The difference between the new Triumph Bonneville Street Twin and the previous Bonneville is only one thing: everything. It has a new engine, new chassis, new instruments, new ride-by-wire throttle, new traction control, new yadda, new razzmatazz, and new glafuncles.
But, sure, it’s hard to see changes on a bike that is an updated retro design that’s equally as retro as the previous retro version. So the Street Twin’s new is a new that’s primarily supposed to be felt, not seen.
You will be able to feel it.
The Street Twin engine is a liquid-cooled, eight-valve, single-overhead-cam parallel twin with sleeveless Nikasil-coated cylinders and a 270-degree crank. Some of the previous powerplants had 360-degree cranks, just like Triumph’s parallel twins had run since the 1930s, but all the new ones are 270 to give a more V-twin-like sound.
This base model’s engine is now 900cc, not 865cc, and has redefined performance parameters, with a claimed 55 rather than 67 hp and 59 versus 50 pound-feet of torque. At a glance that might seem odd to give up so much horsepower. But from Triumph’s perspective it’s not odd. It may be initially disappointing considering the significant update to the platform, but if it’s higher performance you are after, Triumph will refer you to the new, bigger Bonnevilles.
“A Big Twin allows the creation and manipulation of a crafted powerband that’s broad and smooth from bottom to top…
Two counterbalancer shafts quell vibration, one front and one rear, and each, of course, spins in the opposite direction of the crankshaft. Peak horsepower is at 5,900 rpm, and redline is somewhere just beyond that. For a liquid-cooled motorcycle, the Street Twin has air-cooling fins on its head and cylinders, and these fins don’t fib: They actually do, by design, assist in cooling the engine. The transmission has five speeds.
A single 39mm throttle body controls air and fuel. By comparison, the Indian Scout Sixty, at 1,000cc, has a 60mm throttle body. Considering that twice a diameter is four times the volume, these numbers are quite far from each other. Also, considering the Venturi effect, which defines how a constricted path results in a lower pressure yet higher velocity of flow, there’s a significant engineering disagreement here between these brands.
The Street Twin’s fuel-management design results in increased fuel efficiency for a claimed 72.8 mpg at a steady rate of 56 mph and 52 mpg at 75 mph. What we did verify so far is that when the bike is ridden hard for extended mountain miles in second gear, dragging toes through the turns and railing up to redline in the short straights between each of them, mileage was 47.3 mpg, which is very impressive. Very. This shows that the Street Twin achieves a totally plausible 200-plus-mile range with its small 3.2-gallon tank.
The Bonneville Street Twin’s chassis is steel tubes welded to a cast-iron steering head, bolted to an engine cradle. Rake is 25.1 degrees and trail is at 4.0 inches (102.4mm), which are common numbers for a standard-style bike. The suspension in front and rear is by Kayaba, with a 41mm conventional fork up front and preload-adjustable twin shocks in the rear. Both ends have 4.7 inches of travel, and the shocks are set up with ample sag and have progressive springs for a soft initial travel.
The wheels are cast aluminum: 18 x 2.75-inch front, 17 x 4.25-inch rear, with classic-looking Pirelli Phantom tires made to Triumph’s specs. The tires are 100/90-18 front, 150/70R-17 rear. Braking at each end is by single Nissin two-piston floating calipers, mated to a 310mm disc up front and a 255mm one out back. ABS is standard. Seat height is 29.5 inches, and the claimed dry weight is 437 pounds.
Other features include traction control that can be turned off, security immobilizer, and a USB socket under the seat. The hand levers are adjustable.
A single round gauge contains an analog speedometer and a multi-functional LCD display shows gear position, fuel level, range to empty, fuel-consumption rate, traction-control status, service indicator, clock, and odometers.
The Bonneville Street Twin’s class of motorcycles might be best described as the mystery-of-the-missing-horsepower class, defined by bikes with full-size meaty engines blessed with midsize mild performance. It’s a retro-ish, roadster-ish, twin-ish class that includes the likes of Harley-Davidson 883 Sportster, Indian Scout Sixty, Star Bolt, Moto Guzzi V7, Ducati Scrambler, and this Street Twin—maybe one or two others. This niche is now a full-on market center of easy-to-ride-yet-totally-capable motorcycles. Oh, and each bike must have a base model costing less than $9,000, even if it’s only one dollar less.
The aging generation of performance motorcyclists have been long drunk on horsepower as the end-all measure of performance and happiness. But the Street Twin is for a new crowd who values a ride of quality and ease. Triumph providing ABS and traction control as Street Twin standard features, on an otherwise retro bike, is no accident, pun fully intended.
With the Street Twin, its engine-to-horsepower ratio isn’t a matter of dumbing down a beast. A big twin allows the creation and manipulation of a crafted powerband that’s broad and smooth from bottom to top, making the most of the plateau of torque rather than chasing the peak of horsepower. The omission of a tachometer isn’t for keeping costs down; it’s to make a statement because the specific location of redline just doesn’t matter.
Chasing horsepower is a nervous activity, and this bike is designed to be calm. Also, horsepower is a measure over time, and its peak number only exists for an instant at the top end of a revving journey. Most riders never go there, don’t want to go there, and don’t know why anyone would think of going there.
A few company staffers stated that Triumph is an engineering company, above all else. So does the Street Twin show that?
Yes, it does. This bike’s efficiency of travel, both in miles per gallon and in suspension movement, defends this engineering claim—so does the Street Twin’s virtually vibration-free chassis, despite the fact that the engine is solid mounted with no rubber dampers.
On the Street Twin, the ride is soft, the seat is soft, and the power is soft. Overall, the chassis is well controlled with properly tuned damping for both high-speed and low-speed suspension movement, though it can get a bit overwhelmed when pushing through sweepers at terminal speeds. But, as suggested above, riding like a knucklehead isn’t the first thought for most who are shopping in this class.
If the Street Twin is vying for the prize of friendliest streetbike ever, it is certainly a formidable contender. And we’re not talking about little bikes with little engines; we’re talking about serious bikes that can be ridden any distance, exceeding touring speed, and be very cool to own and trust and love.
Something Triumph has as a brand is character, and there’s no extra cost for that. Many of its employees have been with the company since it reopened in the 1980s, with most of those who have left simply retiring. It’s a family—a British family primarily, but it extends to the Thailand factory where all Bonnies are assembled—and they’re proud that they don’t compete with others but do it their own way.
The bike’s character truly resides within its classic Bonneville silhouette. It’s shaped like the history of Triumph. Like in how “pushrod 45-degree V-twin” means Harley-Davidson and “boxer” means BMW, parallel twin means Triumph. It’s so iconic that its shape, configuration, and proportions were copied by others back in the 1970s and all the way up to current times, including the Kawasaki W650/800.
A parallel twin isn’t just an engine layout; it’s the emotional signature of a memory, just as much as a taste can be. Long live the Queen.
|2016 Triumph Bonneville Street Twin
|$8700 black, $8950 color
|54.0 @ 5900 rpm
|59 lb.-ft. @ 3230 rpm