GPS speed test · Motorcycle

Motorcycle Speed Test

Turn your phone into a GPS motorcycle speedometer. Mount it on the bars, press Start and see your true speed, top speed, moving average and distance — then compare it with your bike’s own speedometer, which very likely reads high.

GPS off

0KM/H

Max speed: —
Avg (moving): —
Distance: —
Trip time: —
Moving time: —
Heading: —
Altitude: —

Set Speed Alert

Speed limitkm/h

Beep and vibrate when exceeding this speed.

Trip log

No points recorded yet

Live GPS speed
Top speed & moving average
Speed alert with vibration
Bright, glanceable display
GPX ride export
Location stays on your device

How it works

Turn Your Phone Into a Motorcycle GPS Speedometer

01
Mount It Properly
Use a secure handlebar or stem mount with a vibration damper, and set the screen brightness before you ride.
02
Start Before You Ride
Press Start and allow location access while you are stopped. The screen stays awake while a ride is running.
03
Compare at a Steady Speed
On a straight, safe road, hold a steady speed and compare the GPS reading with your bike’s speedometer.

Accuracy

Why Your Motorcycle Speedometer Reads Differently From GPS

Most motorcycle speedometers over-read by design. Changes to tires and gearing can push the error further either way.

How changes affect a motorcycle speedometer
Change	Sensor on sprocket / gearbox	Sensor on the wheel
Smaller front sprocket	Reads high	No change
Larger rear sprocket	Reads high	No change
Taller (larger) rear tire	Reads low	Reads low (rear-wheel sensor)
Worn rear tire	Reads slightly high	Reads slightly high (rear-wheel sensor)
Taller front tire	No change	Reads low (front-wheel sensor)

Plug-in speedometer correction modules, or a dealer reprogram, can fix a known error. Work out tire-size effects with the speedometer calculator.

A GPS reading sidesteps all of this, because it measures your movement over the ground rather than counting turns of a sprocket or wheel. Use it to find your speedometer’s true error after a gearing change, then calculate tire effects with thespeedometer calculator.

Rider setup

Mounting a Phone on a Motorcycle

Damp the vibration

Apple warns that the strong vibration of high-power motorcycle engines can damage the image stabilisation and autofocus in iPhone cameras, and recommends a vibration-dampening mount on mopeds and scooters. A damper is worth it on any bike.

Mind the heat and rain

Direct sun and a bright, always-on screen can make a phone overheat and dim itself. A shaded, weatherproof case helps on long rides.

Keep it powered

GPS is light on battery, but a screen on full brightness isn’t. A USB socket or a small power bank keeps it running all day.

Phone or dedicated gauge?

For a permanent fit on a custom or classic bike, a universal digital motorcycle speedometer with its own GPS or wheel sensor is the tidier option. For checking accuracy, recording rides or a backup, your phone does the job for free.

Riding a bicycle or e-bike instead? The bike speed test is tuned for cycling speeds. Curious how fast you react on the road? Try the reaction time test and see what it means for yourstopping distance.

FAQ

Motorcycle Speed Test FAQ

How accurate is a GPS motorcycle speedometer?

At a steady speed under open sky, phone GPS is typically accurate to about 1–2 km/h (around 1 mph). Unlike a wheel or sprocket sensor it isn’t affected by tire size, tire wear or gearing.

Does leaning into corners affect GPS speed?

No. GPS measures how fast you move over the ground, so lean angle makes no difference. Tight bends under trees or between buildings can briefly reduce signal quality, though.

Will changing sprockets affect my speedometer?

It depends where your speed sensor is. If it reads the front sprocket or gearbox output, fewer front teeth or more rear teeth make the speedometer read high. If the sensor reads the wheel, sprockets make no difference. Tire size changes affect both.

Why does my motorcycle speedometer read higher than GPS?

Like car speedometers, motorcycle speedometers are built never to read low, so most over-read by a few percent. A worn rear tire or shorter gearing adds to it.

Is it legal to use a phone as a speedometer on a motorcycle?

In most places a securely mounted phone is fine as long as you don’t handle it while riding — but rules vary, so check your local laws. It is not a replacement for the bike’s own speedometer where one is required.

Can I use it on a track day?

Yes — it records top speed and exports your ride as GPX. Phone GPS updates about once a second, so it shows speeds on straights well but won’t capture every corner like a dedicated lap timer.

Related Tools

Motorcycle Speed Test

Turn Your Phone Into a Motorcycle GPS Speedometer

Mount It Properly

Start Before You Ride

Compare at a Steady Speed