• 2021 Triumph Bonneville Street Twin

It’s a really nice combination of charm, performance, and utility

LISTEN 09:42

Triumph generally spruced up its Bonneville-powered models ahead of MY2021 with special attention paid to the Street Twin model. This year, the 900 cc twin is cleaner so it qualifies for the Euro-5 emissions rating, and the seat was padded with deeper foam for better long-distance comfort. New bodywork and detailing sets this bike apart from its forebears, but under the hood, the Street Twin carries ride-quality and safety electronics to rival that of many larger machines currently on the market.

  • 2021 Triumph Bonneville Street Twin
  • Year:
    2021
  • Make:
  • Model:
  • Engine:
    Parallel Twin
  • Displacement:
    900 cc
  • Top Speed:
    120 mph (Est.)
  • Price:
    9400
  • Price:

2021 Triumph Bonneville Street Twin Design

  • Old-school UJM styling
  • LED lighting
  • Analog speedometer and LCD display
  • Liberal blackout
2021 Triumph Bonneville Street Twin
- image 986412
2021 Triumph Bonneville Street Twin
- image 986417
Overall, the Street Twin captures the spirit of Triumph's long-established panache in a timeless yet modern package.

If you’re looking for a ride with deep historical roots and oodles of British-ness on the side, the new Bonneville Street Twin may just be your Huckleberry with its old-school, standard-streetbike build that pretty much serves as the Brit version of the UJM. Bellow gaiters, bobbed fender, and liberal blackout treatment makes a connection to the classic custom scene. The blackout spreads to the headlight can, tripleclamp, handlebar, and mirrors up front, plus the frame, swingarm, and drivetrain to make the dark look the standard and the only splash of color is found in the fuel tank paint.

Classic knee reliefs taper the 3.2-gallon tank to give it an all-up-front look and gobs of that je ne sais quoi that has long set Trumpet machines apart from the pack. A bench seat accommodates pilot and pillion with a faux tuck-and-roll p-pad behind a smooth finish on the driver’s seat with fold-up, frame-mount footpegs to finish the passenger’s amenities. Since the pegs mount to the frame instead of the swingarm (lookin’ at you H-D) the passenger doesn’t have to soak up every bump in the road while trading your riding partner’s comfort and confidence for simplicity’s sake.

A blacked-out rear fender mounts the taillight, turn signals, and taglight – all in LED tech – and it uses the license plate itself as an extension to the coverage in order to keep the sheet metal to a minimum out back. The upswept mufflers make a connection of sorts to the racing world as they are jacked up to avoid scrubbing the silencers on deep corners, but this is mainly an aesthetic feature as the Street Twin isn’t exactly a knee-dragger bike and will likely not lean in far enough that the exhaust clearance becomes a problem.

Overall, the Street Twin captures the spirit of Triumph’s long-established panache in a timeless yet modern package, and you can pencil me in as a fan based on looks alone.

2021 Triumph Bonneville Street Twin Chassis

  • Very agile nature
  • Vanilla suspension
  • ABS
  • Torque-assist clutch
2021 Triumph Bonneville Street Twin
- image 986422
2021 Triumph Bonneville Street Twin
- image 986413
2021 Triumph Bonneville Street Twin
- image 986410
The new Street Twin has a very agile nature that is willing in the corners and quick with the reversals.

Tubular-steel members make up the double-downtube/double-cradle frame on the Street Twin, and that material extends to the yoke-style, rectangular-section swingarm for its strength, durability, and rigidity. The steering head establishes a sharp rake angle of 25.1 degrees with 4 inches of trail over a 57.1-inch wheelbase to give the new Street Twin a very agile nature that is willing in the corners and quick with the reversals. Seat height measures 30.1 inches off the deck, which will be in tiptoe territory for many shorter riders, but it is what it is, and it’s still lower than your garden-variety sportbikes.

A set of 41 mm, rwu front forks float the front end on fixed values with a set of classic bellow gaiters that give it an old-school look and protect the swept area of the inner fork tubes along with the fork seals at the top of the sliders.

Triumph missed an opportunity to make the Street Twin even more representative of historical Bonnevilles in the wheels. Cast aluminum is the material of choice instead of steel wire-spokes and steel or aluminum hubs. The hoops come in a 100/90-18 up front opposite a 150/70-17 out back.

Dual rear shocks support the rear end with the obligatory preload adjuster as the only suspension tweak to be found on this machine. A single anchor takes care of business up front with a four-piston axial Brembo caliper that bites the 310 mm front disc, followed by a twin-piston Nissin caliper and 255 mm rear disc with ABS protection at both ends.

Frame: Tubular steel, with twin cradles
Swingarm: Twin-sided fabrication
Front Suspension: Ø 41mm cartridge forks
Rear Suspension: Twin RSUs with preload adjustment
Rake: 25.1 º
Trail: 4.0 in (102.4 mm) (TBC)
Front Wheel: Cast aluminum alloy multi-spoke, 2.75” x 18”
Rear Wheel: Cast aluminum alloy multi-spoke, 4.25” x 17”
Front Tire: 100/90-18
Rear Tire: 150/70 R17
Front Brakes: Single 310 mm floating disc, Brembo 4-piston fixed axial caliper, ABS
Rear Brakes: Single 255 mm disc, Nissin 2-piston floating caliper, ABS

2021 Triumph Bonneville Street Twin Drivetrain

  • Liquid-cooled 900 cc parallel-twin engine
  • 64.1 hp and 59 lb-ft of torque
  • Ride modes
  • Switchable traction control
2021 Triumph Bonneville Street Twin
- image 986427
2021 Triumph Bonneville Street Twin
- image 986411
2021 Triumph Bonneville Street Twin
- image 986415
The old-school layout of the engine puts its deep roots on display with an undeniable British-ness.

Bonneville power serves as the beating heart for the Street Twin. It comes in a liquid-cooled parallel-twin, but instead of an even 180-out firing order, the crank is offset for a 270-degree interval between sparks one and two. This gives the engine a bit of a lope at idle, and provides a long off-power moment that lets the rear wheel gain purchase before the next power pulse hits for improved rear traction on soft surfaces and in inclement weather.

A single over-head cam times four valves per cylinder to keep the top end light and simple with a classic shape that contributes to the classic look of the Bonneville engine. The old-school layout of the mill puts its deep roots on display with an undeniable British-ness that really completes the ensemble and sells the package.

Nearly square, the bore and stroke measure in at 84.6 mm and 80 mm respectively to give the lump its 900 cc displacement with an 11-to-1 compression ratio that will demand mid-grade gas or an octane booster to prevent knock, ping, and run-on. A ride-by-wire throttle control sends rider demand to the mill, but the final outcome at the rear wheel is modified by a pair of Riding Modes (Rain, Road) and a switchable traction control feature that helps you keep the thing dirty-side down.

A slipper clutch adds another layer of safety netting by preventing excessive backtorque from breaking the rear wheel loose, as you might experience on hard downshifts and engine-braking techniques. It couples engine power to the five-speed gearbox with 64.1 horsepower and 59 pound-feet of torque on tap to turn in a top speed in the neighborhood of the 120 mph mark.

Engine: Liquid cooled, 8 valve, SOHC, 270° crank angle parallel twin
Displacement: 900 cc
Bore s Stroke: 84.6 mm x 80 mm
Compression: 11.0:1
Max Power EC: 64.1 hp @ 7,500 rpm
Max Torque EC: 59 lb-ft @ 3,800 rpm
System: Multipoint sequential electronic fuel injection
Exhaust: Brushed stainless steel 2-into-2 exhaust system with twin silencers
Final Drive: Chain
Clutch: Wet, multi-plate torque assist clutch
Gearbox: 5 speed

2021 Triumph Bonneville Street Twin Price

2021 Triumph Bonneville Street Twin
- image 986414
2021 Triumph Bonneville Street Twin
- image 986416
MSRP runs $9,400 for basic black and $9,700 for a choice of color.

The base model Bonneville Street Twin rolls in Jet Black for $9,400, but if you prefer the Matte Ironstone or Cobalt Blue models, you can expect to shell out another three Benjamins. This year also sees the release of the Limited-Edition Street Twin Gold Line, and you’ll need to pony up $10,150 for one of the 1,000 hand-painted numbered units.

Instrument Display: Analogue speedometer with LCD multi-functional display
Color: Cobalt Blue, Jet Black, Matte Ironstone, Matt Sapphire Black
Price: Black: $9,400, Color: $9,700, Gold Line: $10,150

2021 Triumph Bonneville Street Twin Competitors

2016 - 2021 Harley-Davidson Iron 883
- image 735907
2021 Triumph Bonneville Street Twin
- image 986420

The Street Twin finds itself in a similar displacement and price bracket with a number of bikes around the world, but in the U.S. market, this ride is most likely going to go head-to-head with Harley-Davidson’s newly-reduced Sportster lineup. With that in mind, I grabbed the Iron 883 from the Sportster lineup to see how it stacks up.

