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  1. #1
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    Avid disc on new Calfee

    Having a Calffe built and we are having a problema time getting the rear Avid road BB7 disc brake to work. Running campy intergrated shifters and the levers go all the way to the handlebar and the rear wheel can still be turned y hand. I am ordering the Sidetrack brake power booster Monday morning, hopefully that will solve the problem. My other tandem has Avid disc with shimano levers and while the setup is touchy it does seem to work just fine. I do't understand what the problem is. My shop idicates they have had similar problems on other tandems. Anbody have ideas?

  2. #2
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    There shouldn't be any problem if you have the new Avids. I use Campy levers and they work fine. Just follow the directions to align them and keep the pads close to the disc.

    If they are the old Avids (which I doubt) they may need a booster spring. See TandemGeek's picture here:

    Tubus Fly Rack & Ortlieb Panniers: Such a Deal!
    Last edited by rmac; 12-14-08 at 09:01 PM.

  3. #3
    hors category TandemGeek's Avatar
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    Quote Originally Posted by chichi View Post
    My shop idicates they have had similar problems on other tandems. Anbody have ideas?
    1. Make sure it's really a BB7 road model.
    2. Make sure the rotor has been trued
    3. Make sure the cable housings are no longer than they need need to be.
    4. While you're double checking their work, make sure they've installed the Avid in-line cable adjuster
    5. Make sure there's no cable drag.
    6. Make sure the return spring set screw is all the way in, per the Fine Tuning instructions.
    7. Make sure they're following Avid's instructions for adjusting pad clearance to the letter.
    8. If disc rotor rub is causing them to back off the pads from the rotor tell them to see #2, above.
    9. If the rear brake lever feels dead and doesn't spring back nicely there's not enough pre-load on the reaction arm and/or something's causing drag on the brake cable, e.g., rough cut housing end. As rmac noted, I still use a compression spring on my Avid BB7 to give it a little extra pre-load. However, note that I make sure the reaction arm really is pre-loaded and not sitting all the way open against the rear movement stop: it makes a difference.
    10. I'm not a professional mechanic and I think it may have taken me all of 15 minutes to install and adjust the Avid BB7 on our Calfee each of the three times I've installed it. I'm running Campy Ergo 10 levers and a BB7 Road and there's zero drag, zero rotor rub and now that the brake pads and rotor are seasoned and worn-in I can lock up the rear wheel with Debbie (~114lbs) aboard using only the Avid disc brake. It ain't rocket science so I suspect several of the above steps are not being followed to the letter of Avid's instructions.

    Here's a photo of our install

    Last edited by TandemGeek; 12-14-08 at 09:47 PM.

  4. #4
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    "However, note that I make sure the reaction arm really is pre-loaded and not sitting all the way open against the rear movement stop: it makes a difference."

    All steps apear to be followed although I am not sure what to look for in regards to the rear movement stop

  5. #5
    hors category TandemGeek's Avatar
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    Quote Originally Posted by chichi View Post
    All steps apear to be followed although I am not sure what to look for in regards to the rear movement stop
    Similar to a derailleur, you'd want to have your cable routed through the pinch bolt and instead of just fixing the cable where the reaction arm comes to a stop, you'd want to rotate the reaction arm forward just a few millimeters and then fix the cable so that the brake arm is pulling on the brake cable.

  6. #6
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    "While you're double checking their work, make sure they've installed the Avid in-line cable adjuster"

    Do you make reference to this as a convience item or does it affect braking. There is a cable adjuster installed, I'm not sure if it is an Avis or Jaquire. In looking at your link I see three different adjusters or indicators, care to give some insite?

    Thanks,
    Chichi

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    rear movemnt stop makes sense. Thanks

  8. #8
    hors category TandemGeek's Avatar
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    Quote Originally Posted by chichi View Post
    Do you make reference to this as a convience item or does it affect braking. There is a cable adjuster installed, I'm not sure if it is an Avis or Jaquire. In looking at your link I see three different adjusters or indicators, care to give some insite?
    It's the longer, sleek one with the white Avid logo (just a corner of the logo is visible) installed on the brake cable housing - the upper cable housing that runs into the head tube cable guide where you can see a brake cable exiting along the top tube...



    They now come with all Avid BB7's and are to be installed so that you can adjust-out cable slack on the fly to compensate for pad wear during the break-in process and in the event you find yourself on an epic descent where a lot of brake pad material was consumed.

  9. #9
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    What kind of brake is that on the front and why do you use a disk on the back instead of the same brake used on the front? Also why not use a front disk brake?
    Just curious.

