WhyFi

Bleeding is something that you do when you install the system or when you want/need to flush the fluid, it's not a part of regular maintenance like changing pads. You could do that every few years, and you'd be firmly on the proactive side with that kind of maintenance schedule.

In and of itself, bleeding isn't terribly difficult to do or to wrap your head around, either. With no prior experience, I installed (upgraded from mechanical), filled and bled the brake system on my gravel bike in an afternoon. That was four and a half years ago and the brakes are still performing flawlessly, with the only maintenance being a few pad swaps. IOW, since the install, I've probably devoted less than 30 minutes to maintenance and adjustment of the brakes on that bike, in half a decade or so.

WhyFi

I'm not understanding. It's not really something that sneaks up on you and you don't need to check that there's sufficient pad life before every ride. If you do a lot of riding/braking, do a visual inspection every once in a while (a flashlight might be helpful), starting a handful of months after the initial pad install.

Or are you talking about adjustment of the lever travel as your brake pads wear (increasing the gap between the pads and rim)? That's not something that you have to do with hydraulics.

SoSmellyAir

Thank you, this is what I was curious about and looking for, that one can (relatively easily) check pad thickness with a flashlight. But still not quite as easy as with rim brakes. I am chubby so even at slower speeds there is a bit of kinetic energy that must be converted to heat in order to slow down or stop.

Trevtassie

I suggest you write to him and tell him to harden up then.

msu2001la

I'm not really sure what this means, but isn't Bike Forums a better place to discuss Froome's comments than writing private letters to him?

Oh, I see now... you think that because I'm calling his statement "nonsense" that I'm somehow questioning his "hardness" on his descending ability. I'm not.

Froome may very well be overheating brakes on long/fast descents. What I'm saying is that it's nonsense for him to claim that disc brakes are somehow worse than rim brakes in this context, or that this problem of brakes overheating is somehow unique to disc brakes. Rim brakes, particularly on carbon wheels, have serious downsides when it comes to long sustained mountain descents.

WhyFi

What you're talking about is such a non-issue that it beggars belief.

Trakhak

From what I've read here and elsewhere, it seems that Froome's problem is not with disk brakes per se; it's that the rotors provided by a sponsor, SwissStop, are not up to the task. His statement to the press may have been meant to encourage the team owners to light a fire under SwissStop to improve their rotors.

Dean V

Is there a problem with rim brakes on modern carbon tubulars on mountain descents?
I haven't heard about it.

tankist

I'm very curious how exactly is dealing with rubbing or the opposite, low contact point, centering and bleeding is "much easier"? I've had rim brakes all my life until recently and they never were such a hassle compared to discs.

WhyFi

Sounds like yours were never set up properly. Each of these things is pretty easy to deal with and, once done properly, shouldn't need to be addressed again for quite some time.

tankist

My systems are Shimano Ultegra 11 and Campagnolo Chorus 11 for rim brakes vs SRAM Force eTap HRD 12 for discs. I asked the LBS to take a look at low contact point on the discs which I did not like. Since they could not fix it I had to tinker with it myself. I learned how to do it, but the process is definitely more involved than simple cable adjustment for rim brakes. Same for centering - rims are much easier and rarely need it while my discs love to be re-centered at every opportunity. I shudder at the thought of having to bleed the brakes which, according to SRAM, should be done yearly. I guess you are lucky that your system is more reliable than mine.

tomato coupe

Yeah, his argument is too simplistic. You can't just look at the heat generated in one braking event. You have to consider the number and frequency of braking events, and how efficiently the rotors dissipate heat.

WhyFi

I've had three different Shimano hydraulic systems (I don't want to deal with SRAM and DOT fluid, would rather stick with mineral oil), two of which I installed myself. I'm not sure what you mean by "low contact point." I also don't understand why your calipers would need to be re-centered frequently; the rotor shouldn't be moving, the caliper shouldn't be moving, so why are they moving relative to each other? I've heard of some people having similar issues because of inadequate and/or inconsistent tightening of the TA (or, heaven forbid, QR), but I can't really think of any other plausible reasons.

tankist

Contact point - how much the brake lever is moved until the brake pads touch the rotor. I like it to be high, meaning the lever does not move much and hits the brake sooner. With rim brakes it is trivial. With SRAM I need to do some dancing to adjust that. And with time the contact point increases and I have to adjust again. Maybe all this because SRAM hydraulics are crap compared to Shimano.

Doge

I have a lot of experiance with both braking systems and have several of each. So does my kid who is fast.
For riding - discs are great. For winning a road race on pavement when dry, I would choose rim brakes. You typically win not using brakes and lighter and no drag matters mentally.

