Brake lines length with handle bar MC conversion

Discussion in 'Airheads' started by Hearse, Apr 17, 2013.

  1. Hearse

    Hearse Project n'gagi

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    Hey guys

    R90/6 with my dual disc upgrade is nearing completion in this phase of my project

    I am pitting a splitter under my tank, how long would the brake hoses be from the front calipers to the t-junction? Any stock lengths I could use?

    And how long do you think from the Mc to t junction.

    I know I could measure it - but I'm hoping people would have used some stock lengths to save me making some up or getting customs made

    Cheers guys
    #1
  2. Plaka

    Plaka Brevis illi vita est

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    Depends if you have higher bars or lower ones, if you are running two lines to the calipers or one and a bridge, etc.

    The Spiegler site shows how to specify the line length and fittings. Custom lines incur no great additional expense or lead time. Using some cheap brake line sized vinyl tubing is an easy way to measure and lay out the line routing. Use the pieces for something else later. Look at some pictures of different bikes to get a feel for how much slack to leave in the lines so they don't get stressed at connections as the front wheel turns lock to lock and fork works up and down.
    #2
  3. Plaka

    Plaka Brevis illi vita est

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    Depends if you have higher bars or lower ones, if you are running two lines to the calipers or one and a bridge, etc.

    The Spiegler site shows how to specify the line length and fittings. Custom lines incur no great additional expense or lead time. Using some cheap brake line sized vinyl tubing is an easy way to measure and lay out the line routing. Use the pieces for something else later. Look at some pictures of different bikes to get a feel for how much slack to leave in the lines so they don't get stressed at connections as the front wheel turns lock to lock and fork works up and down.

    The line from your old undertank MC to the caliper hard line should work for that length. It's the Handlebar MC to splitter that's the new one.

    On my RS I have hard lines from the splitter to the fairing, then flex to the fork leg then hard again to the caliper.
    #3
  4. Hookalatch

    Hookalatch Born Under Bad Sign

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    I am not familiar with the various models but at least the 81-84 used the splitter under the tank. BMW offered 2 hoses for the master cylinder to splitter, one for high bars and one for low. I just installed the shorter, low bar version on my 84. I am using Flanders sidecar bars which are similar to the other low bar options. I had to push the splitter as far forward as possible to make it fit but it does fit well without any stresses at either full lock. Your bars are different so I don't know if that stock hose will work for you or not.

    I went with the stock rubber hose in that location hoping to get just a little give in applying the brakes. Prior to modifying my R80RT bike it had non-expanding aftermarket flex lines and the stock metal hard lines. There was no give on the brake lever, it was rock solid. That worked okay but I like just a touch more feel to the lever. Haven't had a chance to try it yet with the new hoses. I did go with non-flexing lines from the splitter to the calipers.

    Chuck
    #4
  5. bmwrench

    bmwrench Long timer

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    Spiegler will know the length you need; they have made hundreds of hoses for these motorcycles, as have I.
    #5
  6. Rob Farmer

    Rob Farmer Long timer

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    The splitter to caliper length remains the same as it was for the under tank master cylinder. You don't need to replace them its only the handlebar to splitter line that needs fitting
    #6
  7. Hearse

    Hearse Project n'gagi

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    Thanks for the reply guys!

    Really appreciate it.

    understood all of the above.

    A little more info:
    * Clip on's
    * 14mm handlebar MC
    * twin discs with 40mm calipers

    Plan:
    * NOT to run SS lines - i want that little bit extra give in the brake lever

    Confusion:
    * do i run dual lines from a splitter or a bridge? Is either preferred over the other? I was thinking of running dual lines - i think it would be easier to bleed and might look neater?

    Thoughts?
    #7
  8. Plaka

    Plaka Brevis illi vita est

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    If you don't have a port for the bridge I doesn't matter, you can't fit one. If you do then you can use one and only a single line strait from the MC, no splitter required.

    You also might look at where the brake light switch is.
    #8
  9. Hearse

    Hearse Project n'gagi

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    Thanks Plaka - appreciate it mate

    I have two "ports" on both of my calipers...if thats what you are referring to?

    So that should be right then - yea? one caliper takes the MC line and then the bridge over to the other caliper where the one port will take the bridge and the other port the bleed nipple?
    #9
  10. bmwrench

    bmwrench Long timer

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    Yes, that's how it's done, but to do this you need to convert to banjo ends at the caliper thread, or get a hose with a male end that swivels. Running separate hoses from the splitter would be easier-you just need an OEM hose if you're committed to rubber hoses. I would go with stainless braided hoses and a smaller master cylinder if you want more lever travel.
    #10
  11. Hearse

    Hearse Project n'gagi

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    good on ya wrencher...thanks for that mate

    I made a booking with the local brakes center. I'm taking my calipers and MC in to them, get them to supply all of the in between bits - they are going to make up some pipes for me. I'll request SS ones.

    Thanks for all your help guys.

    I'll post pics after I get them

    Cheers
    #11
  12. supershaft

    supershaft because I can

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    I think Spiegler lines and many others are too long but that is why I make them myself. Personally, I wouldn't use a splitter. Why have three lines and a splitter when two lines and no splitter will do? I would probably run a double banjo bolt at the MC and run two lines down.
    #12
  13. Hearse

    Hearse Project n'gagi

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    That sounds like a better idea

    I will have to run them through the middle of the forks to keep it neat

    The brake guy told me it was impossible to make my own lines? That there was some massive press that fixed the ends on to the pipe? How do you do it shafty?
    #13
  14. supershaft

    supershaft because I can

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    Google Earls brakes. Now there are a lot of different brands that offer the same thing. From what I have seen, ALL brake line companies use Goodridge (I think it is?) brand fittings like Earls does. Get the stainless fittings. They don't cadnium plate their other fittings anymore and they rust instantly.
    #14