Factor LS gravel bike review: putting the road in ‘groad’

Factor's first foray into gravel offers a focus on saving weight, road-bike-like handling and a considered ride quality.

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Factor is a high-end carbon manufacturer focussed on producing bicycles for racing. And while the company is best known for its road and triathlon bikes, its range now extends into the realms of gravel racing, too. 

The LS is one of the newer bikes in Factor’s small range, and it’s aimed squarely at the performance rider looking to ride and race across mixed surfaces. This high-end race machine offers a noticeably road-bike-like aesthetic, attitude, and low weight that all closely mimic the company’s O2 VAM road bike. And this also means the LS is a pretty interesting quiver-killer type of bike for the person looking to own a single sporty drop-bar bike.  

I’ve had the Factor LS in for review for about three months longer than the company had intended (sorry Factor!), and finally finished off my testing as part of our 2021 Field Test in Victoria’s High Country

A simplified approach to a gravel racer 

Story Highlights

  • What: Factor’s first gravel race bike.
  • Key features: Low weight, pared back design, room for 700×43 mm tyres, road-like geometry, subtle fender mounts.
  • Weight: 950 g frame, 420 g fork, 7.98 kg (17.6 lb) as tested (without pedals).
  • Price: U$2,700 for frame/fork, US$6,999 for the complete bike (as tested).
  • Highs: Feels like a good road bike with fat tyres, ride quality, low weight, fits many standard components.
  • Lows: Toe overlap (a trade-off for the handling), Press-fit bottom bracket, down tube exposed to rock strike.

The LS is Factor’s first proper gravel bike, and it’s pretty evident that the company took to the drawing board with a pencil, tracing paper, and a CAD drawing of its lightweight road bike, the O2 VAM. 

As a result the LS offers similar squared profile tube shapes, slender fork blades, and an integrated styling that sees the fork crown flow into the svelte head tube. Likewise it shares the same minimalist integrated seat clamp wedge that holds onto a regular 27.2 mm round seat post. The modular cable routing – which works with electronic and mechanical shifting in either 1x or 2x formats – is effectively the same. And even Factor’s own asymmetric BBRight’ish press fit bottom bracket design is used here, too (more on this in a moment). 

Following this theme, the material layup is extremely similar to the O2 VAM and many of Factor’s other bikes. The LS uses TexTreme “spread tow” carbon at the base layer for what’s said to assist with smooth material compaction and high strength at a low weight. From there the rest of the layup is similarly high-end for a low-weight end result. A medium painted frame weighs 950 g (+/- 30 g depending on size), while the matching (uncut) fork is 420 g. That’s pretty light among gravel options. 

With similar tube shapes and materials, the torsional (pedalling) stiffness profile is closely comparable, too. According to Factor’s head of engineering, Graham Shrive, the LS offers similar torsional and bottom bracket stiffness to the O2 (which is marginally stiffer than the even-lighter-weight O2 VAM). And interestingly, this UCI-approved gravel bike was lined up for use by Israel Start-Up Nation riders in the event of a muddy Paris-Roubaix, although these bikes were inevitably kept in the team truck (given the 2020 Paris-Roubaix never happened).

Aesthetically there’s plenty in common between the LS and Factor’s O2.

Hitting road-like stiffness figures isn’t that unusual for a gravel bike, but Shrive pointed out that careful consideration was given to the compliance and subsequent ride quality of the frame. “I’ve got some experience with gravel bikes, and one of the most striking things that I’ve found is that when you over-specify the strength requirements for a frame [using mountain bike strength tests – ed.] and then build to accommodate those strength requirements, you start to get a mega stiff frame,” he said.

“I still think it’s important to not overdo the stiffness on a gravel bike. It is entirely too easy to just dismiss that by saying things like ‘the frame stiffness doesn’t matter when you’re riding on 43 mm tires’, which is right up there with ‘weight doesn’t matter on a gravel bike’.”

The outcome for the LS, according to Shrive, is a bike that’s more than strong enough for the intended purpose, but is one that offers a degree of comfort and a paltry low weight. 

Perhaps assisting with that outcome is the fact that this gravel race bike all but ignores aerodynamic design. Yep, Shrive, whose resume includes time as Cervelo’s head of engineering, believes aerodynamics in gravel bike design is somewhat overrated. 

