Shop Talk - Vets' bikes Boom! Shop Talk - Brake Repairs
2CB Shop Talk - Brakes
Jan 2, 2023
Brake cable adjustments

I get a lot of bikes donated. I have refurbished roughly 300, scrapped about 50, handed off another 50 to a bigger operation in Chicago. I have never seen a bicycle with the brake barrel adjusters in any position other than locked down tight against the brake lever housing. I can only surmise that most people have no idea what they are and how to use them. If you are not one of those, skip this post.

I'll start by showing a photo from online ads to clarify what the heck a barrel adjuster is. I encourage ordering replacement(s) if you've crashed and trashed these as I find on mst kids' bikes. Just be sure to get the right thread size. there are several sizes and styles.

It screws into the brake lever housing; the cable sheath fits in it. It has two parts. The bigger part does the work; the other is a collar to lock the adjuster in place. With it screwed all the way in the only possible adjustment is to unlock it by turning the collar to release it and then unscrew it some, tightening the brakes. Thats fine if you just want to take up slack as the shoes wear. But when you want to remove a wheel and the brakes wont let you, don't you wish you had that thing in about the halfway position so you could screw it in and slacken the cable enough to unclip the levers?

If you use it to take up slack as the brakes wear, you might  be able to replace brake shoes without needing to adjust the cable at the wheel end. The less you mess with that connection, the better. I replace a lot of cables with ends messed up to where they cannot be disconnected without replacing.

The reason for the locking collar is so that you can put the barrel in any position, fine-tuning the gap between the brake shoes and rim, minimizing the amount of travel needed at the handle. If the wheel is trued well and the shoes aligned well, you can get a hair-trigger response for excellent braking. If the wheel has a slight offset somewhere you can tune it to just avoid that thub thub thub and still have good braking.

Once you select the barrel position, you keep it still while tightening the collar against the handle so the barrel is locked in place.

 Brakes CAN be adjusted by loosening the nuts holding the cable at the wheel end, and that is necessary for major changes. But the barrel adjuster provides fine-tuning after positioning the cable close to where it should be. Doing fine tuning by clamping and releasing repeatedly is a good way to mess up the cable, start it fraying. I replace up to 4 cables on most of the bikes I get, and many of them are still good except the end looks like a used NYE firecracker. If you lose that little cap off the end, replace it! You can get a package of them online cheaply, like $5 for 100. Just do a web search for bike cable end caps.  Use a few and give them to biking friends as party favors or something. If the cable has come untwisted but not wrecked by a kid's foot repeatedly hitting it, you may be able to restore it.  You'd be surprised how well retwisting a splayed cable can work. Grip it gently with pliers held aligned with the cables, as close as possible to the still-intact section. Rotate the pliers, letting the cable slip but applying a gentle rotary drag to it. Work your way out to the end. If it has not been too deformed you can get it back to a nice smooth tight twist. You may need 2 or 3 repetitions. Clip off enough to make a clean end if needed. Put the cap on & crimp it. be sure to get all the strands in the cap.

Here's a pointer if you ARE adjusting the brake cable at the wheel: