Stuart Wood: PH2 Meets

PH2 catches up with Stuart Wood, Chief Engineer for Triumph's new range of Bonneville models

At the recent launch of Triumph's new range of Bonneville, Thruxton and Street Twin models, PH2 grabbed five minutes with Stuart Wood, the man tasked with revitalizing the iconic Bonneville name. Tough gig...

PH2: Why have the Bonneville models increased in capacity?
SW: "There is definitely a call from some riders for more power from Triumph's modern classics. Personally, I would be one of those customers asking for more as I feel it completes the bikes. The larger engine now means the Bonneville does everything I want of a road bike. It's a capacity choice, for me the smaller older Bonnie model at 70hp wouldn't have suited me as I've ridden sports bikes for a long time and want more power. The huge increase in torque the 1200 offers, which is 64 per cent up on the old 865cc motor, is fun. Factor in the improved handling too and it is a thoroughly modern bike underneath that in the case of the T120 looks faithful to the original 1950s and 1960s Triumphs. The Thruxton, however, is evocative of a cafe racer with a lot of hidden components to ensure it has clean lines, but it is also very contemporary."

PH2: Was water cooling essential?
SW: "Air cooling was always an option, but it would have been a case of wringing it out rather than planning for the future. Water cooling, along with ride-by-wire, allowed us to optimize the engine and deliver 36 per cent better fuel economy as well as far more power. Air cooling would have required degrading the engine's performance to meet emissions laws. This bike's engine is now at the start of its development where an air-cooled one would have been right on its limits. The new Bonnie's engine and chassis has taken as much time, effort and R&D to develop as an equivalent sports bike. In fact, the Bonneville development team was twice as big as any other team Triumph has used to develop a new bike and it still took four years."

PH2: Why change the engine's firing order from a 360-degree crank to a 270-degree one?
SW: "Smoothness and refinement. Do you want a vibrating British single character in a modern machine? I don't. I want it to sound great, which the 270 does, but the main reason is down to the capacity increase. You can get away with a 360 crank on a smaller engine, but the bigger the capacity gets, the less balance you get within the engine. The 270 crank is better balanced and has natural second order vibration cancelling, making it a really smooth motor. When you add bigger pistons you need this smoothness."

PH2: The old Bonnie was a bit of a wobbler; is the chassis stiffer?
SW: "Yes. I can't give you numbers, but you will not notice this on any of the new models. It's a proper, complete chassis."

PH2: But with no suspension adjustment...
SW: "The Thruxton R has fully adjustable suspension, but there is no adjustability aside from spring preload on the other bikes. We feel it isn't needed. From the work we have done with customers they suggest they don't want this, they just want to hop on and ride. If it works correctly, there should be no need to adjust it. The suspension is appropriate to the individual bike and works."

PH2: You say there is very different character between the bikes, is this really true as they share a similar base?
SW: "Yes. When you tell someone about the bike and its spec they will form a mental picture of the bike. Then, when they see it the bike should live up to this image. When they swing a leg over the bike it should feel as they imagine and when the engine fires up it should also sound as they imagined it would. Finally, the ride should also deliver, completing the experience. If you look at a picture of a new Bonnie model and think 'that's the one for me' the riding experience will follow through. They all have their own individual characters."

PH2: Why is there a full race package for the R? Will we see a one make race series?
SW: "That's nothing to do with me, you will have to ask one of the other guys."

PH2: Is the Bonneville's gearbox better?
SW: "Yes, it's as good as the Daytona 675's gearbox."