hydraulic disc brakes v cable disc brakes

Cycle-touring, Expeditions, Adventures, Major cycle routes NOT LeJoG (see other special board)
Angstrom
Posts: 49
Joined: 21 Nov 2018, 6:57am

Re: hydraulic disc brakes v cable disc brakes

Postby Angstrom » 7 Feb 2020, 9:50am

reohn2 wrote:
Angstrom wrote:I'm surprised no-one mentioned the cable actuated hydraulic disk brakes. I don't own any, but from what I've read, they seem to be "best of both worlds".
If I'd be onto getting a new bike/build, that's what I'd lean towards.

Why?
Why not just cable discs?

From what I've read (no personal experience), the big improvement of disk brakes over rim brakes (other than braking in wet conditions) can be
better found on hydro brakes compared to mechanical disk brakes: smoothness, possibility to have the desired braking power with less force on the levers. Also, I've read that cable (mechanical) disk brakes have only one moving pad (the other pad being fixed )and this makes fine-tuning the brakes harder. Hydros have 2 moving pads hence a greater distance from the disk in the rest position.
The stated advantages of cable (mechanical) disk brakes are that it costs less: in many cases, the brifters can remain the same. In case of a fall, replacement hydro brifters are harder to find and cost more.

Now come the cable-actuated hydraulic brakes. They are stated to provide the best of both worlds:
- simplicity, lower cost and versatility of brifters + cables
- modularity, low effort, easier to fine tune, low maintenance of hydros

It wasn't the initial question, I agree, but I think it does bring an interesting complement to that question (or to the answers, rather).

I'm sure this subject can be easily searched and found on the web with articles from people who have first hand experience, unlike myself.

reohn2
Posts: 37370
Joined: 26 Jun 2009, 8:21pm

Re: hydraulic disc brakes v cable disc brakes

Postby reohn2 » 7 Feb 2020, 10:07am

horizon wrote:reohn2: in all the disc brake wars on this forum, it is your posts that have persuaded me that discs might be worth trying (while Brucey and others have reassured me that my rim brakes are OK!). My Sardar is disc brake ready so I'm tempted to try one out (front?) if I come across a cheap wheel (that's the other problem!) and a s/h cable BB7. I really am DOT- phobic!

If I were to only change one brake to disc it'd be the most used and the onenthat gets the most used which would be the rear first.
-----------------------------------------------------------
I cycle therefore I am.

reohn2
Posts: 37370
Joined: 26 Jun 2009, 8:21pm

Re: hydraulic disc brakes v cable disc brakes

Postby reohn2 » 7 Feb 2020, 10:50am

Angstrom wrote:From what I've read (no personal experience), the big improvement of disk brakes over rim brakes (other than braking in wet conditions) can be
better found on hydro brakes compared to mechanical disk brakes: smoothness, possibility to have the desired braking power with less force on the levers.

In over ten years of using BB7 cable discs,2/5ths of that on tandems I/we've never been short of braking power,whatever the the weather.On drops or flats i've never needed more than two fingers on the brake levers and more often than not one finger is enough,that's including loaded tandem tours in the North Wales hills.

Also, I've read that cable (mechanical) disk brakes have only one moving pad (the other pad being fixed )and this makes fine-tuning the brakes harder. Hydros have 2 moving pads hence a greater distance from the disk in the rest position

TPR Spyke/Spyre brakes have two moving pads but IME have other issues(I had them for a short while on a new bike and swapped them for BB7'S)
BB7'S are my brake of choice and only have one moving pad,which is no detrement to either setting up,which is a doddle and takes ten minutes max.With straight and true rotors brakes properly set up and adjusted will not rub or catch the rotor.
The stated advantages of cable (mechanical) disk brakes are that it costs less: in many cases, the brifters can remain the same. In case of a fall, replacement hydro brifters are harder to find and cost more

That's my main concern with Hydros,I ride a lot off road(as do many with hydros) trashing a hydro brake lever means a series of costly actions to replace,trashing a road hydro STI lever is an arm and a leg.I've just bought a pair of Shimano flat cable levers for £15.Cable operated hydros remove the trashed brake lever cost problem.

Now come the cable-actuated hydraulic brakes. They are stated to provide the best of both worlds:
- simplicity, lower cost and versatility of brifters + cables
- modularity, low effort, easier to fine tune, low maintenance of hydros

All things being equal I agree but do they do anything more than good(BB7) cable discs?

