When Commencal introduced their Supreme DH V4 and its high-pivot rear suspension, they included diagrams in their press release of the 160mm-travel test mule that was used as a proof of concept in the early stages of its development. It turned out that lots of people were asking about the mule, rather than the production downhiller. Commencal responded by building the Supreme SX, a 180mm-travel monster that is basically a downhill bike with its seat tube situated in the right place to help you get back up the hill.
The Supreme SX is available as a frame-only option for €1599 / $1599 USD (without shock) and Commencal also offers the bike in a standard build kit, decked out in either black or orange for €3699 ($3699 USD). Finally, the brand offers an 'A La Carte' version of the Supreme SX, which allows riders to individually choose all the components from the palette of options that Commencal stocks. My bike was delivered in the standard build kit, with the exception of an upgrade to E*13 wheels and a SRAM XO1 11-speed drivetrain.
Commencal have done a killer job on the details, including this plastic guard that keeps the downtube and linkage protected from incoming geology.
Construction and Features
The Supreme SX is a long-travel brute that shares many similarities to its DH bro, including the updated "Contact System" linkage, frame protection, and an adjustable head tube. The swingarm is a one-piece design, where the DH bike has bolt-on dropouts for extra adjustability.
Commencal has also done a great job of soundproofing the bike with the ribbed rubber chain-slap guard, pipe lagging around the cable housing and moto foam filling the void underneath the shock.
A press-fit bottom bracket on an aluminum bike park shredder? I'm already prepping my popcorn for reading the comments.
The Supreme SX comes with a dedicated 180mm post mount for the rear brake and a stealth Maxle to lock down the rear wheel.
The SX's geometry clearly directs it towards bike park and downhill trails; the straight 1.5" headtube allows for the 65º head angle to be tweaked +/-1º or add/remove 10mm to the frame's reach. The reach is already a chunk longer than the Supreme DH, with the maximum range of sizes stretching between 412mm and 502mm (with the use of cups). The chainstay is the same 425mm length as the DH bike, but the bottom bracket (when static) is an extra 5mm lower.
The straight 1.5" headtube allows adjustment to the frame size and head angle.
The Supreme SX uses the same-style linkage to drive the metric shock as the DH V4.2.
Why a high pivot? Raising the height of the pivot well above the bottom bracket has a few advantages, namely that the rear wheel can move backward, and then over obstacles more easily. A normal chain line would stretch too far in this situation and induce huge amounts of pedal kickback, so routing the chain over an idler wheel eliminates this problem. There are downsides, however, as the design also adds extra friction and maintenance to the equation. Some riders report that this rearward axle path can also make it difficult to stay balanced on the bike, especially in corners as the rider's COG moves forward between the axles as the suspension compresses.
Another arguable downside of the HPP is that braking forces have a large effect on the suspension movement. This high anti-rise figure will make the bike squat when the brakes are pulled and inhibit the free movement of the suspension.
The chain runs through the swingarm, this means there is no way of losing the chain and pressure on the idler-wheel is even on either side of its bearings.
Most of my climbing time on the Supreme SX was limited to spinning road miles or catching a chairlift to the top. The Supreme SX climbs as well as I could expect of any 180mm travel bike with a downhill build kit, and pedaling through rough terrain is a breeze as the idler wheel prevents the feeling of your cranks being tugged as you pedal over bumps.
The only time I felt the bike struggle was when pedaling hard at a low cadence, which did make the bike wallow, but the compression-mode adjuster firmed the bike up effectively and kept the back of the bike high in the sag.
The 75º (actual) seat angle placed me nicely above the pedals to get on with the job, and yes, my saddle looks like it's in a funny position, but you should try it one day if you are going to lug yourself up a couple of hours hill climbing in one day.
Well this is what we are here for – downhill performance. It's pretty hard not to simply re-write Kazimer's review of the Supreme DH V4.2, as I agree with everything he said.