WhyFi

Ah, that. Yeah, on some Shimano levers (Ultegra level and above, IIRC), there's the Free Stroke adjustment - it's a screw under the hood cover - to adjust lever travel before engagement. I've never messed with it, never felt the need, but don't see why lever travel would/should change over time; the pistons should adjust as the pads wear, maintaining a consistent gap between the pads/rotor and the lever engagement point shouldn't wander (and hasn't, in my experience).

If I travel long distances with my bike, an air bubble can work out of the reservoir (in the hoods) and get in to the brake line (between the master cylinder and caliper), which will result in more lever travel and mushiness, but pumping the brakes, lever flicks, jiggling, etc, will usually take care of that by getting the bubble(s) back up and out of the line.

Russ Roth

One thing I've wondered, watching the TDF and the Giro last year is if the brakes don't increase the crash rate when descending and braking through corners. Bike tires don't really have that much contact with the road for the speeds and the cornering limits that racers hit. Toss in faster stopping and it would seem to make questionable situations sketchier and increase the chances of breaking traction and crashing.

I installed hydro disc on both my kids' bikes so they could stop better, custom ordered my cross with disc and made sure the new gravel frame only used disc. Don't own a single carbon rim and don't plan to, I just like consistent, reliable stopping in any conditions. I'm better that's true for a lot of people.

I installed new discs today, took me 20 min each between screaming kids to cut the lines, route them through the frame, bleed them and set the calipers. Probably close to twice the time road rim brakes would take but pad replacement on the discs is much faster. I push a screw driver between the old pads to compress the piston, pull off the cotter pin, undo the screw that holds them in, slide out the old, slide in the new, reinstall screw and pin, install wheel and squeeze the lever. Sounds like more work but calipers require aligning the pads, toeing them in, releasing the previously taken up cable with the barrel adjuster or the fixing bolt, recentering the caliper and adjusting the cable to the new pads. If the pads have spacers, conical washers or in the case of V-brakes lots of both, it gets tedious not dropping those putting the pad fixing bolt in place. Cantis can be the worst with the straddle cable and getting the pads the same settings on both sides. Considering discs can go years with no trouble, I like them.

I'm a little beyond chubby and will really push the braking on my bike in the woods, fade has yet to be an issue.

What is a lot contact point? Not certain I've seen this one. As I mentioned above, with hydraulics centering and bleeding is quick and easy. Centering with cable disc can be annoying, but a properly set up thru axle bike really doesn't have disc issues in my experience.

woodcraft

Good sig line

big john

They're comparing stopping a road bike from 60kph to stopping a mountain bike from 30kph. When does that happen? Do road racers stop during the race?

A more realistic comparison would be to compare the heat generated during a long, steep descent. When I'm on my mtb, the bike is 14 pounds heavier than my road bike plus I am carrying a Camelbak and the descents are steeper and I need hard braking to save my ass more often than on a road ride.

When riding we use the brakes to control speed. We don't just get up to speed and then stop over and over.

grizzly59

Rim brakes are brick simple, most issues can be fixed by the rider on the fly good enough to finish the race with minimal time loss. Issues with disk brakes / rotors that would cause any extra unwanted friction (rubbing) may not be so simple in the context of professional racing. How important is braking to a professional rider?

big john

I wouldn't think there would be an issue of rubbing during a race, at least it would be rare and probably insignificant. A pro could just get another bike, in many cases.

Having watched a bit of racing, a pro racer trying to fix anything is usually ludicrous. They are seldom able to get their chain back on.

noodle soup

This true for Shimano brakes, but SRAM/Avid brakes require bleeding far more frequently(and the process is a bit of a PITA).

WhyFi

I take it you haven't used discs?

Rubbing with discs is almost always a non-issue with regard to sapping energy - kissing a high spot on a rotor makes an annoying noise, but it's nothing like a rubber brake pad dragging on a rim. You need to forcefully sandwich a rotor to brake - compared to rim brakes, there's less friction between the rotor/pad and there's rotor deflection if the pressure is only coming from one side.

And yeah - who needs brakes? They only slow you down, amiright?

WhyFi

Yeah, the more I hear about SRAM, the more I'm glad that I decided to avoid.

big john

I had Avid Juicy 3 brakes on my old mtb and I rode it for 10 years and never bled them. I know, I should have, it might have prevented the sticky piston thing before I sold it.

I faded the rear brake once on a long, steep drop, one of the ones you can't actually stop on unless you lay it down. It got pretty exciting when the lever went all the way to the bar. Luckily I was close to the bottom and there was plenty of run out. If I was going to do it over I would have just locked the rear wheel for most of it, the surface was soft and loose.

My newer mtb has cheap Shimano brakes and they have never faded.