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Old 10-26-08, 06:15 PM   #1
Crast
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Mech. Advantage, Cantis, Crosstop levers and brifters.

I've got my commuter cyclocross bike dialed in to about as good as the I can get it, but the braking just doesn't seem right to me. I'm using a yoke+transverse cable which came with the bike, not a link cable. I've read through all of sheldon brown's pages on adjusting cantis, and tried a whole range of different yoke heights, settling somewhere in the middle.

My problem is this: I have it adjusted so that the yoke angle at rest is somewhere around 90 degrees. Both the brifters and crosstops seem to be smushing the brakes quite well against the rim so that the brakes actually get compressed, so the mech advantage seems correct. But then when I go out on the road, the stopping power when using the brifters is nonexistent, while if I use the crosstops I can stop on a dime. The brifters don't bottom out, it's just that they hit the rim and I'm squeezing hard but the bike isn't stopping.

My setup includes: Tektro Oryx cantis, Tektro RL70 crosstop levers, and Sora brifters. Also on the front is a steerer-tube mounted cable stop. The yoke is some cheapo looking thing: shown here. I could lower the yoke for more M.A., but I don't think I need more; if I do that won't it make the crosstops have too much?

What if I replaced the yoke?
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Old 10-26-08, 06:36 PM   #2
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I've got a similar problem to you.

Shimano cantilevers, tiagra sti and tektro interrupters.
Aztec red brake pads
Using the shimano link wire, size E.

I rarely use the interrupters so haven't noticed what they're like. What I have noticed is the following
1) You need to run the pads far too close to the rim for riding in mud.
2) I can never get the right trade off between mechanical advantage and cable pull.
3) I can never get the front brakes not to make a sound
4) The braking is not as powerful as it could be, I can not lift the rear wheel off the ground.

Things I've tried doing
1) Fork crown mounted brake hanger
2) Variety of brake pads
3) Various degrees of toe-in
4) Cleaning the rims to the point you could eat off them.

Things I'm considering
1) Replacing the link wire with an extra wide yoke and using a straddle wire.
2) Adding a brake booster
3) Replacing the brakes with avid shorty 6 (2009)
4) Replacing the brakes with v-brakes and using a travel adjuster to compensate for the difference in cable pull.

Any other ideas?
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Old 10-26-08, 08:01 PM   #3
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it's probably cable bind caused by a tight bend in the cable housing.
I ran into a similar problem when using cross tops with narrow 40cm c-c drop bars. The cable would have to take an extreme bend and would result in the cable binding.

solution: put your cross tops at a wider stance to ease the cable bends, get a steerer tube cable stop that sits lower.
Also check that your cable housing doesn't move around on the bars and that they are bottoming out between the levers.
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Old 10-26-08, 09:50 PM   #4
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Crast, when you grab the levers on the brifters, how far down the lever are you grabbing? I used to make the newbie mistake of holding the brake lever too close to the pivot and my brakes felt weak because of it. Grabbing further down gives much more mechanical advantage. Given that your interupter levers work good, I'm inclined to think the above is your problem.
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Old 10-26-08, 09:53 PM   #5
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Yeah, brifters needs to be used from the drops for maximum lever-leverage. Trying to use the brakes from the hoods don't give anywhere close to the same braking-power.

Also, something in between the brifters and cross-tops could be introducing friction or binding into the system.
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Old 10-26-08, 10:17 PM   #6
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Sometimes the cable stop mounted on the steerer tube comes with a noodle, ostensibly to provide a better cable run. They look like this
http://www.benscycle.net/bmz_cache/d...age.100x71.jpg
Often they just make for a messy routing, and the routing is often better just doing without.
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Old 10-26-08, 10:45 PM   #7
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Attached some pics to detail the setup. To clarify what I said about braking from the brifters being ineffective, I mean that when I get in the drops and yank hard with four fingers, it's as if I were pulling lightly with my pinky only on a normal road brake. Barely braking at all, though the pads connect without bottoming out the lever. When I pull on the crosstop levers it does what it ought to, and I can stop in a reasonable distance.

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Originally Posted by fuzz2050 View Post
Sometimes the cable stop mounted on the steerer tube comes with a noodle, ostensibly to provide a better cable run. Often they just make for a messy routing, and the routing is often better just doing without.
I have the noodle. I'll try without, though I'm not sure the housing will reach to the cable stop then. I'll buy some more housing if that's the case.

Quote:
Originally Posted by DannoXYZ View Post
Yeah, brifters needs to be used from the drops for maximum lever-leverage. Trying to use the brakes from the hoods don't give anywhere close to the same braking-power.
I do 90% of my riding on the hoods though, and I've never had problems braking from there on my road bike. c'est la vie.

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Originally Posted by joejack951 View Post
Crast, when you grab the levers on the brifters, how far down the lever are you grabbing?
If braking from the hoods, about halfway down the lever; I hook my thumbs around the hood and pull with my four fingers right where the lever makes its inward curve.

Quote:
Originally Posted by AEO View Post
solution: put your cross tops at a wider stance to ease the cable bends, get a steerer tube cable stop that sits lower.
Also check that your cable housing doesn't move around on the bars and that they are bottoming out between the levers.
One thing which occurred to me is that when I pull the crosstop levers, the housing moves, but when using brifters, the housing stays where it is. It could be that I am getting a better cable bend (especially on the front brake) when it's being pulled vs. when it's not. My bars are about 40 or 42cm wide, though I'd prefer 44's. Maybe I'll consider new bars, re-doing the levers, cable runs and tape all in one shot.
Attached Images
File Type: jpg img_4379.jpg (67.7 KB, 23 views)
File Type: jpg img_4380.jpg (51.1 KB, 26 views)
File Type: jpg img_4381.jpg (85.9 KB, 25 views)

Last edited by Crast; 10-26-08 at 10:51 PM.
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Old 10-26-08, 11:03 PM   #8
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I would put the yoke lower, just barely above the fork eyelet
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Old 10-27-08, 05:44 AM   #9
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Had a colleague who couldn't get is CX to brake properly. Turned out that the brifters sat so high on the drop bar that levers bottomed out against the bar before they'd pulled enough cable to activate the brakes properly.

Might be worth looking into.
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Old 10-27-08, 07:37 AM   #10
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Quote:
Originally Posted by AEO View Post
I would put the yoke lower, just barely above the fork eyelet
+1

That cable carrier is set really really high (which leads to decreased braking power).

Another thing you might want to try is to ditch the noodle on the cable hanger. It seems like you should have enough space to simply run the cable housing directly into the hanger (with a ferrule on the end of the housing of course).
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