Is this a thing? I haven't found anything in the service manual that suggests this can be done. Will I run into issues w/ the IMU/traction/slide control with a taller tire? I know Ducatis have a recalibration mode. R1Ms also ship with a larger rear tire than the R1, but is it factory calibrated?
The wheelspeed sensor only knows how many rpms the wheel is turning and acceleration/deceleration. As far as intervention for TC, you shouldn’t see any different behavior, just as you would not when you change gearing.
Right, but the front rpm relative to the rear rpms will change depending on the relative diameters of the tire. So for example, if the front is doing 600 rpm and the rear is doing 600 rpm from the factory, putting a smaller rear tire would increase the rear rpm at the same given speed, which in a vacuum, would indicate your rear tire is slipping. It is not the same as changing the gearing, because gearing doesn't change the front and rear wheel rotation speeds relative to each other, it only changes the engine speed relative to the wheel speed. Ducati has a tire size calibration feature where you enable the mode and ride around at 30+ mph for a few seconds and it will adjust the computer accordingly, but I haven't seen indication anywhere that Yamaha has this or if it auto-calibrates. For reference, see: http://ducatiforum.com/ducati-hypermotard/38727-tire-calibration.html http://ducatiforum.com/ducati-v4/31213-stock-tire-height-200-60-zr17-changing-200-55-zr-17-a.html
With the 2017 GSXR 1000 and Yosh Kit ECU you have the ability to adjust tire diameter along with final drive ratio and internal gear ratio. I also confirmed with Yosh Japan race team that changing the tire diameter will have a direct affect on how traction control behaves.
Using OEM ECU, there will be a diffence in the TC/SCS calculation, but it's not too bad (info from BSB R1 superstock racers). In the YEC KIT ECU it can be adjusted. Realistically though, the time when you most want this electrical intervention is when the bike is leaned over. At that time, the tyre is on the part of the profile which has almost exactly the same diameter as the OEM tires, as they have the same sidewall heights, so there isn't any real need to worry about changing the TC/SC maps.
