My sick bike

One of the requirements of the MS 150 is that bikes be inspected at an MS 150-approved bike shop.  Luckily for me, the shop where I bought my bike and have it serviced is one of those.  I called, and asked to make an appointment to bring the bike in.  They said I wouldn’t need an appointment for that, so I put the bike in the car, and drove over.  

I was waited on by the only mechanic in there who didn’t have arms, neck, and other places decorated with tattoos.  (I’ve come to believe that tattoos are part of a bike mechanic’s uniform.)  He put it on the stand, and started going through the inspection, spinning the pedals, shifting through the gears.  Then he picked up one of those gizmos you use to measure chains.

“Uh oh,” he said.  “This chain is worn.  In fact, I’d call it ‘beyond worn.'”  Was it shifting OK?  Yes, I told him.  “Ugh.  That’s bad,” he grunted.  Huh?  “It means the cassette has worn along with the chain,” he said.

How many miles are on the bike?  About 3,000, I said.  “You really need to replace the chain every 1200-1500 miles,” he said.*

He went into a back room, and came out with a new chain.  “This is a Shimano 105 chain for nine speeds,” he said, “so it’ll match your drive train.”  He put on the new chain, adjusted the cable tension, and told me to do a parking lot test with it.  “Really mash down on the pedals when you shift gears,” he said.  “But be careful.  The chain might pop off.”  

I took it into the parking lot for a quick spin.  The chain didn’t pop off, but shifting was clunky.  Back in the shop, he made more adjustments.  I took it to the lot for another spin.  This time it was better, but still clunky.

“Yep, you need a new cassette,” he said.  I was surprised to see that his computer search of their inventory turned up no 12-28 nine speed Shimano 105 cassettes.  I thought it was a model in wide use.  “The 10-speeds are taking over,” he said.

He found another, a SRAM, that he said would work fine, and put it on order.  In the meantime, I can ride the bike, he said, but he again warned me about the possibility of throwing the chain.

When I first saw that the MS 150 required bike inspections (they put a little sticker on your stem to show that you’ve had it), I thought it was just another pain in the butt.  After today’s experience, I’m glad I went.  The new chain and cassette together, and the labor to install them, will come in well under $100, and I’ll have peace of mind that on a 180-mile bike ride, at least I won’t be worried about that.

*There is apparently much debate about that.  The late Sheldon Brown’s thorough discussion of chain wear doesn’t mention how often it needs to be replaced.


  1. says

    IMHO, the reason why Sheldon (or any other expert, for that matter) doesn’t discuss how often it needs to be replaced is that 1000 miles on my bike is different from 1000 miles on your bike. We each use different gearing and different brands of chain and have different sorts of crap getting deposited on our bikes and whatnot. So you cannot make much of a mileage-based assessment of how long before a chain is worn because the guy who rides sand dunes isn’t going to have much chain life.

    Pretty much, best way to check is to examine the chain length, like Sheldon says.

    And if you compare a chain for a 9 or 10 speed cassette (meaning really an 18, 27, 20, or 30 speed bike) vs something for an old 10 speed bike made back in the day, you start to realize that compared to back then, we go through chains like tissues these days.

    Now, the ways and means of how to make it last longer.. that’s a matter for holy wars on Internet forums.

    As a matter of perspective, my bike has around 2300 miles on it and I just put the third chain on… although the most recent chain was only about 50% to gone when I managed to bend a link.

  2. says

    I’ve got 900 miles on my chain at the moment, it has stretched by 1/32 of an inch. When it gets to 1/16th I will replace it. Hopefully this will be in around 600 miles time but it may come earlier. I may even get lucky and have it last another 900 miles.

    From what I understand, for optimal shifiting, a chain replacement should happen when the chain has stretched by 1/16″ and the cassette should be replaced with every other chain. Alternatively you could wait until it has strecthed by 1/8″ and replace both the chain and cassette at the same time.

  3. says

    I finally went out and got a park chain checker that I keep in the top drawer of my tool box. Any time one of my bikes comes in for any other work, I check the chain wear. I know you can do it with a ruler, but the actual tool is cheap and makes it that much faster and easier to do as a matter of routine. I had to do the whole chain/cassette/rings replacement once and even with a prodeal and my own labor, it felt pretty expensive.

  4. tracywilkins says

    You know that chain/cassette replacement question is kind of sticky wicket for me. I try not to replace the chain until it’s necessary (by measuring), but then when I do and don’t replace the cassette I very often get cruddy shifting. If it’s not too bad, I’ve been known to live with it, but have found that doing that seems to cause pre-mature wear on the new chain.

    I guess the only sure-fire way to ensure smooth shifts is to replace them both at the same time every time.

  5. CR1 Rider says

    Was all this work done on the Specialized Elite? If it has a compact crank (34/50) you have some major low gears with the 12/28. Anyway, I once was told the same thing about my chain/cassette needing replacing, went to a pro mechanic and he told me no way. The chain was not even close to needing replacing. If you take good care of your drivetrain, you shouldnt need to replace all that that soon. If the bike was not shifting properly or skipping gears that would be a sign of replacment needed. IMO

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