Help
Frequently asked questions
Can't find it here? Email hello@dirtwatts.com and a person will answer.
Equipment
Which trainers work?
DirtWatts controls Bluetooth smart trainers that use the FTMS standard, which covers most trainers from Wahoo, Elite, Saris, JetBlack, Zwift (Hub) and others from the last several years, plus Tacx trainers over Bluetooth. ANT+ can't be used from a browser.
Which computers and browsers?
Chrome or Edge on Windows, macOS or ChromeOS. Safari and Firefox don't support Web Bluetooth, and no browser on iPhone or iPad does, so they can't pair a trainer. A Windows and Mac desktop app is on the roadmap.
Will it run on my laptop?
Low graphics run smoothly on recent laptops with integrated graphics. High needs WebGL2, which nearly every current machine has. Ultra is for gaming GPUs and is marked experimental while we tune it.
Do I need a power meter or heart rate strap?
No. Your smart trainer measures power. A Bluetooth heart rate strap is optional and adds heart rate zones to the HUD and your FIT file.
Do I shift with my real gears?
Yes. The trainer sets resistance from the grade and you shift your bike as you would on the trail. Virtual shifting on trainers (a 1x12 drivetrain driven from the HUD or a gamepad) is in development.
Trails and physics
Where do the trails come from?
Each trail starts as a real ride recorded on a GPS device. We clean up the line by hand on a map, then rebuild the terrain around it from the USGS 3D Elevation Program's 1-meter bare-earth lidar, with vegetation and imagery data for the scenery.
Why lidar instead of GPS elevation?
GPS and barometric elevation drift under trees and jump on switchbacks, which turns singletrack into a saw-tooth of fake walls and flat spots. Lidar measures the ground directly, so the grade on screen, and the resistance at your pedals, matches the trail.
How is the physics calibrated?
We replay a real power-meter ride on mountain bike trails through the model and fit rolling resistance and drag until the simulated ride matches the recorded speeds. Air gets thinner with altitude, your weight from your rider profile counts on every climb, and trail sections carry their surface, so hardpack rolls faster than loose dirt. Per-surface values are still being refined with more test rides.
Which trails are there?
The library starts in Utah: aspen singletrack above Park City, high-desert loops and Moab slickrock. We add trails every month. Free riders get two featured trails, rotated monthly; subscribers ride them all.
Can I ride my own local trail?
Soon. Subscribers will be able to send a GPX or FIT of a trail in the US each month, and we'll bake it from lidar. Requested trails join the public library, with the start and end trimmed so they don't reveal anyone's home.
Rides and data
Does it upload to Strava or Garmin?
Every ride ends with a FIT file download, which you can upload to Strava, Garmin Connect or intervals.icu. Automatic Strava upload is coming for subscribers.
Can I ride with friends?
Not yet. Group rides are on the roadmap after leaderboards.
What data do you keep?
Your email, rider profile (weight, FTP, heart rate settings) and, once ride history ships, your ride summaries. Trainer data stays in your browser during the ride. See the privacy policy.
Plans and early access
Is there really a free tier?
Yes, with no card and no time limit: two featured trails each month with full physics and trainer control.
How does early access work?
Join the list with your email. We send invites in batches so we can watch performance and fix issues fast. Bug reports and ideas go straight to the person building it.
What does the founding price get me?
Early riders can subscribe yearly at $39.99 instead of $49.99, and keep that price at every renewal while the subscription stays active.
How do I cancel or get a refund?
Cancel any time from your account. You keep access until the end of the paid period. Ask within 14 days of a charge for a full refund; see the refund policy.
Ready to ride?
Join the early access list. Founding riders lock in $39.99 a year.
Make a free account in seconds. No card, no time limit.