Aluto
vsLS
Two Factor gravel bikes, two definitions of fast.
The Aluto is the road-centric generalist with 47 mm clearance. The LS is the older, lighter, race-focused weapon that rides like an O2 with knobs.
Aluto
- Wider tire clearance — 47 mm rear, 52 mm front opens up rougher routes the LS can't touch.
- Thoughtful service standards — T47a threaded BB, 27.2 mm round seatpost, SRAM UDH. Easy to live with.
- Configurable cockpit at checkout — Cyclingnews counted ~20 Black Inc HB05 bar/stem combos plus crank length options.
- 1x SRAM XPLR only — no 2x road option, and the stock 44T can feel over-geared on steep climbs.
- Downtube storage is consistently called 'useless' by reviewers — too small for a mini-pump or CO2.
LS
- Featherweight frame — a 950 g frame, ~7.95 kg complete builds, makes the LS one of the lightest gravel bikes around.
- Doubles as a road bike — optimized 2x builds and 32 mm slick compatibility make it a genuine quiver-killer.
- Drivetrain choice — ships in 2x SRAM Force, 2x Shimano Ultegra Di2, or 1x SRAM Force XPLR.
- 40–43 mm max tire clearance limits it to faster, smoother gravel.
- Stiff race-bred chassis is, in Cyclingnews's words, 'unapologetically jarring' on chunky terrain.
Editor’s analysis
Same brand, same Black Inc cockpit, same Toray carbon — but two different answers to the question what is a gravel bike for?
Factor only sells four drop-bar bikes. Two of them are gravel: the Factor LS, the 2020 race machine that put the road in 'groad,' and the Factor Aluto, the 2026 generalist that walked back just enough of the LS's edge to make it livable. They aren't replacements for each other — they're Factor's bookends on what a fast gravel bike can be.
The Factor LS is the older, sharper tool. A 950 g frame, geometry traced almost directly from the O2 VAM road bike, 40–43 mm tire clearance, and a 71.9° head angle paired with a 60 mm trail at size 52. Velo called it 'a no-holds-barred gravel racer.' Cyclingnews went further: 'a razor-sharp instrument designed for the racer, not the Sunday rider.' It will hum at 40 km/h on smooth dirt and feel like a road bike with knobs. It will also beat you up on chunky surfaces and run out of clearance the moment the route gets serious.
The Factor Aluto keeps the racing DNA but loosens it deliberately. Same 71.9° head angle at size 52, same 420 mm chainstays, but trail grows to 61.8 mm, the bottom bracket drops, and clearance jumps to 47 mm rear / 52 mm front. Reviewers describe it as 'snappy, sharp,' 'eager,' and 'road bike-like' — but on a wider envelope of terrain. The trade-off: it's only sold as a 1x SRAM XPLR build with a 44T ring, which Cyclingnews flagged as 'a little over-geared' on steep climbs.
Put another way: the Factor LS is what you buy when your gravel rides are basically road rides on dirt and you also want one bike that takes 32 mm slicks for a crit. The Factor Aluto is what you buy when you'd like that same lively road-bike feel on a wider menu of surfaces, and you've made peace with running 1x.
Where the builds differ.
Comparing our editor's-pick builds side-by-side. Winners highlighted row-by-row — lower price and weight, and the better-spec component, each mark a point.
Build variants & pricing
The Aluto is 1x XPLR only — Force or Red. The LS spans 2x road builds plus a 1x XPLR variant, all on the same frame.
Prices are current US MSRP. Both bikes are offered frameset-only (Aluto from $3,999; LS from $2,700) for custom builds. Editor's-pick column compares the matched 1x SRAM Force XPLR build on each side — same drivetrain, same wheels, same cockpit family, frame and clearance do the talking.
How they fit, how they steer.
Both at size 52 — the fit-picked frame for a 5'8" rider on each. Identical 71.9° head angle and 547 mm stack. The Aluto runs 7 mm more reach (385 vs 378), 1.8 mm more trail, and a slightly longer wheelbase (1002.5 vs 998 mm) — small numbers, but they push the Aluto a touch more planted, the LS a touch quicker.
Which size should I buy?
Sizing follows stack, reach, and effective top tube. The two ranges line up almost size-for-size at the small-to-mid end; the Aluto extends one size further at the top with a 61.
→These are starting points. Flexibility, riding style, and preferred position all shift the answer — if you’re between sizes, a professional fit beats a chart.
What the magazines said.
Published reviews from trusted cycling outlets. Click through for the full write-up.
Which one should you buy?
If your gravel rides regularly hit 45 mm tire territory, get the Aluto. If your gravel is fast smooth dirt and you'd also like one bike for the road, get the LS.
Aluto
If your gravel is a mix of pavement, champagne dirt, and the occasional Cat-1 chunk, the Aluto delivers that lively Factor feel on a wider envelope of terrain. The 47 mm clearance and lower bottom bracket make it the more usable of the two — provided you're happy on 1x.
LS
If your idea of gravel is fast smooth dirt and you want one bike that also takes 32 mm slicks for a road race, the LS is the sharper instrument. Lighter, stiffer, more drivetrain options — but you accept 43 mm max rubber and a firmer ride when the surface gets rough.
