX file and/or start an activity. The app is designed to work entirely offline, in your pocket, without much of a GUI, providing voiced turn-by-turn directions if following a route.

While you are riding, it allows you to ask questions or give commands into your Bluetooth headset, like, “What’s the distance until the next aid station?”, “Route me back to the beginning on the flattest possible route.”, “What’s my best 20-minute normalized power so far?”, “What’s my current distance?”, “What’s my net elevation gain?”, “What mile has the beginning of the biggest climb on the route?”.

Utilizing the physics simulator code and your riding so far, it could even determine when you’ll be where, so you can ask, “How much longer until I’m back on pavement?”, “When should I start heading back to avoid the sun going down when cycling?”.

I also plan on having it continuously monitor and analyze your ride, so if you finish a climb it can recognize this and state “Nice job! You managed 340 watts for 3 minutes up the last 300ft climb!”.

Basically, the idea is, that this could replace your head unit (or accompany it nicely).

I even intend it to have rerouting capabilities, i.e. “take me to the nearest gas station”.

So far, I’ve managed to develop a functioning Android app that works entirely offline, monitoring for speech using webRTCVAD, recording speech to memory, transcribing speech using a specially trained Mozilla Deepspeech model, on the phone, tokenizing the transcription with a WordPeice algorithm, and feeding it to a specially trained BERT Tensorflow model which maps your intent to a particular function.

I plan on developing this app no matter what for my purposes as I feel having practically limitless knowledge of the entire route, and the activity thus far, as well as voiced turn-by-turn directions that function entirely offline could help me with upcoming gravel races. However, if people find this concept interesting, I’d buy a MacBook to make an IOS version and flesh out the interface to be more user-friendly and have things like, a login, a connect with Strava feature, etc.


This sounds vaguely interesting, but:

  • I don’t ride with headphones, and very few people (close to zero) I ride with ride with headphones
  • What do you see as the core problem this solves vs. current functionality that a Garmin has? I’m only mentioning Garmin has I don’t have a Wahoo / Karoo / etc. head unit to know their navigation features

I see people using Shokz all the time…

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Garmin has limited data screens, this is something you could ask potentially thousands of questions to, i.e. “at what point in the course is the largest climb”, “what was my best 5 second power so far?”

So, that’s the main advantage I see. Frankly, I do a solid effort up a hill sometimes and get annoyed when I don’t even see a Strava segment for it later and I have to hunt through graphs to try and find this data, when I could ask for it right after the climb.

Practically everyone I know including myself has Shokz, that’s the main target if I decide to make a true production version.

Quoting (at least the gist) my intro to marketing professor at business school: you are all weird, never extrapolate your personal preferences to the larger world. Not weird in a bad way, just weird in that your personal preferences don’t extrapolate well.

I quote the above because my experience riding in San Francisco is that no one wears headphones. So your experience and mine are diametrically opposed. Both are probably outliers, but take this into account

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I agree, which is precisely why I threw this post together. It’s totally something I would use, but I’m not going to go through the effort to make it into a production thing or make an IOS version of others don’t find it valuable.


2016 before buying a bike computer I was using RideWithGPS app on iOS. It works offline and you can (usually) hear the turn by turn with phone in jersey pocket.

Yeah, I’ve done similar in the past, but I’d make it free, and make it so you can ask it things like, “how far away am I from the nearest public water?”, “route me to the nearest public water.”

It irks me the amount of things RideWithGPS charges for, voiced turn by turn directions? Premium, download a route with cues for aid stations? Premium.

I’ve used Google maps in a similar way in the past, but it doesn’t really work offline.

Sounds very useful. Everyone I ride with uses headphones for at least for some of their riding.

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Personally, I think it sounds great! “How much longer to the cafe” is a common question on our group rides. I think a people that ride long distances on their own, especially in audax riding or ultra racing would also love to be able to ask for the next shop or petrol/gas station. Yes, you could stop and look at the map and find something, but not stopping is much better. I think that is a fairly small user group though.

Personally, I’d be less interested in live stats, but I guess it doesn’t take much to have that in the app too, because you’ve got all the code already.

One thing that would concern me is the battery drain on the phone. I usually try not to use my phone during rides, so I’d have battery for an emergency. That means I also turn bluetooth and gps off on the phone, which I guess would be needed for it to work!

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Take it a step further and consider you aren’t looking for them on others because you don’t own them yourself.

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That’s a solid point, in my testing so far it doesn’t appear to have much of a draw, additionally, I intend to loop in my server when there is internet connection which will offload a lot of the Deepspeech/BERT model processing off the phone. I was just designing it with offline being the initial priority, as I commonly lose data access in my area.

Prioritizing keeping the screen off and keeping it in your pocket seems to keep the energy usage quite low in general, frankly, so far it appears to use less battery than spotify (for both the phone and headphones).

I was thinking it might be useful in disciplines other than cycling as well, like hiking. However, it’d have to have a bit of a community cycling wise for me to really consider expanding it, I’m working on a bunch of other projects.

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Same, thanks for the feedback!

Just another comment that I think headphones on “training” cyclists is pretty rare where I live. I do occasionally see “training” cyclists with headphones, but it’s mostly on the people on the bike path or riding for life reasons, not those training. (I don’t mean that as an insult to people who are riding as a part of their life outside training, I just couldn’t think of a better word to use to differentiate the two user groups). I do hear the point of it being good for ultra distance solo riders though, as I often see those people with headphones, with phones on the bars hooked up to batteries, etc. I just wonder how big that user base is and if they would find your app.

It’s so interesting to me how common customs vary from area to area. I have a number of friends who literally never ride without headphones and I’m consistently amazed by how many people ride with headphones on group rides. Even at a few recent gravel events I noticed a surprising percentage of riders using them.

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I think of those people as the difference between “Cyclists” and “Bicyclists”… lol Additionally, that’s what I’m trying to pinpoint, is there a big enough userbase to justify more engineering? I’m not sure, I’m also not ruling out individuals with sight disabilities that make it challenging to read and navigate using a headunit who may have just given up on headunits and don’t have a better choice.

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I’d imagine it has to do with scenery, I often forget I even have headphones on when I’m cycling through incredible gorges and epic coastlines, but use them like a lifeline when passing farmfield after farmfield…

I haven’t done group rides since before COVID (social distancing made me realize I prefer to ride alone), but on the group rides I did do, you would not be allowed to participate with headphones on. It was considered unsafe for the group just like using aero bars or not wearing a helmet.

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I never thought I would use headphones during a race but I used them during a 4 hour gravel race recently just to try it because I was expecting to possibly be alone for a long time. It was pretty amazing how much the music reduced RPE, it was a lot of climbing just grinding out the miles. I started cramping at hour 3 and just kept going. Headphones seems pretty valuable for long gravel races.