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-   -   Any rear brake hints or tricks? (http://www.bikeforums.net/tandem-cycling/891767-any-rear-brake-hints-tricks.html)

Camilo 05-25-13 06:13 PM

Any rear brake hints or tricks?
 
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 very experienced riding and know how to use the front and rear brakes, and am perfectly comfortable using the front brake first and most often, and doing it correctly. So, overall braking is adequate.

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.

Team Fab 05-25-13 08:50 PM

Jagwire claims to have 30% less compression than standard cables?

Camilo 05-26-13 01:06 AM

Quote:

Originally Posted by Team Fab (Post 15667846)
Jagwire claims to have 30% less compression than standard cables?

I think the housings I'm using are whatever Jagwire housing the LBS sells off a bulk roll. They are Jagwire, normal black plastic covered brake cable housings, I don't know if they're any special variety.

PMK 05-26-13 05:03 AM

On your cable housings, run the ends on a belt sander or similar without overheating them. A Dremel tool work carefully can wdo it also. You want the ends square and flat.

Without seeing the run, is it a full cable housing or several short housings?

Also, realize it really is about stopping. Consider testing various brake pads and even try slip in pad holders from higher end MTB brakes if possible. Thin high grip pads and padholders like on XT or XTR brakes flex very little and provide more net force onto the rim.

Also, if you run a metal noodle, ensure the angle of the noodle (they offer different ones) is providing no cable wind-up. The noodle should see no movement except towards the motion of clamping the brakes.

Last, consider finding or building a brake booster to stop frame outward bowing / flex. These should be an easy find on some type of clearance. If you want to be crafty, these are easily fabricated. Ensure you have a high strength aluminum like 2024 or 7075 for best results.

PK

Onegun 05-26-13 05:49 AM

KoolStop Salmon brake blox, (if you're not already using them), and Nokon cable housing housing together will offer an "Oh wow!" performance increase. Much as I detest the ridiculous price of the stuff, "30% less flex" is nice but zero flex is better, particularly on the long run of the rear brake on a tandem. You don't really appreciate how much standard cable housing compresses until you use a Nokon setup.

As we got heavier, :cry:, we went downhill even faster, :D, and I got progressively more nervous :eek: about a tandem's inability to stand on its nose. I messed with the brake setups for a long time and a long dollar trying to get it to stop like my single. (A task they said couldn't be achieved, incidentally. Whoever "they" are.) Braking is now within a single digit percentage of my single, and I'm happy.

Camilo 05-26-13 05:54 PM

thanks for the suggestions - just what I was looking for. I'll start with the simple stuff, and move forward until I get it as good as I can.

Team Fab 05-27-13 01:49 PM

If you try the nokon could you post results please.

Onegun 05-27-13 02:44 PM

Quote:

Originally Posted by Team Fab (Post 15672784)
If you try the nokon could you post results please.

I thought I just did. :rolleyes:

Oh, you mean you need data points from more than one off-the-deep-end, maniacial, fanatic believer-in-something on which to base your opinion? You're not from this country, are you? ;)

waynesulak 05-27-13 03:00 PM

I recently spent the money to try Nokon brake cables. I did not buy the gear cables.

The installation took a while because i have a diificult little curve for the rear brake and there was a little trial and error involved. Each time adding or subtracting a link and changing the length of the linner.

I am happy with the results. Much more possitive rear brake feel. The outer did start to creak after a few hundrend miles. Appeantly this is caused by the aluminum link interfaces moving as the cable flexs. I applied some Boeshield to the outer, let it dry before the next ride and that seems to have solved the problem.

Overall I would suggest it for the rear brake. I am concerned about loosingi links if a cable needs road side repair. The links are held together by the tension of the cable . It would be pretty depressing to have a spare cable but have some links co down a drain or hide in the grass.

born2pdl 05-27-13 03:45 PM

If you've gone to a narrow slick tire, you have room for a mini v-brake. Tektro makes a good one (read a review here):

http://bikehabit.blogspot.com/2010/1...-v-brakes.html

We use the tektro 926 mini v-brake at the rear with an in-line barrel cable adjuster up front where I can get to it, with ultegra 6600 road lever's. on an old trek t2000. Works well for us.


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