It wasn't the initial question, I agree, but I think it does bring an interesting complement to that question (or to the answers, rather)

Agreed,it widens disc brake possibilities

I'm sure this subject can be easily searched and found on the web with articles from people who have first hand experience, unlike myself)



I'm sure there are many people who will prefer whatever system they have,I can only say I've no need to change as BB7'S offer excellent braking power in all conditions along with very good modulation and needing very little maintenance other than a adjusting the pads now and again in ordiany road conditions and once every other ride in mucky off road condition the proviso being to use sintered pads,organic pads wear out alarmingly fast in bad mucky conditions.
-----------------------------------------------------------
I cycle therefore I am.

User avatar
horizon
Posts: 9968
Joined: 9 Jan 2007, 11:24am
Location: Cornwall

Re: hydraulic disc brakes v cable disc brakes

Postby horizon » 7 Feb 2020, 11:16am

The experience of travel is something that you have to pay for but can never buy. Ho Ri Zon Chinese philosopher

User avatar
horizon
Posts: 9968
Joined: 9 Jan 2007, 11:24am
Location: Cornwall

Re: hydraulic disc brakes v cable disc brakes

Postby horizon » 7 Feb 2020, 11:18am

ludo wrote:Thank you for all your responses. You have convinced me to go for hydraulic brakes. Much appreciated.


Did you/do you intend to take your bike to an LBS for brake servicing or to do it yourself as you said that was one of your concerns.
The experience of travel is something that you have to pay for but can never buy. Ho Ri Zon Chinese philosopher

User avatar
horizon
Posts: 9968
Joined: 9 Jan 2007, 11:24am
Location: Cornwall

Re: hydraulic disc brakes v cable disc brakes

Postby horizon » 7 Feb 2020, 12:12pm

Two more videos here:

https://www.youtube.com/watch?v=6sSjO6eQ4I4

This one is a nice take on the argument. Oddly I was just searching for a comparison and didn't expect the first video to come down in favour of cable.

This one goes through the bleeding process:

https://www.youtube.com/watch?v=_M2l6LKI5Yk

While it is enough to put me off hydraulics, I'm guessing that (a) most people will get the LBS to do it so it's not an issue (b) there are plenty of people who are capable of doing it and (c) it won't have to be done for a long time (though 6 months seems to be recommended for DOT fluid).

Once again, no matter where I look, the argument appears to be that hydraulic disc brakes are supremely good at braking but cost more and are more demanding to maintain (as well as making sure that DOT fluid doesn't go anywhere). The problem for people like me who might consider putting their toe in the water is that if the choice comes down to cable, then a lot of the allure of better braking disappears and we are back to cable discs versus rim brakes, not such a dazzling prospect but maybe still worth considering.
The experience of travel is something that you have to pay for but can never buy. Ho Ri Zon Chinese philosopher

User avatar
pjclinch
Posts: 3842
Joined: 29 Oct 2007, 2:32pm
Location: Dundee, Scotland
Contact:

Re: hydraulic disc brakes v cable disc brakes

Postby pjclinch » 7 Feb 2020, 12:25pm

While most of my hydraulic brake experience is with Maggie HS33 rim brakes, a datum for "how much fuss are they?" from the hydraulic aspect is that I was assured about 15 odd years ago it'd be as close to "fit and forget" as I was likely to find, and that's what I've found. They'never gone wrong, never needed bleeding, always worked well. These are on my touring bike, btw. Absolutely never regretted putting them on.

My MTB has hydraulic discs, I find them better in use than various mech discs I've come across over the years, and notionally you'd guess they'd be more prone to prangs than tourers. None of the folk I know with MTBs use anything else now if their bike is under (guess) 5 years old seem to have suffered brake prang issues.

Pete.
Often seen riding a bike around Dundee...

Biospace
Posts: 11
Joined: 24 Jun 2019, 12:23pm
Location: North Yorkshire

Re: hydraulic disc brakes v cable disc brakes

Postby Biospace » 7 Feb 2020, 1:44pm

I had to take a (quality) modern bike for a few days touring last summer rather than the preferred steel machine, it had Deore hydraulic brakes front and rear. I wasn't particularly heavily loaded since we weren't camping, my main concern was the aluminium forks, not the superb brakes.

