Triumph Street Twin - The Bonnie lives on with the water

09 February 2017
Story: Mick Matheson Photos: Jeff Crow, Triumph

The Black Spur is one of the perfect roads for a Bonneville. Tight, twisty, and neither fast nor slow but somewhere in between. The new Street Twin hooked in, its Arrow slip-ons singing with delight and the footpegs adding their rough screech to the tune every time they clawed the tar. It’d only taken me a few corners to ditch any attempts to muscle the little bike as if it were a modern machine, and now I rode it like the old bike it mimics. Smooth, flowing. Sympathetically. And as a result, fast.

Well, fast enough. It felt faster than the speedo measured it, but if there’d been a Street Triple behind me I’d have been holding it up. The Street Twin operates at a gentler level where you have time to savour the experience rather than riding it like a thoroughbred. Corner entries come on with the grace to allow you to choose you line just right. Apexes can last long enough for you to know you’ve got them just right. The instant you crack open the throttle to arc onto the straight you’ll know whether or not you got it just right. If the Street Twin is not the fastest thing on the Black Spur, you wouldn’t know it if you ignored the speedo. I judged it by the speedo driven by my own satisfaction, and the needle wound a long way around the dial.

The Street Twin is quite capable of doing longer rides on country roads.

This is the way it has been with Hinckley Bonnevilles and all their derivatives since Triumph introduced its retro line at the turn of the Millennium. One of my first rides on one back then was along this same road, and I was exceptionally relieved when I realised nothing had really changed. Change was what worried me most before I rode this all-new 2016 Bonnie, because so much has changed in a machine that represents staunch resistance to change.

The big change, the one that could have been the death of retro, is liquid-cooling for the traditional-looking twin-cylinder engine. Coolant is anathema to the memory of Edward Turner’s 1930s parallel-twin cylinder engine design, the first of its kind. The inevitability of it, though, must have scared the hell out of Triumph’s engineers as they stared down the barrel of ever-tightening emissions regulations. The laws of the lands said they had to shape up or shut down the production lines. The law of the market said it wouldn’t be worth maintaining a production line if they couldn’t design a retro-bike the buyers would believe in. No one had managed to turn an air-cooled retro into a liquid-cooled replica without making awkward, or awful, compromises.

Luckily, Hinckley’s crew has done it. You have to do more than simply glance at the Street Twin to see it’s any different to the 16 years’ worth of Bonnevilles that came before it, and it still bears a striking resemblance to the bikes of the 1960s and ’70s that inspired it. Its cooling fins stand proud, uncluttered by any hoses or pipes. The slim radiator is as discreet as can be, feeding its contents almost directly into the front of the engine. There’s no external sign of a water pump. The coolant tank is very well hidden behind the engine, under the swingarm. They have done the best job of modernising this engine’s structure without losing the apparently simplicity that was crucial to its acceptance.

You don’t get a badge, but the decals provide cool styling

And while they were at it, they’ve added electronic technology that would blow of Edward Turner’s mind. Not just anti-lock brakes, but ride-by-wire throttle and traction control. This is retro with a serious twist.

But it is also retro with a new soundtrack. One of the many changes to the Triumph Bonneville is that its crankshaft now has 270-degree firing intervals, just like the America, the Thunderbirds and most of the other parallel twins from Hinckley. In fact, except there are no 360-degree cranks left in the range, so they all sound like 90-degree V-twins. Personally, I’m with Seddo (ARR #122) in lamenting the loss of that age-old Bonneville purr, but at the same time I agree the new sound is a better one that’ll have more appeal in this day and age. More so as the exhaust note is louder than it used to be, thanks to the quieter mechanical noise of the engine. You can really hear this baby, and she does sing a lovely tune.

You’d never guess it was liquid cooled, but note the filler below the swingarm pivot

Not only have they uncorked the sound, they’ve improved the power. Well, not the outright power, which is actually down about 1hp, but the grunt. By that, I mean that there’s more torque and power in the bottom end and midrange where you’ll appreciate it most. The engine has grown from 865cc to 900cc, and its new state of tune endows it with a much more useful kind of power. At best, torque output is up 18 per cent and it peaks early: 80Nm at just 3230rpm.

To show how serious Triumph has been about the style of this bike’s power output, they’ve gone retro with the bore and stroke. While the rest of world races to perfect massive bore sizes and minimal stroke, the new Street Twin has squeezed its bore from 90mm to 84.6 and extended the piston stroke from just 68mm to a pretty decent 80mm. That’s about as close to square as you’ll find anywhere in motorcycling these days, and that kind of ratio is always going to enhance bottom-end torque at the expense of the ability to rev high … and isn’t that exactly what we want our retro-bikes to do?

Triumph Street Twin: Urban kitted and Scrambler and variations

The effect is spot on. This 900 pulls from about 50-60km/h in top gear, with just enough power and smoothness to get away with it. From there up, it’s accelerates well all the way through to somewhere about the imperial ton, but not much further. It’s flexible about which gear you use at any time, and frequently goes faster if you take corners in a higher gear than you could. Snick through the gears to keep the revs in the very rewarding midrange and you’ll swing along at a good pace, not feeling bum-crushing performance by any means but having fun with solid acceleration and engine braking. It is ‘only’ a 900, not a 1200 like the new T120 and Thruxton, but the Street Twin hustles along well. It’s still just a 55hp bike, though, so expect grace more than pace.

