Advertise on Bikeforums.net



User Tag List

Results 1 to 19 of 19
  1. #1
    Senior Member
    Join Date
    Aug 2013
    Posts
    54
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Road Bike Disc Brake Setup

    I've been doing all my own wrenching on my bikes for a year or so, and I've now built up 3 bikes without any major issues. The bike I built in May now has 1500 great miles on it.

    But I'm completely new to disc brakes. I've just built up a bike that's meant to be my winter road bike, but also serve some light off-road duty. It's a cx frame that will let me run either skinny road tires or wider cx tires for gravel. I figured it made sense to go with disc brakes.

    I'm running campy ergo controllers with Avid BB7 road calipers and 160mm rotors front and rear. After many days of reading and setting them up over and over, here's where I stand: I find it basically impossible to get good feel at the brake lever (with short pulls) while also having the rotors NOT rub the pads. I can dial them in perfectly on the stand (no rub, and good short pulls) but then they rub on the road. I can then back off the pads so that they don't rub, but now I really only get the brake to engage fully with the brake lever almost pulled all the way to the bars.

    I've trued the rotors, and I've aligned the caliper MANY times – so many that I now feel confident I'm doing it right – and I've made certain that the both wheels are fully in the dropouts with good, tight QR levers. So here are some questions I have:

    1. Is a little bit of run just how road disc brakes work? Do other people just live with a bit of scraping? Or do they just live with pulling the brake lever ALL the way to the bars?

    2. Any chance that there is something wrong with my brand new cx forks and they are flexing enough to cause this? (I can get no rub on the bike stand but they still rub on the road until I back them off even further.)

    3. Any chance the rub will go away after a couple hundred miles (I have 25 test miles, including up and down steep hills, on them now).

    4. Finally, what about the TRP Spyre? I'm told these are less finicky to set up, and also told that they work better with campy levers. If those things are true, I'll happily spend the few extra bucks to switch to them, but if they are going to have the same problems, then why bother. Before I make that move I'm trying to find out if they really are a better mechanical disc setup for roadbikes, or just a better disc brake that has the same fundamental issues.

    5. Anything else I'm missing?

  2. #2
    Senior Member
    Join Date
    Apr 2009
    Location
    New Rochelle, NY
    My Bikes
    too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
    Posts
    21,002
    Mentioned
    47 Post(s)
    Tagged
    1 Thread(s)
    I'm not sure of the sequence of events or history, but I suspect that disc brakes came after V-brakes for mtb. If that's right, then odds are that disc brakes are designed around the longer cable pull of V-brake levers, rather than that of canti or road caliper brakes. Therefore, you simply may not have enough travel in the lever to pull enough cable.

    You might be able to improve things slightly by modifying the leverage ratios, for instance attaching the cable inboard of the pinch bolt (if possible).

    Otherwise, you have to see if you can find a cable "de-multiplier" or "travel agent" like device to match the lever throw to the brake's throw.
    FB
    Chain-L site

    An ounce of diagnosis is worth a pound of cure.

    “Never argue with an idiot. He will only bring you down to his level and beat you with experience.”, George Carlin

    “One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN

    WARNING, I'm from New York. Thin skinned people should maintain safe distance.

  3. #3
    Senior Member
    Join Date
    Feb 2001
    Location
    England
    Posts
    12,275
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)
    Avid BB7 road calipers have cable pull matched to road levers.
    Check your brake model.

  4. #4
    Senior Member cderalow's Avatar
    Join Date
    Sep 2012
    Location
    Potomac, MD
    My Bikes
    2012 GT Transeo 3 2014 Cannondale CAAD 10 105
    Posts
    411
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by MichaelW View Post
    Avid BB7 road calipers have cable pull matched to road levers.
    Check your brake model.

    this.

    my bb5-r distinctly say 'road' on the side.

    barring that being an issue, I will say getting road discs setup is very finicky.

    I've found the best way to do it is to crank the pads all the way out off the bike. install on bike with disc in place/wheels in place.

    set on ground. use a thin cardboard spacer (cereal box cardboard) on either side of the disc, then center the caliper on the disc that way by cranking the moveable pad in.

    i think avid recommends 1mm of space on either side of the rotor when installed.

    once i've got the caliper centered, i then hook the cable on with the barrel adjuster all the way down. use a 4th hand to install cable at like 95% of lever throw.

    then use the barrel adjuster and an inline adjuster to get it perfect.

    once it's on, i sure as hell try not to remove my cable. removing wheel seems fine and doesn't affect rubbing, but least bit of messing with adjusters and cable restarts the whole process.

  5. #5
    Senior Member
    Join Date
    Feb 2014
    Location
    Southern Ontario
    Posts
    82
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    I found the same thing. I finally gave up and changed the levers. I was using bar end shifters so changing levers was fairly easy for me.

