My first mountain bike ran cantis. I bought it just before V-brakes came out. When V brakes came out the adverts all said how they stop in rain and mud and snow so much better than cantis do. All the magazine reviewers agreed. I liked the idea that you didn't need a cross wire for them. Discs originally arrived for DH racers who flew down mountain passes on their gravity rockets. There were also disc brakes on road bikes in the '70s, hydraulic even.I guess they didn't know how to market those as they didn't see the '80s.
I have never had disc brakes on a bike, though I might look into it for my next bike. I can respect mechanical disc brakes for saving rims. Of course my last set of rims on my old 7300 are 5 yrs old, and they are due as the wear indicator is gone pretty much.
What I could never get though is hydraulic discs. I just don't see adding that complexity to a perfectly simple machine. Even for mountain biking. I know my V Brakes on my present bike can jack up my rear tire in a sudden stop, I just don't need anymore power than that.

I've always run rim brakes. To get the best performance out of 'em, I'm fastidious about truing, so that I can get the pads as close to the rim (less "play") as possible. I use the pads as a truing guide.

With discs, there'd be no need to true for brake function...and I'd have to pop the wheel off and put it on a truing stand each time...

Seems to me that the combo of "rim brakes+true wheels" > "discs+wheels trued 'whenever I get around to it'."

The Avid hydraulics on my MTB have excellent feel, even better than well-aligned BB5 or BB7 calipers I've also owned. You can almost feel the pads hit the rotor, whereas the mechanical setups still had a bit of sponginess. The effort feels lighter, too. Overall, they're really nice for offroading.

Viewed another way, you can be sure that with disc brakes, a rim that gets knocked out of true won't affect braking at all.

Personally, I don't run the conventional rim brakes on my other bikes (road calipers and cantis) so close to the rim -- I like to have some travel before the pads hit, giving my fingers more "curl" over the brake lever.

If your discs are dragging, they're not adjusted properly.

Ceramic pads from Price Point will turn your head -- power AND modulation are enhanced! As is serviceable life....

You can call yourself 'biased', but in fact you're uninformed. Never having used discs, you really can't form an opinion. The advantages are -- trust me -- NOT overstated. I HAVE had trouble stopping with rim brakes!

Discs aren't necessarily a "need", but a major enhancement -- and not just in the wet. Don't pigeonhole the product.

They all stop YOUR bikes in the same distance; congrats. If that's where you and your rides are, good for you. But a blanket statement that discs are no better than rims is foolish.

If your wheels are built correctly, you shouldn't need to true them unless the wheel has been damaged. Frequent truing = incorrectly built wheel.

On the first point, sure, if you are riding at slow speeds on flat roads in "normal" conditions (not ice and snow), the cantis are essentially as good as a good disc setup.

To the second point, this has not been my experience, having used cantis, V brakes and discs, single pivot and dual pivot road brakes, all on high-end perfromance machines in their respective ilks, with upgraded pads, etc. When the conditions turn nasty there is no comparison. I've used them all, and discs are head and shoulders above rim brakes in these conditions.

No, my statement isn't foolish. I, unlike neil, have used both hydraulic and mechanical discs. If anything the discs are a step down from rim brakes. The hydraulic brakes I have are digital, they are either on or off with no gradation in between. Modulation, as in being able to apply the brakes in a manner using finesse, is nonexistent. A tiny amount of pressure locks the rear up.

Rim brakes, on the other hand, have always given me the ability to apply enough pressure to scrub some speed or lock the wheel with all kinds of modulation between the extremes. This includes the cantilevers I have, the v-brakes and the side pull calipers.

I've found the opposite to be true - My discs modulate beautifully. I think it's a setup (and to some extent make/model) thing.

To be fair, rim brakes can be set up to modulate well, too. For example, I was able to get phenominal modulation from my Avid V-brakes (SD7 ti with the SD 7 levers). My Campy Record dual pivots were excellent, as well.

