New BMC Fourstroke gets self-dropping dropper seatpost and updated frame

BMC’s cross-country mountain bike has updated kinematics and new rear triangle design

BMC-Fourstoke-ONE

BMC has updated its Fourstroke cross-country mountain bike, with a new frame seeing refreshed suspension layout, updated geometry and increased water bottle capacity.

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BMC has released three new Fourstoke models. The Fourstroke and Fourstroke 01 have 100mm of travel front and rear, and Fourstroke LT which has 120mm of travel front and rear. While these three bikes share the same frame, differences in carbon construction, suspension travel, and dropper post technology make each suitable for different types of cross-country riding.

A highlight from the range is the Fourstroke 01, which includes BMC’s Autodrop dropper post – the first-ever fully integrated automatic dropper seatpost.

BMC has introduced plenty of new specifications across the three new models. The Fourstroke has four specifications to choose from with prices ranging from £4,300 / $4,699 to £7,200 / $7,999.

The Fourstroke 01 has three models plus a frame kit. Pricing ranges from £5,800 / $5,999 for the frameset to £12,400 / $13,499.

Finally, the Fourstroke LT range includes three specifications with prices starting at £4,500 / $4,999 and going up to £11,499 / $12,499.

BMC APS updated

The shock now sits under the top tube but BMC still uses its twin-link APS suspension platform to fine-tune the kinematics.
Paul Foulonneau

The most obvious change to the BMC Fourstroke from its predecessor is the bike’s new suspension layout.

BMC still uses its twin-link APS (Advanced Pivot System) suspension to drive the shock. However, the shock now sits horizontally underneath the top tube rather than vertically.

BMC says it updated the kinematics of the system to increase traction and suspension performance on climbs and descents. In addition, BMC believes the virtual pivot designs allow it to design complex kinematics with performance gains that outweigh those of lightweight systems such as flex stays and single pivots.

BMC has tuned the Fourstroke’s anti-squat to fall off through the travel to keep the suspension active deeper in the travel while maintaining pedalling efficiency nearer the sag point.

All-new Autodrop

The Autodrop post is integrated into the frame and provides 80mm of travel.
Paul Foulonneau

The new Autodrop dropper post technology is available on the Fourstroke 01 range of bikes. The two-position dropper post has 80mm of travel.

Unlike all other dropper posts, the Autodrop allows the rider to drop the post automatically without squatting on the saddle to lower it.

This valve on the outside fills an air tank in the down tube which is used to activate the dropper post with the need for the rider to lower it by sitting on it.
Paul Foulonneau

Inside the down tube of the frame is an air tank. This is filled via a port on the seat tube. When you press the dropper lever, the pressurised air runs through a hose to compress a spring in the dropper post, dropping the post without you having to sit on the saddle.

Pressing the dropper lever again returns the saddle to its pedalling height. No details were given on how many times this can be used before the tank needs to be topped up to keep the pressure correct for activation.

BMC claims Autodrop is for the race enthusiasts who want the maximum time powering on the pedals without having to sit down before dropping into a descent. If you’re using a dropper post dozens of times per race, the fractions of seconds saved by using the Autodrop post could amount to valuable time and energy savings.

The Fourstroke 01 bikes feature an additional port on the seat tube to provide easy access for Autodrop maintenance.

The Foustroke and Fourstroke LT use a conventional dropper post.

Increased pedalling efficiency

The rear triangle now has a second vertical strut on the drive side to increase pedalling stiffness.
Paul Foulonneau

Frame stiffness is another area BMC addresses with the new Fourstroke. The rear triangle now uses a second strut that BMC says adds a 20 per cent increase in pedalling efficiency.

The bottom bracket area has also been beefed up to reduce torsional flex in the frame and aid power transfer.

Frame features

The new frame can carry two bottles in the front triangle.
BMC

BMC says it took feedback from its athletes when designing the bike and, as a result, the Fourstroke can now fit two water bottles in the frame. To fit two bottles, you’ll have to use side-loading bottle cages and they can’t be larger than 550ml.