  6. #6
    Senior Member
    Join Date
    Feb 2014
    Location
    Wind Tunnels of Cheyenne
    My Bikes
    Burley Duet [of some unknown year]; And always one less than I think I really need.
    Posts
    190
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    There is a pretty lengthy thread about the TRP Spyer (which was sort of hijacked by the TRP HY-RD) calipers on the tandem forum (sorry, screen reading software doesn't play well with the site and I can't post the link, but I thin the thread is "TRP Spyer Equals Bee's Knees). I think most calipers use one "stationary" pad and one moving pad which flexes the disc into the other while [again I think] the TRPs move both pads (making adjustments and set-up easier). The HY-RD (mechanical to hydraulic) versions also adjust to pad wear.

    The OP's issue really sounds like a lack of cable pull. OP mentioned "short pull" Campys, even with the right Avid road calipers could this be an [the] issue?

  7. #7
    ot.net slave
    Join Date
    Feb 2006
    Location
    Canberra, Australia
    My Bikes
    Salsa mtb * 3, Intense mtb * 1, Abeni SS rd * 1, Salsa road/touring * 2, Trek Damn one * 1, Vintage/projects * many
    Posts
    538
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    I'm using campy veloce levers with bb7 road callipers on my la Cruz and they work fine. If you have drag in your cables, the calliper may not retract properly. Similarly, you can retract the pad adjust knob and advance the lever arm by tightening the cable. This has the effect of increasing the spring tension which can make the difference between a brake that rubs and one that does not. Getting it mostly right then riding it will fix any small brake rub points on the pads. The bb7 is a great brake and can be made to work without too much drama.

    - joel

  8. #8
    coprolite fietsbob's Avatar
    Join Date
    Jun 2010
    Location
    NW,Oregon Coast
    My Bikes
    7
    Posts
    570
    Mentioned
    31 Post(s)
    Tagged
    0 Thread(s)
    Spyre is the TRP (a Tektro division) cable disc brake.. they are trying to make a mechanical brake act like a hydraulic,
    Namely double acting .. both pads Move towards the disc .. Gusset and IRD also have their calipers trying to do the same.

    all other mechanical discs, 1 pad moves, the other is stationary ..

    Bike Shop visit and having some one, in person, show you how to do the adjustments, should not be avoided .
    Last edited by fietsbob; 08-15-14 at 10:38 AM.

  9. #9
    Senior Member dwmckee's Avatar
    Join Date
    Jun 2008
    Location
    Pittsburgh, PA
    My Bikes
    Co-Motion Cappuccino Tandem, Jamis Xenith Race,'88 Bob Jackson Touring Bike (I love this one best), Co-Motion Cascadia Touring Bike, Salsa Fargo, Burley TAB
    Posts
    732
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by cderalow View Post
    this.

    my bb5-r distinctly say 'road' on the side.

    barring that being an issue, I will say getting road discs setup is very finicky.

    I've found the best way to do it is to crank the pads all the way out off the bike. install on bike with disc in place/wheels in place.

    set on ground. use a thin cardboard spacer (cereal box cardboard) on either side of the disc, then center the caliper on the disc that way by cranking the moveable pad in.

    i think avid recommends 1mm of space on either side of the rotor when installed.

    once i've got the caliper centered, i then hook the cable on with the barrel adjuster all the way down. use a 4th hand to install cable at like 95% of lever throw.

    then use the barrel adjuster and an inline adjuster to get it perfect.

    once it's on, i sure as hell try not to remove my cable. removing wheel seems fine and doesn't affect rubbing, but least bit of messing with adjusters and cable restarts the whole process.
    Wow, this set of instructions has almost nothing similar to the instructions provided by Avid for the BB7s. I just follow the instructions Avid provides, which works great. The Avids are designed to have one pad press into the rotor then slightly flex the rotor to push the other side to contact the stationary pad. Sounds very strange but it works pretty well in practice.

    Regardless, it sounds like you might be using an Avid MTB caliper (requires a longer pull) with road levers (shorter pull) so you can barely pull enough cable to actuate the brakes when set up according to directions. If this is the case you have to change either the levers or calipers to be sure they are meant to work together.

    I just dumped my Avid BB7s for the TRP Hy/RD calipers and am never going back!

  10. #10
    Junior Member
    Join Date
    May 2010
    Posts
    24
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    As others have stated, best bet is to dump the BB7s and get some TRPs (either Spyre or Hy/Rd).

  11. #11
    Senior Member
    Join Date
    Aug 2013
    Posts
    54
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Hi all,

    Thanks for all the helpful replies. Just a couple of quick responses:

    1. I am running BB7 ROAD disc brakes, not the MTB version.

    2. I can't be certain, but I'm 95% sure I don't have any cable drag issues.

    3. In a general sense, I know I have these setup correctly. But it seems pretty clear that getting them set up with no rub and without running out of lever is not completely simple.

