Tools for shortening disc hoses?

I have my first disc brake bike, and now I’ve dialled in my fit the hose length that came very the factory is way too long.

What tools do I need for shortening the lines? Can I jus my cut them “wet” ?

Thinking shopping list is:

  • Shimano bleed kit
  • Hose cutter (jag wire elite as per Dave’s article)
  • barb installer tool
  • brake hose spanner

I think the procedure is then just:

  • remove hose at calliper end
  • cut to length (prepare for fluid to fly everywhere out of the cut piece)
  • install barb
  • re install to calliper

Any tips/cheats greatly appreciated!

I’m sure the Jagwire elite is a very nice tool but I’m equally sure it is overkill.

The ordinary tube cutters available for as little as $1 on Alibaba work well enough.

The bleed kit and /or your brakes box should have a little plastic device (usually yellow) that helps hold the hose in your vice while you insert the barb; whilst not absolutely necessary it makes the job much easier. Push comes to shove you can cut the hose using this as a cutting guide: a sharp chisel will do a very good job.

If you stick a bamboo kitchen skewer in the bit of the hose you are about to cut off it plugs the end so you don’t lose all the oil.

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I have always used simple cutting pliers with the yellow plastic device from my first bleed kit mentionned above to handle the hose and act as a guise for a straight cut.

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Did exactly this a little while back on a Shimano setup. Full shopping list / procedure documented over on YouTube here.

The TL-BH62 is brilliant. Used it this week again swapping Ultegra 8070 over to 8170.

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Ah yes! Thank you

Also side note, love the channel, used a load of your stuff before :slight_smile:

I woud also snag a crowfoot flare nut wrench (7 & 8mm) like the one from pedros(or similar) so you can get that torque right

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I ordered the park tool spanner that combines crows foot and spanner :slight_smile:

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Just watched video but st work so low sound, excuse if you mentioned, but do I have to shorten at lever like you did? Think I can shorten calliper end? Saves un taping the bars

Either end will work. Less chance of any air bubbles getting in doing it from the top. Not really a problem if you have the full bleed kit.

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Just be aware that if you use a crow’s foot on a torque wrench the torque delivered will not necessarily equal the torque measured.

The error is easy enough to calculate if you know the distance between the crow’s foot and the head of the torque wrench, the distance between the head of the torque wrench and its centre of pressure and the angle between those two vectors ( eg the lines that join these three points).

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so if I torque a hose nut to 5nm with a torque wrench and Pedros crowfoot (at 90deg. to the wrench beam), will the ‘actual’ torque be higher or lower than the 5nm the torque wrench is telling me?

another question for the braintrust- can you reinstall a hose end with a previously tightened/compressed olive without leaks, i.e. can an already compressed olive be reused successfully?

do you notice any significant differences between 8070 and 8170 braking and feel?

After two rides, no. The 8070 was always really good as it was. I switched from a 140mm->160mm rotor on the front and to XTR rotors. The only notable difference was no ‘schwing schwing schwing’ for a few seconds after hard braking down a steep grade that I’d get with the 8070/140mm on the front.

Absolutely not worth the upgrade… other than I wanted to be familiar with the new group and I have to feed the YouTube algorithm.

The answer depends on the angle between the torque wrench and the crow’s foot (it also depends on the direction in which the force on the torque wrench is applied but we are going to ignore that for now).

In the simplest case where the crow’s foot is directly inline with the handle of the torque wrench, the torque delivered to the nut will be greater than the indicated torque. Calling the actuation length of the torque wrench “L1” and that of the crow’s foot “L2”, the ratio will be ( L1 + L2 ) / L1.

Calling the angle between L1 and L2 “A”, and for the above case A = 0 and assuming the force applied to the torque wrench is normal to the actuation length L1, the more general solution is that the ratio will be (L1 + L2 * COS A) / L1. For zero degrees COS A = 1 hence the first solution is a case of the second.

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Hey Ben,

You may have seen this already but this article should give you multiple good options that won’t break the bank: Cool Tool Tuesday #8: The best tools for installing hydraulic disc brakes - CyclingTips

The TRP/Tektro Hose Cutter and Barb Press tool is well worth a look. It’s about US$15 and will make both the cut and barb press an easier task.

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I said the angle was the standard 90deg. to the torque wrench beam with a Pedros crowfoot, is the reading on the torque wrench low or high? I’m guessing lower with the crowfoot oriented 90deg. to the torque wrench handle/beam since it would actually be higher than the reading with the crowfoot inline with the handle.

Hey Dave,
Yep, I actually reference the article above! You’ve already cost me a bunch of cash :wink:

Struggled to find a dealer for the TRP/Tektro in the Uk, but did manage to find one so hopefully it works out.

Also got the Shimano bleed kit (the newest one) and the park took spanner you recommend.

Sorry I missed that bit. In theory there is no change at 90 degrees if the force on the torque wrench is also at 90 degrees (because Cos 90 = 0).

In practice there would be a small change because you aren’t going to have the force at exactly 90 degrees, you are more likely to exert the force somewhere near 90 degrees to the new line between the torque wrench handle and the crow’s foot. This variation is likely too small to matter.

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Does this image help Sean?
Excuse the units, I was making it easy with 345 triangles.
Basically you get 0 error if the foot and torque wrench is perfect right angle and you perfectly apply the force to the torque wrench at 90 degrees.
If you use “in line” you want the torque wrench to be significantly longer than the crows foot length (or a ratio to the point where it’s smaller than the precision of your reading)

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Hi Stanley,
How so? Isn’t it just resolving torque along a beam?

https://physics.stackexchange.com/questions/39693/calculating-torque-adjustment-for-offset-of-pivot-point

Happy to hear if I’ve made a mistake though!