The LS may offer a number of elements that other brands would market as aero features, but efficiency in smoothing airflow wasn’t Factor’s intention here.

“The reality is that at normal gravel speeds, (less than 40 km/h) the Reynolds number starts to get so low that regardless of your aerofoil shape you’re not very likely to get any kind of attachment,” Shrive said. “Those Reynolds numbers pretty well represent the ‘energy’ in the flow stream, and the realistic evaluation of a bike and rider grinding along a gravel road shows that honestly it probably won’t make any difference if the down tube resembles some kind of NACA profile.

“There might be some fringe cases where a fully aero gravel bike would help, but to be honest, we feel the rider is better off by us keeping the frame weight down as low as possible. I don’t want to undermine people that are putting aero features on gravel bikes, but when we looked at the relative outcomes we just felt that lower weight would be a net benefit for the rider.“ 

So far the LS just sounds like a road bike, but there are a few key differences. The seatstays of the LS differ: they’re thin, bowed and dropped whereas the O2 takes a more classic path. Meanwhile the chainstays have been pinched tight to accept up to 700 x 43 mm rubber. That’s not a huge amount of room for a fresh gravel bike, but it’s arguably enough for the sportier nature of this machine and Factor has achieved that without resorting to any odd component fitments or long chainstays. And what about 650B? Well, *shrug emoji*.  

A 41.5 mm-measured tyre and room for a big mud cake.
And it’s a similar story out the back.

Similarly, Factor has added a few more mounting points compared to on its road bikes, although you should certainly look elsewhere if you’re wanting to carry a week’s worth of dried food. There are three water bottle mounts (one of which is under the down tube) and a set of bolts for a bento box at the top tube. Additionally, there are subtly placed fender mounts front and rear. And according to Factor, the more open frame shaping within the main front triangle was done to optimise room for a small frame bag.

Performance-focussed geometry 

Factor has clearly intended the LS to fit and feel familiar for the road rider, and as a result, the reach figures across the five frame sizes are comparable to what Factor uses in its performance road range. Meanwhile, the stack numbers earn approximately 20 mm of relaxation and are better compared to some of the sportier endurance road bikes on the market such as the Cervelo Caledonia, BMC RoadMachine, and Canyon Endurace. Or when speaking specifically of gravel bikes, the LS is actually a little more upright than the popular Cervelo Aspero and is closely comparable in stack to the Santa Cruz Stigmata.  

That stack height is also somewhat adjustable, with Factor supplying two different-height headset top caps (5 and 20 mm) and a number of matching spacers for an integrated look. 

Factor has optimised the bike with 700 x 40 mm rubber in mind, and as a result the bottom bracket height has been dropped to 76 mm, while the rear centre length has grown out to 420 mm. 

Up front the head angle is slackened off by approximately a degree (71.9º for a 52 cm) from an equivalent road racer, while the 50 mm fork offset used across all frame sizes helps return the trail figure to a fairly neutral 62 mm figure (with a 40 mm tyre). 

Many of these figures are extremely close to what a road-going bike like the Cervelo Caledonia employs, and it shows the LS is quite ready to receive some 30 or 32 mm slicks and prance around like it’s a road bike. 

“Philosophically, we believe that a larger diameter tyre (even when sagged at normal pressures) increases the trail to the point that there is no compelling reason to further increase the trail by way of head tube angle and rake just because it’s on a gravel bike,” explained Shrive of the fairly traditional front-end angle on such a new bike. 

The Ostro VAM road bike made it clear that Factor believes in using multiple fork offsets across a size range. However the LS shares the same fork for all five frame sizes.

“Having had the privilege of working with many pro athletes, and having built and worked on many Roubaix ‘special’ bikes, one of the most compelling takeaways has always been that professionals do not want a docile-handling bike for the cobbles – they want a fast-handling bike so they can hop on wheels, dodge potholes, and make moves when it counts. We’ve applied this same thinking to the LS, a fast bike for a discerning rider.”

That “fast bike” approach also applies to the relatively tight wheelbase length which measures less than a metre on a 52 cm. 