The first thing to notice is that the bike is beautifully quiet as it's almost impossible for the chain to connect to any metal that it shouldn't. Secondly, it simply floats over bumps and seems to carry speed superbly. Many times the front wheel strikes an obstacle and you are bracing for it to hit the rear wheel, and in the meantime, it has seemingly disappeared.
I think that high-pivot bikes with no pedal-kickback make the lives of flat-pedal riders so much easier. My feet stayed connected, secure and in the right place, even when plowing into really rough stuff.
The Super Deluxe in metric length was a completely different world to an imperially measured shock. Just joking. It's impossible to single out the length factor on an all-new bike, but it did perform superbly with the bike's layout and I was not asking for more progression or need for adjustment. It functioned quietly and there was little sign of performance change with heat build up. SRAM are confident that all of the improvements made to the Super Deluxe over the previous Monarch platform were only possible by changing the entire architecture of the shock, but it's hard to say in practice without trying both on the same frame which would require specific linkages.
Many people's main worry around HPP bikes is the "deadly brake jack." I have never found this a problem and actually prefer this to some degree for downhill riding, why? When you brake there is no noticeable effect until the wheel hits a bump; when this happens it makes the suspension sink into its travel, which helps to counteract the rear of the bike lifting as you slow down. I think this provides a more confidence-inspiring ride. This anti-rise is one of the more extreme examples on the Supreme SX and the situation when it did feel out of place was during steep steps in to sharp corners. If the back brake is applied to the point of skidding and then you hit a big step, it can drive the bike out in front and away from you; this was remedied through experience, though, by braking carefully and contracting my upper-body muscles to keep centered on the bike.
My main point of reference to how well a bike performs is how much confidence it gives me, and how it allows me to push myself and make use of what little skills I have left. The SX does just that. The bike does the hard work so you don't have to, then you can just get on with the task in front of you - the trail
Ride Alpha Components:
The Ride Alpha components are well thought out and must help keep the price of this machine very reasonable. The 810mm handlebar gives scope to cut down to any rider's needs, the etched markings are actually useful for lining up brake levers and angle with the stem. My only bugbear was the 8mm hex key to tighten the stem top cap. Honestly, who puts an 8mm up there?
RockShox Super Deluxe:
I had no issues with the Super Deluxe and it was nice to see Commencal prioritize the best version of this damper (as well as the RCT3 cartridge in the Lyrik) on the affordable build kit. After the first ride, I thought "This bike would be perfect for the new handlebar remote version for the SuperDeluxe. I will order the cable and lever from RockShox tonight." Not so fast, it turns out that to add the remote to this shock requires a whole new piggyback reservoir, which means a full shock rebuild too.
RockShox first launched their Torque Caps with the RS-1 and then more recently with the all-new Lyrik. They add stiffness at the dropouts as the surface area connection between the hub's end caps and fork dropout. Unfortunately, if you have a standard hub-cap, like on these E*13 wheels, the wheel floats around as you try to locate the axle – it's a small complaint, but it feels like two steps forward then one step back in an industry of things not quite fitting properly and always needing to source small parts for products to work perfectly.
Nooks and Crannies:
Those holes are designed to attach the same Commencal mudguard as the DH Supreme V4.2, although the guard is not supplied as mud clearance isn't ideal on this frame. Without it, there is a plenty of nooks and crannies to fill with dirt and grime, or in my case, tubeless fluid from a puncture that wouldn't quite seal.
A 'downhill bike that you can pedal' is oft-touted, but the Supreme SX is a real brute on the descents with good enough capability on the climbs, if you're not against the clock. The bike is easy to ride, features great attention to detail, a great build and plenty of value for money.— Paul Aston
About the Reviewer Stats: Age: 31 • Height: 6'1” • Ape Index: +4" • Weight: 75kg • Industry affiliations / sponsors: None • Instagram: astonator Paul Aston is a racer and dirt-jumper at heart. Previously adding to the list of non-qualifiers at World Cup DH events, he attacked enduro before it was fashionable, then realized he was old and achy. From the UK, but often found residing in mainland Europe.