Sunday, November 28, 2010

The Ibis Remains Grounded

To continue my ultra exciting series on the dead Ibis, I present yet another chapter. Crank up the DVR, this may soon be a mini series on the Fox network. To refresh your memory, Chapter 1 starts with the rear derailleur mysteriously exploding off the spiffy carbon Ibis, during a commute home - many weeks ago. Quite strange.

Chapter 2 included replacing the derailleur hanger, only to discover the derailleur itself completely tweaked - so replaced as well. However, shifting was still off and no time to further diagnose. With my annual winter slump starting a bit early (burp), 'cross races, recent snow, the old school steel Ibis still functioning, and mountain biking on (most) weekends - the carbon Ibis remained hanging in the garage. Today I took some time to look at it once again, so I now present Chapter 3 of this saga. Time to pop some popcorn and break out the hankies...

After I threw the bike on the workstand, didn't take long see what's up. Please note the chain about to separate, masterlink pin poking out from the side plate. Yikes. That could have been ugly, if snapped during a sprint or powering up a hill while standing. The chain is also twisted a bit as well. I don't know if this occurred while the hanger busted, or somehow caused the whole mess, or even during test riding after installing the new derailleur and hanger. Weird chain of events - pun intended. In any case, the chain is toast.

Here's where it gets fun - and expensive. The entire drivetrain has almost 10,000 miles on it - so, the cassette, chainrings and chain have all worn together. Installing a new chain to the worn cassette and rings is just asking for shifting woes, skipping chain, and other festivities of doom. There's two schools of thought for drivetrain maintenance. One is to replace the chain regularly, before it wears, increasing the life of the cassette and chainrings. The second is to wear everything out at the same time, then replace all at once.

I subscribe to the second theory - kill and replace all at once. I think the cost breaks out evenly, since replacing the chain every 1000 miles or so, at a cost of $30 - $40 a whack, means I would have worn out $300 worth of chains already. Even if the chain was replaced every 2000 miles, we're still talking $150 and the time spent measuring and replacing chains. I'll probably spend $200 to replace the Ultegra cassette, chain and chainrings. Get the picture?

I already had a new Ultegra chain on the workbench. Let's see how far the worn chain "stretched" in 9500 miles, compared to a new chain. How does a chain stretch? As the many pins and rollers wear, they develop more play, increasing the length of the chain. Here you can see the pins of both chains look fairly even at this point.

By the end of the chain - not so cool, eh? The worn (dirty) chain on the bottom is few millimeters longer. As you can see, the pins no longer line up. The cassette and chainrings have also worn to match the chain. A new chain added to the mix is a recipe for headaches.

Please note: The new chain has yet to be cut to the correct length - that's why it's a few links longer. I hope you enjoyed this little Bike Repair 101 course. Yes, this will be on the final exam.

The Ibis will remain without a chain until I dig up everything needed to make it fly once again.

With that, I hereby end this tale of woe for now. With the old school steel Ibis requiring a drivetrain replacement as well - though still rideable - and Christmas looming around the corner, this Ibis may remain grounded for a bit longer then expected.


  1. Poor poor IBIS, my Trek Xo2 CX is about there too. About 10,000 miles on drive train. I'm thinking whole work$$$$.
    I guess addictive habits are costly.
    Keep on riding bro.

  2. Just went thru some of this on my Mountain bike, a real headache, lucky for you, you have Steel, Steels the Deal