Choose from a frameset or a single build kit 

Factor is big on selling framesets; a bare LS frame, fork, and headset sells for US$2,700 / £2,208 / AU$4,155. Now that’s not small money by any means, but it’s not excessively expensive when put up against a number of premium carbon gravel options. In fact, the pricing puts the LS directly in the middle between a Santa Cruz Stigmata CC and a 3T Exploro RaceMax. 

After a whole bike? Factor offers just the one. It features a full SRAM Force AXS Wide groupset and a long list of carbon components from Factor’s sister company Black Inc. It’s priced at US$6,999 / £5,832 (approx. AU$9,000 at the time of publishing).

Factor offers a single build kit option for the LS.

Those Black Inc components include a carbon seatpost and the one-piece carbon handlebar and stem that’s identical to what Factor equips on some of its road bikes. And that road-going handlebar certainly aligns with the LS’ approach of bringing a road attitude to gravel. 

While you can’t change the model of handlebar supplied, it’s worth noting that Factor does allow you to specify the sizing and fit of these components. You get a choice in seatpost set-back, crank length, handlebar width, and stem length. 

Our tester was shipped with SRAM’s equivalent of compact road gearing. The production spec features new SRAM Force Wide gearing (11-36T cassette paired with 43/30T chainrings. The ideal gearing will depend on where you live and how you plan on using this bike.

The rolling stock is Factor’s newly updated Thirty wheelset which offers a hooked rim design and a 21.45 mm internal rim width. These shallow aero wheels feature a fairly wide 30.3 mm external profile and tip the scales at 1,529 g including tubeless tape and valves. 

Factor supplies the bike with Goodyear’s Connector 40 mm tyres, which I actually found to be a great match for this bike prior to switching over to my more familiar Continental Terra Speeds which I’ve spent a bunch of time on since our first Field Test in Sedona

All up my 52 cm sample weighed 7.98 kg (17.6 lb) without pedals. It’s worth noting that the model I tested had a pre-production specification with a regular SRAM Force AXS group, and so the Wide group is likely to add a few grams. However I can attest that the small weight gain of the wider-range gearing is worth it as I was regularly seeking an extra gear or two when tackling off-road steeps. 

The ride

It doesn’t take many pedal strokes before the LS’ character shines through. As you may expect, the LS pretty much feels like a well-balanced road bike that’s had some fat tyres shoved into it. And that’s not necessarily a bad thing. Hear me out.

Even with tyres measuring 41.5 mm (Goodyear Connectors – the Conti Terra Speeds measure closer to 39.5 mm) the handling remains obviously quick and those coming from a more race-orientated road bike or even a cyclocross race bike will feel right at home here. With minimal input, you really can carve a tight turn or rapidly change direction with such a tight wheelbase as this. 

The LS feels great on well-kept gravel roads.

That whippy feeling only becomes even more lively as you narrow the tyres, and I was pretty impressed with just how good this bike felt with 32 mm slicks fitted. Here the trail figure reduces to the 60 mm range, and it’s only the slightly elongated wheelbase and taller front stance that keeps you from thinking this is a dedicated tarmac ripper. 

However, do be aware that such quick handling comes with compromise. The LS will inevitably become skittish as soon as the terrain descends steeply and/or on a poor surface. Similarly, the extremely noticeable amount of toe overlap (at least with 40 mm tyres) is enough to tell you that Factor didn’t intend this bike for the sort of singletrack doodling some other gravel bikes manage. And this bike is never going to handle amazingly once loaded down with bikepacking bags (although that’s certainly not the intention here).

Efforts of athletic greatness are rewarded in a familiar way to how a lightweight road race machine responds. The cranks feel directly attached to the rear hub and the bike’s front end also doesn’t waver when you’re reefing on the bars. There are many bikes that are stiffer again, especially through the length of the front triangle, but I admire the balance that Factor has managed to strike and I feel it shows the company is maturing in its designs.   

The LS strikes a balance of being stiff enough without pushing it too far.

And while our comments in the video above may make it sound like the frame is stiffer than a fresh breadstick, that’s not fully the case. Those skinny fork blades, a smaller 1 3/8″ lower headset bearing, the 27.2 mm seat post, and the general pared-back frame design all add up to a bike that is stiff enough to feel superbly efficient but not enough to moonlight as a jackhammer.

