Chain and Cassette Replacement

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Aug 282011
 

Question:
I recently had a mechanic tell me it is a good idea to replace my chain before it wears down my chainrings and cassette. I don’t know how many miles I have on it but I’ve had the bike for three years. Is this the case, and if so, how do you know when it is time to buy a new chain?

Answer:
Your mechanic is mostly right, but it really depends on how much you ride, and your overall maintenance philosophy. There are really two different maintenance philosophies when it comes to bicycles. By way of example, let’s consider vampires.

Subject A–let’s call her “Sookie”–has a bit of a thing for vampires. Let’s just say she’s “known” them (in the Biblical sense). A lot. And because she “knows” vampires a lot, Sookie’s made a commitment to certain things the average Joe might not. She stays up really late, battles witches, and runs and screams a lot. She probably takes vitamin supplements, gets checked for hepatitis and lyme disease. That sort of thing. The Sookie level cyclist “knows” bikes, and is willing to make sacrifices in time and money to keep them performing. He or she usually owns more expensive parts, and wants to maximize the lifespan of those parts. For the Sookie style rider, starting with three or four new chains and alternating them throughout the lifespan of a single cassette is a trick that’s carried over from racing teams, and the logic is pretty simple: cassettes generally cost more than chains (sometimes much, much more) and drivetrain components all tend to wear out together. Chains undergo something called “stretching,” which is really just a loosening of the pins and plates over time that effectively increases the spaces between pins. Once your chain is worn and those spaces have increased, the teeth of the cassette will try to accommodate the slightly different distances between pins on the chain. A cassette adapts to a stretched chain by reducing the amount of material around each tooth–in other words, by wearing out. By keeping a fresh chain on the bike, the teeth of the cassette don’t have to go through that adaptation, and instead get to retain their original shape longer. It’s all about the teeth.

Subject B–let’s call him “Bieber”–wouldn’t know a vampire if it came up and kissed him on the forehead. For him, Sookie’s life seems strange and unnecessarily complicated. The Bieber biker buys a bicycle, rides it, and replaces parts only when it becomes necessary. This person usually puts in fewer miles, and has less expensive parts, so isn’t as concerned with preserving the life of a cassette. Once the whole drivetrain is worn, the whole drivetrain will be replaced. It’s a lifestyle that just works for Bieber, and a lot of us. Alternating chains frequently is a commitment most people aren’t willing to make, even if it does lead to a longer cassette life. For the Bieber, it’s all about avoiding messy complications.

Regardless of which one you most resemble, you can use a simple chain tool to determine if your chain has stretched and needs replaced. Park and nearly every other tool manufacturer offers one of these cheap and simple tools, which is basically a cross between a business card and a ninja throwing star. It fits into your chain and lets you know if it’s still in an acceptable range, or if it’s stretched and needs replaced.

Guilt on Three Wheels

 Bikes  1 Response »
Aug 242011
 

There is no such thing as a boring bicycle ride when you’re towing a child. In various combinations of tandems and trailers, I’ve taken my kids along for some of the best rides of my life, and yet I still can’t figure out exactly why I do this. Kids make everything more difficult, and cycling is no exception. Almost the entire point of a longer mountain or road ride is to leave life’s obligations, including the kids, behind. As anti-social behavior goes, attaching the little creature you’re supposed to love and protect at all costs to a bicycle and venturing out into a world of jagged rocks or blaring car horns requires a contempt for civilized society normally reserved for rock stars and the criminally insane.

First, there’s the equipment: there is no way to infuse one of these rides with Rapha-like panache. Kids’ helmets all tend to be just a little bit insulting. I’d owned a bike shop for a long time, so at least my kids all ended up finding the smallest versions of helmets made for adults–slightly more tasteful black and gray things without any cartoon cats or blue flames–but still, kids in helmets all tend to have a certain look.

On our recent ride, my son Baden wore his custom dryer-shrunk Garneau gloves first inside out, then upside down, before finally settling on simply “on the wrong hands.” I didn’t bother correcting this last one, as they actually seemed to fit better with the thumbs sticking out of the pinkie holes.

At any rate, you and your child, or whatever child you’ve borrowed for the occasion, are going to look ridiculous. Own that ridiculousness. Its stench will distract passers by from the slightly funkier stink of your gross negligence as a caregiver.

