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Factor O2 VAM SRAM Red eTap AXS review

Outstanding climbing performance delivered by a near-spotless build

Our rating 
4.0 out of 5 star rating 4.0
GBP £11,800.00 RRP | USD $11,799.00 | EUR €11,349.00 | AUD $18,990.00
Pack shot of the Factor O2 VAM SRAM Red AXS road bike

Our review

Although the O2 VAM isn’t flawless, it packs an enticing punch with its premium specification and price
Pros: Light; very stiff and responsive; excellent wheelset for climbing; good compliance and ride stability
Cons: Expensive; clincher tyres don’t maximise performance with wheelset; one early quality issue
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The Factor O2 VAM is the brand’s dedicated lightweight race bike, and it was subject to an update this summer.

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The bike, which was ridden by Israel-Premier Tech at the 2023 Tour de France, is claimed to cut the aerodynamic difference between the Ostro VAM aero bike and the previous O2 VAM.

Meanwhile, a reprofiled frame, a new lightweight seat mast design and the use of a new lightweight Black Inc wheelset all combine to produce a UCI weight limit-troubling build.

It sounds like a climber’s dream, and on that score at least, it’s breathtakingly good.

It also has a considerate ride position, handles sharply and feels surprisingly comfortable without feeling unduly hampered on the flat.

While my sample bike had a quality control issue worth noting (we’re told this has been remedied for all bikes going on sale), the O2 VAM is a highly impressive, almost no-expense-spared high-performance race bike.

Factor O2 VAM SRAM Red eTap AXS frame

Factor O2 VAM SRAM Red AXS road bike
The new O2 VAM is said to cut the aero difference between the old O2 VAM and the Ostro VAM.
Russell Burton / Our Media

According to Rob Gitelis, CEO of Factor, the latest O2 VAM was developed to be “a bike pro riders would use”.

He’s alluding to the fact that, like many professional teams and riders, the performance dial has long since swung towards optimising aerodynamics over squeaking over the UCI weight limit.

The fact that the vast majority of 2023 Tour de France bikes were significantly over the 6.8kg UCI weight limit speaks for itself, while in recent times Gitelis says Israel-Premier Tech riders would usually opt for the Ostro VAM aero bike over the old O2 VAM – even in the mountains.

The new O2 VAM has a completely redesigned frame, which Factor says was the result of its “unique” development process.

While shallow tube shapes are the main order of business, the brand says it has employed NACA (National Advisory Committee for Aeronautics) profiling to improve its aerodynamic prowess, alongside a slimmed-down headtube.

Factor O2 VAM SRAM Red AXS road bike
Shall we start with the seat mast, or that heavily tapered top tube?
Russell Burton / Our Media

The top tube tapers to just 10mm wide as it meets the extended seat tube, over which fits a new external, sleeved seat mast.

The brand says it uses a combination of high-modulus Toray T1000, pitch fibre, pan fibre, M60J and TeXtreme carbon, with as much excess material cut from the frame as possible.

This results in a claimed 730g frame weight in a size 54cm, including the seat mast and paint, while Factor says it’s just 5 watts worse off than the Ostro VAM in a wind tunnel at 48kph (across yaw angles of +/- 15 degrees).

Compared to the previous O2 VAM, it’s said to be around 35 per cent stiffer, accounting for frame size variances.

The frame can officially accommodate road bike tyres measuring 32mm wide (as opposed to all nominal 700x32mm tyres) and sports a T47A threaded bottom bracket.

The headset uses CeramicSpeed’s SLT (Solid Lubrication Technology) tech, around a proprietary mix of 1-1/8in and 1-3/8in bearings designed to accommodate a Black Inc Integrated Barstem cockpit.

Factor O2 VAM SRAM Red eTap AXS geometry

Factor O2 VAM SRAM Red AXS road bike
The bike’s setup, including hood placement, looks geared towards climbing. This, of course, can be modified.
Russell Burton / Our Media

Unsurprisingly the O2 VAM has a geometry befitting a WorldTour race bike.

In my size 56cm test bike, a steep 73.3-degree head tube angle is married to a 58.6mm trail.

The head tube angle especially helps to keep handling sharp, while Factor has aimed to preserve the trail figure as consistently as possible to keep the same behaviour regardless of size.

The 73.5-steep seat tube angle aims to pitch the rider forward over the bottom bracket. In theory, this should help with optimal power delivery as it helps to open the hip angle.

Male cyclist in purple top riding the Factor O2 VAM SRAM Red AXS road bike
The bike has a racy, but not too aggressive, fit.
Russell Burton / Our Media

The 389mm reach is compact compared to a 56cm Canyon Ultimate CFR (401mm) and Specialized Tarmac SL7 (398mm), which are both pitched as all-rounders rather than dedicated climbing bikes.