    4. cderalow's setup instructions are different from Avid's, but I have a hunch he may be on to something with that approach.

    I may try the Spyre's out just to see if they are a less finicky setup. hounslow is not the first to say that once gone to the TRP's the BB7's start to look like old and problematic technology.

    thanks again to everyone for the help. I'll report back after doing some more work on the bike.

  12. #12
    Senior Member
    Join Date
    Aug 2013
    Posts
    54
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Update

    OK, I've gone a few more round with the bike and I've now installed the Spyre TRP brakes. Here's what I can report:

    1. The TRP is clearly the same fundamental approach – it's a mechanical disk brake for road bikes – but it is also obviously a much better improvement on the overall design. The fact that both brake pads move DOES make them easier to set up. But the instructions say to align the calipers buy pulling on the brakes, and this just doesn't work for me. But unlike the BB7's I have been able to get these setup with NO rub and the ability to stop the bike!

    2. I'd still like to have a much shorter brake pull than I have. I'm not fully stopping the rotor in the caliper until the brake lever is less than an inch from the handlebars. If I move the pads closer to shorten this throw, I get pad rub.

    3. I have two theories about what I might be able to do to get firmer lever feel (other than just needing the brakes to bed in):

    A – I am running jagwire ripcord compressionless housing with the jagwire cable. Spyre says to run wound cable for the handlebars and then connect that cable to compressionless. I haven't seen this recommending/required anywhere else, and I don't know what to make of it. Maybe this is a problem?

    B – I filed down the heads on the Jagwire brake cable ends to get them to fit into my chorus shifters. But I notice that when I squeeze the brake lever I can still make the head of the cable (as it fits into that metal piece inside the lever) rock back and forth. On my campy road bike the head is seated down into that metal piece and there's no movement. I wonder if this slack is translating into my lack of tight/short lever throw?

    Any thoughts or wisdom would again be much appreciated. I can also add pics, if that helps...

  13. #13
    Senior Member
    Join Date
    Apr 2009
    Location
    New Rochelle, NY
    My Bikes
    too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
    Posts
    21,002
    Mentioned
    47 Post(s)
    Tagged
    1 Thread(s)
    Quote Originally Posted by fronesis View Post

    A – I am running jagwire ripcord compressionless housing with the jagwire cable. Spyre says to run wound cable for the handlebars and then connect that cable to compressionless. I haven't seen this recommending/required anywhere else, and I don't know what to make of it. Maybe this is a problem?

    Any thoughts or wisdom would again be much appreciated. I can also add pics, if that helps...
    One critical consideration. Compressionless housing's long spiral wires are end-on to the fittings and ferrules. If not used with special flat bottom or reverse cone ferrules designed for them, the housing strands can work down the conical bottom of typical fittings and either bind the wire, or extrude through leading to total brake failure. This may be why the brake maker suggest standard spring wind brake housing.

    Also, when used for brakes, the housing must be of a design buttressed with a structural layer surrounding the strands. Otherwise, as the plastic outer cover degrades, the wires can burst through and buckle leaving you without a brake (of course, the odds of both failing are near zero).
    FB
    Chain-L site

    An ounce of diagnosis is worth a pound of cure.

    “Never argue with an idiot. He will only bring you down to his level and beat you with experience.”, George Carlin

    “One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN

    WARNING, I'm from New York. Thin skinned people should maintain safe distance.

  14. #14
    Senior Member
    Join Date
    Aug 2013
    Posts
    54
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by FBinNY View Post
    One critical consideration. Compressionless housing's long spiral wires are end-on to the fittings and ferrules. If not used with special flat bottom or reverse cone ferrules designed for them, the housing strands can work down the conical bottom of typical fittings and either bind the wire, or extrude through leading to total brake failure. This may be why the brake maker suggest standard spring wind brake housing.

    Also, when used for brakes, the housing must be of a design buttressed with a structural layer surrounding the strands. Otherwise, as the plastic outer cover degrades, the wires can burst through and buckle leaving you without a brake (of course, the odds of both failing are near zero).
    Thanks – that's very helpful.

    I'm using the Jagwire-supplied ferrules on the caliper end of things, and since I'm running campy levers, I'm using no ferrules at the brake lever end. I was very careful to cut the housing square, open it up with a pick tool, and grind it down perfectly flat with a dremel tool.

    It may be that what I have now is a good setup, and I just need to let the brakes bed in and then I'll have firmer lever feel. I should probably put some miles on this setup before I tinker any longer.

  15. #15
    Senior Member
    Join Date
    Apr 2009
    Location
    New Rochelle, NY
    My Bikes
    too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
    Posts
    21,002
    Mentioned
    47 Post(s)
    Tagged
    1 Thread(s)
    Quote Originally Posted by fronesis View Post
    Thanks – that's very helpful.

