Any tricks for rear brakes?
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  1. #1
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    Any tricks for rear brakes?

    We have a 26" wheel tandem (Trek T900) with linear pull brakes that we've gradually changed to more of a road bike style - narrower slick tires, road bike handlebars, bar end shifters and brake levers intended for linear pull brakes.

    The rear braking is adequate - I can lock the wheel - but just barely - it is quite mushy. I'm pretty experienced at cabling and think I do a decent job in minimizing excess housing, making the runs as efficient as possible, etc. For what it's worth, the rear derailleur, in spite of the long run, works pretty darn well. Front shifting and braking is solid.

    But on this bike, of course, the rear brake cable is really, really long. There are unavoidable loops, and when I hit the brakes on the work stands (I use two stands to work on the tandem!), I can see fairly significant movement in the cable housings in a couple of places where it loops. The biggest culprit is a loop it makes from near the rear seat tube around to the brake. The other is in the front where the housing goes from the handlebars down to the top tube where it heads back to the rear. I believe it's this flopping around that causes a lot of the mushy-ness. I've never seen this sort of flopping around on the road or mountain bikes I've cabled.

    I've got the pads adjusted to the rims as close as practical. Even with the brakes adjusted like this, I have to take the lever to the bar to get good braking. Again, like I mentioned, the levers are the tektro ones intended for linear pull brakes. The front brake feels as tight and solid as my road bike brake.

    So, I'm just looking for some hints as to ways I can mitigate this issue, aside from buying a new tandem with hydrolic dics in back!

    Thanks.

  2. #2
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    Unless those V Brakes are a poor quality they should work fine. Maybe due to the long cable run they feel mushy, if the brakes are a high quality try using stainless steel cable with a high quality housing. If you've done that then check the pads for glazing or perhaps their low end pads, or you need to clean and sand the rim to get junk off the rim. Glazing can be taken care of using some fine sand or emery paper and sand off the glaze. New pads would probably be best served using Kool Stop Thinline Salmon pads, and make sure their just very slightly toed in. Also make sure you spray some lube on cables like TriFlow if you already have nice cables.

    You shouldn't have to go to disk brakes, tandems for many years have been stopping just fine with sidepulls, cantilevers, and now linear brakes. You just need to get it dialed in. See this for more info: Park Tool Co. ParkTool Blog Linear Pull Brake Service (V-brake style)

  3. #3
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    Thanks Froze. The cables and housings are good quality. But I'll go through the set up again from a-z and check the pads again too.

  4. #4
    your text here
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    1) brake glazing
    2) rim glazing
    3) toe-in

    do you have an inline barrel adjuster? you say you have linear-specific road levers, so you dont have that adjustment unless you added an inline adjuster. you wont even have that on the brake end. instead of the adjuster, you might just need to pull a lil bit of cable out. but i would invest in an adjuster.

    there are two main types you can get: one goes "in-line" and the other goes right at the brake.
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  5. #5
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    I have been using a Travel Agent V-Brake / Lever Adapter Tandem Adjusting Barrel for STI for almost 20 yrs now, they work great

  6. #6
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    Camilo, without a picture I can not say for sure, but I would say it may have something to do with how far in you had to adjust your V-brakes to reach the rim. What I am getting at is depending on how narrow your new rim is the brake arms may be at such a angle past the pivot point that it is not allowing the full force to be applied. If you could post photos that would help a bit.

  7. #7
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    Try using derailleur housing instead of brake housing. It often does help mushy brakes feel better
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  8. #8
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    Jwiffle, I understand that brake cable will fit in deraileur housing ,but I would think it would cause to much restriction on such a long run? Have you done this and were you successfull?

  9. #9
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    Cable stretch and housing compression are minimal factors in tandem rear brake performance.

    The problem with this setup is too much of the package weight is too far forward of the rear wheel, along with the increased mass of 2 riders. During braking, the rear wheel is unloaded more so than on a single bike because much of the riders' weight is too far forward.

    I also don't think disc brakes would solve the issue. The OP also doesn't mention how effective actual rear brake application is, although I can assume he's transferring his complaint from poor braking to this perceived cable stretch.

    One alternative would be to add a drum brake operated by the stoker.

  10. #10
    I love to climb!
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    I've not tried it on a tandem, just regular bikes. Odyssey makes the linear slick cable for use on bmx bikes that is basically a brake cable with a derailleur housing. I've used in on mtbs to help with mushy feeling rear brakes. I don't that it is sold in a length long enough for a tandem, but you can get bulk derailleur housing at any shop. Shouldn't cause any more restriction than the brake housing does, I wouldn't think.

  11. #11
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    I used the Jagwire Racer XL cable kit when I built up my Cannondale. I'm using the TRP Hy/Rd discs, which you may have heard are quite sensitive to which type of housing is used. Braking is excellent on both ends.

    Check cable lengths on the Jagwire site. I seem to recall having to use a longer cable for the front derailleur than what came in the kit. Everything else worked fine.

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  12. #12
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    I don't accept disk brakes as an acceptable system, the cost to maintain them is very high, pads alone cost around $25 and will last anywhere from 100 miles to 1200 miles...but they won't last anywhere near 1200 miles on a tandem! At to that the cost of a rotor every 10,000 miles at a cost of $50 each.

    In addition to the cost on a tandem on long descents the rotors can get very hot, so hot they have been known to bake hub bearings. Drum brakes have long been used on tandem bikes on the rear because they dissipate heat better than disk. And drum brake maintenance is very low and will last a long long time and are most trouble free brake ever designed for a bike. However you have to check to see if your tandem is built to accept drums, most are, and you have to rebuild the rim of course.

  13. #13
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    Brake arch. Also check the pads for glaze/ dry rubber
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  14. #14
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    Whenever I have troubles with cables, I tend to pull them out of the housing, and carefully grease the cables as I put them back in. It seems to help a bit. My next experiment will be with teflon lined cable housing.

    If it is a tandem problem, then perhaps it should use bare cables and cable guides, but it is a bit too late to do on a finished bike.

  15. #15
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    perhaps you've found resolution to the problem by now. I see two issues. The problem began when you moved to "linear pull" drop bar levers. These never work as well as MTB levers-it seems the cable pull, though more than standard road levers, is not as much as MTB levers. It would seem almost better to use standard road levers with a travel agent, or mini-V's. It sounds like the brakes themselves are already adjusted with the pads as close as practical.
    The second problem is cable stretch due to length, always a problem with the long rear brake cable of a tandem. Compressionless brake housing, does help a great deal. The problem with shifter housing as another poster had suggested, is the risk of the housing "bursting" due to lack of reinforcement of the linear housing strands, even with a metal ferrule. The compressionless housings (such as the Jagwire that cyclo-phile suggested, or Yokozuna Reaction) reinforce the housing to avoid this.

    Things like brake shoe glazing will not affect the mushy, "lever to the bar" issue that the OP complained about, but will affect brake performance ultimately.

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