Prototype in testing on a Mk2 Escort RS2000
RevDrive replaces the speedometer cable on a classic car with a small GPS-driven motor behind the clocks. Your original speedo and odometer keep working, and they read your real speed, whatever gearbox, diff or tyres you run.
A mechanical speedometer only reads right when the gearbox, diff and tyres match what the car left the factory with. Change one and the needle is wrong, or there is nowhere left to plug the cable in.
Five-speed and race box conversions often lose the speedo drive or change its ratio. RevDrive doesn't need one.
Speed comes from satellites ten times a second, so diff ratios and tyre sizes stop mattering.
No digital dash, no cutting. The original needle and odometer are driven exactly as the cable used to drive them.
A u-blox GPS module measures ground speed ten times a second, straight from the satellites.
The controller ignores weak fixes, holds zero when you're parked, and smooths the speed so the needle moves like a real one.
Each mph is turned into the exact motor speed your dial needs, from a table set up for your speedometer.
A brushless motor with position feedback spins the speedometer input, mounted on a bracket behind the clocks.
RevDrive makes its own Wi-Fi hotspot. Join it, open the app in your phone's browser, and you're in. No internet, no laptop, nothing to install.
Big live GPS speed to check against your needle while you drive.
Pick any speed and watch the needle go there on the bench.
Nudge the motor speed mark by mark until the needle sits exactly on each one, then save it to the unit.
App screens shown with demo data.
Mechanical speedometers aren't perfectly linear, especially at the bottom of the dial. So RevDrive doesn't use one fixed ratio. It stores the motor speed for each mark on your dial.
Measured on our test clocks, 10 to 80 mph. Your speedometer gets its own table.
RevDrive is a working prototype, not a product you can buy yet. Here's the build so far, and what comes next.
Smooth and cool-running from 30 to 2,000 RPM on the bench.
Ten updates a second, with filtering for parked cars and weak signal.
Mk2 Escort RS2000 speedometer set up from 10 to 80 mph.
Road, Test and Calibrate screens built into the unit.
Refining the mounting to remove vibration, then testing on the road.
Custom circuit board and printed parts for a tidy install.
Tell us your car and speedometer, and we'll let you know when kits are ready.
Or email info@revdrivegps.co.uk