Harley-Davidson Iron 883

2016 - 2021 Harley-Davidson Iron 883
- image 870631

In the looks department, H-D hits many of the same high notes with liberal blackout treatment, bellowed fork gaiters, and an old-school panache that hails all the way back to the K-Model of the early fifties to give it an equal historical footing with the Brit. Like the Bonneville plant, the Sportster’s V-twin engine contributes a certain amount of charm to the package and comes with a natural offset to the firing order for that unmistakable lope at idle.

Harley starts to slip in the power figures with only 53.8 pounds o’ grunt on tap against the Bonnie’s 59 pounds, but with a 118 mph top speed its top end is comparable at the end of the day. What isn’t comparable is the electronics. The Sportster rolls with nothing in the way of ride-quality and safety equipment with no answer for Triumph’s traction control and rider modes features. Even the ABS is optional equipment on the Sporty – a $795 one at that – so keep that in mind when considering the $9,499 starting price on the H-D ride.

Read our full review of the Harley-Davidson Sportster 883.

He Said

“The factory doesn’t exactly bill this as an entry-level machine, but I submit that it would make a dandy learner’s bike, especially here in the States where we don’t suffer the restriction of the tiered licensing system. Sure, it has some training wheels built in with its traction control and such, but honestly, that tech is more ubiquitous with every passing model-year, so a rider has a reasonable expectation of finding similar protection if/when they decide to up-size their ride.”

She Said

My wife and fellow motorcycle writer, Allyn Hinton, says, “Triumph has a style all its own. It’s a British-ness that you can see, but not really identify. The Street Twin isn’t the fastest bike or lightest bike or whatever-else-est bike in the Heritage lineup, so you might scroll right past it when comparing specs. That would be a shame because the bike as a whole is a really nice combination of charm, performance, and utility. It’s an entry-level-friendly bike, so don’t let the 900 cc engine scare you off. Power delivery is unintimidating, but there is enough there for purposeful roll-on and the high-torque engine has plenty of grunt low in the rev range for some happy giddy-up. It’s a nice bike for folks that don’t need to try to impress anyone and who just want a fun ride on their own terms.”

2021 Triumph Bonneville Street Twin Specifications

Engine & Drivetrain:
Engine: Liquid cooled, 8 valve, SOHC, 270° crank angle parallel twin
Displacement: 900 cc
Bore s Stroke: 84.6 mm x 80 mm
Compression: 11.0:1
Max Power EC: 64.1 hp @ 7,500 rpm
Max Torque EC: 59 lb-ft @ 3,800 rpm
System: Multipoint sequential electronic fuel injection
Exhaust: Brushed stainless steel 2-into-2 exhaust system with twin silencers
Final Drive: Chain
Clutch: Wet, multi-plate torque assist clutch
Gearbox: 5 speed
Chassis:
Frame: Tubular steel, with twin cradles
Swingarm: Twin-sided fabrication
Front Suspension: Ø 41mm cartridge forks
Rear Suspension: Twin RSUs with preload adjustment
Rake: 25.1º
Trail: 4.0 in (102.4 mm) (TBC)
Front Wheel: Cast aluminum alloy multi-spoke, 2.75” x 18”
Rear Wheel: Cast aluminum alloy multi-spoke, 4.25” x 17”
Front Tire: 100/90-18
Rear Tire: 150/70 R17
Front Brakes: Single 310 mm floating disc, Brembo 4-piston fixed axial caliper, ABS
Rear Brakes: Single 255 mm disc, Nissin 2-piston floating caliper, ABS
Dimensions & Capacities:
Width Handlebars: 30.7 in (780 mm)
Height Without Mirror: 43.7 in (1,110 mm)
Seat Height: 30.1 in (765 mm)
Wheelbase: 57.1 in (1,450 mm)
Dry Weight: 476 lb (216 kg)
Tank Capacity: 3.2 gal (12 liters)
Details:
Instrument Display: Analogue speedometer with LCD multi-functional display
Color: Cobalt Blue, Jet Black, Matte Ironstone, Matt Sapphire Black
Price: Black: $9,400, Color: $9,700, Gold Line: $10,150

Further Reading

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TJ Hinton
TJ Hinton
T.J got an early start from his father and other family members who owned and rode motorcycles, and by helping with various mechanical repairs throughout childhood. That planted a seed that grew into a well-rounded appreciation of all things mechanical, and eventually, into a formal education of same. Though primarily a Harley rider, he has an appreciation for all sorts of bikes and doesn't discriminate against any particular brand or region of origin. He currently holds an Associate's degree in applied mechanical science from his time at the M.M.I.  Read full bio
About the author

All images featured on this website are copyrighted to their respective rightful owners. No infringement is intended. Image Source: triumphmotorcycles.com, harley-davidson.com

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