Skip to main content

Factor LS gravel bike review

Factor's first attempt at the gravel bike concept has delivered an all-terrain-conquering racing machine - and speed is its number one priority

Factor LS gravel bike
(Image: © Aaron Borrill)

Our Verdict

As far as gravel bikes go, the Factor LS is a razor-sharp instrument designed for the racer, not Sunday rider. That said, it can double up as a road bike should you enjoy mixing up your training loops

For

  • Super-lightweight performance
  • Agile handling
  • Ability to accommodate rubber of up to 43mm
  • GRX Di2 performs flawlessly in any setting
  • Can double up as a road bike

Against

  • Ride quality can come across quite harsh on choppy singletrack and dirt roads
Image 1 of 6

Factor LS gravel bike

The Factor LS takes its design cues from the O2 road bike (Image credit: Aaron Borrill)
Image 2 of 6

Factor LS gravel bike

At 7.95kg (for a medium, 54cm) it's one of the lightest gravel bikes on the market (Image credit: Aaron Borrill)
Image 3 of 6

Factor LS gravel bike

The bike is optimised to accommodate tyre sizes between 40 - 43mm (Image credit: Aaron Borrill)
Image 4 of 6

Factor LS gravel bike

The shorter seat stays help when it comes to agility, allowing the rider to manoeuvre the bike through twisty, sinuous singletracks (Image credit: Aaron Borrill)
Image 5 of 6

Factor LS gravel bike

As with all Factor products, the level of detailing is exquisite (Image credit: Aaron Borrill)
Image 6 of 6

Factor LS gravel bike

It's compatible with 1x or 2x, mechanical or electronic shifting (Image credit: Aaron Borrill)

Factor's bike portfolio has grown significantly over the past 18 months, boasting a smorgasbord of new race offerings, which includes the expansion of its off-road line-up. Joining the all-road Factor Vista is the new LS, the company's first attempt at a bona fide gravel bike. It comes as no surprise that Factor has pegged the LS squarely at the racer, choosing to eschew the bump-softening gadgets of its rivals in favour of creating one of the stiffest and tactile riding experiences in the segment. We spent a few weeks putting the Factor LS through its paces over a selection of challenging terrain surfaces to establish where it sits in the gravel bike hierarchy. 

Image 1 of 6

Factor LS gravel bike

Like the Vista you get the same half-tone motif running across the top tube and seat tube (Image credit: Aaron Borrill)
Image 2 of 6

Factor LS gravel bike

The LS moniker is located just below the dropped seat stays (Image credit: Aaron Borrill)
Image 3 of 6

Factor LS gravel bike

Along with other bits and pieces, Black Inc takes care of the carbon bottle cages (Image credit: Aaron Borrill)
Image 4 of 6

Factor LS gravel bike

The bike is built around a Shimano GRX Di2 groupset (Image credit: Aaron Borrill)
Image 5 of 6

Factor LS gravel bike

The LS keeps things fairly understated using Factor's traditional bold wordmark logo and diagonal colour blocks to keep the visuals uniform across the range (Image credit: Aaron Borrill)
Image 6 of 6

Factor LS gravel bike

Geometry and bike size sticker is located behind the seat tube (Image credit: Aaron Borrill)

Design and geometry

No surprises here. The Factor LS retains much of the brand's design DNA and slots in seamlessly with the current range, bearing a rather uncanny resemblance to the O2 road bike. In terms of aesthetics, the LS is fairly understated using Factor's traditional bold wordmark logo and diagonal colour blocks to keep the visuals uniform across the range. Like the Vista, there's a half-tone motif that runs across the top tube and seat tube, which work together to bookend the LS moniker located just below the dropped seat stays. Closer examination of the frame reveals the mottled, raw appearance of the unidirectional carbon fibre - a nod to the bike's lightweight properties. In fact, Factor quotes the frame weight at a scant 950g which is a phenomenal figure for a gravel bike.

Compared to its stablemates, the O2 and Vista, the LS benefits from a slightly slacker but still relatively steep head angle of 72.3 degrees. It also gets marginally longer chainstays and a longer wheelbase, while the shorter seat stays and trail value of 60 help bring about an added sense of balance and agility - key parameters for developing a planted and responsive character. Other notable geometry numbers include the reach (383mm) and stack (566mm) which reside on the racier end of gravel bike scale.

Image 1 of 10

Factor LS gravel bike

Like all its products, Black Inc componentry and accessories feature heavily on the Factor LS (Image credit: Aaron Borrill)
Image 2 of 10

Factor LS gravel bike

The one-piece, carbon bar/stem from Black Inc (Image credit: Aaron Borrill)
Image 3 of 10

Factor LS gravel bike

Fizik's 3D-printed Antares Versus Evo R3 Adaptive saddle (Image credit: Aaron Borrill)
Image 4 of 10

Factor LS gravel bike

The GRX-branded rear derailleur shares its design blueprint with the brand's XT/XTR mountain bike stock (Image credit: Aaron Borrill)
Image 5 of 10

Factor LS gravel bike

Shimano's proven clutch-actuated rear derailleur is bombproof and helps thwart chain slap (Image credit: Aaron Borrill)
Image 6 of 10

Factor LS gravel bike

2x Shimano GRX Di2 ensures a wider range of gearing for any situation (Image credit: Aaron Borrill)
Image 7 of 10

Factor LS gravel bike

Tried-and-tested XT pedals add a bit of weight to the build but are super reliable (Image credit: Aaron Borrill)
Image 8 of 10

Factor LS gravel bike

The raw, copper-like carbon finish offsets the anodized CeramicSpeed bottom bracket cups (Image credit: Aaron Borrill)
Image 9 of 10

Factor LS gravel bike

GRX-branded calipers bite onto disc rotors that measure 160mm front/rear (Image credit: Aaron Borrill)
Image 10 of 10

Factor LS gravel bike

The 11-32T cassette comes courtesy of Shimano (Image credit: Aaron Borrill)

Components and build

Like its stablemates, the LS can be specced as a complete build or purchased as a frameset only, the latter of which will set you back £2,650. A complete build such as the bike you see here comes in at a smidgeon below £7,000.

