sstorkel

That certainly hasn't been my experience. It feels to me like it takes a noticeable amount of time for rim brakes to clear the water and gunk from the rims before the bike starts to slow appreciably. In contrast, discs seem to slow the bike almost immediately. Once the rims are clean, Koolstop salmon pads do provide great stopping power.

StephenH

One thing to note, is that if you have the bike on a rack (or, in my case, flipped upside down), you can adjust the brakes where they feel okay when you just spin the wheel, but then when you actually have weight on the bike, they're not doing much. My guess, if a shop just got done with them, is that this was the issue. In which case, ask whoever adjusted them to ride around the parking lot, and they'd probably say "whoa!" and run right back in to adjust 'em better.

Sayre Kulp 

Disks. Period. No fancy explanation necessary.

OiS

One key reason why discs are better is that it is not uncommon for wheels to go a little out of true, when that happens, no big deal if it is just a little bit, if you have disc brakes, if you have traditional rim brakes, you will need to loosen a little so they don't rub, which in turn will reduce your braking power as the brake pads then have further to travel before gaining good grip on the rims.

Of course the answer to fixing this issue is to ensure your wheels are always perfectly trued, but rim brakes make this necessary, whereas disc brakes give you a little more tolerance in this regard.

meanwhile

Interesting. My experience has been that pink kools have no real wet rim penalty, and that's what one of the big German cycling magazines found when they did a test - kool pinks stopped only abouy 5-10% slower with wet rims. Maybe this is somewhat rim dependent? Have you tried cleaning your rims? And is it possible that you're simply not hitting the front brake hard enough? I'm pretty sure that I do exert more force in the rain. It might be worth reading this and checking for the problems discussed - brake bit in the rain with pinks should be, at worst, *almost* instant:

https://www.cyclechat.net/threads/koo...oblems.113271/

Of course it could just be that we have different standards for what a "noticeable" amount of time is!

meanwhile

If you're not inspecting your bike well enough to notice a rim so warped that it will serious reduce rim brake power (squishy brake blocks will compensate for a quite a bit of variation) then you really are not cycling safely.

chasm54

This isn't the greatest idea. There's far more stopping power in the front, so whichever type of brake you are using, you are taking longer than necessary to stop as well as increasing the risk of a skid. Unless the surface is loose or slippery it is much better to brake with the front.

meanwhile

It depends on the geometry of the bike, but the shortest front stop is usually around half the length of the shortest rear stop. You do have to practice controlling the brake and keeping your weight back to get the best effect - rather coming over the bars. Google "sheldon brown braking."

donalson

in my experience discs is not a bad way to go here... the obvious wet/nasty weather advantage is nice... but even more was a few years ago when I did a 100k charity ride.. by the end of the ride I was 3 spokes down out back on a 32 spoke wheel... i'm sure had i had rim brakes that wouldn't have worked out for me.



I'm considering buying a disc trucker here soon to be my city bike (right now thats my 1x1 modified for gears with a titec H bar and shimano dual control)... the 1x1 just doesn't fit quite right (to much seat to bar drop)


this is pretty much what i'm after without the bars being quite that high

elcruxio

You should get in trouble. That's not true. Rims are not a huge rotor. Rim brakes have almost nothing in common with discs, especially hydraulics.
the function is different, the mechanical advantage factor difference is huge, a cable stretches, oil doesn't (neither does steel woven hose), you wouldn't want metallic pads against alloy or carbon rims.

Or you could do what I did years ago and get a rack and fenders that fit disc brakes?

It can't be much weaker. I mean MTB wheels can take some damage and nowdays they are all offset dish with disc rotors... Or could it be, that the wheel just needs to be correctly built and tensioned and a wheel that isn't will fall apart no matter which style of build it uses.

marginally. 20/24 radial will make weaker wheels. 3x 28/32 with a good v-section rim will last a nuclear war, disc or no disc. And umm... is 100 grams going to make a difference to us clydes? seriously now.

modulation, power, feel, long term maintenance (this depens on the brake naturally, cheap like avid elixir 1's is going to suck anyways but good ol' magura will last for years with no maintenance other than pad changes) wet weather performance, cold weather performance (ever had frozen rims? not fun when you lose all braking power even if you are pulling the lever to the handle)


The test you lnked is the one where the rider misused the brakes (which were cx brakes if I remember correctly) Can't be sure since the page doesn't load for me. But with modern road discs the heat problems have been pretty much solved. With the sram red discs there was some signifigant heat testing and attempts at over heating the brakes. The attempts were not successfull.
There isn't all that much to it. There are several technologies that help with heat dissipation in both rotor and brake caliper.

cyccommute 

A hub mounted disc brake is a spinning rotor of metal that is squeezed between two friction pads on either side of the rotor. A rim brake is a spinning rotor of metal that is squeezed between tow friction pads on either side of the rotor. There is no functional difference between them. There are some differences in materials but that is trivial. While you may not want to use metallic pads agains carbon or alloy rims, there is no reason that you could not. Sure you'd have wear issues but that wouldn't keep you from using them.

As for mechanical advantage of the hub mounted disc being huge, it isn't. I have a bike with a cable actuated hub mounted disc on the front and a v-brake on the rear. There is no difference between the amount of effort needed to pull the brake lever for the front or rear. I also have other bikes that I ride regularly that have cantilever front brakes and there is no difference between the amount of hand strength that I use for those brakes either. Further, I have a set of hydraulic brakes on yet another bike. Again, I find no difference between that brake and any of the other brakes.

All of the brake systems I have are capable of stopping the bike they are mounted on as well as all being capable of skidding (or even lifting) the rear tire or even throwing me over the bars. That is the limit of braking ability. You can add all the advantage you like but once you've lifted the rear tire, you reached the limit of the bike's braking ability.

I have yet to see a rack for a disc brake equipped bike that is much more than a bandaid approach to the problem nor one that doesn't interfere with the caliper in some way. Even the ones with large standoff still get in the way. And a front rack and fenders is even more problematic.

donalson

well said man...

but for racks and discs... if it's setup right it can be (and has been) done
here is the disc trucker take on it

squirtdad

Yeah I get a 404 on it now also. But why do you say the rider misused brakes. I don't recall reading that from the article. The guy was descending and and the brakes overheated, losing any ability to provide braking functions. This was from 2012 so I don't know why you would suggest that they were not modern. What difference would cx brakes be from road brakes?

My point is that for certain applications i.e long descents on a a road bike with smallish disks there have been issues with disk brakes and until that is clearly not an issue, then it should be one consideration in an individuals decision process, until it is clearly not a issue.

elcruxio

It should be a non issue by now. Like I said the sram red brakes have no overheat problems.
The misuse was the fact that he kept the brakes on just a little bit for a long time.
I've done that. With rim brakes. Blew my tire off and burned my fingers. You can make any system dangerous if you try. You can delaminate carbon rims by over heating and I can't see how rubber gives a lot of stopping power when it starts to melt on your rim.

sstorkel

As I recall, the rider was dragging the brakes through the entire descent which contributed to the overheating. Remember that cyclocross racing usually consists of multiple laps around a shorter (1-3 mile?) course in a lower-traction (read: mud) environment. One could imagine that brakes designed to work optimally in that environment wouldn't be designed to withstand the heat generated by a long, fast road descent...