Internal cable routing is guided through the front triangle, link, and rear triangle for ease of maintenance. An integrated fork stopper, chainstay protector and the lower link mud flap protect the frame further.

The rear stays have clearance for 2.4in mountain bike tyres. The rear hub is Boost 12x148mm spacing, and the frame uses a press-fit bottom bracket.

New bike, updated geometry

The Fourstroke’s geometry is now longer, lower and slacker.
Paul Foulonneau

BMC has revised the Fourstroke’s geometry giving it the longer, lower, slacker treatment.

The Fourstroke and Fourstroke 01 share the same geometry. The Fourstroke LT has similar geometry figures but its longer suspension travel means it sits higher off the ground.

The head tube angle shaves a degree off the outgoing model to 66.5-degrees, and the effective seat tube angles have been steepened to 76.7-degrees.

Reach numbers have grown to 437mm on the smaller frames to a stretched-out 500mm on the extra-large. That said, the effective top tubes are slightly shorter than the outgoing Fourstroke due to the increased steepness of the effective seat tube angle and slacker head tubes.

Chainstay lengths are short and snappy at 432mm on all sizes. The bottom bracket drop is lowered by 9mm to 53mm on the Fourstroke and Fourstroke 01. It sits 38mm lower than the axles on the Fourstroke LT.

BMC Fourstroke geometry

Fourstroke

SizeSMLXL
Seat tube angle (degrees)76.776.776.776.7
Head tube angle (degrees)66.566.566.566.5
Chainstay (mm)432432432432
Bottom bracket drop (mm)53535353
Seat tube (mm)420440470510
Effective top tube (mm)574597621649
Head tube (mm)8494101118
Wheelbase (mm)1,1391,1711,1881,218
Stack (mm)584592600615
Reach (mm)437457477500

Fourstroke LT

SizeSMLXL
Seat tube angle (degrees)76.776.776.776.7
Head tube angle (degrees)66.566.566.566.5
Chainstay (mm)432432432432
Bottom bracket drop (mm)38383838
Seat tube (mm)420430460500
Effective top tube (mm)576599623651
Head tube (mm)8494101118
Wheelbase (mm)1,1401,1721,1891,219
Stack (mm)584592600615
Reach (mm)437457477500

BMC Fourstroke specs and pricing and availability

The new Fourstrokerange has 11 models. The bikes are specced with a mix of Fox and RockShox forks and shocks and Shimano and SRAM drivetrains and brakes.

There are four frame sizes to choose from, S, M, L and XL, which BMC says covers riders from under 172cm to over 188cm.

BMC Fourstroke 01 LTD

BMC Fourstroke 01 LTD.
BMC
  • Frame: Fourstroke 01 Premium Carbon with Autodrop Technology, 100mm travel
  • Fork: Fox Float 32 SC Factory DT Swiss Remote Lockout, 100mm travel
  • Shock: Fox Float DPS Factory DT Swiss Remote Lockout
  • Drivetrain: SRAM XX1 Eagle AXS
  • Brakes: SRAM Level Ultimate, 160mm rotors (s and m), 180/160mm rotors (l and xl)
  • Wheelset: DT Swiss XRC 1200
  • Tyres: Vittoria Mezcal 2.35
  • Handlebar: BMC MFB01 Carbon, 760mm
  • Stem: BMC MSM01
  • Saddle: Prologo Dimension NDR T4.0
  • Seatpost: BMC Autodrop Integrated Dropper Seatpost, 80mm drop
  • Price: £12,400 / $13,499 / €12,999 / CHF 13,499
  • Availability: June 2023

BMC Fourstroke 01 ONE

BMC Fourstroke 01 ONE.
BMC
  • Frame: Fourstroke 01 Premium Carbon with Autodrop Technology, 100mm travel
  • Fork: Rock Shox SID Ultimate – TwistLoc, 100mm travel
  • Shock: Rock Shox SIDLUXE Ultimate – TwistLoc
  • Drivetrain: SRAM X01 Eagle AXS
  • Brakes: SRAM Level Ultimate, 160mm rotors (s and m), 180/160mm rotors (l and xl)
  • Wheelset: DT Swiss XRC 1501
  • Tyres: Vittoria Mezcal 2.35
  • Handlebar: BMC MFB01 Carbon, 760mm
  • Stem: BMC MSM01
  • Saddle: Prologo Dimension NDR STN
  • Seatpost: BMC Autodrop Integrated Dropper Seatpost, 80mm drop
  • Price: £10,699 / $11,499 / €10,999 / CHF 11,499
  • Availability: June 2023

