Looking to replace drive sprocket with 1 tooth lower. Have already looked at alternative of changing the rear sprocket and having spoken to Ducati mechanics am happy with my decision. What I didn't ask was "where is speedo reading taken from"? Is it from sensors on the rear wheel, drive sprocket shaft, or somewhere else? Will I need to get speedo recalibrated, and if so, how? Thanks
By changing the front or rear sprocket you do not affect the speedo accuracy. All that changes is the nmber of revs per wheel revolution. Smaller sprocket, more revs for the same speed. Andy
Speed is taken from the wheel speed sensor on the brake disc, which doubles as the abs sensor. Smaller sprocket at the front equals more revs at given speed but smaller sprocket at the rear lengthens the gearing so lowers the revs at a given speed. Bigger rear sprocket is worth doing to try and help it jump out of corners better but will effect top speed and fuel economy marginally
Depends on where the speedo reading is taken from. If it's the wheel, there's no change. If it's from the shaft, then a 1 tooth smaller drive sprocket would mean the speed would only be about 93% of the indicated reading. edited. As phil has advised it's taken from the wheel, then there are no calibration issues to deal with - 130 kph = 130 kph regardless of sprocket sizes. Thanks all!
In my handbook it tells me that the speedo is set optimistic by 7 kmh. The GPS seems to agree with that. I have gone down a tooth on the front sprocket and it is much nicer to ride.
