While enjoying some suspension fork troubleshooting at work today I got to thinking back to when I was still terrified of things in general. Like hydraulic brakes and suspension components. Like commitment, failure, self-assertion, dancing; there's plenty of things to be afraid of if you're prone to anxiety and self-deprecation. But hydraulic brakes and suspension components really aren't complicated. My hang up was what I think many mechanics have--simple fear of the unknown.
In a brake, the lever pushes some fluid and it displaces the pistons toward the rotor. That's really it. There's a couple different ways you can push the fluid, and that accounts for the only differences between various brake systems. In suspension, it's slightly more complicated, but only slightly- you've got a spring, you've got some oil moving through various types of holes, and you've got a bunch of o-rings. All the forks and shocks out there are pretty much the same with some minor differences that do change performance drastically. Once you get over the voodoo and take a few apart (and i mean actually take them apart, not just pop new dust seals in and follow the directions) it's laughably simple. I'm embarrassed by how long it took me to get over the fear.
I always had the attitude of not wanting to make things worse, and assuming it was probably too complicated for me, or not having enough time to take it slow and really learn while doing it. Which is the worst attitude because it only prolonged the fear.
Then I got out of the bike industry, learned what it's like to work under power tripping assholes, saw some gory, Tarantino-style human death up close, had my (fourth or fifth) existential crisis, and decided to stop giving two fucks about it all. Forks are cool; let's take them apart.
Once in possession of the correct attitude, I could learn much faster. It didn't take long to see how you can make a lot of it work better. I just took apart all the old junk laying around. That's important- and it held me back earlier- go out of your way to find junk to take apart. Old blown fox vanillas have the exact same things going on inside as the newest stuff. When it's junk there's really nothing to be afraid of (except spraying oil at 200psi all over yourself/wear eye protection).
The bike industry spews out a lot of shit. Both in marketing and manufacturing. But by studying it you can go through the shit and pick out the undigested corn kernels that are still worth something. And maybe even make them into tortillas!
Like my beloved Manitou Minute fork. It's got this wonderful digressive damper (both compression and rebound), and a linear to progressive hybrid air-coil spring. Really about all you could ask for except the bushings have a ton of play and the classic manitou top-out bummper gives a clunk everytime the front wheel comes off the ground. Bushings I'm kind of at a loss with, I even warrantied the thing and got one in return with equal play.
The reason for the lack of negative spring is that the MARS air spring has a coil and air spring in series. I'm not exactly sure how much the coil moves before the air spring piston lifts off its seat, but it's more than on a normal air sprung fork of course. Coil springs have no energy at full extension, so technically speaking the low speed rebound circuit should control the rebound until the coil loses all its energy at the top of the stroke, so a little bumper is all you need. It really makes the fork "stand-up" in it's travel, which is nice at times. But unless you run the LSR really slow, there's some left over energy (air piston still moving? preload on coil?) and it tops-out harsh.
But I was relatively easily able to replace the top-out bumper with a coil spring from ace hardware. The top out bumper was something like 20mm long and I figured it compressed a little bit at top out, so I found a spring the correct diameter that is about 2" long extended but can't compress to shorter than 15mm or so, when all the coils hit each other. I felt like that gave me good margin for error in terms of maintaining adequate bushing overlap, though I didn't do any measuring of the stanchions etc. It has smoothed the initial travel and top out massively. Since it's a linear (coil) negative spring you can feel the transition when it releases if you're pushing on the fork, but it's invisible while riding. I squeezed a few springs and got one that felt stiff enough to to compress almost completely at top-out. I got lucky and it was right the first time. I'm sure these Ace springs are quite cheap and I keep waiting for it to break, but so far so good.
An update from last year:
The Fox Float RP2 rebuild was extremely unsatisfying. I changed the propedal needle valve spring (found some weird tiny spring at work that fit and was stiffer and longer) to increase platform, and then fucked with the shim stack a little. IIRC, I pulled all the Belleville stacks off and put a regular stack in their place. But I also called FOX twice and begged and pleaded for damper seals to no avail. I also called some factory authorized service centers with the same result. Then I spent hours at the O-ring store but replacing the main Viton damper body seal with BUNA-N just didn't work. Too soft I guess, blew out after riding twice around the block. I had a few bounces of enlightenment when I started feeling what the mods had achieved (Much more low speed compression with propedal on but not enough damping in OPEN mode), and then it blew up so I gave up and bought a Monarch. Which is a great shock and completely user serviceable and I haven't had a reason to take it apart yet. Much more heavily damped than the Fox with a nice crisp shim-stacky feel.