BMC Fourstroke 01 TWO

BMC Fourstroke 01 TWO.
BMC
  • Frame: Fourstroke 01 Premium Carbon with Autodrop Technology, 100mm travel
  • Fork: Rock RockShox SID SL Select+ TwistLoc, 100mm travel
  • Shock: RockShox SIDLUXE Select+ – TwistLoc
  • Drivetrain: SRAM GX Eagle AXS
  • Brakes: SRAM Level TLM, 160mm rotors (s and m), 180/160mm rotors (l and xl)
  • Wheelset: DT Swiss XR 1700
  • Tyres: Vittoria Mezcal 2.35
  • Handlebar: BMC MFB01 Carbon, 760mm
  • Stem: BMC MSM01
  • Saddle: Fizik Antares R7
  • Seatpost: BMC Autodrop Integrated Dropper Seatpost, 80mm drop
  • Price: £8,800 / $9,499 / €8,999 / CHF 9,499
  • Availability: October 2022

BMC Fourstroke 01 FRS V1 frameset

BMC Fourstroke 01 FRS V1.
BMC
  • Frame: Fourstroke 01 Premium Carbon with Autodrop Technology, 100mm travel
  • Fork: Fox Float 32 SC Factory DT Swiss Remote Lockout, 100mm travel
  • Shock: Fox Float DPS Factory, Kashima Coating – DT Swiss Remote Lockout
  • Stem: BMC MSM01
  • Seatpost: BMC Autodrop Integrated Dropper Seatpost, 80mm drop
  • Price: £5,800 / $5,999 / €5,499 / CHF 5,999
  • Availability: February 2023

BMC Fourstroke ONE

BMC Fourstroke ONE.
BMC
  • Frame: Fourstroke Carbon, 100mm travel
  • Fork: RockShox SID SL Select+ TwistLoc, 100mm travel
  • Shock: RockShox SIDLUXE Select+ TwistLoc
  • Drivetrain: SRAM GX Eagle AXS
  • Brakes: SRAM Level TLM, 160mm rotors (s and m), 180/160mm rotors (l and xl)
  • Wheelset: DT Swiss XR 1700
  • Tyres: Vittoria Mezcal 2.35
  • Handlebar: BMC MFB01 Carbon, 760mm
  • Stem: BMC MSM01
  • Saddle: Fizik Antares R7
  • Seatpost: Bikeyoke Divine
  • Price: £7,200 / $7,999 / €7,499 / CHF 7,999
  • Availability: October 2022

BMC Fourstroke TWO

BMC Fourstroke TWO.
BMC
  • Frame: Fourstroke Carbon, 100mm travel
  • Fork: Fox Float 32 Step Cast Performance DT Swiss Remote Lockout, 100mm travel
  • Shock: Fox Float DPS Performance DT Swiss Remote Lockout
  • Drivetrain: Shimano Deore XT, 1×12
  • Brakes: Shimano Deore XT, 160mm rotors (s and m), 180/160mm rotors (l and xl)
  • Wheelset: DT Swiss XR 1700
  • Tyres: Vittoria Mezcal 2.35
  • Handlebar: BMC MFB01 Carbon, 760mm
  • Stem: BMC MSM01
  • Saddle: Fizik Antares R7
  • Seatpost: Bikeyoke Divine
  • Price: £6,400 / $6,999 / €6,499 / CHF 6,999
  • Availability: April 2023

