The Ducati ST series is a set of Italian sport touring motorcycles manufactured by Ducati from 1997 through 2007. In order of release it comprised five models: the ST2, ST4, ST4S, ST3 and ST3S. They were intended to compete with sport tourers such as the Honda VFR.
Ducati ST series at a glance
| Maker | Ducati, Borgo Panigale |
|---|---|
| Production | 1997–2007 |
| Models | ST2, ST4, ST4S, ST3, ST3S |
| Numeral after ST | number of valves per cylinder |
| Frame | tubular steel trellis |
| Suspension | upside-down forks and a rear monoshock |
| Engines | liquid-cooled desmodromic V-twins |
| 2004 update | new nose, headlight, ABS option, 11 kg less dry weight |
| ST3 and ST3S sales, 2007 | 1,011 units worldwide |
History of the Ducati ST series
One frame, five engines
All five bikes were outwardly similar, sharing the same frame, bodywork and cycle parts, but each had a different engine, all liquid-cooled desmodromic V-twins. The numeral after ST, 2, 3 or 4, indicates the number of valves per cylinder. In the Ducati tradition the frame was a tubular steel trellis, and the conventional suspension was upside-down forks and a rear monoshock. The ST bikes had a full fairing, a large dual seat, a relaxed riding position for rider and pillion, a centre stand and optional matching luggage.
ST2, 1997
The series first appeared in 1997 in Europe, with shipments to the United States in 1998. The ST2 had a 944 cc Desmodue two-valve engine derived from the 907 Paso, with 10.2:1 compression and Weber-Marelli electronic fuel injection, one injector and one spark plug per cylinder, and a heavier flywheel suited to touring. Its frame was similar to the 916’s in torsional rigidity and lightness, with fully adjustable Showa upside-down forks and a Sachs rear shock, the same as the 916 but with softer damping. The front brakes were twin 320 mm floating Brembo discs with four-piston calipers and the rear a single 245 mm disc with a twin-piston caliper. The ST2 replaced the Paso and was Ducati’s more focused entry into sport touring; it was made until 2003.
ST4 and ST4s
In 1999 Ducati added the ST4, which used the four-valve Desmoquattro engine derived from the 916, retuned for the ST. After the 996 appeared in 1999, Ducati began to phase out the 916 engine, which was last used in the 2003 ST4. In late 2001 the ST4s joined the range with the 996 Desmoquattro engine and improved suspension, available in 2002. The 40° valve angle was unchanged, but the intake throttle bodies were 4 mm smaller than the 996’s 54 mm, and the more compact cylinder head shared with the 748 and Monster S4 was needed for chassis clearance. Despite the smaller intakes the ST4s made slightly more power and torque than the 996 Superbike, thanks to the mostly straight-through exhaust against the Superbike’s underseat system.
ST3 and ST3s
In 2004 the ST2 and ST4 were deleted and replaced by the ST3 with the new three-valve Desmotre engine of 992 cc, which needed less maintenance than the notoriously expensive ST4s. The ST4s nevertheless remained the top model until 2006, when it gave way to the ST3s, which inherited its enhanced suspension but kept the Desmotre engine. The reason given was that the 996 engine would not pass Euro 3 emissions while the ST3 engine could. In 2005 Ducati fitted a wet clutch to the ST series, reducing the effort needed to engage it. Both S bikes could be ordered with ABS from 2003. The 2004 update brought a modified nose fairing and dashboard, adjustable ergonomics, a trip computer, hazard flashers, a digital speedometer, a dashboard-controlled headlight, a new seat, a Euro 2 catalytic exhaust and simplified CAN-bus wiring, cutting 11 kg of dry weight. The series ended in 2008 after the ST3 and ST3s sold only 1,011 units worldwide in 2007, and Ducati’s 2008–2010 plan dropped sport touring altogether.
Design and features
- Shared body: one frame, fairing and cycle package with five different engines.
- Valve count in the name: ST2 two valves, ST3 three, ST4 four per cylinder.
- Tourer comfort: full fairing, dual seat, centre stand and optional luggage.
- ST4s exhaust: straight-through system that gave slightly more power than the 996 Superbike.
- 2004 update: new nose, ABS option, trip computer and 11 kg less weight.
Ducati ST series versions
- ST2 (1997–2003): 944 cc two-valve Desmodue.
- ST4 (1999–2005): four-valve Desmoquattro from the 916.
- ST4s (2002–2006): 996 engine and better suspension.
- ST3 (2004–2007): 992 cc three-valve Desmotre.
- ST3s (2006–2007): Desmotre engine with ST4s suspension.
The ST4 used the engine of the Ducati 916 and the ST4s that of the 996. The ST2 replaced the Ducati Paso. More Ducatis are in the Ducati collection.
Sources
- Ducati ST series, English Wikipedia: models, engines, updates, end of production
