MotoSpecs

2008 Triumph Rocket III Specifications

Custom / cruiser • Specs last verified 13 July 2026

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2008 Triumph Rocket III Overview

For 2008, Triumph offers the Rocket III as a custom / cruiser motorcycle with 2294 cc on tap. The 2008 Triumph Rocket III is built around a Four stroke, longitudinal three cylinder, DOHC, 4 valves per cylinder engine, a compression ratio of 8.7:1. Out on the road, the Rocket III delivers 103.6 kW @ 5750 rpm of peak power and 200 Nm @ 2500 rpm of torque. Flat out, it's quoted at 219.4 km/h. In everyday use, the 2008 Rocket III tips the scales at 350 kg, carries a 24-litre fuel tank, offers a seat height of 740 mm and spans a 1695 mm wheelbase. That's roughly 49.4 kg heavier than the average custom / cruiser motorcycle in our database. Every technical detail, from suspension travel to tyre sizes, is covered in the full 2008 Triumph Rocket III spec sheet below.

2008 Rocket III - Pros & Cons

Strengths

  • Strong power output: Peak output on the Rocket III is 103.6 kW @ 5750 rpm and 200 Nm @ 2500 rpm of torque - strong numbers for what it is.
  • Accessible seat height: At just 740 mm, flat-footing at a stop is easy for most riders - a genuine confidence builder for less experienced owners.
  • Large fuel range: With a 24-litre tank, this isn't a bike you'll be stopping for fuel every hour - a real asset on longer trips.
  • Low-maintenance final drive: Shaft final drive is about as close to maintenance-free as motorcycle drivetrains get.

Considerations

  • Age-related wear: No particular mechanical concern flags for the Rocket III - condition on any used example comes down to how well it's been looked after.

Wear Points & Servicing Notes

Cooling system servicing

With Liquid cooled, thermal management is largely automatic, but the coolant has a service life of its own - replace it on the manufacturer's interval to protect the water passages and thermostat.

Brake disc and pad wear

2 x 320mm Discs, 4 piston calipers up front provides the primary stopping power; inspect disc thickness and pad wear at each tyre change to catch scoring before it becomes a rotor replacement.

Suspension condition on used examples

Suspension duties are handled by 43 mm Upside down forks up front and Chromed spring twin shocks with adjustable preload at the rear. Weeping fork seals aren't a dealbreaker on a used bike, but they're a fair basis for negotiating price.

Final drive maintenance

Shaft final drive on the Rocket III removes chain and belt maintenance entirely - the trade-off is a little extra unsprung weight and periodic gear-oil changes.

Frame & chassis check

The Tubular steel, twin spine chassis holds up well with normal use; on a used bike it's still worth checking the head-stock and swingarm pivot area for impact damage or corrosion.

Handling the weight at a standstill

The Rocket III's 350 kg kerb weight is worth factoring into how you handle it at a standstill - parking-lot manoeuvres need a bit more deliberate technique than on a lighter machine.

Rocket III - Buying & Maintenance Guide

What to check before buying

A pre-purchase check on the 2008 Triumph Rocket III should cover the same ground every time: service history, chain and sprocket condition, and any oil seepage around the casings. Start it from cold if you can - a well-kept Rocket III settles to a smooth idle within seconds.

Oil and filter changes

Oil changes are the cheapest insurance you can buy for a Rocket III's engine - keep to the manufacturer's interval rather than stretching it. Use the viscosity grade the manual specifies, not whatever's on sale.

