A 900g frameset and Black Inc. finishing kit target all out speed
(Image credit: Factor)
The new Factor Ostro Gravel isn't the brand’s first foray away from tarmac. It already has what it calls THE gravel race bike (a title which, one assumes, will be transferred to the Ostro) in the LS model, and the Vista, which is more of an endurance road bike with some gravelly capabilities.
Taking the name of the brand’s do it all, aero road bike and tacking ‘gravel’ onto it does give you some indication of the stated aims of the new Ostro Gravel; speed, winning gravel races, and finally some more speed. Gravel racing appears to be here to stay, and this is a gravel race bike with its sights set firmly on the top step of the podium.
The Factor Ostro Gravel is attuned to fast courses (Image credit: Factor)
UCI legality
The little UCI sticker, tucked away at the top of the seattube on every UCI legal bike, is something that’s easy to miss, and until recently it was something not overly necessary for bike companies to consider when making a gravel bike. Now though, with UCI sanctioned gravel races it is a prerequisite for entry, and given the Factor LS isn’t UCI legal if the brand wants to compete then it had to either re-engineer the LS or create a new bike, and evidently they chose the latter option, leaving the LS as more of a do it all model by comparison.
Performance details
While low weight has taken a back seat in recent years to aero optimisation, having a sub-kilogram weight for the frameset is certainly up there with the best gravel race bikes. It also indicates there is little additional spare carbon kicking about for load carrying; no fork bosses, but there are double sets for a bolt-on top tube bento box and on the downtube for what Factor described as an ‘E.coli catcher’, or a third bottle for you and I.
While 900g is feathery for a gravel frameset (in the ‘Naked Grunge’ paint option - essentially raw with some splashes), there is still material enough to sculpt the tubing into the prerequisite aero optimised shapes, and the DNA of the OSTRO VAM is pretty clear to see, creating what Factor claims as ‘class leading aerodynamics’. The headtube is particularly deep, more akin to the best aero road bikes than those attuned to the rough stuff, with the usual truncated aerofoils on the downtube and seattube too. It stopped short of a hinge-based headtube, opting instead for a round steerer and more standard headset for strength, with the spacer stack being aero optimised to offset any downsides from round leading edges.
The Factor Ostro Gravel has already been used in the biggest gravel races on the calendar (Image credit: Factor)
Tyre size and the dreaded wheel flop
With the usually slacker head angles and correspondingly higher trail figures that usually set gravel bikes apart from their road counterparts the front wheel can flop over at low speeds. It’s excellent for more sketchy descents, but does play with the handling on slower climbs. With this in mind Factor has opted for a slightly steeper than ‘normal’ head angle of 71.2-72.3 degrees, depending on the size, with two offsets to the fork also depending on size. The aim is to keep the front end super snappy when using the maximum 43mm tyre size.
This also has a compound benefit of creating a handling package more akin to an endurance road bike, something Factor are keen to promote as a clear secondary use case for the Ostro Gravel.
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White it is a gravel bike, the Ostro Gravel is also aimed at endurance road too (Image credit: Factor)
Black Inc. finishing kit
A best in class aero frameset is one thing, but without the right build it’ll still be hamstrung. Factor’s in-house component brand Black Inc. takes care of proceedings, providing a new wheelset, the Thirty-Four, optimised for tyres larger than 30mm. Hookless, with hubs housing Ceramicspeed bearings we assume an internal width around the 22mm mark, but this is as yet unconfirmed.
A new, lightly flared, integrated bar-stem combo is also fitted, and features internal routing for brake hoses, as well as a computer mount based on the Go-Pro mounting system to better handle the added load of things like bike lights and action cameras that so often get slung under a computer. Given the performance aspirations it’s not a surprise to see the Factor Ostro Gravel is electronic only, and saying it’s also disc only does kind of go without saying at this point.
A clearly aero-optimised fork, and the 'Naked Grunge' is essentially raw carbon with some flourishes (Image credit: Factor)
Build options and pricing
The Factor Ostro Gravel is available in either the aforementioned Naked Grunge, or the slightly heavier White Grunge, and in a series of build and semi-build options.
The frameset is available, including the fork, seatpost, bar-stem, Ceramicspeed T47A BB and Ceramicspeed Headset, for £4,730/$5,499/€5,450, while a rolling chassis option is available as the frameset but with the Black Inc. Thirty-Four wheels for £6,450/$7,499/€7,430.
Full builds are available too in SRAM only as follows:
Will joined the Cyclingnews team as a reviews writer in 2022, having previously written for Cyclist, BikeRadar and Advntr. He’s tried his hand at most cycling disciplines, from the standard mix of road, gravel, and mountain bike, to the more unusual like bike polo and tracklocross. He’s made his own bike frames, covered tech news from the biggest races on the planet, and published countless premium galleries thanks to his excellent photographic eye. Also, given he doesn’t ever ride indoors he’s become a real expert on foul-weather riding gear. His collection of bikes is a real smorgasbord, with everything from vintage-style steel tourers through to superlight flat bar hill climb machines.
