Why would you take the time to build your own shock when there are plenty of great options on the market? Well, it was clear to see after talking to World Cup MTB mechanic to the stars, Hugues Postic, the main reason he has done this… because he bloody loves it.
Hugues has previously wrenched for Fabien Barel, Damien Spagnolo, Morganne Charre, and currently, tends to the needs of World Cup winner Alex Fayolle. Living close to La Clusaz in the French Alps, he has access to plenty of serious downhill on his doorstep, as well as the high-tech engineering vicinities around Annecy and Cluses.
The Polygon UR team has moved to SR Suntour suspension for 2017, the Rux downhill fork is poised on the front of their race bikes, but a downhill racing shock is currently being prototyped. The team is free to use any rear shock they choose this year. Ohlins is the current choice of the team riders, though Mick Hannah did race on a prototype SR Suntour air shock this weekend in Les Gets. Alex Fayolle, on the other hand, has something particularly special. Some say he only won at Lourdes due to the rain, he and his mechanic have some serious speed and technology up their sleeves.
All the changes are made inside the shock. There are no adjusters, just shims, valves and 'taps' to change the flow. Inside the main chamber, there is an oil-filled bladder and air pressure around its exterior, inflated between 100 and 200 psi. There are high and low-speed compression and rebound control in the main body, but there is also a high and 'middle' speed control in the central portion of the piggyback.
The hydraulic lockout controls the low-speed compression and is set differently for each track dependant upon how extreme they need the lock out to be. We have seen an influx of shock lockout levers at recent downhill races in anticipation of the monster sprint at the end of the Cairns World Championship track, which will be a pedal to the medals in September. But, Hughes was running a lockout on his previous version of this shock
at World Cups during 2016.
The shock uses a spherical bearing at the lower eyelet for a number of reasons: it helps to protect the shock shaft from side loads, reduces rotational friction and friction on the shaft, thirdly it allows the shaft and the coil spring to rotate slightly to negate coil bind. Coil bind is when the spring wants to rotate and twist as it is compressed.
Hugues designed the shock himself, and his friend, local rider, and owner of Aravis Précision built the units. Marc Genans runs the engineering firm and makes short production and prototype parts for Moto GP teams.
The CNC body could take a few more passes from the cutting blades, but they left the machining rough to keep costs down. Relatively down, as the body cost €3,000. All the internals including the shims and super-expensive seals come to around €1,000, and they currently have four shocks for testing. Hugues hopes that by the time Crankworx Whistler kicks off, the whole team will be racing his pride and joy.
The data acquisition was bought from and Italian brand who supplies Moto GP racing teams. It can record the suspension travel and speeds, various forces, wheel speeds and braking pressure. It also works in conjunction with GPS.