Questions buyers actually ask.
Short answers to the things we get emailed about most often.
01Which one fits wider tires?
The Factor Aluto, by a comfortable margin. Factor publishes 47 mm rear and 52 mm front clearance on the Aluto, vs 40–43 mm on the LS.
In practice, that's the line between 'this can handle Cat-2 gravel and the occasional Cat-3' and 'this is happiest on Cat-1 smooth dirt.' Reviewers were clear that pushing the Aluto past 47 mm rear risks paint rub at the chainstays, so 47 mm is a real ceiling, not a marketing one.
02Which is lighter?
The Factor LS, noticeably. The LS frame is a published 950 g and complete builds come in around 7.95–7.98 kg in reviewer testing. The Aluto is heavier overall — Velo measured a complete Aluto at 8.9 kg in size 56.
That's roughly a kilogram of difference at the complete-bike level, most of it in the frame. On long climbs, you'll feel it.
03Why doesn't the Aluto come in a 2x build?
Factor positions the Aluto exclusively as a 1x SRAM XPLR platform — Force or Red, both with power meters, both running a 44T chainring. It's a deliberate choice tied to the bike's gravel-first identity.
If you want a 2x drivetrain on a Factor gravel frame, the LS is the only option in the lineup — it ships in 2x SRAM Force AXS or 2x Shimano Ultegra Di2 in addition to a 1x SRAM Force XPLR variant.
Reviewers did flag that the Aluto's stock 44T ring can feel over-geared on steep climbs, particularly for less-fit riders or bikepacking loads — Cyclingnews and the YouTube reviewer both swapped or wished they could swap to a smaller ring.
04How do they compare on geometry at the same size?
At size 52, the head tube angle is identical (71.9°) and the stack is the same (547 mm). The differences are in the bookkeeping:
- Reach: Aluto 385 mm vs LS 378 mm — the Aluto is 7 mm longer.
- Trail: Aluto 61.8 mm vs LS 60.0 mm — Aluto is slightly more relaxed.
- Wheelbase: Aluto 1002.5 mm vs LS 998 mm.
- Chainstays: identical at 420 mm.
Small numbers, but the direction is consistent — the Aluto is a touch more planted, the LS a touch quicker. Both are still firmly on the agile end of the gravel spectrum.
05Is the bottom bracket threaded on both?
On the Aluto, yes — it ships with a T47a threaded bottom bracket, which reviewers consistently called out as a service-friendly win.
The original LS launched with a press-fit bottom bracket (which Velo's long-term test sample developed creaks on). Recent LS spec sheets now list a T47A bottom bracket, so current production units appear to have made the switch. If this matters to you, confirm with Factor or your dealer at point of sale that the unit shipping is the threaded version.
06Can either one double as a road bike?
The LS is explicitly designed for it — Velo and Cyclingnews both noted it 'feels great' with 32 mm slicks fitted, and the 2x Shimano Ultegra Di2 build with a 52/36T crank is configured exactly like a road bike.
The Aluto can technically run skinnier rubber, but it's only sold as 1x SRAM XPLR with a 44T chainring — gearing that's pure gravel, not road-race friendly. Factor's pitch for the Aluto is gravel-first; the LS is the dual-purpose machine.
07What's the deal with the Aluto's downtube storage?
It exists, and reviewers did not love it. Cyclingnews flatly called it 'basically useless' — the internal cable trunking eats most of the cavity, leaving no room for a mini-pump or CO2 canister. The same review reported the door rattled and needed electrical tape.
Velo described the storage as having 'limited space,' useful only for a TPU tube, tire levers, and a plug kit. If you rely on frame storage for tools, plan to use a top tube or saddle bag instead. The LS skips downtube storage entirely and offers top tube bento mounts.
08Which is the better value?
Apples-to-apples on the matched 1x SRAM Force XPLR with power meter build, the LS is $600 cheaper ($6,599 vs $7,199 for the Aluto). Same drivetrain, same Black Inc Thirty-Four wheels, same Black Inc integrated cockpit family.
What you're paying $600 more for on the Aluto: 4–9 mm of extra tire clearance, a slacker bottom bracket, the threaded T47a, and the newer frame design. Whether that's worth it depends entirely on whether you'll actually use the wider clearance — if you mostly ride smooth gravel and road, the LS is the harder bike to argue against.
Similar bikes
If your priorities don’t map cleanly onto either of these, one of these adjacent bikes probably fits better.
Crux
The Aluto's most obvious cross-shop — Cyclingnews compared them directly. Same skinny, do-it-all gravel philosophy and the same 47 mm clearance, often at a similar price for an equivalent build.
Compare →
Ostro Gravel
Factor's specialist alternative — the aero-tubed gravel racer the Aluto deliberately walked back from. If you only ride smooth, fast courses and want every watt back, this is what David Millar would point you to.
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Aspero
Cervelo's answer for the same road-bred gravel racer the LS targets. Race-focused geometry, fast handling, and the kind of bike that rewards a roadie's instincts on dirt.
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