But to say discs don't modulate well (as a general "truth") is incorrect.

I've been riding for years, used rim brakes starting in 1972 on a steel rimmed Collegiate, through the years used single pivot, dual pivot, center pulls, v-brake, cantis and Suntour cams. None of them work as well as a cheap tektro disc brake system (much less compared to a BB7), esp for modulation in bad weather. I've switched my commuter over to front disc, the difference in stopping distance is significant. I'll never go back to all weather riding with rim brakes. If a bike of mine has fenders, it will have drums or discs.

all 3 of my bikes have rim brakes - calipers on the road bike, cantis on the mountain bike, v-brakes on the folding bike - and they all stop my bike just fine the vast majority of the time. however, after having just come through my first season of winter bike commuting, i did notice some braking deficiency with the cantis on my winter bike when the roads were really sloppy and dirty. vigilance to keep the pads and rims as clean as possible helped, but i can see how a disc set-up would be preferable for sloppy weather riding. it's too bad that my mountain bike is too old to accept disc brakes. if i ever get a new bike to build into a true winter/foul weather machine, it will definitely be disc-equipped.

rim brakes can work for sloppy winter riding, but i found the constant rim cleaning to be tedious and annoying after a while.


by the way, what are the performance differences between mechanical and hydraulic disc brake systems. is one system clearly better than the other, or is it more of a personal preference thing (just like everything else in the cycling world)?

Drum or disc is the only way for me. Rim brakes are too much of a fiddle and are further disqualified by wearing out the rims.

Paul

Indeed. If your discs, especially hydraulic, don't seem to modulate, they're probably either set up incorrectly or the modulation difficulty is in the rider, not the discs. A light touch will give you very precise control.

The irony there is that many people ride "beaters" in the winter. "Disc brakes" and "beater" don't tend to go together.

I don't have personal experience with mechanical discs, but what I usually hear is that hydraulic discs provide superior power and more positive control; mechanical can be a touch "mushy" or "spongy" (though by no means bad). I know my hydraulic discs will let me safely stop in a reasonable distance using just one finger on each lever, and will stop me in about 2 bike lengths if I really clamp down.

I switched from Hayes to Avids on my disc bike, and experimented with rotors (thicker, thinner, more cutouts, fewer), but can't detect any performance advantage sufficient to let me tolerate the squeal. So that bike is pretty much a hobby bike only never a commuter.

A rim failure would definitely get my attention.

It only takes one instance of freezing rain on the rims leading to complete brake failure to convince.

Any bike I need to ride in the winter will have disc brakes.

If I bought something like a touring bike that I knew would definitely not be ridden when there's a possibility of freezing, I'd probably go with rim brakes simply because they're easier to find and standard and can be repaired by any bike shop anywhere.

Your point might be valid if I were new to bicycling or if I didn't know anything about bicycle mechanics. However, I've been riding mountain bikes...as mountain bikes on terrain that they were designed for...since 1983. I know how to brake, I know the difference between grabby brakes and well modulated brakes and I know how to set up brakes.

Disc brakes have very little in the way of adjustment. The gap between the pads and the rotor are not adjustable. It is what it is. You can't 'set them up' to change the modulation...something you can do with rim brakes. The only way to control the modulation is in the application of the brake. And, since there is very little movement from completely off to completely on (on the order of a few millimeters), it takes a fine touch indeed for precise control. Too fine for the brakes to have 'superior modulation' if, by modulation, you mean a gradation of brake application.

Freezing rain will coat the rotors of a disc brake just as well as it coats the rims. Ice on rotors would have the same effect as ice on rims...poor braking. And braking on ice isn't limited by the brake power but by tire cohesion. I would want less powerful brakes with a whole lot of modulation on ice to avoid locking the front wheel. A disc, particularly a hydraulic disc, isn't going to make stopping on ice any easier.