Two-thirds way down a longish hill I lost all braking, just before laying the bike over I pumped them into giving a little bit of braking. White knuckles, better than bloody ones. Over supper we realised there's nowhere near enough of a heat sink for when more heat is put in to the disc than it can lose to air, or at least the heat uses the caliper and piston, and oil/fluid as the sink. Off road and casual use clearly doesn't cause a problem or it would be better publicised. A disc with a sufficient heat capacity for fast road touring would be three or four millimetres thick, I guess.

I'd descended well within speeds and loads of what I'd managed in years passed, so a fortnight later I took my trad tourer back to the same place, with a little more weight up, and tried again. The rims were hot, but the brakes were working better at the bottom than at the top. Clever stuff, using such a massive brake disc as the carrier for rim, tyre and hub also.

Discs are wonderful for riding through traffic on a wet day, but as always you don't get owt for nowt. Half a kilo of extra mass to pedal around, the loss of supple forks which silently mop up washboard surfaces and greater, asymmetrical loads on the forks and frame. I've seen aluminium forks corroding merrily on the lhs while the other side is like new.

Angstrom
Posts: 49
Joined: 21 Nov 2018, 6:57am

Re: hydraulic disc brakes v cable disc brakes

Postby Angstrom » 7 Feb 2020, 2:46pm

I think you make a great point about disks potentially not being able to dissipate enough heat in long descents on a loaded tourer.
One member of a cycle tourism French forum mentioned his accident in a downhill in a mountainous area in which he could have lost his life due to a disk brake failure (he is a disabled person riding on a special recumbant tricycle I think). He lost use of the brakes a few km into a descent then eventually flew off the road in a corner at high speed into a ravine where he lost consciousness for 30 mn. Luckily he was able to reach out to his phone, had cell network coverage (not a given in the mountains) and could call a friend who came to rescue him. He ended up in hospital for many months, undergoing numerous operations and many months of physiotherapy to recover (story in French here, but G Translate does an amazing good job on this short text).
The problem: his pads "glazed", probably because of overheating. That means that the compound on the pads lost their friction function.

For different reasons, both MTBs and road racing bikes have different set of constraints than loaded touring bikes (and recumbants, seems like).
On a MTB, the speed is lower. The total weight is also lower. Braking is more on/off so there is more slots of time to cool down. A race bike is faster than an MTB but not always than a tourer. However, at least that's true for me, I have more time to let go between braking sequences, hence provide some relief for the brakes to cool down. A bit like on an MTB.
On a laden bike on steep, fast and long downhills, I tend to keep the brakes for longer periods and therefore, reminded of this story above, I might not take the risk of fitting my loaded touring bike with disk brakes lest they glaze.
Last edited by Angstrom on 7 Feb 2020, 3:13pm, edited 3 times in total.

Greystoke
Posts: 214
Joined: 8 May 2018, 7:41am
Location: Lincolnshire

Re: hydraulic disc brakes v cable disc brakes

Postby Greystoke » 7 Feb 2020, 2:58pm

Well having read all this I'll stick with my old rim brakes.
My rally car has regularly had glowing discs with no brake fade so perhaps my previous post about discs is incorrect.....for cycles at least.

reohn2
Posts: 37370
Joined: 26 Jun 2009, 8:21pm

Re: hydraulic disc brakes v cable disc brakes

Postby reohn2 » 7 Feb 2020, 8:05pm

A point on discs not being able to dissipate heat,as I posted up thread,the BB7'S on our Cannondale road tandem 203mm rotors,never ever faded with an all up combined weight of bike,two riders,and luggage of 190ish kg on some very steep Welsh hills,we've even turned the rotors(mainly the rear)a nice straw to blue colour.
The problem with heat dissipation on any disc brake bike isn't the rotor(though I believe some Shimano sandwich steel/alu rotors can be a exception)it's the caliper and if hydraulic brakes fade the fluid can boil up and leave you with no brake at all.