The Orbea Orca is more similarly focussed as a lightweight climber, but it’s also a bit longer at 398mm in a size 57 and 391mm in a size 55.

The O2 VAM’s 574mm stack is right in the ballpark of the Orca’s measurements, too. This should keep the front end sensibly tall for those who require it.

Stack (mm)502514535552574597611
Reach (mm)360367373381389401410
Head tube length (mm)109117134154172196211
Rear centre (mm)405405405405405408412
Front centre (mm)574573573587587608621
Wheelbase (mm)9709699719859821,0061,022
Bottom bracket drop (mm)72727270707072
Seat tube angle (degrees)75.574.5747473.573.573.5
Head tube angle (degrees)71.171.772.572.573.373.373.3
Top tube length (effective) (mm)493510527539557578591
Seat tube length (mm)405425465495525545570
Fork length (mm)368368368368368368368
Fork offset (mm)57534848434343
Trail (mm)5858585858.658.658.6

Factor O2 VAM SRAM Red eTap AXS build

Factor O2 VAM SRAM Red AXS road bike
SRAM Red eTap AXS awaits an update following recent update to Force AXS.
Russell Burton / Our Media

As has become customary with Factor bikes, the build leaves practically no stone unturned in the search for efficiency.

My test build featured a SRAM Red eTap AXS groupset and tipped the scales at 6.63kg, without pedals or a bottle cage.

The groupset has 48/35-tooth chainrings, married to a 10-33 tooth cassette, delivering more than enough range for the vast majority of climbs.

With the recent arrival of a new SRAM Force AXS, with notable improvements to shifter ergonomics alongside other positive tweaks, I’d be hesitant to opt for a Red AXS-built O2 VAM at the current time, if I wanted to feel sure that I had the best SRAM can offer for years to come.

That said, it performed just like a top-end groupset should, with slick shifting and impressive (albeit squealy when wet) braking.

Elsewhere, the finishing kit is a mix of Factor, Black Inc and CeramicSpeed components.

Factor O2 VAM SRAM Red AXS road bike
The Black Inc integrated barstem is well-shaped; the tops are well-profiled to grasp for long periods.
Russell Burton / Our Media

Fundamental to the bike’s design is the carbon seat mast, which slides over the seat tube and is clamped externally.

Factor says it’s available in three lengths for different frame sizes, with zero and 25mm setback variants. My test bike had the zero setback model.

It’s unlikely that many will need to stray away from the standard recommended lengths for each frame size (each one offers 30mm adjustment once fitted), but Factor says customers have free choice of setback.

This swapping policy applies to the Black Inc Integrated Barstem, too. The stem is available in 19 size variants, ranging from 38cm wide with a 90mm long stem, to a 44cm/130mm configuration. This turns on CeramicSpeed SLT ceramic bearings.

The bottom bracket is also a CeramicSpeed model.

Factor O2 VAM SRAM Red AXS road bike
A CeramicSpeed bottom bracket makes its presence known – at least visually.
Russell Burton / Our Media

The bike rolls on a Black Inc 28//32 carbon wheelset, which is designed to complement the frame. Aside from the wheel-less frame kit, every O2 VAM is shipped with a set.

The wheelset has 23mm internal and 28.5mm external rim widths and uses a mini-hook design to preserve clincher compatibility. That said, it’s designed to work optimally with 28mm tubeless tyres.

The rims are laced via Black Inc Aero carbon spokes, with an offset spoke bed intended to better balance spoke tension, according to Factor. The freehub features a 36-tooth clutch ratchet mechanism for fast engagement, while it spins on CeramicSpeed bearings, too.

The shallow 28mm front and 32mm rear rim depths help contribute to the wheelset’s low 1,146g claimed weight.

All bikes come with Goodyear Eagle F1 R clincher tyres, and a Selle Italia SLR Boost Superflow saddle.

Factor O2 VAM SRAM Red AXS road bike
The seat mast offers a decent amount of adjustment.
Russell Burton / Our Media

Given the Black Inc wheelset is designed to work best with tubeless tyres, I’d have preferred a set to be fitted from the get-go (the Eagle F1 R TLR is among the best all-round performance road tyres available today).

All-in, the O2 VAM is a costly purchase at £11,800/$11,799/€11,349/AU$18,990.

While the bike has a heady pro-level build, it’s a shame not to see a power meter installed for this kind of money. You need to spend another £400/$400/€350/AU$700 for the same build with a Quarq power meter, while equivalent Shimano builds don’t include one at all.

If your heart is set on an O2 VAM and you need a power meter, the recently-updated SRAM Force AXS with power meter model is arguably a smarter choice at the time of review, at £10,100/$10,099/€9,699/AU$16,290.

Meanwhile, the latest Orbea Orca OMX with a comparable SRAM Red AXS build costs a similar £11,999/$11,599/€10,999, including said wattage measurer.

