Are the brake hoses on your road bike too long?

Because I opted for Shimano’s J-kit hydraulic brake caliper and STI lever bundle, on mine, they definitely were.

All that brake hose flapping about…not very clean looking.

That’s the price I paid for a convenient install, which is invaluable for the bike assembling factory folks the J-kit bundle is meant for. Assembly time saved means more bikes out the door available for sale.

As Hyro is my bike, however, I decided to do something about the excess hose length. You’ll need the following to proceed.

A bag of brass brake olives and BH59 end fittings for Shimano hydraulic brake lines. The BH59 fittings have a groove around the lip.
  • A set of relevant brake hose end fittings and olives. These are specific to your brake system. Most Shimano road bike hydraulic brakes use BH59 hoses, and those require BH59 end fittings.
  • A brake hose clamping block. Shimano calls theirs the TL-BH61, looking like two halves of a small pencil sharpener. It’s meant to hold brake hose in a vise or clamp without crushing it. It should come with the parts bag for your braking system; alternatively, some brake bleed kits will have an equivalent.
  • A bench vise. Alternatively you can use locking pliers such as Vise-Grips, like what I’ll be doing here, but a free, mobile vise is definitely the best tool for the job.
  • A small or medium hammer, or equivalent. One of the few bicycle mechanic jobs where a hammer is actually needed.
  • An 8 mm open wrench or adjustable wrench.
  • A sharp knife. I used an X-Acto hobby knife with a #11 blade.
  • A plastic bag and rubber band you can use to wrap your front brake caliper with, to avoid mineral oil spillage.
  • A rag or paper towel.

This method will shorten the hose at the STI lever. Start by undoing the bar tape, cutting any sticky tape holding the brake hose in place, and peeling back the brake hood on the back end to expose the hose nut.

Take your 8 mm wrench and undo the hose nut. Once loose, slide it down the brake hose. We will need it again later.

Note how different this olive looks from a fresh unused one. It looks like a tiny beer keg.

At this point there is no longer anything holding the brake hose in place except for the friction in its present olive. Pull on the brake hose to break the olive free from the STI lever body. Watch out for leaks.

The brake hose is now free. As with brake cable housing, you can now measure to size it down accordingly. As this is a front brake hose, the only real sizing consideration is it should be long enough to reach the STI lever with not too much slack. One of the best practices is to take into account the movement of the handlebar into resizing the brake hose, though, making sure it can be turned all the way to both sides without binding.

In Hyro’s case, everything past my thumb is slack brake hose. That’s a lot of slack. Be very sure about the sizing: “measure twice, cut once” as some people say.

Once committed to a hose length, break out your knife and cut the hose as perpendicular as you can get it. I have a rag underneath to catch the mineral oil that will leak out.

After cutting, sandwich the hose into the brake hose clamping block, and clamp the whole thing in a vise.

Take one of the brake hose end fittings and push it into the inner lining of the brake hose to get it started. Hammer it down all the way in afterward.

You want the brake hose end fitting’s lip to be as flush with the brake hose’s inner lining as possible. Once done, you can release the hose from the clamping block.

Thread a new brass olive onto the brake hose, then push it into the STI lever body. Keep inserting pressure on the brake hose as you move the olive and hose nut into position for reattachment.

Once the threads on the hose nut catch onto the STI lever body, tighten it down with the 8 mm wrench. This will effectively crush the new brass olive, deforming it into a shape that will seal the brake hose end. Tighten the hose nut to 7-8 Nm of torque, which is quite a bit of hand force, but nothing too crazy.

That’s job done; the nice thing about this is you’re likely going to do it just once per bike, unless the hoses themselves get damaged. Return the brake hoods into place. You’ll want to check the brake lever action; pull on the lever and see if it feels spongy or has too much travel before biting. If all went well, the brake lever should feel exactly the same as before; if not, you may have lost too much mineral oil while the hose was disconnected. That will call for a bleed job – the main periodic maintenance job for hydraulic disc brakes – which I’ll cover next time.

And just in case you wanted to see how Hyro’s brake hoses looked post-surgery, here they are.