Suspension is one of the most important aspects of a proper downhill bike. It can make or break the handling of a machine. If a bike is shod with the most high end shock and fork and it isn't set up properly, it won't perform at optimum levels and the rider won't be able to ride… at optimum levels.
This is especially true with DH bikes, considering the speed and roughness of a proper DH course, and similar to motocross, typical bike park jumps these days are big and require proper skill and bike set up to ride properly. This is even more true in a bike park setting with high speeds and lots of big jumps in succession. Where one incident of getting flung off of a jump face because of improper suspension set up, could mean a trip to the hospital.
Last season, I aquired a base model Devinci Wilson XP to use as my DH park and occasional race bike for the next few seasons. I have lots of parts on other bikes and just laying around so I figured I would start with the base model and mount up my preferred accessories. The Wilson came stock with a Fox DHX RC2 rear shock, with a rebound dial, low speed compression dial, and an air boost valve for bottoming resistance. Devinci claims it has Dave Weagle's custom valving to match the Wilson's linkage ratio. I set it up with the proper spring for my body weight, got some base line settings from Devinci and hit the bike park. It rode ok out of the box. The bike handled fine at speed and jumped level, but it seemed to pack up after successive hits and it felt terrible on square edges and anything ledgy. I dialed the rebound knob out, hoping to get less rebound dampening, speeding up the return stroke, resulting in less of a packing up feeling, but not enough rebound dampening caused the bike to get bad traction in corners and feel sketchy off of jump faces, with the rear jumping higher than the front, not good. I was able to get the bike to feel Ok but not great and some days I kept make adjustments all day trying to get a better feel.
After a few months, it was time to send the shock into Avalanche Suspension to see if they can fix the issues I was having. I know a lot of riders that use the open bath Avalanche Fork Cartridge and have great things to say about it, and the same can be said for the rear shock modification. After reading all the info on the Avalanche Racing website, finding lots of technical info and visual diagrams about what modifications are made, it was a no brainer to get the service. The website is simple and efficient and gets the job done easily. I emailed Avalanche to get the ball rolling and see what features I needed. This is where the story gets better. I was pleased to get a friendly return email quite soon after sending, and was able to figure out exactly what I needed after I described my likes and dislikes of the stock shock. Avalanche customer service is professional and expedient with a touch of personal flavor that lets the customer know they're getting individual attention that equals well set up suspension for each individual rider.
I informed them about the issues I had with the stock shock. Checked all of the boxes, including my body weight, riding style, and that I spent a lot time riding lift access bike parks, jumping, and some racing. I was informed to order Build 2, to match the leverage ratio of the Devinci Wilson, and Options 1 and 2 (see below).
Check here for that info: http://www.avalanchedownhillracing.com/Fox%20DHX/Fox%20RC4%20Speed%20Sensitive%20Adjuster%20Kit.htm
TECHNICALITIES
Exactly what does Avalanche do and what is SSD? SSD stands for Speed Sensitive Damper. In a nutshell, (I'm a rider, not a suspension engineer) the valving is affected by the speed of the shock shaft as it moves through the travel as apposed to the Position Sensitive Dampener that relies on the position of the shaft in relation to it's position in the travel. I won't get into the debate about why or why not one is better than the other. My goal is to solve the problems of the stock shock by getting the Avalanche treatment and letting people know the results.
This is what Avalanche says about Build 2: Removal of the Boost Valve and the high speed adjuster will be modified to independently increase high speed damping and along with the linkage, it will give you all the end stroke damping you will need. For rising rate linkages the High/low adjuster will be completely redesigned to create what we are calling a FvAT/HSB,
this will allow the rider to blend the low speed into the mid speed damping will maintaining pedal performance and low speed plushness.
The RC2 will be preset with our custom high speed tune.
The SSD valve will become an option only if needed for low rising rate systems and more aggressive free riding.
This is where it gets a bit more complicated and the three Stage treatment is explained:
Stage 1 (included)
Removing the boost valve and replacing it with our Speed Sensitive Valving.
This fixes the middle to bottom of the stroke by removing the position sensitive portion and making it speed sensitive,
It still prevents bottoming and will now blow-off when needed on high speed square bumps, that the RC4/RC2 fails to do.
