I have a 2015 TE300 which I want to use as an enduro in the winter and supermoto in the summer. Got myself some 17" wheels now and re calibrated the speedo tonight so I thought I'd share how I did it. I measured the front tyre circumference,1952mm, unclipped the headlight cowl, unplugged the only 3 wire block connector that has brown, black and red wires coming out of the speedo, the speedo loses its backlight at this point but it is still easy to read. Then I held the bottom left and right buttons simultaneously for 3 to 5 seconds and the display started to flash. It would flash the word of what can be altered such as Clock, 24 hr, Tire etc. If Tire isn't the first word to flash, just wait a few seconds and the next word will flash and so on. When Tire flashes, use the left or right buttons to increase or decrease the size as required n.b. make a note of previous setting, 2205mm, so you can revert back to the 21" wheel setting as required. Once the size has been put in, let the dash scroll on its own through to the next word and it will eventually stop flashing and automatically save your setting. Then plug the block connector back together and the dash backlight starts working again. Any questions, just ask!