Still sketchier than the uniform are the devices that carry kids. While I have deep respect for the “high center of gravity and long way down” variety, I’ve always opted for trailers, and my personal favorite: the half-bike. Variously known also as the “trailer bike” or “half-wheeler,” half-bikes are basically a bike with a boom and angry-looking clamp in place of a proper fork and front wheel. Giant manufactured the particular one I use sometime around 2005, the year my daughter became old enough to grip handlebars and scream “car back!”

It has most of the parts that would make is an otherwise horrible little bicycle–a garbage shifter and a pot metal rear derailleur, along with a giant metal clamp seemingly designed for crushing any modern seat post. (Fortunately, I’ve used several different high quality alloy seat posts from Thomson, Ritchey, and RaceFace, and have rarely completed a ride without the child still attached.)

In the interest of looking ridiculous enough to blind both uneducated onlookers as well as seasoned cycling professionals to my flamboyant negligence as a father, I’ve towed a double trailer with a bright green tandem; routinely picked a kid up from school towing a half-bike on a hipster fixie; and towed a kid on a half-bike which in turn was towing a trailer with two other kids, while riding a Moots road bike with carbon rims. Come to think of it, I might’ve had a carbon stem on the bike at that time, too.

But why? Why go to such lengths to include a kid, or two, or three? For many years, my theory was this: guilt.

Having grown up properly Catholic and thus with a crushing sense of guilt in all things remotely enjoyable, when our daughter was born I somehow convinced myself that the only way I could go do longer road and mountain rides guilt-free, was to take my five-year-old daughter with me. Fueled by guilt and my desire to be on a bicycle and still be a dad, my daughter and I had adventures, including a 35-mile mountain bike ride, a pre-ride on the hairy Seven Springs race course, and an attempt to outrun a dog (fail) that eventually caught us (and bit me). We also slogged up a lot of climbs, including, one summer day, a local climb called Snowball Hill. My memory is still cloudy, and hopefully my daughter repressed the whole thing (I’m pretty sure all my mantras turned to profanity before the first third of the climb had finished turning my legs to jello), but I do remember having trouble keeping the front of the bike down even while standing, having to consciously weight the rear wheel the way I would a mountain bike climb, because the rear tire was squeaking and spinning, and a foot exploding out of my pedal like a bottle rocket and very nearly sending my throbbing knee right into my chin.

It was that climb, more than anything, that first started to put things into perspective for me. Guilt and obligation were playing some sort of enormous role in everything I did. They’d motivated me to build a successful business, but one that was made of fourteen-hour work days and no vacation in over a decade. Here was something significantly wrong with my life, and, though I recognized it that day–and probably every day–it would still take me five years to sell the company, nearly kill myself in an uphill battle to keep it alive under the new ownership, grow painfully disillusioned, and finally walk away. I quit. Having relocated to Chicago to oversee the company for the new owners, I made the long drive home to my family in Pennsylvania, broken but happy. For fourteen years, each day had handed me an absurd list of challenges and dared me to blink. Now I had, and there was a kind of dizzying freedom in that. I had been doing what I thought I was supposed to do as a husband and a father, even though it was keeping me from being both.

So there must have been a certain look on my face when one of my twin boys, Baden, declared–seemingly out of the blue–that he wanted to ride up Snowball Hill with me today, like I had with Riley years ago.

My wife was at work, my daughter was in Montana with my in-laws, and my other son was at a party. I could have left Baden at the party, too, and done a perfectly enjoyable ride all by myself like any red-blooded American Male, but Baden wanted to try to ride up Snowball Hill together, and something other than guilt seemed to be driving me to smile and nod. I wanted to see if we could do it.

As omens go, before we’d made it anywhere near the climb, a sudden weight shift from Baden as a truck passed us had hauled me off the shoulder of the road and into a gravel rain gutter, which we rode for a while (the decision to go with the ‘cross bike instead of a full-on road bike was looking wise) before I could get the whole contraption stopped. There followed one of the weirdest moments in my life. Both legs and hands still visibly trembling from the “incident,” I proceeded to deliver a speech about road etiquette that quickly turned into a tangled mess of memories. When you hear a car coming, don’t turn around to look at it. Here I was once again explaining that. Here I was in that moment with one of my kids. An odd mix of calm mingled with the twitching terror still dancing around in my legs and arms. The cumulative effect being witnessed by passing motorists probably resembled an interpretive dance expressing a nervous breakdown, but I was riding a bike with one of my kids, and I was having a good time.