  10. #10
    Tandem Mountain Climber
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    Quote Originally Posted by jnbrown View Post
    What kind of brake is that on the front and why do you use a disk on the back instead of the same brake used on the front? Also why not use a front disk brake?
    Just curious.
    Brake on front = Campy Record

    Why Disc on back:
    To add heat capacity and a bit more power. The weight of a tandem team on a long descent can require a bit of braking energy, sometimes too much for the heat capacity of a 100% rim brake system. In other words, your rims will heat up to a high temp raising the pressure of your tires and potentially cause a blowout. The disc can take more heat, and does not effect the rim temperature.The back wheel can take a lot of braking force before locking up, so why not add more power when you have the traction to accommodate it. Solo road bikes would not really benefit from a more powerful brake in the rear since it would lock up so easily, but tandems can benefit here.

    Why no disc up front:
    - More weight, less aero
    - Power isn't really required
    - Need a Disc specific + Tandem rated fork. Only options are the WoundUp Duo (tandem rated) or a cross fork (may not be strong enough for tandem use)
    - Disc brakes put a ton of force on a front fork. Honesty, I don't know if I would trust anything but the beefiest of forks for a front disc brake on a tandem.
    - You have to build a dished front wheel.

    Bottom line, is just having one disc helps enough with increased heat capacity and power.

  11. #11
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    I like how Calfee uses the dropout to mount the disk caliper.
    That bike is on my list if I can ever afford one.

  12. #12
    Senior Member VaultGuru's Avatar
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    chichi, take a look at the chain tension thread. You will need to know the torque settings as you work with your new ride.
    VG

  13. #13
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    The shop has installed a housing that is similar to shift housing except it also has a s/s braid. The idea is that it is compresionless and therefor usable with indexed shifting and the s/s braid makes it safe for brake use. Down side of the housing is that it is somewhat stiff so it will not be used from the handlebar to the steering tube, they may install it under tha handlebar tape.
    The shop has also ordered the Brake Power Booster.

  14. #14
    hors category TandemGeek's Avatar
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    Quote Originally Posted by chichi View Post
    The shop has installed a housing that is similar to shift housing except it also has a s/s braid. The idea is that it is compresionless and therefor usable with indexed shifting and the s/s braid makes it safe for brake use. Down side of the housing is that it is somewhat stiff so it will not be used from the handlebar to the steering tube, they may install it under tha handlebar tape.
    The shop has also ordered the Brake Power Booster.

  15. #15
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    ????

  16. #16
    hors category TandemGeek's Avatar
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    Quote Originally Posted by chichi View Post
    ????
    Ok, lets assume that for whatever reason there's insufficient cable pull: the brake booster will solve that in spades. What's the point of putting on the braded housing, further assuming they used descent quality housing in the first place?

    Again, let me re-iterate... I've never used pixie dust when setting up our Avids.

    1. Campy Ergo lever
    2. Campy brake cable housing w/Avid in-line adjuster
    3. Various types of brake cables
    4. A clean and direct run with no slop
    5. In-line cable connector because they have both been travel tandems
    6. Stock Avid BB7 Road: '02 model and '07 model.
    7. Aforementioned compression spring added
    8. Reaction arm pre-loaded before adjusting brake pad clearance & fixing caliper position.
    9. Rotor trued to near-zero run-out
    10. Caliper centered and brake pad bias / clearance adjusted per Avid's instructions.

    It just works... no fancy housing and no brake pull booster.

    BTW, just for kicks ask the shop where they intend to install the booster (i.e., near the handlebars or near the caliper) and then ask them why. Both ways work, but there's a difference and it plays into the logic behind using the compressionless housing, or lack thereof.

  17. #17
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    Just to reinforce what T-G said: make sure you have a ROAD caliper, not a MTB caliper. The symptoms you descibe match using a mtb caliper with road levers.
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  18. #18
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    [QUOTE=TandemGeek;8035085]Ok, lets assume that for whatever reason there's insufficient cable pull: the brake booster will solve that in spades. What's the point of putting on the braded housing, further assuming they used descent quality housing in the first place?

    Again, let me re-iterate... I've never used pixie dust when setting up our Avids.

    1. Campy Ergo lever (check)

    2. Campy brake cable housing w/Avid in-line adjuster (Campy brake wire at bars, jagwire upgraded to braide at rear triangle, in line adjuster)
    3. Various types of brake cables (brake wire with proven track record,check)
    4. A clean and direct run with no slop (TG I do notice that you apear to run the housing very straight at the back of the bike is it something you do because you like the look or have you found that it makes a difference in performance?)
    5. In-line cable connector because they have both been travel tandems (check)
    6. Stock Avid BB7 Road: '02 model and '07 model. ( is definatley a road model not sure what year)
    7. Aforementioned compression spring added (check)
    8. Reaction arm pre-loaded before adjusting brake pad clearance & fixing caliper position. (have to check,)
    9. Rotor trued to near-zero run-out (check)
    10. Caliper centered and brake pad bias / clearance adjusted per Avid's instructions. (check)

    It just works... no fancy housing and no brake pull booster.

