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Why are pads on linear-pull brakes so much longer?

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Why are pads on linear-pull brakes so much longer?

Old 06-24-19, 01:05 PM
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MEversbergII
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Why are pads on linear-pull brakes so much longer?

I've had a few bikes with a couple of different brake systems on them in the past. I have noted that of all of them, linear-pull ("V") brakes always seem to have distinctively long pads. Why is this? Is there something about the mechanics of that sort of brake that requires a longer pad (so long that it follows the wheel's arc, even) as compared to seemingly every other form of rim-brake?
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Old 06-24-19, 02:21 PM
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When you pull the lever, it exerts less force, which is compensated by longer pads?
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Old 06-25-19, 09:16 AM
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Originally Posted by ChinookTx View Post
When you pull the lever, it exerts less force, which is compensated by longer pads?
Do you know that or is it a guess? It seems unlikely to me, otherwise why use linear pull brakes. I'd always assumed that it was because they are generally found on the sort of bike that needs better stopping power or good stopping power in adverse conditions. I'm sure it isn't coincidence that disk brakes appeared first on mountain bikes.
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Old 06-25-19, 09:36 AM
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Originally Posted by ChinookTx View Post
When you pull the lever, it exerts less force, which is compensated by longer pads?
That would be my first guess, too. In my limited experience, double pivot side pull rim brakes feel more powerful than v-brakes and the pad lengths are shorter on the double pivot brakes.

It would seem that at least one reason that v-brakes are used is that they can reach around wide tires and give more clearance when unhooked to remove those wheels with wide tires on them.
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Old 06-25-19, 10:41 AM
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Originally Posted by ChinookTx View Post
When you pull the lever, it exerts less force, which is compensated by longer pads?
I believe you have this backwards. Pressure increases as surface area decreases (smaller brake pads). (P = F/A) Longer pads effectively decrease pressure, which would imply stronger forces are applied by v-brakes, which corresponds with my experience.
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Old 06-25-19, 10:41 AM
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You can put on shorter pads if you wish, I did so on my 16" wheel Bike Friday..

The stock pads came from the makers of the brakes, with the part.

and no one had any profit motive, in changing that.






....
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Old 06-25-19, 11:04 AM
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Originally Posted by VictorKnox View Post
I believe you have this backwards. Pressure increases as surface area decreases (smaller brake pads). (P = F/A) Longer pads effectively decrease pressure, which would imply stronger forces are applied by v-brakes, which corresponds with my experience.
This is correct. Early V-brakes were very grabby, too on/off with no modulation. This resulted in lots of of OTBs (esp since everyone on mtn bikes back in the day was coming off the previous cantilever brakes, which lacked leverage).

Longer pads have more modulation because the pressure can be applied more gradually.
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Old 06-25-19, 01:21 PM
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Originally Posted by VictorKnox View Post
I believe you have this backwards. Pressure increases as surface area decreases (smaller brake pads). (P = F/A) Longer pads effectively decrease pressure, which would imply stronger forces are applied by v-brakes, which corresponds with my experience.
Originally Posted by Ken2 View Post
This is correct. Early V-brakes were very grabby, too on/off with no modulation. This resulted in lots of of OTBs (esp since everyone on mtn bikes back in the day was coming off the previous cantilever brakes, which lacked leverage).

Longer pads have more modulation because the pressure can be applied more gradually.
Makes sense. I almost always get things bassackwards in my thoughts. It's only Tuesday, and I really don't drink anymore, but I'm thinking a little whiskey after work would put my brain in the right place this evening.
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Old 06-25-19, 01:31 PM
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Modulator noodles , come on entry level bike V brakes for casual users.
housing sits and pushes against a spring, then the spring sits against the shoulder, of the noodle,
rather than the housing end sitting directly against that shoulder..
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Old 06-25-19, 01:40 PM
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Brake force will be the same with small or large pads. Small pads have more pressure, but over smaller surface.

The advantage of larger pads is they heat up less (less heat per area) and need less frequent replacement. Works similar for disc brakes.
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Old 06-25-19, 06:05 PM
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Originally Posted by fietsbob View Post
Modulator noodles , come on entry level bike V brakes for casual users.
housing sits and pushes against a spring, then the spring sits against the shoulder, of the noodle,
rather than the housing end sitting directly against that shoulder..
I was going nuts trying to diagnose my spouse's brakes until I found and removed those springs.
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Old 06-25-19, 06:06 PM
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Vee brakes have more space for longer pads without running into clearance issues with some forks.
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Old 06-25-19, 08:52 PM
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Originally Posted by Gresp15C View Post
I was going nuts trying to diagnose my spouse's brakes until I found and removed those springs.
Are they inside the silver tube?
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Old 06-25-19, 09:14 PM
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Originally Posted by MEversbergII View Post
Are they inside the silver tube?
Yes. The wider portion that the housing fits into. You might have to fish it out with a small hook. Now, I finally replaced the noodles because one of them had a dent in it, and the new noodles didn't have the springs.

Note that I'm not an engineer, and I don't know if there is some massive safety reason for needing the springs, that I haven't thought of. But caliper brakes don't have those springs.
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Old 06-25-19, 10:57 PM
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i use ultegra/dura ace holders , with shimano r55c4s , i dont do much MTB but the ones i have always do right by me for road and cross !!!!
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