The British-designed Pinnacle Arkose has been a firm favourite of ours in the past, thanks to its capable geometry, well-appointed frameset and a series of well-priced options.
The new Arkose X, however, might well be the best-value model yet, not least in today’s market, with its combination of the brilliant Shimano GRX Di2 groupset and WTB’s Tubeless Proterra i23 wheelset for £2,249.
Add in the Arkose’s smart finish, well-thought-out geometry and versatility beyond gravel riding, and this is a mightily impressive package.
Pinnacle Arkose X frame
The Arkose X frame is very cleanly finished with consistent welds throughout the 6061-aluminium frame, internal routing and a metallic green paint finish highlighted by reflective graphics.
The hydroformed top tube tapers and flattens along its length, making for a stable base to hang a frame bag from.
While it doesn’t have top tube bento box mounts, the flat surface means strap-on bags fit securely and don’t slip.
The down tube has triple bottle bosses and an additional set of bosses on the underside. A third set of bottle cage mounts adorns the seat tube.
The slender rear stays have a proper bridge for mounting mudguards and, with rack bosses to boot, all this makes the Arkose a great option for adventurers and commuters alike.
At the front, the full carbon fork also has mudguard bosses and a drilled bridge, along with internal routing for a dynamo light, again bolstering the Arkose’s credentials.
|Effective top tube (mm)||537||550||566||582||598|
|Seat tube length (mm)||440||470||500||530||560|
|Head tube length (mm)||115||135||160||180||200|
|BB drop (mm)||80||80||76||76||76|
|Chainstay length (mm)||436||436||436||436||436|
|Effective seat angle (degrees)||73.5||73.5||73.5||73.5||73.5|
|Head angle (degrees)||71||71||71.5||71.5||71.5|
|Fork length (mm)||400||400||400||400||400|
|Fork offset / rake (mm)||50||50||50||50||50|
|Stem length (mm)||80||80||90||90||100|
|Crank length (mm)||170||170||172.5||172.5||175|
|Handlebar width (mm)||440||440||440||480||480|
Pinnacle Arkose X specification
In short, the build is impressive.
Pinnacle has certainly put the money where it matters. For starters, the WTB Proterra i23 650b wheelset is top grade for a bike at this price.
The Arkose can take up to a 50mm 650b tyre, should you want to go a bit bigger, while 47mm is the maximum (official) tyre clearance with 700c wheels, if you switch to the larger-diameter wheel size.
The alloy seatpost is topped off with WTB’s Volt saddle – solid mid-range components that do the job well. Up-front, Pinnacle has used a shorter stem (90mm) to keep the steering quick.
What elevates it above most GRX Di2 bikes is that Pinnacle has included the EW-WU111 Bluetooth antenna, which is something we’ve seen omitted from some of the most expensive Di2-equipped gravel bikes.
The WU111 antenna enables the Di2 system to communicate with Shimano’s E-Tube app, so you can adjust and tune the system, upgrade firmware and more.
You can also now connect the Di2 to a Garmin Edge head unit, to get gear and battery information on-screen.
You can also use the hidden buttons on the STI units to switch Garmin data screens without having to take your hands from the bars.
Pinnacle Arkose X performance
The aluminium frame at the heart of the bike provides a solid basis for pedalling, while the geometry numbers lend the Arkose to technical gravel riding.
The relaxed 71.5-degree head angle is combined with the fork’s 50mm offset, ensuring the Arkose’s steering is nimble and accurate. That’s emphasised further by using 650b wheels, which combine to give the Arkose a 53mm trail figure.
This makes the Arkose a great bike for riding singletrack and technical trails, and helps define it as a British take on a gravel bike.
The fact that Pinnacle has also appointed the frame with a generous spread of fixtures and fittings ensures it’s plenty versatile for commuting and touring, as well as adventure and gravel riding.
Elsewhere, the Proterra wheels are stiff in all the right places, while still offering plenty of compliance when riding over rutted, choppy surfaces – all aided by the big-volume tyres.
