hydraulic disc brakes v cable disc brakes

Cycle-touring, Expeditions, Adventures, Major cycle routes NOT LeJoG (see other special board)
reohn2
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Re: hydraulic disc brakes v cable disc brakes

Postby reohn2 » 9 Feb 2020, 11:39am

Morzedec wrote:As a 'heavy', long distance tourist, I'd never, ever, use disc brakes: the risk of damage on bad surfaces, lack of available spares, and time taken on repairs all outweigh the use of rim brakes. Change a cable, change a block, and get going: your next camp site may be 100km away.

But then, I'm old-fashioned, as are all my bikes.

Happy days,

TBH,I can understand that POV.
Years ago when we were concidering a tandem for winter and UK tours with no long Alpine like descents,I was pretty sceptical about using discs having no experience of them,I looked into it and became averse to Hydraulics from an overheating boiling brake fluid and roadside repair POV.
We had the chance of a test ride on a BB7 cable disc equiped bike and liked both the ride but mainly the very good braking.But I was still a bit concerned about roadside repairs of the caliper and rotor damage,I watched a strip down/rebuild video on YouTube I was amazed how simple the caliper was and how quick easy it was to strip,repair and change pads.I consoled myself that should we bend a rotor on tour we could always carry a spare tucked down the flatside of a pannier,but after riding the bike for a few months I realised we wouldn't need to and after a rainy no ride day with nothing to do I stripped and rebuilt a caliper for fun in about 25minutes and realised there's nothing to them for anyone with a bit of mechanical nous.
Fact is I've never been stood at the side of a road or track with a broken caliper,changing pads,(which last a LOT longer than rim brake pads especially in mucky conditions)and setting up the brake is a doddle once the short and not very steep learning curve is climbed.
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djb
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Re: hydraulic disc brakes v cable disc brakes

Postby djb » 9 Feb 2020, 2:03pm

reohn2 wrote:
ludo wrote:I plan to purchase a steel framed touring bike but I would appreciate advice on whether to go for one with hydraulic disc brakes or cable disc brakes. The concern I have about hydraulic brakes is that if the hydraulics fail they can only be repaired by a bike shop. If I am on a tour and some distance from civilisation then I will have a problem. With cable brakes I will have a replacement cable and can fix the problem myself. Does anyone have en opinion on this??


I believe good quality modern hydros are very reliable,stop well,and are self adjusting.

Good cable discs(BB7'S in my case)also stop just as well,are very reliable IME in over ten years of use,though need manual adjustment.
The plusses with cable discs and my reason for sticking with them are:-
a)they can be stripped and rebuilt roadside with a small and lighweight spares kit.
b)because they need to be manually adjusted it gives the owner an idea of pad wear.
c) any brake lever with the correct cable pull(MTN or Road) can be used and which are easily available should one be broken in say in a crash situation.
From a power POV,I've never found BB7's lacking in power with one finger braking,they also have very good modulation.

My 2d's worth


Ludo, these comments mirror pretty much exactly my experiences with mechanical discs, BB7's also.
I especially like the rather astute comment on how the manual adjustment (very infrequent in my case) gives the owner an idea of pad wear.
ditto on power of braking, and I have toured extensively in very mountainy areas with a heavily loaded touring bike.

djb
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Re: hydraulic disc brakes v cable disc brakes

Postby djb » 9 Feb 2020, 2:49pm

Ludo, have you toured before and where do you think you may want to go touring?