I am not, like Sting or the men in infomercials, more fit at 40 than I was at 25. And I wasn’t very fit at 25. As I remembered it, Snowball Hill was made up of three tiers. A long, grinding initial slog under a canopy of oaks and maples emptied out of the trees into a stretch of bleached pavement that looked almost vertical in the distance. As we cleared the last rise of the first section and saw the next climb on the road ahead, my son said, “I looks like somebody put pavement up a building.” It was such a horrible thing to be spoken at that point that I actually started laughing. He also asked if that was the end, and of course, it wasn’t. Beyond that I knew one last kicker was waiting to cut short any celebration. Taken alone, the last twisting left-hand climb wouldn’t have been so bad, but, following the first two sections, the last kick upward was also a beast. There was a cemetery on the right of the last section, which always seemed convenient.

We put in a valiant effort, but in the end we had to stop almost exactly where I’d been forced to stop with my daughter Riley years ago. And just like then, I was somehow able to get started up again by cutting diagonally across the road to build speed then yelling for Baden to lean into the hill and carving back into a straight climb up it again. I gave up trying to control my breathing and went with more of a dying Shakespearean villain sound that could probably be heard for quite a distance. All the while, Baden was talking, explaining some complex geometric principle at play in the design of Legos. There was only a brief moment of quiet in the middle of my breathing process where I could actually hear him, but I could tell that he was talking non-stop. I imagined him still talking, even if I fell off the bike and rolled slowly back down the hill. He’d roll into the grass on the side of the road the way I’d shown him in case we ever wrecked, struggle to drag our mess of bikes off the road as best he could, and then start walking back down the hill to finish telling me something.

It hit me then that there was something other than guilt at work here. I loved this. I was happier with him there at that moment than I would have been alone–happier even than I would have been with friends. I was standing, trying to keep the mad swaying of the half-bike under control, trying to keep the front of my bike down, and trying to keep my revolutions from slowing to a complete stall, but I was genuinely happy. I was happy because Baden was happy, and because it was a beautiful day, and because we were alive, and my son Beckett, frozen in the air with a look of wild abandon just above the surface of a swimming pool, was alive, and my daughter, watching mountain goats through binoculars in Glacier National Park, was alive. Even if we all wouldn’t be like that forever, we were right then, and I wanted to be towing all of them up that hill while they talked about Legos, and lizards, and books they’d read. “Dad,” Baden said, expecting a conversational response in that way he has of being completely oblivious to the severity of a situation, and I loved him for it. It might’ve just been the lack of oxygen, but for a moment there, I wanted the climb to just keep going.

Speed Compatibility

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Aug 222011
 

Question:
Compatibility Question for Mr. Manic… I understand that SRAM and Shimano derailluers are not interchangeable because of the amount of cable the shifters pull, and the resulting movement of the parallelogram linkage in the derailleur, right? But what about using a 10-speed SRAM shifter with a 9-speed SRAM rear derailleur? Mountain doubles make so much more sense to me, but I don’t want to spend my hard-earned cash for a new derailleur if the old one can be made to work.

Answer:
Right on. If you’re looking to simplify your life, a double chainring configuration is a good start. Only three things in this world are worse than a mountain bike with a triple chainring crankset: cannibalism, Russel Brand, and a road bike with a triple (in that order). Unfortunately, you can’t substitute a 9-speed SRAM rear derailleur for a 10-speed model. I know it seems like you should be able to do this, but, according to SRAM, the “Exact Actuation” leverage ratio found on all their 10-speed rear derailleurs is actually different from the “1:1” ratio used on 9-speed derailleurs, so trying to mix those up would lead to the same kind of shifting problems you’d encounter if mixing SRAM shifters and Shimano rear derailleurs. Even though the shifter is the brains of the operation, telling the rear derailleur how much to move for each shift, the leverage ratio on the rear derailleur ultimately determines how to translate those increments, and the 9-speed derailleurs don’t use the same ratio as the 10-speeds.

If making the move to 10-speed all at once is a bit much (now that rear derailleurs cost more than many bikes), consider going with a 9-speed double ring configuration. Most 11-34t 9-speed cassettes offer a pretty broad range, and it turns out companies like Blackspire offer chainrings purported to work with both 9 and 10-speed systems and available in hip, dualie configurations, like a 26-tooth inner ring and a 38-tooth outer. Once your ship comes in, you could buy a 10-speed rear derailleur, rear shifter, chain, and cassette, and become what historians call “contemporary.”

Size Matters

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Aug 202011
 

Question:
I need to replace my rear derailleur. What are the differences between the short/medium/long cage? Does the length of the cage matter that much?

Answer:
The easy answer is, if you have to ask, get a long cage. A long cage will work in every situation. I’m one of those “teach a guy to fish, so he quits asking me to give him fish” types, though, so let’s impart us some knowledge.

