The crew at Shockspital have been getting a lot of requests to tune Fox rear shocks from XC racers that are riding Trek bikes. It seems that over the past few years Fox rear shocks have had less "platform". The Pro-Pedal seems to have been dialed down leaving these bikes suffering from excessive pedal bob. The problem is that Fox does not yet allow anyone to service their rear shock dampers. This not only prevents us from tuning the dampers but it prevents us from servicing them when they go bad, and they seem to go bad more than other brands. Our solution is to replace the Fox rear shocks with a Rock Shox Monarch. The following is a review from one of our team members.
"First, let me describe myself as when I read reviews I like to know that riders bike and riding style is to see how it applies to me. I am 6'2", a fit #195 pds and an aggressive rider. I race on weekends in the Midwest. Lots of single track, some hills, berms, ruts, and rock gardens but overall, no big west coast drops. I have raced with this shock on tight single track and long 100 mile endurance rides. I ride a 2012 Fisher Superfly 21 inch frame. The bike came with the Fox RP23 shock but I kept blowing out the damper seals and needing it overhauled every couple of months. In addition, the Fox was to plush for me.
Shockspital (part of Freewheel Bike in Minneapolis) suggested I try the Rock Shock Monarch RT3 shock. It fits the same as the Fox on the Superfly. I went with the medium compression tune as it offers the widest range of damping adjustment. It is also what the guys at Trek recommend for my bike. The staff at Shockspital are aware that I am a aggressive rider (take the most direct route from A to B) who wants a more planted, stable feel through corners which the medium compression offers. I have not tried the high or low compression tunes so not sure how that would affect the compression. I am not a techie person so I will not get into the details of the "guts" of the shock, but rather how it performs for me. One word "AWESOME". I have raced on it for the past 6 months and have not needed any service. I set the sag at 20% which for me was about 175 psi. Make sure you measure the sag with the platform set at OFF. The monarch has gradients on the shock making it easier to set up sag. No more need to use zip ties. I must add that 20% is pretty firm and have set it at 25% if I am hitting a very rough course (ie Afton for those who are local). No leaks to date. A plus is that the compression lever is longer than other shocks I have tried, making it easier to adjust the rebound setting. The platform settings are more distinct than the Fox float and I use all 3 settings. It also has a red dial to control the rebound. Rabbit for fast and turtle for slow. I have mine at setting 4.
Unless I am racing down a steep rock garden or over ruts, I have the compression lever in position two or three. I keep the rebound in the 4th setting. What I notice on the tight single track is that it gives me a stiffer feeling in corners, it does not compress as much and feels more responsive. The shock seems to "roll" over the ground which provides for much better traction. I make the analogy that my old shock felt more like a Buick suspension (some riders like that) but this is more of a tight responsive European car feeling. The old shock felt more sluggish, this is more lively and gives me more control. I used to bottom out my compression on berms but the Monarch feels more firm but still compresses when you hit the "big stuff".I am also able to pump out speed with this shock in flowing single track trails. Also, on hills or flats I do not get the peddle bob, allowing me to conserve more energy. At 195 lbs, I need all the help I can get to chase the younger 160pd racers up the hills. You feel the added control and power. I have ridden the bike on courses with lots of ruts and notice that it is sensitive at the start of the stroke, it absorbs the small bumps well.
Bottom line, I get the best adjustability for the terrain I am riding. The feel of a hard tail for climbing hills, responsiveness in tight single track, excellent cornering but then can lower the compression when the trail gets rough. Setting 3 is almost a full lock out but it still gives you some suspension for going up a rocky hill but feels firm.Try one out, you will not be disappointed."
If you would like to upgrade your rear shock to a Monarch you will need to know the length of the shock from eyelet to eyelet, referred to as eye to eye, how much the shock needs to be able to compress or stroke, the width of the frame mounts or end width, and the bolt diameter. For Trek bike that information can be found here. Then you have to decide on your tune. If you aren't sure what tune you need Shockspital has rental Monarch shocks so that you can try before you buy. Once you know which one you want you can order it here.