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Phil from San Diego
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Discussion Starter · #1 · (Edited)
Couple of questions on brakes.

I keep hearing "modulation"... what does that mean?

Second, my 04 Giant Yukon came with Hayes GX2 disc brakes... on my 30day check up, they swapped out the rear brakes for a Avid BB7 for free which now feels alot more powerful. My front brake is still the crappy GX2 and it just feel so weak. I can't get it to lock when trying to do a front wheelie no matter how hard I pull on the brakes. But I can lock the rear Avids with one finger. Just came back from my 60day check-up... the front still feel weak. So my question is... are disc brakes designed so they aren't supposed to lock? The new kid at the bike shop said disc brakes aren't supposed to be more powerful then Vbrakes?!! but they do modulate better... Now i'm all confused.

The new guy also said I might need to replace the brake pads... but I've only been riding the bike for 2 months for a total of maybe 6 rides totally less then 100miles. Do disc brake pads wear out that fast?

Thanks.

Phil.
 

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what broke?

your bike has no breaks, Phil. Brakes, maybe. :rolleyes:

You shouldn't be able to LOCK them up, they are designed to modulate, or NOT lock, but rather to increase/decrease power to the brake pistons relative to your lever pressure.

Go to the brakes forum and read up on disc brakes using the
FAQ, and get all your answers.

Jim
 

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get disc brake check out !

Your disc brakes shouldn't lock up. The guy at the bike shop told you wrong info about disc brake and V brake. Disc brakes are always more powerful than V brakes. The fluid in the disc brakes can self adjust according to how hard you squeeze the lever. That's called modulation.

You have to get the bike shop to check the fluid of the disc brake and the calipers if they are setup properly. If you are not satisfy, get a different mechanic to examine the brake before you get into accident on next ride.
 

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modulation is

OK, you drive a car right? If you step down on the brakes (pedal), you expect them to respond relative to the pressure of your foot. & You expect them not to lock, as then you skid.

That's
modulation. variable power reaction. My words, Jim
 

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you go ahead
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Strange. My brakes in the past (all V-brakes) lock the wheel at a certain point.

Maybe we're thinking about different meanings of 'lock.'
I thought when a wheel locks, the brakes are tight enough to stop the wheel's roataion and make it skid...
 

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we're talking discs

not vbrakes. FWIW. Well we were, until you introduced them to this thread. for reasons I'm not sure of????
Second said:
Strange. My brakes in the past (all V-brakes) lock the wheel at a certain point.

Maybe we're thinking about different meanings of 'lock.'
I thought when a wheel locks, the brakes are tight enough to stop the wheel's rotation and make it skid...
 

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Phil from San Diego
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Discussion Starter · #8 ·
hmm... getting close to understanding modulation... but... if disc brakes are more powerful then Vbrakes... why then is it easier to get Vbrakes to lock? and if disc brakes are more powerful, shouldn't it take less effort to get it to lock?


Phil.
 

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Picard said:
Your disc brakes shouldn't lock up. The guy at the bike shop told you wrong info about disc brake and V brake. Disc brakes are always more powerful than V brakes. ...
You have to get the bike shop to check the fluid of the disc brake and the calipers if they are setup properly. If you are not satisfy, get a different mechanic to examine the brake before you get into accident on next ride.
V-brakes are not "more powerful" than v-brakes.

Also he has mechanical disc brakes so there is no bleeding involved.
 

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mtb_biker said:
V-brakes are not "more powerful" than v-brakes.

Also he has mechanical disc brakes so there is no bleeding involved.
I'm guessing you meant disc brakes there :)

Anyway, I just want to throw in my 2 cents and say the same thing as well, disc brakes are not more powerful than rim/vbrakes but they do have their own set of benefits, the least of which being that you can brake for longer periods of time with less effort and zero wear to your rimset.

I've got Avid mechanical discs front and rear and I can do a one fingered brake stand. With proper setup and decent pads, good mechanicals are superior in to hydros any day IMHO And I do downhill with them just fine, say what you want. I've had hydros, they're just not for me too many cons.

Now as food for thought, consider this- no trials riders are using discs (at least that I am aware of) and they definitely need some powerful braking ability.
 

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hmn well....

Now as food for thought, consider this- no trials riders are using discs (at least that I am aware of) and they definitely need some powerful braking ability.[/QUOTE]

So if I take the Gustavs off my 47lb FR bike, the V's are more powerful and will be better stopping my 250lb total mass, downhill at 45 degrees, in a rainstorm, on the Norshore?

The only ones you see here with V's are struggling way behind back in the woods. Even in dry conditions, your hands give out after 1 day of hard riding with V's, not enough power. Not to mention using up a set of pads per ride, and new rims every six months.

Maybe where you live they are OK, here they are a cruel joke.

Jim
 

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The reason V's lock up more easily is they have way more leverage (26" as oposed to 6,7,8") but that means worse modulation because that tiny zone between no power and full grab is very small with such high leverage. Not to mention the fact that rotors dont flex since theyre so thin the two compressing pads dont allow the braking surface to flex which is always happening with V-brake to a certain extent depending on the construction of the rim.
 

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If I could just edit a bit?

nnn said:
The reason V's lock up more easily IF IT'S NOT WET is they have way more leverage (26" as opposed to 6,7,8") but that means worse modulation because that tiny zone between no power and full grab is very small with such high leverage. Not to mention the fact that rotors don't flex since they're so thin the two compressing pads don't allow the braking surface to flex which is always happening with V-brake to a certain extent depending on the construction of the rim.
If wet, there's no grip on the rim, hence no power or braking effect. Known as "no brakes" here ;)

Jim
 

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JimC. said:
So if I take the Gustavs off my 47lb FR bike, the V's are more powerful and will be better stopping my 250lb total mass, downhill at 45 degrees, in a rainstorm, on the Norshore?

The only ones you see here with V's are struggling way behind back in the woods. Even in dry conditions, your hands give out after 1 day of hard riding with V's, not enough power. Not to mention using up a set of pads per ride, and new rims every six months.

Maybe where you live they are OK, here they are a cruel joke.

Jim
Of course not, I was speaking strictly on a technical level. Wet stopping power etc fall into what I was talking about when I mentioned the other benefits of discs. I personally haven't run rim brakes for many years, I'm quite happy with my mechanical discs, can't beat em. ;)
 
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