Understanding the differences in cage length means understanding both things a rear derailleur does. We all know a rear derailleur moves the chain in and out from one cog to another, but the other, equally important thing a derailleur does is move forward and back, taking up chain slack that varies as you change gears. Imagine your geared bike as a singlespeed with a bunch of gears in the back, but no rear derailleur. Suppose you had a chain that was the exact perfect length to wrap around your 32-tooth ring up front and your 34-tooth cog in the back without being too tight, or too saggy. Great. Now leave the chain on the same ring up front, but move it to the 11-tooth in the back. Saggy, isn’t it? If only there was a way have the same length chain adjust itself for smaller or larger gears. Luckily, a bunch of people in the 1800s had the same problem, and realized some sort of spring tension on the chain was the answer. The bigger the difference between the sizes of your gears, the more chain you need your derailleur to be able to take up. The ability of a rear derailleur to handle a range of chain lengths is referred to as the derailleur’s “chain wrap capacity.” You can calculate your chain wrap capacity by subtracting the number of teeth on your largest front chainring from the number of teeth on your smallest front chainring, doing the same with the gears on your rear cassette, then adding the two values. So necessary chain wrap capacity on a bike with a 44-tooth big ring, 22-tooth small ring, and 11-34-tooth cassette, would work out like this:

(44-22) + (34-11) = 45

The longer the cage of a rear derailleur, the more flappy chain it can pull tight, so the wider variance you can have between gears. Sometimes a manufacturer will tell you the chain wrap capacity of their rear derailleur, but the bottom line is you should always be sure you have enough chain to reach every gear combination—even the crossed-up ones you shouldn’t use, but might shift into accidentally. For most mountain triples, that amount of chain requires a long cage rear derailleur, and those work just fine.

So why do people try to use any shorter cages? In theory, a medium or short cage derailleur may shift just a fraction better because a shorter cage equals a stiffer cage, and they’re slightly less vulnerable to getting smote by rocks and the local flora, so experimentation is fine, provided you’re careful. In fact, most configurations will accept a medium cage rear derailleur, but only if chain length is set up carefully, and you error on the side of leaving more chain than you think you need. It also helps if you get rid of your biggest or smallest cog to lower that required chain wrap number. For most people, the added risk and configuration challenges aren’t worth the time, making the long cage the go-to option.

Sticker Shock

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Aug 152011
 

Question:
I have acquired a used XT 770 crankset. The big ring is trashed and I am going into sticker shock at Shimano’s replacement prices. Anyone have luck with other brands i.e. Blackspire, FSA, Race Face for this particular model? I have a hard time throwing down 60-100 dollars for a chainring that is not going to last long.

Answer:
I sympathize with your plight. Shimano does seem to subscribe to the same OE replacement parts pricing as car dealerships and national defense contractors. The big ring on a 770 series crankset actually has a 104mm 4-bolt pattern, the same pattern used by most other brands, so other rings will match up, but be careful. Much in the same way you can’t imagine being married to a unicorn or living in a world where dogs can drive, Shimano can’t conceive of a world in which people buy FSA or Blackspire rings and bolt them to their XT cranksets. If you know the history of Shimano chainrings over the past few years, you’ll appreciate what a miracle it is that even the bolt pattern happens to match now.

So the good news is that nearly everyone makes an aftermarket 104mm bolt-pattern 4-bolt 44-tooth ring that will match up to the bolt hole pattern on your 770 crankset. The bad news is that it won’t work as well as the Shimano. This is partly because Shimano just makes excellent cranksets and chainrings, but mostly because all Shimano parts are designed specifically to work only with other Shimano parts. They don’t intentionally prevent other rings from bolting on, but they don’t test for them either. This means that, even if something else can technically bolt up, it probably won’t mesh all pro-like to the crankset’s spider–it will most likely be slightly too wide or too narrow, and some rings may even need sections filed down if they’re making contact with the Shimano spider or arm itself. Generally, a Shimano crankset with another company’s ring on it also won’t shift as well, because chains, chainrings and cranksets are one of the things Shimano still does extremely well.

So it comes down to you: if you’re the ultra anal-retentive type who demands perfection, you should shell out for the Shimano ring. If, on the other hand, you’re more the frugal rebel type who can smile while pressing a shifter paddle a bit harder to convince the chain to shift into a less expensive big ring, look for the most basic-looking 44t 4-bolt, 104mm bolt pattern ring you can find and get your rogue on.