2008 Triumph Rocket III - Frequently Asked Questions

What engine does the 2008 Triumph Rocket III have?
The 2008 Triumph Rocket III uses a Four stroke, longitudinal three cylinder, DOHC, 4 valves per cylinder engine with 2294 cc of displacement. It is liquid cooled.
What is the top speed of the 2008 Triumph Rocket III?
The 2008 Triumph Rocket III has a factory-quoted top speed of 219.4 km/h. Real-world speeds vary depending on rider weight, conditions and state of tune.
How much does the 2008 Triumph Rocket III weigh?
The 2008 Triumph Rocket III weighs 350 kg. This is the manufacturer's wet figure.
How much power does the 2008 Triumph Rocket III make?
The 2008 Triumph Rocket III produces 103.6 kW @ 5750 rpm of power and 200 Nm @ 2500 rpm of torque. These are peak figures.
What is the fuel tank capacity of the 2008 Triumph Rocket III?
The 2008 Triumph Rocket III has a 24-litre fuel tank. At around 5-6 litres per 100 km, that is roughly 400-480 km between stops.
Is the 2008 Triumph Rocket III suitable for shorter riders?
The 2008 Triumph Rocket III has a seat height of 740 mm. This is a comfortable, accessible height for most riders.
What brakes does the 2008 Triumph Rocket III have?
The 2008 Triumph Rocket III uses 2 x 320mm Discs, 4 piston calipers at the front and Single 316 mm disc, 2 piston caliper at the rear.
What tyre sizes does the 2008 Triumph Rocket III use?
The 2008 Triumph Rocket III runs 150/80 V17 front and 240/50 V16 rear tyres. A good selection of sport, touring and all-weather rubber is available in these sizes.
What gearbox does the 2008 Triumph Rocket III have?
The 2008 Triumph Rocket III is fitted with a 5 Speed transmission.

Key Specifications

Engine

Four stroke, longitudinal three cylinder, DOHC, 4 valves per cylinder

Power

103.6 kW / 140 hp @ 5750 rpm

Torque

200 Nm / 20.4 kgf-m / 147ft.lbf @ 2500 rpm

Top Speed

219.4 km/h / 136.3 mph

Weight

350 kg / 771.6 lbs

Fuel Capacity

24 Litres / 6.3 US gal / 5.3 Imp gal

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Full 2008 Triumph Rocket III Specifications

Year 2008 - 09
Make Model Triumph Rocket III
Seat Height 740 mm / 29.1 in
Wheelbase 1695 mm / 66.7 in
Height 1165 mm / 45.9 in
Length 2500 mm / 98.4 in
Width 970 mm / 38.2 in
Dry Weight 320 kg / 704 lbs
Fuel Capacity 24 Litres / 6.3 US gal / 5.3 Imp gal
Wet Weight 350 kg / 771.6 lbs
Top Speed 219.4 km/h / 136.3 mph
Max Power 103.6 kW / 140 hp @ 5750 rpm
Max Torque 200 Nm / 20.4 kgf-m / 147ft.lbf @ 2500 rpm
Standing Start ¼ Mile 12.2 sec
Displacement 2294 cc / 140 cu in
Engine Detail Four stroke, longitudinal three cylinder, DOHC, 4 valves per cylinder
Bore x Stroke 101.6 x 94.3 mm
Compression Ratio 8.7:1
Cooling System Liquid cooled
Fuel Consumption 6.4 L/100 km / 15.6 km/l / 36.7 US mpg / 44.1 Imp mpg
Ignition Digital inductive type via electronic engine management
Starter Electric
Clutch Wet, multi-plate
Final Drive Shaft
Transmission / Drive 5 Speed
Frame Type Tubular steel, twin spine
Suspension - Front 43 mm Upside down forks
Suspension - Rear Chromed spring twin shocks with adjustable preload
Rake 32°
Trail 152mm / 6.0 in
Brakes - Front 2 x 320mm Discs, 4 piston calipers
Brakes - Rear Single 316 mm disc, 2 piston caliper
Tyres - Front 150/80 V17
Tyres - Rear 240/50 V16
Wheels - Front 3.5 x 17, 5 spoke
Wheels - Rear 7.5 x 16, 5 spoke

Specifications are compiled from manufacturer documentation and cross-referenced technical sources, and corrected on an ongoing basis. Spot an error? Let us know.

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Rocket III Years

2009 2007

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Triumph Rocket III - other years

2009 2007
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