Endless Bike Kick Ass Cog and Fibonacci Spacer Kit review and actual weights

We recently got an opportunity to try out Endless Bike Company’s Kick Ass Cog and Fibonacci Spacer Kit.  For those of you who haven’t heard of Endless, they’re a small company out of Western North Carolina that makes, well, single speed cogs and spacer kits all right here in the good ol’  U. S. of A.  So what sets these apart (after all, there are few things on your bike simpler than a spacer or a single speed cog)?  For starters, they epitomize what we single speeders love: they’re sleek, silent, and simple.  Specs, details, and more on how these cogs kick ass after the break.


Endless Bike Kick Ass Cog and Fibonacci Spacer Kit review and actual weights

Right out of the box these bad boys shine.  Both are available in eight anodized colors (orange, pink, gold, green, purple, blue, black, or red), although the Fibonacci spacers and cog won’t necessarily match like colors due to the different materials they’re made out of, so it’s recommended you choose two different colors.

Endless Bike Kick Ass Cog and Fibonacci Spacer Kit review and actual weights

The Kick Ass Cogs are made of high strength 7075 T-6 alloy and are a full quarter inch wide at the base so they won’t dig into your freehub.  They’re machined to be tight and there is some variance in freehub body sizes; therefore, some may have to file them down a bit, but I had no problem with my American Classic hubs.  There’s also a simple, silver non-anodized Kick Ass Cog for those of you who prefer a more classic look.  Endless claims, “The specially engineered tooth profile on Kick-Ass-Cogs improves both cog and chain life while minimizing drive train friction. With a Kick-Ass-Cog on your bike, you can expect a smooth, quiet drivetrain for miles to come.”  I guess I’ll have to rack on some miles and let you know.

Endless Bike Kick Ass Cog and Fibonacci Spacer Kit review and actual weights

The Fibonacci Spacer Kit comes with aluminum spacers whose thickness follow the Fibonacci sequence (1, 1, 2, 3, 5, 8, 13, 21) which Endless claims allows the user to fine tune a perfect chainline, no matter what width is needed, with three or fewer spacers on the inboard side of the cog.  Just like the cogs, the Fibonacci spacer kit is available in eight anodized colors (again, which may not match the cogs perfectly, but look great in contrasting colors) and a simple silver non-anodized version.

Endless Bike Kick Ass Cog and Fibonacci Spacer Kit review and actual weights

Weights, as you can see, are respectable, 30 grams for a very thick 19 tooth cog and 26 grams for a full spacer kit.  You get about 10mm more than you need after you set up that perfect chainline, so the actual weight on your bike is a few grams less.


Endless Bike Kick Ass Cog and Fibonacci Spacer Kit review and actual weights

The Fibonacci spacer kit comes with easy to follow instructions on how to set up the perfect chainline, so rather than eyeballing it like many of us do, I thought I’d try it out.  First, measure from your chain ring to the center of your seat tube.  It can be tricky to measure precisely to the middle of a round tube when looking at it from an angle, but I was pretty happy with what I ended up with, so maybe they’re on to something.  Next, subtract that measurement from 70mm.  Take that number and measure in from the dropouts with the wheel on the bike.

Endless Bike Kick Ass Cog and Fibonacci Spacer Kit review and actual weights

Now mark that spot and that’s where your cog should be.  I deviated a bit here after second guessing my measurements and seeing how far out my cog was ending up.  You’re supposed to stack spacers up to your mark, then put your cog on.  I didn’t quite make it to the mark with my spacers and put the cog over it instead.  This was still farther out than my eyeballing with previous cogs and worked well when all was said and done.

Endless Bike Kick Ass Cog and Fibonacci Spacer Kit review and actual weights

The cog was tight, remember, Endless does say you might have to file it out a little if your freehub happens to run a smidgen big, but it went on fine.  Once I got it set up, it was nice and snug with no play at all, which I really liked.  The last step of Endless’s instructions is to “get out and ride the smoothest chainline you’ve ever felt,” so I did just that.  I was kind of expecting to not notice much.  Like I said, these are pretty simple components, but I was pleasantly surprised.  I’ve been riding singlespeed for years and thought I had it figured out, but sure enough, my bike was noticeably quieter.  I didn’t even know it wasn’t quiet before.  It was kind of like sitting in a quiet house, then the motor on the fridge clicks off and you realize just how quiet it wasn’t.  So far so smooth.  Stay tuned and we’ll put it through the ringer and let you know if Endless’s claims about longevity hold up too.


  1. Endless cogs kick ass! Far superior to King, Niner, etc., in my experience as they’re more robust, expertly machined and available in sexy colors; I’ve never had to file any and am always amazed by how many miles I can get out of one (and the chain) before wear is an issue. Made in Asheville, NC by great folks, too.

  2. I have been very pleased with my Endless Cog and Fibonacci spacers. Light, durable, good looking and made right here in Beer City USA (Asheville, NC)! Doesn’t get much better than that.

  3. I’ve been using mine for about 3 years now and it has been excellent! The only negative I ever noticed was when I ran it on a bike that wasn’t SS specific and I ran a chain tensioner from Paul Components. There was noticeable skipping and lack of engagement no matter how I set up the tensioner. When I switched to a bike with an eccentric bb and no longer used the tensioner, everything ran like silk.

  4. As already stated; good stuff.

    I get way more miles out their aluminum cogs than I thought I would. I’ve got a 19T that I’ve run for the last 3 winters (I drop to a 20 when actually mountains become rideable), and it shows very little wear.

  5. Been running the Endless Cogs for 7 years.
    A file does ease the install on old I9 SS hubs.
    Remember; these are symmetrical,
    so flip them with each new chain
    for superior wear duration! Jason.

  6. Deciding on converting my Cannondale Flash to single speed I was told to go with an a Endless cog. I was surprised that it was considered acceptable to get out a file to make it fit on a hub if necessary. Would have been helpful to have known this tip from the onset as I nearly ruined my hub body trying to get the damn thing on before I spent time online investigating this process. Endless should include some sort of a disclaimer in the packaging for newbies like me on the possibility of needing to resort to such extreme measures to make it work.

  7. Beat the shit out of my endless cog going on two years now and thousands of miles, can’t seem to wear it out. I know for sure when I do where to get another one. If I ever buck up and get a tattoo, think I know what it might look like, just have to decide on the color. You know it endless bike girl!!!

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