Triumph Press Information
Changes to the Sprint ST engine from the Daytona 955i:
1. Different camshafts.
2. Cast pistons and steel liners for the Sprint whereas the 955i uses forged pistons and coated aluminium liners to cope with higher maximum power.
3. Fuel injection mapping revised.
4. New header and silencer system.
5. Cooling system.
The Chassis
As with the engine, the 955i’s frame provided an excellent starting point for the Sprint ST, but Triumph felt changes would still be needed for it to perfectly suit the sports-tourer role, such as additional strength in the rear subframe for luggage carrying. But simply adapting the 955i’s frame would have been complicated and expensive, so Triumph opted for an all new twin spar aluminium perimeter frame.
This gave various advantages. It allowed enough space above the engine for the fuel injection, and as the design is extremely stiff the number of engine mounting points could be reduced from the eight used on the 955i to six, making manufacture easier, reducing weight and also reducing the amount of heat transmitted to the frame from the engine. Triumph has also been able to retain the low centre of gravity of the 955i despite lifting the Sprint’s engine to allow the exhaust to be packaged inside the bodywork, while maintaining class leading ground clearance.
The geometry of the Sprint is altered from the 955i to optimise stability, especially when carrying luggage, but Triumph found the fundamental design was so good it could go further than that. After the wheelbase was increased to enhance stability Triumph found the steering could be made even lighter than originally planned without any adverse effects - so much so that in certain circumstances the Sprint ST comes very close indeed to the handling performance of the 955i!
The 955i single-sided swingarm proved ideal for the Sprint ST as it allowed the exhaust system to be tucked in very tight to the rear wheel, allowing the fitment of good sized panniers without badly compromising the bike’s width or style. To add versatility in this respect, the design team chose to fit a moveable exhaust which could be raised with the pannier removed for increased ground clearance.
The suspension development came through a combination of science, experience and rider feedback. There were clear starting points such as the amount of suspension travel required at each end, after which relentless testing with data logging equipment backing up the comments of Triumph’s highly experienced test riders and dialogue with the suspension manufacturer resulted in the final production set-up.
The outcome is exceptionally good high speed behaviour, manifested as increased stability and feedback to the rider.
Ergonomically the Sprint matches the highest standards in the sector, partly as a result of the work Triumph has put into it’s aerodynamics (more than on any previous Triumph). Air flow to the radiator and engine accounts for much of this, but the rider also benefits from reduced wind noise and a smoothed Out slipstream, with as much weather protection as is expected of a sports-tourer. This element of comfort is backed up by a relaxed seat-footrest-handlebar relationship which is typical of the class, and the relatively long, flat seat essential for the bike to feel comfortable and natural for riders of a wide range of statures.