On the Trail Air spring:
The Durolux's beginning stroke sensitivity was excellent right out of the box, with no break-in period required. After some experimentation, I settled on 70psi in the air chamber, with one volume spacer installed for my 160-pound weight. The air spring does ramp up more quickly than I'm used to – even without any spacers there's a distinct difference between the first half of the travel and the second half. I'd rather have the progression begin a little later in the stroke, or take place more gradually, in order to make the most of the 160mm of travel. Damper:
This is where the Durolux's performance pales in comparison to similar options from RockShox or Fox. Partway through my second ride, the fork began to act erratically, delivering a harsh, almost locked-out feeling whenever a rapid succession of bumps was encountered. The first few impacts would be absorbed without any issue, but then the next impact would be incredibly jarring, and a couple of times I was afraid my hands were going to blow off the grips. In short, a far from ideal sensation.
I sent the cartridge back to SR Suntour, and they discovered that the high-speed rebound shims had started to bend, which meant that not enough oil flow was occurring during those quicker hits, in turn causing the harshness I had experienced. Not willing to write off the Durolux completely, next I installed a replacement R2C2 cartridge that SR Suntour had fitted with a higher flow rebound piston. Unfortunately, the same rebound issue occurred – the fork still couldn't keep up with multiple impacts in a row, and the erratic nature of the issue made it difficult to feel confident charging into rough sections of trail.
As a final step, I swapped to an RC2 PCS cartridge, which uses a fixed, shim-based rebound piston design. This made a significant difference, and there was a welcome return to a more consistent feel out on the trail. Except for one thing - the noise
. Now, SR Suntour's forks have always been on the louder side of things, and while I'd rather have complete silence, I can handle some squelching / squishing noises. The key word there is 'some' – the noise with this cartridge was louder than anything I'd experienced before.
Once again, it was time for some tinkering. SR Suntour sent out a small spring, which I installed into the damping cartridge, stacking it on top of the spring that was already in place above the internal floating piston (IFP). The theory was that by altering the position of the IFP, the cavitation noise would be reduced. That did the trick, and although the fork was still louder than a Fox or RockShox, it was much more tolerable out on the trail.
With the RC2 PCS cartridge installed and the additional spring above the IFP the Durolux's manners improved significantly – the rebound issues were gone, and repeated impacts were handled without any surprises. As a whole, the performance was much more predictable, and if given the choice I would pick the RC2 PCS cartridge over the R2C2 every time. Going with that cartridge also drops the total cost down to $700, although I'd still say that the RockShox Yari or a GRIP damper equipped Fox 36 still have the edge at that pricepoint.SR Suntour's Response:
"SR Suntour would like to thank Pinkbike for their in-depth testing and honest evaluation. The R2C2 cartridge has been ridden and evolving for 2 years now under toughest conditions. It has seen multiple WC DH wins, Rampage wins, Megavalanche wins and NAET overall titles.
However, technologies on such a level can fail sometimes and we have realized it is not perfect. Its long-term performance is not meeting our goals and we are immediately seeking the reasons and will relaunch once solutions exceed those goals. We believe the RC2 PCS platform is solid and reliable, we are looking at reducing the possible noise. Customers with R2C2 forks/ cartridges please contact one of our global service centers or via Facebook or Instagram for a tuned replacement."Pinkbike's Take: