BMC’s Twostroke is a go-fast machine that doesn’t cost the earth

The Swiss company's latest XC race bike looks rapid, has smart features and might not blow the bank

The BMC Twostroke

BMC has released a brand new 29in cross-country race hardtail, the Twostroke, to sit alongside its full-suspension XC bike, the Fourstroke.

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The Twostroke will be offered in both aluminium and carbon, and is designed for the rigours of modern XC and marathon racing.

Six models will be available, ranging in price from €1,199 to €3,999, bucking the trend for super-pricey top-flight race bikes.

BMC Twostroke corners
BMC says it’s given the down tube and chainstays plenty of stiffness for effective power transfer.
Jérémie Reuiller / BMC

BMC Twostroke design

XC hardtail designers have a number of competing demands when it comes to designing a bike. They need to keep the bikes light and stiff, for the most effective responses to pedal inputs on punchy climbs, while also ensuring the bikes are able to cope with technical courses and keep riders fresh during long days out.

The old adage used to be that races were won on the climbs and lost on the descents, but BMC reckons nowadays races are won on both the climbs and descents, so bikes have to be as capable up as they are down.

In a slightly surprising move, BMC has moved away from the elastomer based softtail design of its previous XC hardtail, the Teamelite, instead opting for a traditional rigid frame.

With cross-country courses getting tougher and fast riders still demanding compliance from their bikes, BMC recognises the need for a compliant frame.

It says that modern frame design and construction methods, along with the latest generation of voluminous XC race tyres, give all the comfort and control needed on a hardtail, though.

BMC Twostroke tyre clearance
BMC says it’s given the frame plenty of clearance for wide tyres.
Jérémie Reuiller / BMC

BMC’s Twostroke concept was for a light, stiff and responsive frame that gives “explosive accelerations and precise handling” while still being up to the task of everyday racing and riding.

At the same time, it’s borrowed the ‘Tuned Compliance Concept’ from its road bikes for the Twostroke’s carbon frames, seeing a fine-tuning of the carbon layup to provide the ideal amount of vertical deflection.

This is realised through the chainstays, which are designed to give that vertical deflection along with the use of a D-shaped seatpost and seat tube, which BMC has found to aid fore-aft deflection, again boosting comfort.

BMC D-shaped seatpost
The D-shaped profile of the seat tube and seat post adds compliance.
Jérémie Reuiller / BMC

Alloy frames use a hydroformed, ‘smoothwelded’ construction method and come with a 31.6mm round seat tube.

Further reflecting the development of cross-country, BMC says that it’s given the Twostroke ‘radical geometry’ in order to allow you to hit the race course with the utmost confidence.

This effectively means slack head angles, 44mm short-offset forks, a steeper seat angle and short chainstays.

BMC Twostroke jumping
Reflecting the development of XC, the Twostroke has very contemporary geometry.
Jérémie Reuiller / BMC

BMC Twostroke frame details

The Twostroke certainly has a distinctive look, with the top tube and seatstays merging in to one continuous line.

BMC says that it’s removed unnecessary curves from the design and took aesthetic inspiration from the Lockheed Martin X-35 fighter jet, no less!

BMC Twostroke tube junctions
Aesthetically inspired by fighter jets, apparently!
Jérémie Reuiller / BMC

In another slightly surprising move, BMC hasn’t built the frame down to the sub-kilo weights we’ve seen from the likes of Specialized and Orbea, with a medium carbon frame coming in at a claimed 1,037g.

This is because BMC wanted the frames to be stiff and robust. This translates in to wide chainstays that are high in profile, along with a straight, oversized down tube to give torsional stiffness and strength.

The upper bearing of the headset measures 1.5in, which is stepped to accept a tapered fork steerer, reflecting the 1.5in bearing at the bottom of the headset.

Alloy frames come in at a claimed 1,850g for a medium.

BMC Twostroke finishing touches

The straight down tube means that in a crash the fork crown is likely to hit the down tube. As such, the Twostroke comes with an integrated fork stopper to prevent this from happening.

Frame protection continues further back, with an integrated chain-suck plate, chainstay protectors and a chain guide, along with helicopter tape pre-installed on the down tube.

BMC Twostroke top tube
The top tube thins towards the seat tube, aiding compliance.
Jérémie Reuiller / BMC

While the aforementioned D-shaped seatpost and tube might aid deflection, the shape, in theory, means no dropper posts will fit. However, BMC recognises that some riders will want that flexibility.

As such, a shim will be available to reduce the seat tube so it will accept an internally routed 27.2mm dropper post – something that’s having a bit of a resurgence thanks to the growth of the gravel market and it’s requirements for skinny droppers.

Frames are 1x specific, have a 160mm Post Mount brake bracket, provide clearance for 52mm tyres and hold two water bottle cages. The carbon frames take a PF92 bottom bracket, while alloy frames take a threaded BB.

BMC Twostroke down tube
A straight down tube helps keep the frame stiff.
Jérémie Reuiller / BMC

BMC Twostroke geometry

Both the carbon and alloy frames share their geometry. Bikes are available in XS to XL, and details for a Large are detailed below:

  • Reach: 465mm
  • Seat tube: 480mm
  • Chainstays: 425mm
  • Head angle: 67 degrees
  • Seat angle: 75 degrees
  • Wheelbase: 1,161mm
  • Stack: 608mm
  • BB drop: 64mm
BMC Twostroke head tube
A chunky head tube aids front-end stiffness.
Jérémie Reuiller / BMC

BMC Twostroke models

BMC Twostroke 01 One

BMC Twostroke 01 One
The top-tier Twostroke 01 One is ready for the race course.
BMC

This top-level carbon bike is built with a 100mm RockShox SID Select fork, a SRAM X01/X1/GX Eagle groupset with a 34t ring on the carbon cranks and DT Swiss XR 1700 wheels with 2.25in Vittoria Barzo tyres.

Brakes are SRAM’s Level TLM units, while the finishing kit is largely BMC branded componentry. The bike is a claimed 9.33kg.

  • €3,999

BMC Twostroke 01 Two

The second tier carbon bike gets a RockShox Reba RL fork, a SRAM GX Eagle groupset and DT Swiss X 1900 wheels with the same Vittoria tyres.

Finishing kit is courtesy of BMC, while SRAM Level TL brakes complete the build.

  • €2,999

BMC Twostroke 01 Three

This model gets a RockShox Recon Silver RL fork, a NX/SX Eagle groupset, Alex MD25 rims on Shimano hubs and Shimano Deore brakes.

  • €2,499

BMC Twostroke 01 Four

The entry level carbon bike gets a RockShox Judy Silver TK fork, a Shimano Deore 12-speed groupset and Shimano BR-MT400 brakes. It receives a round 27.2mm seatpost within the shim.

  • €1,999

BMC Twostroke AL One

The alloy frameset is built with a RockShox Recon RL fork with a remote lockout lever. It has a mixed SRAM NX/SX Eagle groupset and Shimano Deore brakes.

  • €1,599

BMC Twostroke AL Two

BMC Twostroke AL Two
The Twostroke AL Two is the entry-level XC bike from BMC.
BMC

The entry-level bike in the range has a RockShox Judy TK Remote fork, a Shimano Deore 12-speed groupset and Shimano BR-MT400 brakes.

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  • €1,199