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V brake arm length query

Old 03-16-15, 12:53 PM
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V brake arm length query

Hi,

I'm thinking about trying mini V brakes on my commuter. Right now I have shimano cantis (Br r550) paired with Cane Creek Scr 5c levers, which are the same as the popular tektro, I believe. Anyways, they are standard road pull levers.

I'm looking at the TRP CX9, which according to my measurements, would comfortably clear my 38mm tires. The 8.4 length arms would be really close.

I've read reports that these 9cm mini Vs don't work well with short pull levers--if that is the case, can I simply use road V levers like the tektro 520s? Or will they pull _too_ much cable?

Thanks

Last edited by mpp6937; 03-16-15 at 01:03 PM.
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Old 03-16-15, 01:13 PM
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Opinions differ ,, One of the 2, maybe the 9, was Apparently produced when Shimano Increased the cable pull ratio in their New Brifter .

the brake gets released from the Noodle end to clear the tire, with out setting the brake up to spend a lot of the lever stroke
just getting the pad to begin contacting the rim.

Paul's Mini Moto will give you even more Cross racing Muddy tire clearance.

but really the issue between 9 & 8.4 is tiny, compared with either vs MTB length V brake..

Last edited by fietsbob; 03-21-15 at 09:05 AM.
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Old 03-16-15, 03:53 PM
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Matching lever pull to brake lever length is not an either/or matter. There will be more or less travel/effort needed with different combinations but there is probably a reasonably wide latitude of what is acceptable to an individual rider. More tire clearance will always result in a longer lever arm at the brake and greater travel/less effort at the lever.

Edit: At least with V-brakes and mini-Vs, since they are direct-pull. Cantis are another matter, you can change the leverage by changing the straddle wire length/angle..
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Old 03-20-15, 07:25 PM
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Thanks for the replies. I ordered the brakes and I'll give them a try with standard road levers. If they don't work well I'll just spring for the long pull levers. But not for a bit 'cuz I just wrapped the bars...
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Old 06-13-15, 10:10 PM
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I installed the shimano br r463 mini Vs. They have 90 mm arms.

They work pretty well with standard pull levers, though it was a real struggle to balance pad-to-rim clearance with acceptable pull at the lever. They need to be quite close or the levers bottom out. The rear in particular, due to the longer run of cable, was a bear and is mushier than I would like.

Compared to the Br r550 cantilevers, these are much more powerful and the squealing and occasional chatter in the front (worse in the cold or damp, which is basically summer in Milwaukee this year) is gone. I can get the rear wheel off the ground pretty easily.

I'm not totally sold, though, and may try a v-brake specific lever paired with standard V brakes.

So in summary, much better than cantilevers, but still not perfection.
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Old 06-14-15, 07:04 AM
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I hate mini-v's.

I've worked on several bikes that had them, even bikes that came from the factory with mini-v's. I've never been able to get them adjusted to my satisfaction.

The issue has been lack of travel with standard road brake levers. I can adjust them to operate to my satisfaction but that requires adjusting the pads so close to the rim that I can't open the brake to remove the wheel. I've developed some work arounds over the years like using a noodle that has a barrel adjuster or clipping the nose off of the brake noodle. I don't think that I should have to do that on a properly designed product.

You could solve the problem by using longer pull brake levers of course, but it you're going to do that why not just use standard length brake calipers.
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Old 06-14-15, 07:38 AM
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I used to enjoy setting up canti brakes but when I couldn't eliminate chatter with my carbon fork, I went to mini-v and will never go back. I set them up once and have never had to mess with them! I run campy levers so I have a release on the lever that makes it easier to open the brake for tire removal.

If I'm allowed to link to another site, here is an old guide that discusses mechanical advantage and thee different brake arm lengths so that you can choose the appropriate brake for your bike: My mini-V setup
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