Dental Care for Cogs

Dental Care for Cogs

Of the many tricks I learned as a mechanic, few have had the lasting utility of the folded T-shirt pulled taught. Greg LeMond was on his way to winning his second Tour de France when a co-worker showed me how to fold an old T-shirt and grab the crease so that I could slide it between two cassette cogs and wipe away dirty chain lube and grime. Holy cow.

So effective a technique is it that I have employed it ever since. I’d have written “ever after,” except for three reasons. First, this isn’t a fairy tale. Second, I’m not dead yet. And third, because Finish Line.


Gear Floss, Finish Line calls it. I’m going to venture that if such a name isn’t self-explanatory to someone, that person doesn’t work on their bike to any great degree. Nothing wrong with that. Lucky are they who can pay others to do their bike work. Okay, maybe hard-working is a more accurate term. Nothing against those who work hard and can’t afford to pay someone else to work on their bike. Or against those who still like working on their bike. Oh heck. See where this is going?

Okay, Gear Floss. This stuff is terrific. It’s fluffy in a way that T-shirts are not. Because it’s fluffy, it absorbs degreaser in a highly useful way. It’s long enough that you can get all the way around a really big cassette or even chainrings. Liberal application of degreaser will keep it useful even long after it’s turned black.


I’m not a big fan of scrubbing things with brushes unless you’ve got a significant enclosure, like saying the cooling tower of a nuclear plant. Every time one of those little bristles lets go, there’s a fine misting of blackened degreaser. There’s no T-shirt on earth black enough to hide it. Exposed skin ends up looking like it’s been exposed to some zombification process in a post-apocalyptic movie. Not quite my fave.

So, down on brushes. Up on floss.

For $6.99 you get 20 ropes that are 20 inches in length. It takes me about three of them to get through a full cassette. One more will get me through the worst crannies of a crankset. These are handy in that they’re easy to pick up by the end and set aside once thoroughly used. The same is not necessarily said of T-shirts. More than once I forgot that I’d used a T-shirt for cassette duty only to grab it an hour later and end up with a hand grimier than tar sands. D’oh.

Final thought: If only it came in mint or cinnamon.

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  1. Mike

    Or, you can go to the dollar store and buy 10-15 packs of cheap wash cloths. Each cloth has two sides and four ends. In fact, it’s best to wipe the bike down first, then use the cloth to do the cassette.
    The rope cleaners have been out for a while, but it’s not good economy.

  2. Shawn

    Not bad Finish Line, not bad at all. But . . .

    Pro Tip: Fat shoelaces for kids’ shoes are the go-to cog cleaners. And when the pile of used ones is large enough, they get recycled for another round of flossing thanks to the washing machine and a delicates bag.

    1. Jon

      I’m hesitant to throw my shop rags into the washing machine for fear that it will get grease everywhere and render the machine unusable. What’s your experience with that?

    2. Author

      I used to throw my rags in the washing machine, but that was back when I owned it. I don’t own the one I use now, and as a result, I don’t want to risk doing anything that might leave a residue on plastic parts. After running rags through, I’d use Simple Green to clean the washer. Worked pretty well.

    3. Shawn

      Almost all of my rags go in the machine. Detergent is a degreaser, so no real problem there.

      But I’m reasonable about it. I wouldn’t subject my poor washer to a rag that I had used, for example, to scoop the grease out of an automobile CV joint, or to wipe down the catch basin after changing motor oil.

      And for the sake of your relationshio, don’t throw the dirty rags in the same load with your wife’s clothes!

  3. Kimball

    I did the t-shirt rag thing for years, but a few years back I picked up a 50′ package of 1/4″ cotton rope at the hardware store for less than $5. Cut a 2′ piece, dip it in degreaser or paint thinner and start flossing!

  4. jham

    first off. Love the blog and podcasts! a few years ago I ended up with Finish line floss. Not sure I can escape admitting that I actually paid money for it. Not one of my better moments. Somehow, a bag of rags and old tees got trashed and my cogs were in dire need of cleaning.
    This floss is mediocre. It doesn’t work as well as a rag soaked in degreaser.
    I only use brushes to scrub the crust from spilt lattes and mochas from underneath the downtube and bb of my city bike.
    Bot does that sound rediculous!

  5. John

    I’ve been using a thick chenille yarn, just the right size, absorbs and releases degreaser where it’s needed, and at 4.99 for 30 yards of the stuff, I’m good to go for a couple of years, no matter how obsessive I get.

  6. Eric

    I use a 2 dollar mop head. Every time I clean the cassette, I cut a strand off and have at it. I’ve been using the same mop head for about 2 years now and from the looks of it I still have at least another decade left.

  7. David Gordon

    Eric, thanks the mop head tassels sound like the perfect thing, and CHEAP. I’ve always found that I end up with enough worn out t-shirts to match the supply that I need for my cassettes. I always preferred the collar part, because it was stronger and about the right thickness, 4 between the cogs.

  8. hautacam

    +1 on old t shirts, bed linens, whatever. Just rip a 1-2″ wide strip off, maybe 12″ long, and voila, instant cog floss. I wear undershirts under my dress shirts and they get replaced when they no longer pass inspection, so I cycle new ones into the garage every 12 months or so. Chuck the strip after a couple uses and call it good.

  9. Aaron J. Humphrey

    I use hot paraffin wax on my chains, soaking them in a mini crockpot for about 5 minutes when they start making noise. Once they cool, the wax pops off the plates but stays in the bushings, and they don’t attract dirt. No chain tattoos, smudges in the car, etc., and my cassettes are all shiny and clean. I used to just use the edge of whatever shop towel was in my hand to clean a cassette, now I drink beer for 2 hours waiting for the crockpot to melt the wax. It’s a trade-off I am willing to make.

    1. Fr0hickey

      Agree with the paraffin wax for chains. My drivetrain the much cleaner than with oil that picks up dirt and turns into a grinding compound for the chain. And used tshirts are free.

  10. Barry Adam Johnson

    As someone who has used the t shirt method for decades and has tried various ropes with unsatisfactory results in the past few years I decided to bite the bullet and try the FL Floss after reading your review. If these seem like a First World luxury when I get done with them I’ll spring for a mop head ala Eric

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