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Technical FAQ with Lennard Zinn: Chain wear, shifting issues and powder coating

  • By Lennard Zinn
  • Published Dec. 14, 2011
  • Updated Jan. 5, 2012 at 1:40 AM EDT

Replacing a chain before it becomes severely worn saves wear and tear on more expensive components.

Q. Dear Lennard,

I have a Dura-Ace 7900 chain and cassette (11-25) with 5000 miles on them. What is the rule of thumb on replacement? It seems to work fine, but the LBS advises me to replace them. Seems to me I should just ride until it gives me a bit of annoying feedback. Also I am pretty light (140 pounds) and ride at a pretty high cadence (100 rpm). I figure a high cadence will be putting less load and wear on the drivetrain, even though it goes around more. Make sense?

—Andrew

A. Dear Andrew,

No, your approach does not make sense to me. If you replace your chain before it gets too worn, then you won’t have to replace the cogs or chainrings, both of which cost many times more than a chain.

Yes, your theory makes sense if and only if you only have one rear wheel and you never interchange it. Then you can in theory just keep wearing everything out so that your chain, cogs and chainrings are all shot. At some point, even though they’re all worn together, there will be a time when the rear cogs become so hook-shaped that they still can’t keep the chain from skipping, but that will probably be many years down the road. But at no point (you may already be there after 5,000 miles) will you be able to put somebody else’s wheel on there without ruining his or her cogs within a single ride.

I personally cannot tolerate riding on stuff that is worn out and trashed and doesn’t work as it was originally intended. I don’t let it happen to my car, and I certainly don’t let it happen to any of my bikes. I am convinced that maintaining equipment to its recommended specification also saves money over the long run.

For instance, I have three cyclocross bikes with Campy 10-speed components on them, and I have 10 sets of cyclocross wheels with Campy 10-speed cogsets on them, many of them being Record titanium ones. I replace chains quite frequently on those bikes (I certainly do not get a full cyclocross season out of a chain, even though I’m spreading the usage over three bikes), not only because cyclocross is hard on chains, but also because I refuse to run the risk of ruining all of those expensive cogsets.

I know from making this mistake back when I was a 20-year-old Cat. 1 racer that all it takes is a single, short race on a worn chain to ruin a new cogset. I did it in a single criterium. Back then it was the entire freewheel that had to be replaced, not just the cogs, and on all of my wheels, because I hadn’t noticed how worn the chain was until I got out in that criterium with my new straight block on, and it started skipping like mad as soon as I got out of the saddle to close a gap. When I put a new chain on right afterward, it skipped on that once-used freewheel (as well as all of my other ones that the worn chain had ruined).

I’ve gone over how to check chain length (changes in it equate to wear) in this column many times, and I describe and illustrate many methods of doing it in all of my “Zinn and the Art of” maintenance books. Suffice it to say that if you get a ProGold chain wear gauge and replace your chain when it hits the 100 percent line when you flip the hook into the chain, you will get very long life out of your cogs. I replace all of my chains before the ProGold gauge gets to 100 percent, or as soon as the Rohloff gauge on the “A” side drops fully into the chain.

—Lennard

Q. Dear Lennard,

I have a 2011 SL3 frameset that I had built up with 10-speed Ultegra shifters and Dura-Ace front/rear derailleurs. My LBS mechanic has done his darndest (as have I) to achieve a measure of consistent and reliable shifting at the rear. Despite his eminently capable best efforts the shifting still requires over/under shifting efforts to get to a desired gear.

I have run a Gore totally sealed cable on the brakes and have absolutely no problems and also the front shifting is spot on. I would like to use the rest of the Gore brake/shift kit to try to remedy the issue but the shift cable portals/stops on the frameset will not accommodate the diameter involved with the Gore housing.

I have had zero joy in going through Specialized customer service and my shop’s sales rep on trying to acquire brake cable stops that I could screw into the frame in place of the OEM shift stops.

—Trey

A. Dear Trey,

You didn’t mention which SL3 it is; it makes a big difference, since it could be either a Tarmac SL3 with external cable routing or a Roubaix SL3 with internal cable routing. If it’s a Tarmac, you should be able to see where the cable is being impinged upon and correct it. And if it is indeed a Tarmac, it’s surprising that the external stops don’t fit Gore housing.

With any bike, make sure the derailleur hanger alignment is correct; your LBS mechanic should have the tool for this, and he can correct alignment with it; if it’s not right on, you’ll have problems. Also check the B-screw adjustment on the rear derailleur to ensure that the upper jockey wheel is as close as can be to the cogs without actually pinching the chain against them. If those details are fine, you might even check frame alignment with a string test, but with a molded-and-bonded frame like this, it’s a bit hard to imagine that it’s off significantly.

If it’s a Roubaix, then you should check that the cables are not twisted inside the frame. When threading the cables through the frame, the second cable can get wound around the first cable. When shifting, the cables will pull on each other and not only cause drag but also affect each other’s tension; this can obviously give you problems. Specialized offers this link to the cabling instructions for running the cables through the Roubaix SL3; follow also the link to the video demonstrating it: http://bit.ly/sBJp1o.

—Lennard

Q. Dear Lennard,

My Felt F50 is looking pretty shabby and I want to get it powder coated. Here’s my question. The seat stays are carbon fiber, bonded to both the seat tube and chain stays. Will the powder coat curing process (bake at 400 degrees for up to 45 minutes) compromise either the bond between the stays and the frame or the stays themselves?

—Jim

A. Dear Jim,

Don’t do it! Your bike has an aluminum front end and a carbon rear end. There are a number of problems with powder coating a frame like this.

First, powder coating is an electrostatic process, and the charged powder particles need an oppositely charged metal substrate to attract them. So your front triangle would attract the powder and allow the powder to distribute evenly over it; your rear end would not.

Secondly, the heat required to melt the powder and let it flow out to form a hard, glossy surface would soften the resin in the carbon matrix of the rear end as well as soften the glue bonding it to the front triangle. Obviously, you don’t want either of these things to happen.

—Lennard

Q. Dear Lennard,

I saw what you wrote to Ole in a previous column about using 11 speed Campy derailleurs with 10-speed shifters. I had had a similar thought once, and asked Campy directly about this. Apparently the design of the 11-speed derailleur is different enough that the two are not compatible.

―Jon

Q. Dear Lennard,

The recent Q & A about headset wear leads me to wonder if transporting a bike on a roof rack is harder on a bike than a trunk or hitch rack. With the fork clamped firmly to the vehicle road shock is transmitted to the bike up the fork and the headset. In like manner, wind loads at speed are borne by the fork and headset. A trunk mount usually cradles the top tube, and can have extra padding as well. Which is best?

―Michael

A. Dear Michael,

A roof rack is harder on the headset, if you’re driving on rough roads. But otherwise, I don’t think it matters as long as you don’t run the bike into garages or awnings with a roof mount, or get run into from behind with a hitch mount.

―Lennard

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Lennard Zinn

Lennard Zinn

Our longtime technical writer joined VeloNews in 1987. He is also a framebuilder, a former U.S. National Team rider, and author of many bicycle books, including Zinn and the Art of Mountain Bike Maintenance and Zinn and the Art of Road Bike Maintenance, as well as Zinn and the Art of Triathlon Bikes and Zinn's Cycling Primer: Maintenance Tips and Skill Building for Cyclists. He holds a Bachelor’s degree in physics from Colorado College. Readers can send brief technical questions to Ask LZ.

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