Speedometer / Odometer 27.5 Inch tires

[Neophyte1]

I took my rebuilt ebike on a test ride today to see if it could handle the 14mile ride to work (haven't had a working ebike for 3 years). I ended up riding for a very long time - checked Google maps and I ended up riding about 18 miles (trip computer said 14.5 miles)

I have a Mongoose Terrex 27.5" with a luna branded BBSHD and six 5ah dewalt 20v batteries wired in a 3s2p configuration.

I have a standard C965 Bafang display I got from Lunacycle. I watched a youtube video and adjusted the wheel size from 26" to 27". I'm wondering now how much of a discrepancy will still remain. There are no .5 adjustments in the display I have.

Has anybody else run into this issue before? What display do you recommend? I'm tapped out after replacing the battery pack but I would like to upgrade in the future. I'm happy with the tires I have so a display that more accurately displays my speed and distance would be nice.

 

[dogman dan]

Luna might know how to change that. I'd try 28 if you have that possibility. Might be off, but by less, if your tires are on the fat side.

A separate, regular cycle computer could be adjusted perfectly to your actual tire size, measured around the outside of the wheel in cm. That would be the best way to get a perfect calibration.

You might get used to a mental adjustment faster than you think, every ten miles add two to the reading.

 

[Rassy]

The DPC14 display allows entering wheel circumference from 51cm through 255cm in addition to the basic inch diameters Bafang uses.

Update: entering the circumference via the DPC14 display is easy, but, it only works if the controller is a newer model that accepts it. On mine, everything went wacky until I set it back to the 20" diameter setting.