The torquiness allows Triumph get away with giving it a five-speed gearbox full of nicely spaced ratios so that there’s always a gear for whatever you’re trying to achieve. For me the revs were low enough in top for pleasant highway cruising but I’d be tempted to drop the final gearing fraction for sharper response. The bike has a new, smaller clutch with a lighter pull yet firmer engagement, and combined with the sweet-shifting gearbox it’s a pleasure to use. The gearbox feels decidedly un-retro, in that it’s light, direct, quick and of course has no false neutrals.

Clockwise from top left: The Street Twin almost looks like it’s straight from the 1970s, Cylinder fins give no clues about the engine’s liquid cooling, Levers, grips and mirrors are among some 150 accessories, Slender tank and uncluttered front end are true Bonneville features

The new 900 engine fits into a chassis of about the same size as the old one, with a very accessible seat height of 750mm and a dry weight just under 200kg. It’s such an easy bike to handle that you wonder how long it’ll be till Australia’s states adopt learner laws that ignore engine capacity and permit you ride something like this, but that’s a conversation for another page.

Its steering is effortlessly cooperative, so you automatically find yourself on the line you looked at before entering a bend. At first I thought the cornering clearance was merely adequate until I realised I was achieving pretty decent lean angles before the footpegs scraped. This deceptiveness is more proof of how sweet this machine is. However, don’t think it’s as sharp a tool as a Street Triple of the like, because while its suspension is certainly better than the previous Bonneville’s, it could never have the full control of high-end stuff. In this bike, you get additional rear-wheel travel compared with previously, and better damping rates that find good balance between the smooth ride you like and the consistent handling you want; it’s still slightly under-damped though, which you’ll notice more as speed rises. Treat it roughly and it will not respond well, but ride smoothly and it will. Until big bumps get in the way, this is suspension you can enjoy on the open road. The only adjustment is spring preload, so at least you can wind it up when you’re loaded for a trip.

Scrambler action: it feels the same as the stocker, just looks different

The brakes are equally suitable: well up to stopping the Bonneville in a quick and predictable way. The back brake is more progressive than I expected, and doesn’t lock (or rather, activate the ABS) too readily, while the front anchor is good. The fitment of standard ABS is nice, and just what you’d expect in 2016, but the switchable traction control is a pleasant surprise. Sure, turn it off if you don’t appreciate it, and it’s highly unlikely the Street Twin’s humble horsepower will tax the rear tyre, but as a backup device it’s invaluable. The ultra-modern technology in the Bonneville goes further, making this a very efficient motor. Consumption averaged just 4.5L/100km in mixed riding that included some fun fanging, and as such you can forgive Triumph for shrinking the fuel tank to a meagre 12 litres. You can generally count on 250km or more.

The riding position is classic Brit twin — sitting upright and relaxed. It’s almost too upright if you like to put your head down when running hard, but it’s great for long rides. The seat is thin but cleverly padded, so while it’s no tourer it’s fine. You could always add an Airhawk seat cover. The handlebars vibrate a little bit but overall it’s a comfy little bike.

The only meter in front of you is the speedo, which houses a displays useful info that includes range, consumption, time, traction control status and lots more. Under the seat, there’s a USB plug to charge devices from. You can opt in for tyre-presser monitors and heated grips. It’s all very modern stuff for a retro bike.

Left: Cast alloy wheels are finished in black with red stripe Right: 900 HT stands for the high-torque tuning

So are the amount of plastic and the lack of chrome. The finish is excellent but don’t expect metal guards, headlight etc, nor much bling on this entry-level Bonnie. There are no badges, just stickers. Price has been contained somehow, but the way Triumph has done it is quite OK in my books. The price has barely changed in the transition from Bonneville to Street Twin, which is a good sign. There’s a jump in price, performance and finish to the 1200s, but they’re not out of reach.

Before the end of the year, I aim to buy a classic bike. After riding the Street Twin, I’m now torn between new or old, so reasons that should be obvious by now. Interestingly, I’ve come to the end of this review and almost forgotten to bring things back to the issue of liquid-cooling, so insignificant does it now seem. This bike has the right looks, feel and style to satisfy any lover of tradition, but it brings so many useful and worthwhile modern touches it’s now well ahead of the retro-bike game. It is small and delightful, with lovely torque and a sweet nature that doesn’t quite hide the playfulness that must always be associated with the Bonneville name. Triumph has done well.


There are effectively three new engines in Triumph’s retro range. One’s a 900c unit on what they call high-torque specification. The other two are 1200s, one tuned for solid, torquey performance in T120 guise, the other for greater power in Thruxton form.

Triumph’s smaller-capacity cruisers are going to get the water-cooled engines next, but we’re yet to find out what the range will look like. They’re certainly use both the 900 and 1200 engines. A 900 America and a 1200 Speed Master, perhaps? Or new names altogether? We’ll see.


The water-cooled engine will make it a little harder to build out-there customs based on the parallel twin, but it certainly won’t be impossible. One question that comes to mind is whether anyone will be able to completely hide the cooling system. After all, the engine shows few external signs of it, so it’s just a matter of hiding the radiator and finding a way to conceal the pipes carrying coolant to it. Route them inside the frame rails, maybe? 

As for your own little touches, Triumph has kits to build your Street Twin into a cafe-racer, a scrambler, and a “brat tracker”, plus a total of 150 accessories specifically for the new 900.