    I'm using the Jagwire-supplied ferrules on the caliper end of things, and since I'm running campy levers, I'm using no ferrules at the brake lever end. I was very careful to cut the housing square, open it up with a pick tool, and grind it down perfectly flat with a dremel tool. ....
    You absolutely, positively need a ferrule, or flat stop washer on the lever body when using compressionless brake housing with ergo levers. The body is plastic, and the ends of the strands will nibble at it, and the hole is big enough for the housing to pinch in and extrude through.

    I'm not saying you'll lose the brakes tomorrow or on the first emergency stop, but you will never get rock solid performance, and some time down the road will find the pockets in the lever body worn through (not a cheap repair).

    On levers, where the cable/leverbody combination precludes a ferrule, I use flat stainless washers as dead stops at the bottom of the lever. For normal brake cable, I use one, but for compressionless I use two (though you have to put me into a half nelson before I'll use long spiral brake housing).
    FB
    Chain-L site

    An ounce of diagnosis is worth a pound of cure.

    “Never argue with an idiot. He will only bring you down to his level and beat you with experience.”, George Carlin

    “One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN

    WARNING, I'm from New York. Thin skinned people should maintain safe distance.

  16. #16
    Senior Member
    Join Date
    Aug 2013
    Posts
    54
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by FBinNY View Post
    You absolutely, positively need a ferrule, or flat stop washer on the lever body when using compressionless brake housing with ergo levers. The body is plastic, and the ends of the strands will nibble at it, and the hole is big enough for the housing to pinch in and extrude through.

    I'm not saying you'll lose the brakes tomorrow or on the first emergency stop, but you will never get rock solid performance, and some time down the road will find the pockets in the lever body worn through (not a cheap repair).

    On levers, where the cable/leverbody combination precludes a ferrule, I use flat stainless washers as dead stops at the bottom of the lever. For normal brake cable, I use one, but for compressionless I use two (though you have to put me into a half nelson before I'll use long spiral brake housing).
    Wow, OK, thank you for the important warning. I was just following two bits of advice: 1) Campy says don't use ferrules on ergo levers, and 2) I was informed I should use compressionless housing for disc brakes. But it's clear from what you say here that those pieces of advice conflict.

    I see two options:

    A) install regular campy brake housing, with no ferrules, from the levers to just past the bars, and then connect that housing to the compressionless housing.

    B) add a ferrule (or a washer) at the levers to the jagwire compressionless housing.

    May I ask your advice on which of those you'd choose?

    Can't thank you enough for the help.

  17. #17
    Senior Member
    Join Date
    Aug 2013
    Posts
    54
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    A bit more info on this:

    1) The Jagwire Ripcord cable is Kevlar reinforced, and as I understand it that design is specifically in place to avoid the sort of failures that FBinNY is describing above.

    2) The Campy Ergo levers have a brass washer in place inside the lever, at the base of the cable channel, that (again, as I understand it) is designed to function just like a ferrule.

    When I add these two points up I wonder if that means it is OK to run the Jagwire ripcord cable in the ergo levers without a ferrule (especially since I'm not sure a ferrule would fit).

  18. #18
    Senior Member
    Join Date
    Apr 2009
    Location
    New Rochelle, NY
    My Bikes
    too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
    Posts
    21,002
    Mentioned
    47 Post(s)
    Tagged
    1 Thread(s)
    Quote Originally Posted by fronesis View Post
    A bit more info on this:

    1) The Jagwire Ripcord cable is Kevlar reinforced, and as I understand it that design is specifically in place to avoid the sort of failures that FBinNY is describing above.

    2) The Campy Ergo levers have a brass washer in place inside the lever, at the base of the cable channel, that (again, as I understand it) is designed to function just like a ferrule.

    When I add these two points up I wonder if that means it is OK to run the Jagwire ripcord cable in the ergo levers without a ferrule (especially since I'm not sure a ferrule would fit).
    I mentioned specific considerations and necessities. If the setup addresses them it's OK whether it's a manufacturer or user change.
    FB
    Chain-L site

    An ounce of diagnosis is worth a pound of cure.

    “Never argue with an idiot. He will only bring you down to his level and beat you with experience.”, George Carlin

    “One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN

    WARNING, I'm from New York. Thin skinned people should maintain safe distance.

  19. #19
    Senior Member
    Join Date
    Aug 2013
    Posts
    54
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by FBinNY View Post
    I mentioned specific considerations and necessities. If the setup addresses them it's OK whether it's a manufacturer or user change.
    OK, makes sense.

    I'm still a bit uncertain about whether my current setup is OK, but I've emailed Jagwire to see what they say.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •