TachoSpeed

Turn your phone into a live analog tachometer dial for vehicles with a broken or missing speedometer. One-time calibration, GPS-only, no OBD-II adapter needed.

TachoSpeed is a standalone GPS tachometer and speedometer for vehicles whose speedometer doesn't work but whose tachometer does — classic cars, restorations, project cars, anything with a working dash tach but a stuck or missing speedo.

You calibrate once. Pick a cruising gear, settle at a steady speed, read the exact RPM off your dash tachometer, and tap to log. That single point is enough — because gear ratios are linear within a gear, TachoSpeed can derive your engine RPM from any future GPS speed.

From then on, you get a live analog tachometer dial with:

• An RPM scale around the outer ring with adjustable max and redline • A matching road-speed scale on the inner ring, so a single needle reads both at once • Current GPS speed shown as a large digital readout in the lower wedge of the dial

The RPM dial is accurate in the gear you calibrated. The digital GPS speed is accurate in any gear — including downshifts, neutral, and the moments between shifts.

No OBD-II adapter. No cables. No accounts. No ads. No tracking. TachoSpeed makes no network requests of any kind — your GPS speed is read from the phone's location services and processed entirely on-device. Nothing leaves your phone.

KEY FEATURES

• Live analog tachometer dial driven by your phone's GPS • One-time calibration in any gear of your choice; recalibrate any time • Adjustable dial maximum from 4,000 to 12,000 RPM and adjustable redline • MPH or KM/H, your choice — both scales update instantly • Screen stays awake on the tachometer view • Built-in safety notice — please don't operate the app while driving; mount your phone or have a passenger hold it • Universal app — iPhone and iPad, plus "Designed for iPad" on Apple Silicon Macs

BUILT FOR

Classic-car owners. Vintage motorcyclists (use it as a passenger). Restoration shops. Track-day drivers running cars where the original Smiths or Stewart-Warner speedometer cable finally gave up. Anyone whose dash speedo reads zero but whose tach still works.

TachoSpeed is published by Skunk River Restorations, the same team behind LastDrive and Fuel Pre-Pay Estimator.