V power versus Disc

[Scott]

Check out this link. A German mag, as usual, has done some objective tests on disc power versus vees-I was surprised as was most of the weight weenies there!!  Don't know what's wrong with the states bike mags, but it seems they never really dig for answers relying on seat o the pants for most reviews....

http://forums13.consumerreview.com/crforum?[email]viewall@1.bRLdacrUtWi[/email]^0@.ef946c3  

[jimbo]

I won't give my disc

[Matno]

V-brakes would be much more powerful than discs if: a) the rims were always clean, and b) the rims didn't have any flex to them. Since that's not likely to ever happen, discs are a better option for many of us. Funny how comparisons between the two types of brakes seem to overlook the fact that there is no "give" when you squeeze a rotor from both sides. With a rim, you would have to make a solid chunk of metal between the pads to achieve the same result. I don't even want to think about how much that would weigh... However, some rims come pretty close. Some of them that are used for trials are pretty dang solid. That might explain why trials riders still prefer rim brakes - they have better "lock up" power.

As for me, V-brakes were always powerful enough when clean. It was the situations where they were muddy or caked with a layer of ice that I knew I needed discs!

[GrimJack]

Matno, you are absolutely correct.  Clean Hydro rim brakes are the most powerful thing on the market for locking a wheel.  And keeping your rims in primo condition is easy when you ride trials!

Unfortunately, keeping MTB rims in the same condition is impossible.  Add in the durability factor (I literally blew through rim brake pads in ONE run down the shore, about 90 minutes of riding), the fact that cables stretch, plug up, or fray, (hell, I'd run hydraulic SHIFTERS if someone would make them) and finally, the fact that Vs don't work worth a tinker's damn unless the rims they are running on are perfectly true.  I don't know about the rest of you, but my rims haven't been in good enough shape to run Vs since the first ride after I built them!  

To top it all off, rim brakes wear through your rims.  Unlacing a wheel and installing a new rim is a pain is the ass.  Taking a wheel off, unscrewing 6 bolts, and installing a new rotor, is easy.  Not that I know anyone who has managed to wear out a rotor - break one, sure, but never wear one out.

Oh, and I forgot to mention the pad replacement.  Pull it out.  Put in another one.  DONE.  None of this remove the pads, align the new ones very carefully, squeeze the brakes, put a coin under the trailing edge, squeeze them again, tighten them up, but not so tight that they slip out of alignment... you guys get the idea.

Sure, Vs work great in the lab.  Problem is, they stay that way for a very short time on the trail, whereas discs are good for a long time, in the lab and on the trail.

The people who did these tests have some valid results, which prove some points.  Unfortunately, these points aren't really valid on the trail - well, at least not the trails that I ride every week.

[GET]

Besides all of the great advantages of disc brakes mentioned above, I have found others.  I can't recall anyone questioning the power of linear pull (v) brakes.  At the start of braking, they can provide maximum braking.  But, they almost immediately start to fade under heavy braking.  The elastomer pads loose their coefficient of friction under a number of conditions.  First is heating.  Others have already mentioned wet & muddy conditions.  Even under dry conditions, our trails have a high content of small silica particles.  These particles build up (stick in) the elastomer brake pads and severely reduce braking effectiveness.  I would actually scrape the pads to keep them up to specs.  Well enough said for now.


I do not intend to go back to vees, but I have often told people that they do not have to rush to discs.  If you can afford the conversion or are building new, I do recommend discs.

[Dennis]

guys, keep in mind that "rim brakes" ARE disc brakes.
the wheel is the rotor, the problem is that they get dirty, wet and everything else, plus they are not getting rid of heat at all efficiently.
excuse a bit of science here, but all brakes do is convert kinetic energy ("energy of motion") to heat, and thats what slows us down.
"disc brakes" work better because they are more efficient at converting KE to heat because the rotors can be made to be efficient at dissipating the heat that builds up, eliminating (or at least minimizing) fade. plus, the rotor is away from all the nastiness on the ground that can reduce the coefficient of fricition between the pad and the rotor.
so, the "disc brakes", if made properly, should be better especially in wet conditions, which I think we all know they are.
sorry for all this, I haven't taught anything since yesterday and am suffering withdrawal. Please don't kick me the forum for this, I can talk about other things.

[slowride]

I switched to disc brakes mainly for 2 reasons: My rims never stay true enough for the Vs to work optimally, and I hate having to readjust my brake every time I take off the rear wheel. I never found a V brake that could open wide enough to get the wheel out without either deflating the tire or screwing up the pad adjustment.

I do like the less fade part quite a bit too.

[IFO]

ok as usual im gunna stir up the hornets nest...

first off V-brakes suk ass... if you like em thats fine...
but if you come ride the Shore with me, i 100%quarentee WILL convert u to disc brakes...

running V-brakes reg. on teh shore is only done by people who cant afford discs...its that simple.
the Shore is the perfect proving ground for any peice of bike technology...its not the that Shore is only one type of riding... in fact the shore emcompass's every type of riding...

and as far as Trials riders go, they use rear rim hydros cuz tey have to... no one has invended a rear disc tab strong enuf to survive the punishment a trials rider places on the frame/ brake....

most trials riders today use a frt hydro, cuz it works better but for teh rear still use the Magura rim hydro... i have heard of several trials bike makers are worknig on a rear disc setup that is able to survive, but so far its all talk...

ok, chew and that and lets go for round 2. hahahaahah

[GET]

Now IFO, let's not mince words.  How do you really feel?

Disc brakes are superior in sooooooo many ways!  What more can I say?

[5500C]

Allright we found IFO another topic to rant on besides Noleen Mega-Air Shocks!!!

[IFO]

u mean i cant rant about Nollen shit shocks in here?

[Dennis]

IFO,  we all agree that disc brakes are better than disc brakes that operate with the rim as the rotor.
You won't find any argument here on that point.

[5500C]

u mean i cant rant about Nollen shit shocks in here?

You can rant all you want on whatever you want.  I'm just trying to find you new topics!!!

Besides you helped me transform my bike from a good bike, to the ultimate trail/bomber!!!