I can't speak to hydraulics, but the modulation setup for mechanical discs is very simillar to V-brakes - pad selection and brake lever configuration. The Avid Speed Dial series brake levers offer excellent adjustment options.

My wife's hydros do not seem to have any form of adjustment, so pad and rotor choice would influence things to some degree. Nevertheless, the brakes seem to modulate quite well as they are. From the point of pad contact I can modulate just fine. Granted, the amount of input to modulate is much lower - more subtle, but it s still there, and it still takes a willful act to lock thing s up.

It sounds to me like you have plenty of experience to draw from (as many of us do) and from your experiences you've made your choice. Cool. However, consider the possibility that there are folks who have personally experienced modulation with discs. It can actually happen

BB7's with avid speed dial levers have a great amount of adjustability. You can change the pad spacing. With the levers you can adjust the reach and the pad contact, works for me YRMV. You can also change the cable leverage point for balance between power and modulation. These are a cable disk brakes. I use them on a commuter, a touring and a mountain bike. The reason they work great for me is that the disks are out of the mud , slop and snow, unlike rim brakes. There is a reason that disks are sold on almost every new mountain bike over $ 750.00.

I've never seen my rotors ice in freezing rain. Even if they did the ice would be instantly scrapped off. Non issue. Disks are better. Period. Where is my popcorn...?

Well, sorta. There's less water splashing onto the hub in the center than on the rim. And though there is ice on the rotor, it strips off instantly (well, in a single revolution) when I squeeze the brake, because the disc brake pad edge is sharp and hard. I've watched it happen, when I squeeze the brake, the ice just flies off and the brakes begin working within a second. On the rim brakes I once had to dump into a snowbank and do a sort of half jumping Fred Flintstone stop after the brakes completely failed to do anything for many yards on the way down a hill.

I just wanted to clarify...my comment about rims being better because they force you (well, me anyway) to stay on top of truing was more about acknowledging my personal foibles than a blanket statement. I guess what I meant was, "I prefer rims to discs because they discourage me from getting lazy about wheel truing, which I suspect is what would happen if I ran discs."

I've ridden on plenty of bikes with discs, though, and find them an aesthetically superior choice to rim brakes, in much the same way that a Lotus 7 would be an aesthetically superior choice to a pickup truck for driving a twisty back road.

Both'll get you where you're going, though.

My current commuter is my first disc brake bike. I like the stopping power, but I wish it were easier to mount a rear rack on a disc bike. Why hasn't it occurred to whomever it is that makes the dropouts that people will want to do this? How hard would it be to add another pair of eyelets above the brake mounting points?

If this is what you believe, then I can only say that you DON'T know how to set them up. I don't have an issue adjusting any of the 'non-adjustable' features you speak of. But, you believe what you believe.

How about this: you ride your non-adjustable discs, and I'll ride my wonderful ones. We won't argue any more, and we will accept each other's personal experiences. Yours is yours, mine is mine, and never the twain shall meet. You good?

Just FTR, though, I'm sure there are people who've been riding MTB longer than you who would also disagree with you.

Once I dumped the junk wheels my hybrid came with and built my own, I ran the next 16,000 miles, 35% of it over gravel road which was quite rough at times, without touching them. Both wheels have now been replaced for other reasons, but they sit in my garage still dead true, or within 1mm or so. I can't see any wobble in them at all, anyway. So I'm not sure it makes that much difference, at least if you're running sturdy wheels. My current set has about 6000 miles on them and I've never touched them, and they're dead true too.

I commuted for approx two years on a disc brake cross bike, and have been back on rim brakes for about two years now. When I first got discs I loved them, but now I don't feel as strongly about them.

I don't like the long lever pull (of road discs) compared to caliper brakes. I also didn't care for a seatstay mounted brake caliper.

Were I getting a custom commuter built today, I'm really not sure whether I'd go long reach caliper or disc. Honestly, as long as it wasn't a canti, I'm sure I'd be happy with either.