It's an impressive build to say the least. Our LS test bike employs the gravel-specific 2x Shimano GRX Di2 groupset, which comes as no surprise given its intended use. GRX is a firm favourite at Cyclingnews - its rock-solid and reliable nature adds assurance to the package and bestows the LS with an added sense of purpose. Some standout features of GRX include the hood design which arches backwards for extra purchase and leverage when negotiating corrugated roads and the clutch-actuated rear derailleur that keeps the chain in check, thwarting slap and ensuring crisp, reliable shifting. 

Our specific build comprised a bouquet of Black Inc parts, including the firm's fabled 30 Carbon gravel bike wheels, bar/stem, seatpost and computer mount not forgetting the customary CeramicSpeed bottom bracket and headset. The specification list is rounded off by a 3D-printed saddle, the Fizik Antares Versus Evo R3 Adaptive. 

Image 1 of 4

Factor LS gravel bike

The Black Inc 30 Carbon wheel come shod in 35mm Panaracer GravelKing SK tyres (Image credit: Aaron Borrill)
Image 2 of 4

Factor LS gravel bike

The GRX-specific chainrings measure in at 48/31T (Image credit: Aaron Borrill)
Image 3 of 4

Factor LS gravel bike

The LS also has provisions for up to three bottle cages, a top tube mount and a slimline frame bag (Image credit: Aaron Borrill)
Image 4 of 4

Factor LS gravel bike

The Shimano GRX crankset in all its glory (Image credit: Aaron Borrill)

Ride, handling and performance

The LS is an exceptionally stiff machine and this is echoed in the ride quality - not surprising given the fact it shares much of its DNA with the O2 road bike. It's naturally very reactive to pedal inputs which helps when attacking the flats as well as overcoming steep climbs and rolling terrain. Of course, the stiffness factor is not going to find favour with everyone but the upshot to this is its ability to double up as road bike.

While our LS came shod with Panaracer GravelKing SK 35mm rubber, the bike has been optimised around 40 to 43mm gravel tyres, options that will no doubt ramp up the grip threshold and ride comfort. That said, after tweaking the tyre pressures to 32/38 psi front/rear I was able to not only reduce some of the trail buzz but also improve cornering adhesion. In terms of handling, the LS offers the stability and agility needed to negotiate anything from the tightest singletrack to a series of lefts and rights - a fact no doubt owing to the trail figure and low bottom bracket. Having tested it on my designated 7km XCO-style test track in Surrey's Puttenham Common, its exemplary handling manners and ability to deal with negative gradients truly impressed me despite the paucity of suspension trickery.

The Factor LS, however, is best enjoyed on the open gravel road. Whether it's barreling along the flats at 40km/h or sailing up rolling hills, the rate at which it consumes the miles is astonishing. The 48/31, 11-32T drivetrain setup provides a good spread of gearing, particularly when it comes to top-end speed, while the bottom gears are still friendly enough to ensure the steepest of kickers are effectively dispatched. Speaking of climbs, it's in a lumpy setting where the LS truly shines thanks to its feathery 7.95kg weight and stiff bottom bracket area which is super-responsive to pedal inputs.

Factor LS gravel bike

Despite the lack of suspension gadgetry, the Factor LS is able to hold its own no matter the terrain or territory (Image credit: Aaron Borrill)

Verdict

Using its road bike-manufacturing know-how, Factor's first attempt at a dedicated gravel bike is truly impressive. The Factor LS is a fast, no-holds-barred gravel racer - rich in feel, feedback and outright speed. While the unapologetically jarring ride quality won't win over any recreational riders, its communicative underpinnings and direct-ride feel will find favour with those looking to one-up their rivals when racing between the tape.

That said, there is still scope to set it up for the odd bikepacking adventure thanks to provisions for up to three bottle cages, a top tube mount and a slimline frame bag - but to outfit it in such garb would be to misunderstand the LS concept completely. So while the Factor LS gravel bike can easily do it all - adventuring included - it much prefers doing things at speed, and that usually involves scything through the gravel tracks that make up your local training loop. 

How does it compare to current contenders in the gravel bike segment? It's certainly up there with the likes of the Diverge, Topstone, Palta, 3T Exploro and Grail, delivering one of the purest experiences around but its race-bred attributes are likely to see it overlooked in favour of more comfy options. 

Logbook

  • Temperature: 14-25 degrees  
  • Weather: Dry, windy
  • Trail/road surface: Dry, corrugated
  • Route: Tarmac, singletrack, gravel roads 
  • Mileage: 312km

Tech specs: Factor LS GRX Di2 

  • RRP: £2,650 (frameset), £6,999 (Shimano GRX Di2 build)  
  • Frame: Factor LS carbon
  • Size: Medium, 54cm
  • Weight: 7.95kg (medium, actual)
  • Groupset: Shimano GRX Di2
  • Crankset: Shimano GRX 48/31T, 11-32T cassette
  • Wheels: Black Inc 30 Carbon
  • Tyres: Panaracer GravelKing SK 35c 
  • Brakes: Shimano GRX, 160mm rotors front/rear
  • Pedals: Shimano XT
  • Bar/stem: Black Inc
  • Bottle cages: Black Inc Carbon
  • Seatpost: Black Inc 25mm offset
  • Saddle: Fizik Antares Versus Evo R3 Adaptive