Just to reiterate,in ten years of BB7 use on tandems and solos in all kinds of terrain I/we've never experienced brake faded or malfunction of these brakes.
I use 160mm rotors on solos.
-----------------------------------------------------------
I cycle therefore I am.

m-gineering
Posts: 147
Joined: 23 May 2015, 12:01pm

Re: hydraulic disc brakes v cable disc brakes

Postby m-gineering » 7 Feb 2020, 9:12pm

If you enjoy descending at speed, and only brake for hairpins when you have to, you're reducing your chances of brakefade. You're scrubbing of a lot of energy by wind resistance, and everything can cool off for the next application of brakes. Same when the hill is so rough you have to take things very slowly, then you're spreading the heat over a very long interval. Descending hills with the brakes on all the time trying to stay 'safe' is the tricky scenario: you have to convert all your potential energy in heat in a fairly short time, without giving the brakes a chance to recover
Marten

Touring advice for NL: www.m-gineering.nl/touringg.htm

Thehairs1970
Posts: 181
Joined: 11 Aug 2018, 9:30am

Re: hydraulic disc brakes v cable disc brakes

Postby Thehairs1970 » 7 Feb 2020, 9:21pm

FWIW I love disc brakes and reckon the problems mentioned while real, don't mean they should be ignored. Rim brakes also have issues. Needing constant adjustment, being relatively crap in wet weather and slowly destroying your rims by grinding them away.

The worst problem I've had with discs is that the oil absorbs water over time. This can mean removing some oil to allow pistons to retract. But that's on my MTB which rather too regularly spends times in water.

No probs with my Trek 520, fitted with Spyres while fully loaded in the Alps this summer. However, my wife says I go too fast downhill so maybe I don't use my brakes enough!

User avatar
Tigerbiten
Posts: 1978
Joined: 29 Jun 2009, 6:49am

Re: hydraulic disc brakes v cable disc brakes

Postby Tigerbiten » 7 Feb 2020, 10:36pm

Another vote for BB7's over hydraulic if you're going to be doing a lot of high speed/energy type descents.
I not only blued a couple of rotors with BB7's, I got the calipers hot enough the melt the plastic adjustment wheels on them ...... :shock:
That was on a long speed twisty descent were I had to work hard to my my speed in the 30-40 mph range.
I daren't do that type descent with my hydraulic brakes as they'll fade.
But I do think the hydraulics are better a low speeds, more controllable stopping power for less effort.
Hence my vote for hydraulics overall.

Luck ............. :D

Biospace
Posts: 11
Joined: 24 Jun 2019, 12:23pm
Location: North Yorkshire

Re: hydraulic disc brakes v cable disc brakes

Postby Biospace » 7 Feb 2020, 10:43pm

Thehairs1970 wrote:FWIW I love disc brakes and reckon the problems mentioned while real, don't mean they should be ignored. Rim brakes also have issues. Needing constant adjustment, being relatively crap in wet weather and slowly destroying your rims by grinding them away.



Disc brakes on bikes are wonderful things when used for the purpose intended - off road when rims are often submerged through mud and water and when a rim has been knocked out of true. And so they also work well on bikes used in the wet through heavy traffic.

Dragging around an extra half kilo of mass and losing the ability of forks to smooth over washboard surfaces is enough for me to not choose them on a bike intended for carrying luggage over a distance - add in the cooling problems which mean severe brake fade when really hot and the risk of boiling fluid if there's hydraulic actuation.

Cable setups are simple (sadly there's a mistaken belief around today which associates simple with bad) and aren't affected by severe heat generated by hub disc brakes, something which rules out any hydraulics on a bike used for touring, for me.

Every system has its good and less good points, perhaps over-familiarity helps hide the clever aspects of cable operation as well as rim braking. Making use of a couple of massive, seperate and well-cooled disc surfaces which load the forks evenly at the frame end instead of lob-sidedly at the hub is a very logical and intelligent, if unfashionable choice. Using these huge discs as an integral part of the wheel is clever engineering. For sure there's the issue of rims wearing over a few thousand miles (but if the use has been so hard the braking surfaces have worn thin, chances are the wheels are ready for rebuild/replacement anyway) and the couple of minutes' adjustment every few hundred miles in hilly ground, time which is well spent as it encourages a close look at the bike's safety-critical parts.

It's a matter of weighing up the various pros and cons of different systems - I choose hydraulic operated hub disc calipers for relatively low speeds in all weathers on a relatively neglected bike, cables and rim brakes when there's higher speed and more mass and a lot more energy to turn into heat.