Modern Marvels

Frustrating week in the old repair shop so far.

A customer has been having shifting problems with his fancy carbon road bike. This is not uncommon. Cram ten gears in the space formerly occupied by eight and fractions of a millimeter make a difference more than ever before. Thin out the side plates of a chain by a few more thousandths and you get links that twist when you look at them.

The bike industry continues to nurse the illusion that technology will rekindle customer interest. Safe and enjoyable places to ride will rekindle customer interest. That is all. People flocked to mountain bikes because they could be ridden on rougher trails well away from motor traffic. The few hard-core riders who were beating the shit out of themselves and their equipment might have wanted clicky-click shifting and expensive, complex suspension, but the rest of the riding public just had it crammed down their throat along with step-in pedals and shoes that will only work with step-in pedals.

But I digress.

As a mechanic I get to reap what the industry sows. This week it was Shifters That Do You Wrong and the Industry that Loves Them. Two separate bikes had 105 STI front shifters that would for no obvious reason just lock up and leave the chain on the big ring. These are brand-new levers on brand-new bikes. The clicks feel just subliminally mushy. Disconnect the derailleur and pull the cable with all your strength and the shifter functions. Hook it to a front derailleur and it might work or it might not.

The rider bent his chain when it high-sided off the outside of the big chainring. I replaced the original equipment KMC with a Dura Ace. Since this was before his front shifting problem became really apparent, we sent him off to play. He came back reporting that the chain would drop onto the top of the inner chainring and ride over the teeth instead of falling all the way down and engaging them.

We've seen this problem before. It used to happen when replacing mountain bike chainrings, especially granny rings, and middle rings on Shimano cranks that required the use of annoying thin spacers to make up for someone's lack of engineering skill in designing the crankset in the first place. Often one could eliminate the annoying spacers by installing after-market rings. Get the spacing a little wide and the chain might not fall correctly.

With more and more cogs, narrower chains and a complete reliance on index-only systems that make rider skill completely irrelevant, we all depend on the machinery to function perfectly. Students of Japanese military history know that we may well owe our victory in the Pacific in World War II to this dependence on perfection. That and the fact that Shimano was making the guns, so every six months they needed a completely different size ammunition.

Yeah, this stuff works great until it doesn't work at all.

The Dura Ace chain is two tenths of a millimeter wider than the KMC. You'd think this would make it less prone to hang up, but no. Swapping parts back and forth to test every possible combination, we discovered that the KMC hung up much less than the Shimano on the bad crank.

The crank, an FSA, is the same brand that gave us similar fits last year on another rider's brand-new bike. It really only takes a tenth of a millimeter to make something go wrong like this when the difference between a nine-speed chain and a ten-speed is only half a millimeter. You might have a couple of tenths to play with, but when you get to the limit you get an error that acts like the whole difference, not just the last fraction.

We had to cannibalize two new bikes from the sales floor to get our customer's bike working again. And the manufacturers always act like they've never heard of such a thing when we report this stuff from the field.

I'm pleased to say that history generally vindicates us greasy grunts in the end. No shit. It really didn't work and it really was a design or manufacturing flaw. We don't usually get the satisfaction of a confession, but we get to see the change in the next production run.

While we wait for replacement parts for the bikes we plundered to keep our customer happy, I continued to play the Compatibility Follies on a mountain bike a long-time customer had brought in for service a week ago. It's a 1995-ish Cannondale front-suspension mountain bike, ridden hard but not abusively. We've replaced parts as expected over the years. This year it was time for major drive train work.

The bike had one of Shimano's grand illusion cranks from that era. At first glance it looks like it has replaceable chainrings. Yeah? Just try to replace them. If you were so fortunate as to bend or wear out one or more within a couple of years of buying the bike, you might have found the proprietary middle ring as a replacement part. Fat chance now. Fortunately, there's a nice replacement crank with genuinely replaceable rings, for less than the cost of a complete ring set. Unfortunately, it takes a different length bottom bracket spindle. His original UN-51 BB has seen a lot of water, so a new BB couldn't hurt. But the spindle that supposedly goes with that crank put the chain set a hair too far out. This wasn't clear on the stand or test riding on smooth terrain. Since the customer had come from another town and was waiting, I gave it a quick spin and sent him off.

He returned the bike yesterday, reporting that it spits the chain off both ends. Hmm. Chain line problem. No problem, really, we can just tuck it in a little closer with a 115 instead of 118, and tweak the limit screws on the rear derailleur to account for the bushing slop that allows the chain to hop off the inside on the back end.

Good so far, but the twelve- or fourteen-year-old front derailleur is too sloppy to shift cleanly to the granny, especially with the chain set tucked that extra couple of millimeters closer to the seat tube.

It's okay, I have a Deore LX front derailleur.

No it's not okay, this is a nine-speed derailleur. Its narrow and deep cage absolutely will not shift on a seven- or eight-speed crank.

I wanted to get drunk. Very, very drunk. I just didn't want to remain that way for the full duration of an actual drunk.

Stuff like this is why I drink too much coffee. I can slug that stuff with far fewer adverse consequences than guzzling scotch or rum when the frustrating stupidity of modern engineering and marketing drives me to distraction. Why should I have to keep apologizing for the bike industry? Frankly, I don't. My boss hates it, but I refuse to stand out there and act like something's great when it's poorly-thought-out bullshit.

I started the morning by fixing my own bike so I could ride to work. Turns out the busted nipple wasn't the only problem with my everyday wheel. When I put it in the truing stand to touch it up after replacing the nipple, I discovered a big split in another section of the rim. I've put it through hell, I can't complain. But I didn't want to ride to work with my 11-30 touring and exploring block on the back. I hate the steps in that cluster. I'm going to assemble my own, probably using separate Miche cogs, but that's another project (and blog) for another day.

For this morning, I put a new 7-speed 13-28 on my 8-speed rear hub, and slapped the 11 from the 11-30 on to fill up the space. So now I had an 11-28 eight-speed. No one on Earth needs to ride an 11 for the big meat, but better to have a gear I will barely use than a spacer that gives me nothing. When I build my fantasy cluster I'll have a first-position 13 and tighten up some of the steps in the middle on the way to the 30 or 32 at the top of the eight. I just haven't decided where to put my extra close step.

Never more than eight speeds. Always friction shifting. There go 90 percent of your compatibility problems.