I got my Vado SL 4 in March of this year. On the Specialized app Bike Status page, in the Motor section, there is an odometer reading of 825.3 km. This distance is greater that reported on the app's Recorded Bike Activity page (684 km) because I didn't, or forgot to, use the Specialize app to record every ride. I have used the Garmin Connect app to record all of my rides since March. The total on the Garmin app is within 10 km of the Specialized app's odometer figure. Am I correct in assuming that odometer reading on the Specialized app is based on the data recorded by Garmin Connect? If not, how is the Specialized app odometer reading calculated?
Specialized app: Bike Status Odometer
- Thread starter Jay Gee
- Start date
Stefan Mikes
Gravel e-biker
- Region
- Europe
- City
- Mazovia, PL
A Specialized e-bike reads the rear wheel RPM. Wheel Circumference is stored in the TCU (this parameter can be changed by the dealer). Number of revolutions per second times wheel circumference gives the distance travelled by the rear wheel in a second. The readouts are integrated by the e-bike computer and stored as a motor parameter.
The e-bike odometer has nothing to do with Garmin Connect, and the distance ridden is retrieved from the TCU by the Specialized App.
This way, the mileage of my Vado SL 4.0 per the odometer is now 16,374 km (assuming the Wheel Circumference of 2,180 mm stored in the e-bike memory) while the sum of my all rides recorded by Wahoo and transferred to Strava is 15,671 km. The difference is:
- Other people riding my Vado SL
- A few unrecorded rides of mine.
Thanks for the explanation.
I had the LBS replace the OE 700x38 Nimbus II Sport tires (2190 mm circumference) with 700x42 Pathfinder Sport tires (2216 mm circumference). I doubt that they changed the circumference stored in the TCU. Because of the tire change, I calculate that, all other things (e.g. tire pressure) being equal, the motor odometer reading is about 1% lower than the actual distance ridden ridden. I'm not going to lose any sleep over it.
Stefan Mikes
Gravel e-biker
- Region
- Europe
- City
- Mazovia, PL
The actual wheel circumference depends on many factors such as tyre pressure, so indeed lose no sleep over it 
Stefan Mikes
Gravel e-biker
- Region
- Europe
- City
- Mazovia, PL
@Jay Gee: I am occasionally checking the effect of the Wheel Circumference on the reported Distance Ridden as compared to GPS/map data. Here's an interesting finding.Thanks for the explanation.
I had the LBS replace the OE 700x38 Nimbus II Sport tires (2190 mm circumference) with 700x42 Pathfinder Sport tires (2216 mm circumference). I doubt that they changed the circumference stored in the TCU. Because of the tire change, I calculate that, all other things (e.g. tire pressure) being equal, the motor odometer reading is about 1% lower than the actual distance ridden ridden. I'm not going to lose any sleep over it.
While I cannot modify the Wheel Circumference in the TCU myself (it is 2180 mm for 700x38c), I can set the value in my Wahoo bike GPS computer. Wahoo gets the RPM of the rear wheel from Vado SL and recalculates the data into the cruising speed and the distance ridden. After a longer ride, I check the distance ridden in Strava, and can also get the distance adjusted to the ride map.
Now, I ride 700x42 mm Tracer Pro, tubeless, under low pressure of 2.6 bar (roughly 38 psi). You will agree with me the 42 mm tyres should have a significantly greater Wheel Circumference than 38s? I was experimenting with the WhC value in Wahoo, and compared the distance ridden with the ride data. The latest correction tells me I should use as low as 2166 mm!
These matters cannot be predicted, and we cannot expect any reliable value of WhC. Therefore, I decided to return to the default Vado SL value of 2180 mm, as the accuracy would be excellent. I don't care what the theory says, I just want to have the measured ride data close to the map distance!
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