I have struggled with my Fox 36 for the last year. Long story short, but the air spring is wildy inconsistent. The issue is wide known and Fox no long uses this style of air spring, however several manufacturers offer fixes. MRP, Vorsprung and a few one-man shops try to address this with various approaches. After talking with Craig at Avalanche he brought up that he too offers a solution to address this and that I should give it a try before spending money on a new chassis. The 2015-2017 Fox NA air spring uses a transfer rod to equalize the positive and negative air springs at full extension. A small dimple in this rod does the equalizing. As the rod travels through the air piston an o-ring and 2 washers seal the transfer rod shaft and separate the two chambers. Craig suggest that there is not enough squish on the o-ring to provide consistent equalization and thus results in a build up of pressure in the negative chamber. This pulls the fork down in its travel upsetting the geometry of the bike. As a result the rider tends to adjust the fork (via spring pressure and damper clickers) to compensate for a poor preforming fork. As you can imagine this quickly spirals out of control and results in real frustration. I found my fork to preform incredible one-day and horribly the next. As a result my confidence takes a hit and I struggle. I feel like it really effected me during the spring DH race at Windrock and the EWS qualifier.
I implemented Craig’s fix and rode last Friday. But before I could focus on getting the fork feeling good I also struggled on tire pressure. I know my Silca pump reads too high and as a result I have fought flats and cut tires for a long time. I purchased an analog gauge specifically for bikes and turns out it read too low. So in Friday, when I thought I was running 30psi I was running closer to 40psi. Well, with Windrock under some of the toughest conditions it was a recipe for struggling. I crashed twice and again my confidence was shattered. I just could trust anything I was doing and trying to put my tires where I wanted was a real gamble.
I went home Friday evening kind of lost and wondering where to go next. So Saturday morning I delayed a trip to the cabin to reset a few things and headed back to Windrock to wash the bad taste out of my mouth. I set my fork sag to 22%, rear to 23%, adjusted my clickers to a rocky setting (19 compression, 15 rebound), and tires to the thumb test. I would guess they were in the 25psi. Which is risk, but I taking steps to mitigate this. I also swapped to some brand new Maxxis DH MaxxGrip rubber. Wow, what a difference!. The bike was much more planted and that translated to confidence. I was able to go deeper, brake later, and increase the risk. The real trick will be can I get the same performance next weekend.
Since we have phased out the dirt bikes, I have had ideas to re-purpose the field’s use. Mowing with the berms and jumps in place was kind of a pain and created areas that had to be weedeating tp keep the ragweed at bay. Man, that stuff is veracious. So I rented a machine and scooped all the dirt and created some dirt jumps under the oaks, along the west side of the field. I’ve had my eye on this area for dirt jumps for quiet a while. Its well shaded and really only sees morning sun. The dirt in this area always stays nice and moist thus making it a great location for low maintenance dirt jumps.
Clearing with a bobcat is always fun and very satisfying destruction. It went pretty smoothly except a few run ins with some hornet and yellow jacket nests. For the most part the hornets couldn’t puzzle out that a stingable human was in charge of the machine. Whereas those yellow jackets knew right away where to attack.
I huge thanks to Corey for coming up and helping me shape the set. The only other jumps I had a role in was Bigfoot and those where built over years, so working out spacing, angles, etc. worked itself out naturally. Unfortunately I got the spacing between the first and second jumps way off and the second just just isn’t big enough. It needs to be either way taller or longer. I think we will take the dirt from the first jump and make the second longer. The remainder of the dirt will be used to create a nice set-up roller to help get the set speed just right.
The last ride of the trip was to be Agate. Its an epic and fitting to finish off the trip. After the standard climb out the Crest, Agate drops off to the west side of Monarch. As it is also a moto trail, it is wide, straight, and fast. I have been struggling with my Fox 36 chassis forever. The sag measurement is inconsistent and as a result it throws the geometry off. It also tends to ride too low in the travel and results in a whole mess of other ride quality issues. It was particularly bad on this day and I was pretty fed up with it. I got pretty angry and tried to take it out on the trail. I got a top 5 time on Strava, but what could have been if the fork had been working properly.
So I ended up talking to Craig at Avalanche about it and turns out the issue is the positive/negative equalization. Fox relies on a transfer rod through the middle of the piston to accomplish this. In ideal conditions, a dimple at full extension allows the two chambers to equalize. At times that dimple has clogged with grease causing too much air to get trapped in the negative chamber. But ultimately the o-ring seal on that rod doesn’t have enough squish to work properly. Therefore air moves from chamber to chamber in an unreliable fashion giving very inconsistent performance. Of course Fox has moved on from this design, but for those of us still on these forks it is still a huge problem. Craig offers a rebuild kit that adds a harder o-ring and an additional washer to provide better squish on the o-ring. I have subsequently preformed this modification and hope to get better, more consistent performance.
For the last day of the trip we spent the morning in Buena Vista. We had plans to ride there, but everyone was pretty tired. We ended up just walking around, buying a few gifts, and eating at Eddyline Brewery. They have really good wood-fired pizza, great beer, and incredible root-beer for the boys.