    BTW, just for kicks ask the shop where they intend to install the booster (i.e., near the handlebars or near the caliper) and then ask them why. Both ways work, but there's a difference and it plays into the logic behind using the compressionless housing, or lack thereof. (power booster will be used at the back of the bike just before the brake per vaultguru because it looks right!)

  19. #19
    hors category TandemGeek's Avatar
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    Quote Originally Posted by chichi View Post
    I do notice that you apear to run the housing very straight at the back of the bike is it something you do because you like the look or have you found that it makes a difference in performance?
    It's exactly as long as it needs to be, no more and no less, to bridge the span from the rear stop to the caliper. The aesthetics are what they are.

  20. #20
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    Quote Originally Posted by dfcas View Post
    Just to reinforce what T-G said: make sure you have a ROAD caliper, not a MTB caliper. The symptoms you descibe match using a mtb caliper with road levers.
    One more time, are you sure on the caliper arm it says "BB7 Road" as shown in TandemGeek's picture?

  21. #21
    hors category TandemGeek's Avatar
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    Quote Originally Posted by rmac View Post
    One more time, are you sure on the caliper arm it says "BB7 Road" as shown in TandemGeek's picture?
    It's probably the correct caliper (silver, not ti grey or black).

    Based on everything else our friend has shared, the only thing that remains suspect to me is that last step (#10), as that's where things get out of whack.

    I did it to myself when I installed my first Avid BB7 using a cheater trick from MTB installations (lock the brake, fix the caliper and then adjust the pads) and it took me about an hour of fussin' and cussin' to realize that you really did need to follow Avid's printed instructions to the letter: crank the pads in against the caliper to get the caliper centered AND the proper 1/3 to 2/3 bias before fixing the caliper and then back off both the inner and outer pads by just a couple clicks.

    A little brake rubbing noise isn't a big deal when everything is initially installed as that will go away after the brakes are used a few times; however, for max braking power the clearance between the rotor and brake pads must be very narrow. With your brake booster, that precise clearance becomes less of a factor give that you end up with a significant net increase in cable pull at the caliper for the same amount of lever pull. The boosters are a simple fix so once that's installed you should be more than fine.

    Note: With regard to the little in-line cable adjusters provided by Avid, bear in mind the adjuster is intended to be used only for on-the-fly adjustments during a ride when an excessive amount of brake use has degraded brake performance due to pad wear. Once you finish your ride you'll want to undo any adjustment you made using the in-line adjuster and then do a proper pad clearance adjustment back at the caliper, checking for pad wear at the same time.

  22. #22
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    "I did it to myself when I installed my first Avid BB7 using a cheater trick from MTB installations (lock the brake, fix the caliper and then adjust the pads) and it took me about an hour of fussin' and cussin' to realize that you really did need to follow Avid's printed instructions to the letter: crank the pads in against the caliper to get the caliper centered AND the proper 1/3 to 2/3 bias before fixing the caliper and then back off both the inner and outer pads by just a couple clicks. "

    This warrants further investigation, I am not sure how they did the set up.

    Just checked on the bike now has all new style housing vs previous jagwire, feel has improved quite a bit. Caliper is a 2007 BB7 road. Brake Power booster has not arrived yet.

  23. #23
    Senior Member joe@vwvortex's Avatar
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    I fussed around with my Avid BB7 when I first got my CoMo. I'm using Campy ergos as well along with FSW Kwing bars. Due to the shape of the bars and the pull of the levers - there isn't alot of room between the levers before it contacts the bar. I tried it several combinations including no booster, no booster with additional spring in the caliper like TG has it, with booster and with booster and spring. I settled in on booster with no spring. HOWEVER, at the Zona tandems booth at the 2005 Northwest Tandem Rally, a guy was selling longer bolts for the spring tension adjustment. I sure with I remembered who this was. It really made a difference in the feel of the caliper - and worked better than the helper spring along with the brake booster. I also use the stiffer braided steel housing on the back as well which also improved feel a bit.
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  24. #24
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    Joe,

    Are you now using the loger stop bolt only (no BPB no helper spring)?

  25. #25
    hors category TandemGeek's Avatar
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    Quote Originally Posted by joe@vwvortex View Post
    II'm using Campy ergos as well along with FSW Kwing bars. Due to the shape of the bars and the pull of the levers - there isn't alot of room between the levers before it contacts the bar.
    Interesting. I'd have to see what that looks like just to get an appreciation for how much the bar shape and Ergo lever positioning is constraining the lever travel. The E3 bars on our tandem have an ergo bend that works quite well with the Campy levers, which was true of the Ritchey & 3T bars on our Ericksons which also used an ergo-type bend.


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