Thursday, August 30, 2018

Hydraulic Fracturing

El Queso Grande texted me on Tuesday night to say that the workshop was slammed and that several sets of hydraulic disc brakes awaited my healing touch. The repair shop continues to challenge my intellect while depressing me in general. I keep thinking that if I was a real mechanic type, sucking on a Gauloise and not giving a shit about actually riding, I could simply take pride in fixing whatever was dumped in front of me. Or if I was young and smitten with the technology -- or not young and still smitten with the technology -- I would still feel like I worked in the candy store. 

Given the choice I'd take the Gauloise. It reflects my attitude toward the consumerism and the subcultural tribalism that has fractured riding. Less than once a year something comes through the shop that I might actually desire. In truth, all I really desire is to keep my personal bikes rolling in their present form, and be able to replace each as necessary with something as close as possible when the time comes.

Just as the perfect metaphor for consumer goods marketing is cocaine, the perfect metaphor for any service occupation is sex work. Certainly in my case, I now have to handle a lot of fluids I don't want to, and stick things in places I'd rather they didn't go.

I mean brake fluid and internal cable routing, of course.

Speaking of internal cable routing, a local rider was in a crash when last Sunday's group road ride literally ran into a couple of dogs on a back back road in Ossipee. Riders have snapped forks hitting a squirrel, but this guy managed to get halfway over a Jack Russell terrier before the chainring stopped everything. The rider was banged up but able to continue the ride to get back to Wolfe City. (We haven't heard a report on the dog.) He brought me the bike to check over. His wheels needed truing. His bar tape was shredded on one side. We would check any frame and fork carefully after a crash, but with carbon fiber the stakes are higher. Because carbon is an all-or-nothing material, any crack is a serious crack.

Everything seemed remarkably good. Maybe it would have been worse if he'd hit a squirrel. I put the wheels back on and ran it through the gears. The front derailleur was rubbing the chain on the big ring. The rear derailleur was imprecise. I snugged the cables up. Things were better, but not quite perfect enough. Drive trains with 10 and 11 speeds are very sensitive to minor inaccuracies. Electronic shifting avoids the problems of cable-actuated mechanical systems, but introduces its own set of problems.

With internal cable routing, you don't get to see much of the cable. This creates the mistaken impression that the cable is protected, when it is really just inaccessible. Everything looks so clean, so aerodynamic. But what you really have are a bunch of little holes into the interior of your frame. It's a Roach Motel for dirt. Dirt makes shifting unreliable.

I turned the bike up in the work stand to check the bottom bracket cable guides. They're the Achilles heel of internal cable routing systems.
At the very bottom of the bike, closest to the ground, the cables emerge from their little tunnels to be routed to the front derailleur through a short little tube, and to the rear derailleur through a longer sewer. Any attempt to clean this area will simply drive little dirt ninjas deeper into the interior of your frame. Your best chance is to change the cables completely, which is a time consuming and finicky task with internal routing.

I blew dirt away with a lateral burst of air from the compressor. Depending on Bernoulli to help me out, I have used directed air on numerous occasions to suck dirt away rather than blow it in. But under the bottom bracket you have openings in at least two directions at odd angles, so you can't really blast away with any method. Or you can try the shop vac.

The shifting seemed acceptable after all that.

The day had started with one brake job after another. The owner of the first bike had taken his wheel out and then squeezed the lever. He'd managed to pry the pads apart and put the wheel in, but said that the brakes didn't work. Every brake job gets written up as a bleed these days, but after I reset the pistons and cleaned the pads and rotor it seemed to be working fine. The gears were a different story. The bike is a Rockhopper 29er, just old enough to have external cables, but they're in full-length housing. The SRAM rear derailleur didn't want to fold up enough to drop the chain onto the hardest cog. Fine silty dirt and a few crashes have stiffened up the pivots so that the return spring can't retract the parallelogram completely. And fully housed cables aren't really better protected from contamination; the housing seems to produce more drag than shelter.

Next up was a double bleed on a Specialized Stumpjumper 6-Fattie that really emphasizes the evolution of mountain bikes into motorless motorcycles. On the plus side, it had SRAM brakes that take the Bleeding Edge tool, which does seem to make the process somewhat easier. I think I only had to redo the rear brake once. The pads were worn an ambiguous amount, so I put in new ones, which stiffened up the lever feel even more. Because I never get to work without interruption, meticulous procedures take even longer.

One interruption came from a customer who had brought his Orbea Orca to have a skipping problem checked out. The chain was so worn, it skipped on the derailleur pulleys. Changing chain and cassette seemed to set things right, but then he rode it and had more problems. I explained that we would ordinarily have started with cables and housing, but that the chain issue had seemed obvious, and cables and housing would have meant stripping off his sexy bar wrap. I'll sacrifice what's necessary to get a job done, but since the look of the bike was obviously important to him I didn't want to shred the cosmetics unnecessarily. Then, as we were examining the bike in the parking lot, we turned it over and found a crack in one chainstay. This was probably not the cause of the chain problems, because the ding from which it originated was small and fairly fresh. The bike did not flex or make scary noises. He's pursuing replacement through Orbea, and came in to discuss riding position and fit issues. That's never a short conversation.

The last brake bleed had to wait until this morning. The bike came from Bikes Direct to the Repair Shop. I assembled it in early July. The rear brake calipers are already a rust pit.

The bike has SRAM Guide R brakes, nominally the same as the ones that behaved reasonably well on the previous day's Stumpjumper, but these have conventional bleed ports. That calls for a slightly more cumbersome procedure, but I've done it before. The wrinkle this time is that the rider and his buddy tried to bleed the system themselves before giving up and bringing us not only their original problem but the results of whatever they had done.

The lever was whacked out. We had to reposition a couple of parts just to set it up according to the instructions to begin the actual bleeding. I'm not sure how they got things as jammed up as they did, but I could not get fluid to go through the system no matter what I did. I finally faced the fact that I was going to have to open up the lever to see why the piston did not want to move.
This isn't all the parts. The real business was still stuck inside the lever body.
Supposedly, when you take out a spring clip and a washer, you can reach in with the tippy tips of needle nose pliers and extract that piston. I couldn't get it to budge. I tried everything, even things that will put your eye out if you do them wrong. Eventually I was able to poke something through from the brake line end of the lever and push the piston out, but it's a very stiff fit. And between whatever they did, and what I had to do to get it out, it ain't going back in.

Of course all parts for this lever are out of stock for at least three weeks.

So there went a couple of irreplaceable hours of my life. I spend most of my time now working on equipment I would never advise anyone to buy, for a riding style that doesn't interest me in the least.

Motorless motorcycles.

If anyone ever did all the maintenance that the fine print tells them they should, they would never have time to ride. But biking is supposed to be cheap. The biggest expense is the bike, right? They're cheap to fix. There's no motor. How hard can it be?

The owner of the Stumpjumper asked me, "Is it a real pain in the ass to work on these things?"

"Yes," I said. "Everything takes longer, so we're making less money, and it's still expensive for the rider. So how's the ride?"

"It's great!" he said. "Wonderful!"

"Well there you have it then."

Even from supposedly reputable brands, low end bikes are shockingly shoddy. The upper end is staggeringly expensive not only to purchase but to maintain, if you really use it hard. Even if you want to settle for fewer features but well made componentry, it's a treasure hunt to find parts, and you'll need to know how to do your own work.

Biking has no use for elder statesmen. Expertise is only good for a short time. Does anyone in mountain biking today care what the pioneers of the sport think? Only if those pioneers repeat currently popular opinion. You're only as good as your last ride.

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