BMC Fourstroke THREE

BMC Fourstroke THREE.
BMC
  • Frame: Fourstroke Carbon, 100mm travel
  • Fork: RockShox SID SL Select RL TwistLoc Lockout, 100mm travel
  • Shock: RockShox SIDLUXE Select+ TwistLoc
  • Drivetrain: Shimano SLX, 1×12
  • Brakes: Shimano Deore SLX, 160mm rotors (s and m), 180/160mm rotors (l and xl)
  • Wheelset: DT Swiss X 1900
  • Tyres: Vittoria Mezcal 2.35
  • Handlebar: BMC MFB02 Alloy, 750mm
  • Stem: BMC MSM01
  • Saddle: Fizik Antares R7
  • Seatpost: X-Fusion Manic
  • Price: £5,300 / $5,799 / €5,299 / CHF 5,799
  • Availability: June 2023

BMC Fourstroke FOUR

BMC Fourstroke FOUR.
BMC
  • Frame: Fourstroke Carbon, 100mm travel
  • Fork: RockShox SID SL RL TwistLoc Lockout, 100mm travel
  • Shock: RockShox SIDLUXE Select+ TwistLoc Lockout
  • Drivetrain: Shimano Deore, 1×12, Shimano SLX shifter and mech
  • Brakes: Shimano BR-MT500, 160mm rotors (s and m), 180/160mm rotors (l and xl)
  • Wheelset: SHL28OS rims, SHIMANO MT400 (F) / MT410 (R) hubs
  • Tyres: Vittoria Mezcal 2.35
  • Handlebar: BMC MFB02 Alloy, 750mm
  • Stem: BMC MSM01
  • Saddle: Fizik Antares R7
  • Seatpost: BMC MSP03
  • Price: £4,300 / $4,699 / €4,299 / CHF 4,699
  • Availability: September 2023

BMC Fourstroke LT LTD

BMC Fourstroke LT LTD.
BMC
  • Frame: Fourstroke Carbon, 120mm travel
  • Fork: Fox Float 34 SC Factory, 120mm travel
  • Shock: Fox Float DPS Factory EVOL LV
  • Drivetrain: SRAM X01 Eagle AXS, SRAM GX cassette
  • Brakes: SRAM G2 Ultimate, 180mm rotors
  • Wheelset: DT Swiss XRC 1501
  • Tyres: Maxxis Rekon 29×2.4in TR EXO
  • Handlebar: BMC MRB01 Carbon 760mm
  • Stem: Truvativ Atmos 7K
  • Saddle: Fizik Antares R5
  • Seatpost: RockShox Reverb AXS
  • Price: £11,499 / $12,499 / €11,999 / CHF 12,499
  • Availability: April 2023

BMC Fourstroke LT ONE

BMC Fourstroke LT ONE.
BMC
  • Frame: Fourstroke Carbon, 120mm travel
  • Fork: Rock Shox SID Select+, 120mm travel
  • Shock: Rock Shox SIDLUXE Select+
  • Drivetrain: Shimano SLX, 1×12 w Deore chain
  • Brakes: Shimano SLX, 180mm rotors
  • Wheelset: DT Swiss M 1900
  • Tyres: Maxxis Rekon 29×2.4in TR EXO
  • Handlebar: BMC MRB03 760mm
  • Stem: Truvativ Atmos 7K
  • Saddle: Fizik Antares R7
  • Seatpost: Bikeyoke Divine
  • Price: £5,799 / $6,399 / €5,899 / CHF 6,299
  • Availability: January 2023

BMC Fourstroke LT TWO

BMC Fourstroke LT TWO.
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  • Frame: Fourstroke Carbon, 120mm travel
  • Fork: RockShox SID RL, 120mm travel
  • Shock: RockShox SIDLUXE Select+
  • Drivetrain: Shimano Deore, 1×12 w Shimano SLX shifter and mech
  • Brakes: Shimano BR-MT520, 180mm rotors
  • Wheelset: Alex MD30 rims, Shimano MT400 (F) / MT410 (R) hubs
  • Tyres: Maxxis Rekon 29×2.4in TR EXO
  • Handlebar: BMC MRB03 760mm
  • Stem: Truvativ Atmos 6K
  • Saddle: Fizik Antares R7
  • Seatpost: X-Fusion Manic
  • Price: £4,500 / $4,999 / €4,499 / CHF 4,999
  • Availability: September 2023