The LS actually offers a controlled feel that seems to hum effortlessly along over road and smoother gravel grades of 1, 2, and to a lesser extent 3. However, and as my fellow tester Andy van Bergen noted, that compliance finds its limits pretty quickly once the ground gets choppy. Hit a square-edged object fast enough and the frame’s stiffness will be hammered home.

In my opinion nothing defines this bike better than the one-piece handlebar Factor fits to its complete bikes. It’s the same aero-shaped cockpit used on a number of its road bikes, and offers no obvious flare. Clearly Factor intends the LS to feel like a road bike or a sporty all-road bike, and this handlebar goes a long way to making that so. 

Black Inc’s one-piece handlebar is a good indicator of the type of rider this bike is aimed at. Roadies rejoice!

As an added bonus, that handlebar isn’t overly stiff like some other one-piece cockpits. Rather, the flattened shaping of the Black Inc bar offers a subtle amount of forgiveness that further adds to the bike’s ability to quieten the terrain. 

Factor builds its complete bike option with 2×12 gearing, but it’s worth reiterating that this frame can be set up however you choose. This wouldn’t have been anything special 2-3 years ago, but such wide compatibility is slowly becoming harder to come by as more gravel bikes move to 1x-only designs. Similarly the ability to fit just about any seatpost (albeit held with Factor’s own integrated wedge clamp) and stem/handlebar of your choosing remains nothing but a benefit. 

Keen to add a more flexible seatpost from the likes of Canyon, Syntace or Ritchey? Yep, the LS will allow it.

That all said, there is one fitment area that doesn’t spark as much joy and it wasn’t long until my sample developed a knocking sound between the cranks. Yep, it’s the press-fit bottom bracket. 

Rob Gitelis, the owner of Factor has been pretty vocal in recent years that press-fit bottom brackets are the best choice for performance bicycles when made to proper manufacturing tolerances. And Factor even goes so far as to supply its bikes with high-end CeramicSpeed press-fit bottom brackets. That’s all well and good, but personally, I feel that a threaded bottom bracket system is more appealing on a bike that’s destined to get filthy.

Interestingly, the spec on the company’s latest bike, the Ostro VAM, was changed last-minute to include an asymmetric version of a T47 threaded shell. According to Factor, it was done purely as a result of market pressure (consumer demand), and so I’m hopeful that the market will force a similar change for the LS in near time, too. Such a move will add about 50 grams to the bike and I’d be fine with that. 

The CeramicSpeed bottom bracket made some moaning sounds. Some retaining compound solved the issue, but I’d prefer to see threads.

And if I haven’t made it clear just how road-bike-like this gravel bike is, there’s one more point on this matter. The light frame offers a noticeable lack of external protection and reinforcement for fending off rock strikes or similar. I had the same complaint of the Chapter2 AO I reviewed in 2020, and certainly, the sound of a stray rock to the down tube will leave you feeling ill with worry. 

Factor provides a five-year warranty with its frames, but such rock strikes won’t be covered. Thankfully the company does offer a generous crash replacement policy which adds some comfort to the feathery build of this machine.

Putting the road in groad 

Recent years have seen a number of gravel bikes trend into the territory of old mountain bikes, but the LS certainly isn’t among them. This isn’t a freedom or exploration tool. It just feels too light, almost too delicate, to be a bike that you can take everywhere without a damn. 

Rather this bike holds true to where many gravel machines began by effectively tweaking cyclocross race bikes to make them better at covering straighter and rougher terrain across greater distances. 

James Huang and I previously criticized the Santa Cruz Stigmata for being a little vanilla for its price tag, and in many ways, the Factor LS is guilty of much the same. The LS isn’t groundbreaking and doesn’t set any trends, but its ride quality and low mass offer a subtle improvement over many other comparable bikes. 

We’ve previously applauded the Cervelo Aspero for being the right sort of gravel bike if you’re wanting to trade in your road racer. And there’s no doubt that the lighter and subtly more comfortable (albeit more expensive) Factor LS deserves similar praise. This really is a great mixed terrain bike that performance-focused riders will get a kick out of.

It’s a crowded market and there are a number of more-daring options within this premium price bracket, but the LS shows there’s always room for simple design done well.



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