The Lowly Barrel Adjuster

For weeks I’ve been trying to remember which mechanic taught me the back door to proper brake set-up. By proper, what I mean is the way that I’ve come to appreciate as superior to all other variations on the task. As much as I want to say it was Wayne Culpepper, one of the national team mechanics who taught me loads when I got my license, I recently remembered the knowledge goes back further, to Bill Farrell, the inventor of the Fit Kit and proprietor (and faculty) of the New England Cycling Academy (NECA).

In the early ’90s I took Bill’s course for mechanics. The curriculum taught you the purpose and how to use each tool in the full Campy tool kit. You learned how to use a frame alignment table and, the biggest single part of the course, you learned how to fit someone with the Fit Kit and to correctly adjust cleat position with the R.A.D. (Rotational Adjustment Device).

Barely mentioned in the curriculum, and not the primary thing any wrench talked about after finishing the course, was his instruction in how to assemble a bicycle as efficiently as possible. From chasing and facing down to wrapping the bars, Bill, a guy who I don’t think ever worked in a shop, had a method for assembling a bike that allowed me to assemble a bare frame into a ready to go bike in two hours. Boxed bikes from big manufacturers? I could get some of them together in 45 minutes. (These days, a partial overhaul can take me three hours, embarrassing, especially given that I don’t own a single loose ball BB or hub any more.)

One of my favorite tricks he taught me, and one I still use without fail, is to dial a brake’s barrel adjuster half way up its threads before running the cable through. The purpose for this is three-fold. First, and most important, it ensures that after securing the brake cable and seating the housing (cables don’t actually stretch, but housing does seat some) if there isn’t sufficient lever throw, I can dial it in with the barrel adjuster rather than loosening the cable. Next, once I have lever throw in the ball park, I can choose to either tighten or loosen a barrel adjuster to make sure the levers have exactly the same throw. If there’s one thing that will drive me nutty it is if the levers have unequal throw. Finally, this step allows a rider to change wheels and not have to use the brake’s quick release to adjust the lever throw.

This last point is more important than most mechanics consider. I’ve seen riders get a bike tuned up with a set of clinchers on and then swap to a set of tubulars. The wider box section rim will require the quick release to be opened all the way just to allow some lever throw and getting a big tire like a Vittoria CG through the brake blocks could be an iffy proposition.

No one cares that I do it on my bikes, but it gives me a certain reassurance that I’ve been careful, deliberate in my work. What’s better is when I see a friend’s new bike and I notice that the adjusters are dialed in some. That one touch, more than almost anything else I might see on the bike, will cause me to ask who assembled the bike. To me, it’s the sign of a real veteran.


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  1. Kimball

    So…do you do this with the pads touching the rim and then turn the adjusters down a bit to then back them off the rim? How far off the rim do you like your pads? I have read elsewhere that many pros have their bikes set up with the pads set quite far from the rims so as not to add drag by dipping into the film of air that is rotating with the rim surface. Any thoughts on this?
    Sorry for all the questions. A bit sorry you started all this now aren’t you?
    Kimball in Seattle

    1. Author

      Kimball: You ask some great questions and, no, I don’t mind at all. When I’m setting the brakes up, I squeeze them with my hand and get them in the ball park for throw. I’ll squeeze the lever once or twice after tightening the fixing bolt and if I’m too far off, I’ll loosen the fixing bolt and make another stab at it. The difference in aerodynamics between running brakes tight and loose is beyond negligible; I’m not sure the difference could be measured in the wind tunnel. That said, I’ve run across many PROs who run their brakes really loose; it seems that running the brakes with a lot of throw is common to many of the better descenders. This does two things: 1) It prevents over-braking in nervous situations and 2) allows you to grab the brake lever without automatically getting a fistful of brake. Much of the time when I’m descending I have my index fingers on the brake levers and I run them pretty loose so that I can have my fingers grasp them securely.

  2. Andrew

    This kind of approach reminds me of pro musicians- brass players will often tune slightly flat at the gig, and as the instrument warms up and the tuning goes slightly sharp, they fall right into tune.

    One advantage of loose brakes is that you can squeeze the lever much harder when it’s close to the end of its travel- brakes with the pads set very close feel like you’re trying to grab the rim with you bare hand.

    1. Author

      Great example Andrew and a great point as well. I should have mentioned that; our hand strength is greatest when the fingers are closed.

      It’s funny, I’d forgotten about that detail of playing with really good brass players. I played with a funk band for a little while and they always fretted about tuning during a sound check in a cold room. Get three hundred steamy bodies in there and everything changed.

  3. lqdedison

    What I take away from this post is the detail. I see a good mechanic in the details of how a bike is built and finished off. The barrel adjusters on the brakes are certainly one of those details. It says that someone took the time and care to setup up a brake properly. Anyone taking their time to do the job shows that they take pride in their work. That’s a mechanic you want working on your bike.

    A bicycle isn’t very complicated yet there are little details all over the bike, some seen and some unseen, that can really show who knows their stuff. I got to thinking after reading this post about what details really show off a properly build bike or that a bike has been as the hands of a proper wrench. I couldn’t say that there is any one give away but a lot of little things that add up to a finely tuned bicycle.

    Great post by the way.

  4. Eric

    A slightly different view on throw. I actually like the calipers adjusted very close. I like the braking to begin as soon as I pull the lever. This is probably a throw back to my car racing days where brakes are set up in this manner.

    I do not have an issues with grip strength as even with the lever out that far, I can still lock the rear (unless in dirt, I have never been able to lock the front no matter how hard I try). Given that, I do not worry about hand strength as I get 100% braking force.

    Much more important to me is the ability to modulate the brakes. Having a good feel for easing or increasing brake force is far more important to getting into and through a corner on a hard descent. Bikes don’t turn in very well under front braking (understeer) and the back can slide under rear braking (oversteer). Being able to make small adjustments to these from straightline braking, to turn-in, to complete brake release at the apex for me is critical.

    I definately agree that having the same amount of throw for front and rear is preferred. If you do run the calipers tight, remember that wheel true and hub bearing preload become important too. You don’t want the wheel to rub the caliper when cornering forces start pushing the wheel to the side.

    Oh, and I do set the barrel adjuster in the middle on initial set-up as well. I wish I could remember who taught me that trick Padraig 🙂

    “… really good brass players” There is such a thing? Huh!

  5. Dan O

    Great post and comments.

    During my bike shop days during the early ’80s, I’d set up bikes the same way. Having the barrel adjuster set mid-point, also allowed for some wiggle room to compensate for a mid-ride tweaked rim.

    I don’t remember if anyone showed me this trick, or figured it out on my own. It was many years ago!

  6. Tripelt

    The white rubber piece below the barrel adjuster is only meant to stay on the brake for shipping so the adjuster doesn’t fall out. The tension on the cable holds the adjuster in place when on the bike. Talk about a small detail…this bike probably also still has all the warning stickers on it. Almost as annoying as leaving scratch protectors on your new electronics or driving around with the window sticker still in your new car.

    1. Author

      Triplet: Some friends of mine and I took to poking a hole in the assembly cap partly for laughs and partly because where I live it’s so damn sandy I wanted an extra barrier to keep the cable clean within the housing. It’s a trick I learned from Radio Freddy, so if it’s not PRO, we’ll have to blame him.

  7. Pingback: Further Thoughts on Brakes : Red Kite Prayer

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