The six-degree engagement of the rear hub is spot-on for technical gravel riding, where you want pedal inputs to be met with instant movement, as an aid to both traction and low-speed manoeuvres.
Aside from clever connectivity of the GRX groupset, it also has superb shifting across the wide-range 11-42t cassette. I had no problems with the chain staying on the 42t 1x chainring, thanks in part to the switchable rear derailleur clutch for secure chain management when heading out for a rough-and-ready ride.
The gear range is well-suited to off-road endeavours. On my local routes, the 1:1 gear kept me pedalling uphill for as long as I could keep traction during the winter test period. At road speeds, the 42/11t top-end means you’ll be a yard or two behind companions on road bikes, but the Arkose can still keep up a quick pace.
GRX Di2 was Shimano’s first drop-bar groupset to introduce Servowave braking from the brand’s mountain bike groupsets.
Servowave is all about the brake action. Initial lever travel is fast, which means it gets to the pad contact sooner and then the power ramps up rapidly through the lever stroke.
Down in the drops, the superb – and controlled – feel through the levers means its difficult to unexpectedly over-brake, which, along with the Arkose’s on-point geometry, helps maintain speed, especially on twisty technical trails.
Move out of the drops and, well, much has been written about the beautifully ergonomic shape of the GRX Di2 hoods.
One component I struggled with is the wide-flared Pinnacle gravel bar. On my bike, it expands from 48cm wide at the hoods to a huge 62cm at the drops.
I like a wide bar for gravel riding, but even I found this on the extreme side. It puts the STI shifter units at an odd angle, that takes some adjusting to. Some riders may like it, but it’s a component I’d look to change.
Pinnacle Arkose X bottom line
What impressed me most with the Arkose X is just how capable it is off-road. The slick drivetrain and superb braking are great, but it’s the sorted geometry that’s the real winner.
It’s not too racy and not too relaxed, hitting a sensible middle ground that feels spot-on for gravel riding and still at home on more technical terrain.
The smaller 650b wheels may not roll as fast as 700c wheels on more mellow terrain and tarmac, but it remains a fair trade-off for this type of bike.
I’d recommend the Arkose to anyone whose idea of gravel riding is a mix of light off-road terrain – think byways and bridleways in the UK – with forest trails and more technical singletrack mixed in for an adventurous flourish.
|Price||br_price, 5, 3, Price, EUR €3000.00GBP £2249.00USD $3750.00|
|Weight||br_weight, 5, 6, Weight, 9.79kg (L), Array, kg|
|Brand||br_brand, 5, 10, Brand, Pinnacle|
|Features||br_Features, 11, 0, Features, Accessories: Shimano WU111 Bluetooth antenna|
|Available sizes||br_availableSizes, 11, 0, Available sizes, S, M, L, XL|
|Brakes||br_brakes, 11, 0, Brakes, Shimano GRX hydraulic disc BR-RX810|
|Cassette||br_cassette, 11, 0, Cassette, Shimano 11-42|
|Chain||br_chain, 11, 0, Chain, Shimano|
|Cranks||br_cranks, 11, 0, Cranks, Shimano GRX 1x 42t chainring|
|Fork||br_fork, 11, 0, Fork, Full carbon|
|Frame||br_frame, 11, 0, Frame, 6061 aluminium|
|Handlebar||br_handlebar, 11, 0, Handlebar, Pinnacle alloy wide flare gravel bar|
|Rear derailleur||br_rearDerailleur, 11, 0, Rear derailleur, Shimano GRX Di2|
|Saddle||br_saddle, 11, 0, Saddle, WTB Volt|
|Seatpost||br_seatpost, 11, 0, Seatpost, Promax alloy post 27.1mm|
|Shifter||br_shifter, 11, 0, Shifter, Shimano GRX Di2|
|Stem||br_stem, 11, 0, Stem, 90mm Pinnacle alloy|
|Tyres||br_tyres, 11, 0, Tyres, WTB Venture 47mm Tubeless ready 650b tyres|
|Wheels||br_wheels, 11, 0, Wheels, WTB Proterra i23 650b|