2005 Ducati SportTouring ST4s ABS Owners Manual - Page 208

E Transmission Wet clutch operated by a control lever on handlebar left side. Drive is transmitted from engine to gearbox main shaft via spur gears. Gear ratio: 32/59. 6-speed gearbox with constant mesh gears, gear change pedal on left side of motorcycle. Front/rear sprocket ratio: 15/38. Total gear ratios: 1st 15/37 2nd 17/30 3rd 20/27 4th 22/24 5th 24/23 6th 28/24 Drive chain from gearbox to rear wheel: Make: DID Type: 525 HV. Dimensions: 5/8"x5/16" Links: 100. Important The above gear ratios are the homologated ones and under no circumstances must they be modified. If you wish to tune up your motorcycle for competitive trials, you may refer to Ducati Motor Holding S.p.A. who will be glad to provide information about the special ratios available. Relevant instructions and original spare parts are available from your local Dealer or authorised workshop. Warning If the rear sprocket needs replacing, contact a Ducati Dealer or an authorised workshop. If improperly replaced, this component could seriously endanger your safety and that of your passenger, and cause irreparable damage to your motorcycle. 98