Factor O2 VAM SRAM Red eTap AXS ride impressions

Male cyclist in purple top riding the Factor O2 VAM SRAM Red AXS road bike
The O2 VAM is outstanding on climbs.
Russell Burton / Our Media

The Factor O2 VAM feels like a precision tool – its strength lies firmly when the road heads upwards.

On steeper ascents especially, it’s superlative. The overall sense of responsiveness and efficiency is very impressive.

Of course, this is as much down to the performance of the high-spec component ensemble as it is down to any one factor (pun intended).

Starting with the frame, the geometry felt perfectly suited to riding up a long climb. I felt well-positioned over the bottom bracket, while the stack height was tall enough that resting on the bar’s well-profiled tops was easy for long periods.

It was also noticeably comfortable, dealing with the road buzz very well yet providing an informative ride.

Factor O2 VAM SRAM Red AXS road bike
The Goodyear Eagle F1 R clincher tyre is very good, but I’d prefer to see a tubeless version off the bat.
Russell Burton / Our Media

The bike whipped left and right when I attacked steep rises in the road almost without a hint of flex, ably backed up by the Black Inc wheelset.

The wheelset also feels purpose-built for getting up hills, although I sense that a deeper section rim might be more efficient on faster uphill drags because aero efficiency will have a stronger influence than weight savings on progress.

The O2 VAM certainly isn’t slow on faster and flatter terrain, but compared to the latest all-in-one race bikes that often come supplied with deeper rims, it doesn’t feel quite as rapid at 40-50kph.

If ultimate speed across varying tarmacked terrain from a single bike is what you’re after, I’m convinced a more aero-focussed all-rounder (or dedicated aero bike) would work out quicker.

Regardless, accelerating up to speed is notably easy (perhaps due to the use of ceramic bearings in the hubs and bottom bracket), while the truncated tubes and shallow rim dimensions combine to make the bike feel unperturbed by crosswinds.

Factor O2 VAM SRAM Red AXS road bike
The Black Inc hubs are notably loud.
Russell Burton / Our Media

In turn, once I’d adapted to the pin-sharp steering, I found this stability meant I could descend at speed without worrying about errant gusts of wind as much as usual.

Tallying up the impressive comfort and sensible geometry, I’d conclude that the O2 VAM would be on a shortlist of bikes I’d consider riding for a long mountainous sportive or a hill climb event in the UK.

My experience hasn’t been all roses, however. All four of my test bike’s bottle cage rivets came loose when the screws were unwound, with one falling inside the frame cavity and two others detaching but remaining attached to a partially-unwound screw.

Factor confirmed that it’s aware of the issue (which I’m told has been experienced elsewhere), blaming a run of rivets that were used on the “pre-production” test frames.

It says the issue has now been resolved for all O2 VAMs going on sale, although it’s always worth asking questions of your dealer for peace of mind when parting with such a large sum of money for a bike.

Factor O2 VAM SRAM Red AXS bottom line

Male cyclist in purple top riding the Factor O2 VAM SRAM Red AXS road bike
The Factor O2 VAM is a qualified success.
Russell Burton / Our Media

If your goal is to make climbing on a road bike as easy as possible, the Factor O2 VAM is one of the best money can buy today.

There’s no denying it’s expensive, but the frame kit packs in a near-no-compromise specification once you’ve settled on your preferred drivetrain.

In turn, the O2 VAM delivers a noticeably efficient-feeling experience, especially when riding at lower climbing speeds.

The rivet quality issue on my test bike shouldn’t be a problem for customers, but fitting clincher tyres on a wheelset designed to work best with a tubeless setup remains a notable niggle on such a performance-oriented and expensive machine.

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That aside, the O2 VAM is a qualified success.

Product Specifications


Price AUD $18990.00EUR €11349.00GBP £11800.00USD $11799.00
Weight 6.63kg (56cm)
Brand Factor


Available sizes 45, 49, 52, 54, 56, 58, 61cm
Bottom bracket T47A, threaded
Brakes SRAM Red AXS
Cassette SRAM Red AXS, 12-speed, 10-33t
Chain SRAM Red AXS
Cranks SRAM Red AXS, 48/35T
Fork O2 VAM, carbon
Frame O2 VAM, Toray T1000, pitch fibre, pan fibre, M60J and TeXtreme carbon
Front derailleur SRAM Red AXS
Handlebar Black Inc Integrated Barstem, carbon
Rear derailleur SRAM Red AXS
Saddle Selle Italia SLR Boost Superflow
Seatpost Factor O2 VAM seatmast, carbon
Shifter SRAM Red AXS
Stem Black Inc Integrated Barstem, carbon
Tyres Goodyear Eagle F1 R Tube Type, 700x28c
Wheels Black Inc 28//32