Commencal's high pivot, World Cup winning and popular Supreme DH bike – available in both 27.5in and 29in wheels — is now also available with mixed 'mullet' wheel sizes, seeing a 29in front wheel and 27.5in rear.
- Specialized brings mullet wheels to the masses with 2020 Demo downhill bike
- The ultimate guide to bike geometry and handling
Quickly emerging as the most popular and talked-about trend since the UCI relaxed the rules around mixed wheel size use in World Cup racing, plenty of brands have jumped on the mullet wheel bandwagon.
What is a mullet bike?
A mullet bike mixes the most popular MTB wheel sizes from front to back. The front wheel is 29in in diameter, while the rear is 27.5in.
It's claimed that by mixing wheel sizes, it's possible for the bike to have the similar levels of stability of a 29in-wheeled bike and manoeuvrability if a 27.5in wheeled bike.
We conducted our own tests to find out what's faster, a 29er or mullet bike, if you want to check out our findings.
Although, to date, only a few brands are offering official mullet solutions – such as Specialized with its 2020 Demo – plenty of World Cup racers, privateers and weekend warriors alike are experimenting with mixing wheels.
It seems logical, therefore, to presume that Commencal's official DH mullet bike announcement certainly won't be the last.
2021 Commencal Supreme DH 27/29 details
Commencal's press release is a little thin on details about the new bike, but it does claim that the frame's received an overhaul to increase stiffness and precision – traits essential for downhill bikes, especially when they're being hammered down rough, rocky and steep mountains – and decrease energy loss.
It also claims the bike's got a new idler wheel position, a key component for Commencal's high-pivot Supreme DH bike.
A high pivot gives a more reward axle path under suspension compression – where the rear axle, and therefore wheel, move upwards and rewards as the suspension compresses – which means it can absorb bumps better compared to a bike with a vertical or forward axle path.
However, if the chain doesn't run close to the main pivot's location, the bike will suffer from bad pedal kickback because the chain length grows – caused by the rear axle moving further away from the bottom bracket.
High pivot bikes without idler wheels also suffer from pedal bob more than bikes with lower pivots.
Neither pedal kickback nor pedal bob are desirable traits, so to help mitigate against these forces, Commencal says it's moved the idler puller on the Supreme DH 27/29 to help improve pedalling efficiency.
Along with a modified idler wheel location, it's also modified the bike's suspension kinematics by moving the main pivot for "increased agility".
Commencal doesn't say whether it's increased or decreased the progression rate of the bike, though.
The mullet bike version of the Supreme DH runs 200mm of travel front and rear, which is the same as its 2020 Supreme DH 27.5in and 29in models.
2021 Commencal Supreme DH 27/29 geometry
| Frame size | Small | Medium | Large | Extra-large |
|---|---|---|---|---|
| Head tube angle (degrees) | 63.5 | 63.5 | 63.5 | 63.5 |
| Head tube length (mm) | 112 | 112 | 112 | 112 |
| Reach (mm) | 435 | 455 | 480 | 505 |
| Wheelbase (mm) | 1256 | 1290 | 1320 | 1345 |
| Chainstay length (mm) | 448 | 456 | 456 | 456 |
| Top tube length (mm) | 593 | 612 | 638 | 660 |
| Seat tube length (mm) | 400 | 400 | 400 | 400 |
| Seat tube angle (degrees) | 67 | 67 | 67 | 67 |
Unsurprisingly, the Supreme DH 27/29 sits at the sharp end of modern DH bike geometry.
Every size in the range has the same 63.5-degree head-tube angle but reach figures grow from 435mm up to 505mm for the XL bike.
Wheelbases start at 1,256mm and extend up to 1,345mm.
The chainstays for the size small are 8mm shorter than the medium, large and extra-large bikes, presumably to help improve the front-to-rear balance of the bike. Although Commencal doesn't confirm its reasons for the change.
The geometry is certainly well-suited to DH racing, as multiple Downhill World Cup winner Amaury Pierron proved on multiple occasions during the 2018 and 2019 race seasons.
2021 Commencal Supreme DH 27/29 models and prices
The 2021 Commencal Supreme DH 27/29 is available in two models; one with Ohlins suspension and one with RockShox suspension.
The Ohlins bike costs €5,699 / $5,399 / AU$8,799, while the Team bike with RockShox suspension retails for €5,399 / $4,999 / AU$7,999.
2021 Commencal Supreme DH 27/29 Ohlins
- Frame: 2021 Supreme DH 27/29, 200mm travel
- Shock: Ohlins TTX22 coil
- Fork: Ohlins DH38 200mm travel
- Drivetrain: SRAM GX DH 7-speed with Truvativ Descendant DH cranks
- Brakes: Shimano XT four-piston 203mm rotors
- Bar/stem: Truvativ Descendant 25mm rise, 800mm wide, 35mm clamp / Truvatic Descendant DH 35mm clamp, 50mm long
- Wheels: DT Swiss FR560 rims on DT Swiss 350 hubs
- Tyres: Schwalbe Magic Mary 29 x 2.4in Super DH (f), Schwalbe Magic Mary 27.5 x 2.4in Super DH (r)
- Price: €5,699 / $5,399 / AU$8,799
2021 Commencal Supreme DH27/29 Team
- Frame: 2021 Supreme DH 27/29, 200mm travel
- Shock: RockShox SuperDeluxe Ultimate DH
- Fork: RockShox Boxxer Ultimate, 20mm travel
- Drivetrain: SRAM GX DH 7-speed with Truvativ Descendant DH cranks
- Brakes: SRAM Code RSC 220mm rotors
- Bar/stem: Truvativ Descendant 25mm rise, 800mm wide, 35mm clamp / Truvatic Descendant DH 35mm clamp, 50mm long
- Wheels: DT Swiss FR560 rims on DT Swiss 350 hubs
- Tyres: Schwalbe Magic Mary 29 x 2.4in Super DH (f), Schwalbe Magic Mary 27.5 x 2.4in Super DH (r)
- Price: €5,399 / $4,999 / AU$7,999
