Chainline is the Dragy Moto Lab web app: a motorcycle gearing bench plus a phone GPS timer, a Times lab for weather and weight corrections, Spark (an ignition-timing estimate) and live Weather with density altitude.

No. It runs in the browser at /app/. You can add it to your home screen so it opens standalone.

Any modern browser on a phone or computer. On phones, /app/ opens in a full-screen app view. The GPS timer needs a device with GPS and location permission, so use your phone.

The app needs a connection to load, and Weather needs one for its data. Once the GPS timer page is open, timing uses the phone’s GPS. The timer fetches weather separately when it has a connection.

The gearing bench lists 137 bike generations across Aprilia, BMW, Buell, CFMoto, Ducati, Honda, KTM, Kawasaki, MV Agusta, Suzuki, Triumph and Yamaha, from 2005 on, wherever a gearbox and sprocket pair were published. If yours isn’t, choose “Bike not listed” and enter it.

They’re estimates for comparison. Gearing figures come from manuals, spec sheets and catalogs. Pull times are modeled, not a dyno sheet or radar trap. Phone GPS is about 1 Hz and a few meters off. Lab corrections are workshop estimates. Spark is an educational estimate only.

No. The app says it is not affiliated with Dragy Motorsports. The Times lab can import exported Dragy and RaceChrono files.

Open /app/, choose Create account, and enter your email and a password.

On the sign-in screen, tap “Forgot password?” to reset it by email.

On a phone you can choose “Use Lite without an account”. To start a trial or use Pro, sign in.

$4.99 per month (USD), after a 7-day free trial.

Start it from the Pro page or Pricing while signed in. Checkout asks for a card or PayPal and charges $0 today. Pro unlocks right away, we email a reminder 3 days before the trial ends, and $4.99/month starts after 7 days unless you cancel.

No, there’s one free trial per customer. If you’ve had a Chainline subscription or trial before, Pro is billed from the first day.

In My Account › Subscriptions (or Manage subscription on the app’s Pro page). Cancelling stops renewal, and Pro stays on until the end of the period you’ve paid for, or the end of the trial.

We retry after 1, 3 and 7 days. Pro is paused while the payment is overdue and returns when it goes through. If the last retry fails, the subscription is cancelled.

Cards (via Stripe) and PayPal at checkout.

Every tool marked PRO in the app. Today that’s Spark, the ignition estimate with its full RPM × throttle map. Dragy Moto Lab sets the tiers, and the app shows the current one on every tool.

Bikes, profiles, runs, timer history and settings are stored in your browser on that device. They don’t sync between devices, and clearing the site’s data deletes them. Your account email, plan and trial dates are stored on this site.

The GPS timer uses it to time passes and to fetch weather at your position. Weather uses it for “My area”. You can search for a place instead.

Yes. The GPS timer can download a timeslip as JSON or export all history as JSON.