Stage 2 (included)
The main compression valving will be revalved and modified for the linkage system and type of riding.
The rebound valving will be revalved and set for the spring rate needed for the rider,
allowing the rebound adjuster to fine tune the low speed.
The stock RC4/RC2 valving is the same for all spring rates
and the low speed adjustment has to be compromised to compensate for the fixed high speed internal valving.
.
Stage 3 (included)
Seals, bushings, and dust scrapers will be changed to better quality and less friction.
Oil replaced with Spectro Suspension Fluid, Recharged with Nitrogen to reduce fade and heat affected pressure increases.
There are also 3 OPTIONS: Optional SSD valve (1), shape factor anti-bottoming bumpers (2) and extended reservoirs (3) to increase Nitrogen volume
for racers and more aggressive riders and or rising rate linkages to prevent shock fade and heat related pressure build-up.
Includes custom revalve and setup for rider, frame leverage and conditions
and printed set-up chart. We will ask you all the right questions to help you help us with the best possible set-up.
Also includes complete rebuild service, new improved seals and dust wiper system, oil, nitrogen charge and typical wear parts* included in price.
GETTING IT DONE.
I scheduled the service, fed-ex'd the shock to Avalanche and received it on the scheduled date. No problems or issues. The shock arrived with an extensive sticker kit, all adjustment dials are pre-set, and an easy to follow set-up chart is provided if I needed to change anything. A really easy explanation of what adjustments to make and when is on the chart as well.
HOW DOES IT RIDE?
Did all of this technical modification result in a better riding bike out on the dirt? Did it solve the issues I had with the stock shock?
Yes, and Yes. The first time taking the bike out for a test on a local shuttle trail was eye opening to say the least. I didn't touch the settings, trusting that Avalanche knows what's best, and this turned out to be ideal. The bike picked up speed a lot quicker and felt really plush but firm. Pumping seemed to provide more speed than before, I could easily maintain a lot more momentum over rough sections and I felt like the shock was getting full travel but wasn't bottoming out. It stayed up in the travel nicely, even though it also had the right amount of sag. Plush but firm. It totally erased small chatter and square edge hits didn't feel square anymore. The bike carried so much speed into corners, I had to brake sooner, noticeably sooner, and it didn't wallow in corners or get out of shape in the rough, in anyway. Jumping felt solid and the bike landed like a works motocross machine with no harsh bottom feeling and no bucking or swapping. The rear suspension was responsive and predictable, and even though it was plush, it didn't feel sloppy or inefficient when trying to get some pop off of the something small or when pedaling.
A few more test days at Northstar further proved the effectiveness of the Avalanche treatment. I kept the settings the same and the bike felt perfect. The issue of packing up after successive hits was no longer an issue, and there was no need for me to mess with the rebound settings to get the proper feel. Overall, the bike performs better in all areas because of the Avalanche suspension.
The bike now has pop and feels lively, but it also feels like it sticks to the ground and finds excellent traction when I want it.
I can honestly say, I don't feel any negative handling traits, and I am free to shred the bike like it was meant to be.
WHAT ABOUT THE FRONT OF THE BIKE?
With the rear suspension working so well, and the bike carrying so much more speed, I had to make some adjustments to the settings on my fork, a Fox 40 RC2. Firm up the high speed compression a bit, and a click less rebound. I've never had an issue with getting the stock Fox 40 to feel comfortable. With both high and low speed compression, it's easy to find the sweat spot, but it is now obvious that the fork does not match the performance of the rear shock. It's a subtle difference, and it means that I'm now looking forward to getting an Avalanche cartridge for the Fox 40. I'm confident this will provide a balanced ride that outperforms a stock set-up.
GREAT CUSTOMER SERVICE.
I can't say enough about Avalanche's excellent customer service. Quick email replies, all questions answered with no problems. The entire process was smooth as silk. Check out the Avalanche website for more info about suspension, and what will work best for you. They offer rebuilds and services of just about everything and their fork cartridge fits any fork.
http://www.avalanchedownhillracing.com