I ask, simply to put in context telling of my touring experiences over about 30 years, and recently in the last 3 years or so on a bike with mechanical discs, Avid BB7's (tried and true model)

I have toured in mountainy terrain like the Pyrenees back in the early 90s, on rim brakes of course, with many many long hairpin descents on Cols that the Tour go down. I used to have motorcycles and love going fast around corners, and braking hard into corners, and tend to ride sometimes like this on descents on my touring bikes. Yes, I have dragged the brakes a bit too much and / or just braked very hard frequently enough to overheat and start to melt my rim pads, and have had the brakes starting to fade and pulling over in time---but of course, we all used rim brakes and to avoid that, you simply dont overdo it, and especially DONT drag the brakes for more than 15 or 30 seconds or whatever, but rather let the bike run , do a hard short braking action with predominantly front brake, let off to let things cool a bit, then hard application again--never dragging all the time.
Bottom line, use common sense, keep speeds manageable, dont drag the brakes and rim brakes worked for all of us.

caveat-I'm a light guy which helps a lot

move ahead a few decades and when I dreamed of doing some trips in Latin America, I wanted to get a mechanical disc bike. Enough people by then had done lots of long, tough, isolated touring trips with them that I knew they were reliable and a viable option.

the robust aspect of mechanical did, and still does appeal to me for knowing that there is no danger of a brake line being damaged as with a hydro setup, ie fluid loss, or any risk of freezing temps coming into play also with seals going etc. For the types of trips I wanted to do, I knew there was always the chance that my bike might have to put up onto the top of a truck or bus with other material strapped up there, or that sort of scenario, so there is no way I would use an hydro set up, it just doesnt make sense.

re mech disc power and modulation etc--my experience now over the years with having ridden rather heavily loaded through Central America, about half of Mexico, and across France, has proved to me that my mech disc setup with Avid BB7's just plain works.
I get much stronger braking power with much less finger pressure required , compared to rim brakes, and although I rode through lots of very mountainy areas--specifically Guatemala and Honduras, I was very very pleasantly surprised by my pad life.

If push came to shove, I could probably get close to 10,000kms out of pads, BUT the major factor here is proper setup (properly aligned calipers) AND ESPECIALLY how you brake, and of course total bike weight (bike, load and rider)

I do not brake very much in general, and when I do, I never drag the brakes, and therefore keep heat buildup to a minimum.
HARD application, off, then let the bike run, and then HARD application.
Of course, specific conditions apply, but avoiding dragging the brakes is the key to minimizing heat buildup, which will wear pads away, and yes just like rim brakes, can lead to overcooking the braking system, brake fade and potential "holy sh.." moments.

Personally, I very infrequently had to adjust my pads, so not a big deal in the least, and as someone astutely pointed out, this keeps you on top of knowing how your pad thickness is doing, as well as making sure they are wearing evenly and not angled.

as a long time tourer, Ive always put an emphasis on learning and knowing how to do all my own maintenance on my bike, and yes mechanical discs did require a new learning curve on my part mucking around with them.
I made mistakes, but did learn how to do stuff properly eventually, so now I am confident with my abilities.
Not all people like doing mechanical stuff , nor have the aptitude, but I certainly like the fact that I now know my braking system fairly well and can deal with most stuff on my own.

Now of course, hydro discs have been used on mtb bikes now for ages, and those folks crash all the time and stuff, so clearly hydro setups are reliable and tough , and work fantastically, so the chances of stuff going wrong is probably very slim--I just preferred for my uses to stick with the more simple mechanical setups, and my touring using them on a bike carrying more weight than I ever have due to the places I was traveling in, has certainly proven to me that a good mech setup works great also.

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horizon
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Re: hydraulic disc brakes v cable disc brakes

Postby horizon » 9 Feb 2020, 2:58pm

djb wrote:Ludo, have you toured before and where do you think you may want to go touring?



The OP last posted on February 7th so he/she may come back and explain his/her decision etc which would be interesting.
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reohn2
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Re: hydraulic disc brakes v cable disc brakes

Postby reohn2 » 9 Feb 2020, 3:29pm

djb
Your braking technique on big descents pretty much matches my own,let the bike run,brake,let run again and never drag the brakes.If I'm forced to do anything approaching dragging the brakes I alternate front then rear and repeat.I call it 'pulse' braking and find it keeps the heat under control.
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Angstrom
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Re: hydraulic disc brakes v cable disc brakes

Postby Angstrom » 9 Feb 2020, 5:29pm

reohn2 wrote:
Angstrom wrote:I don't think the discussion about discs is about how good they are. Wether hydros or cable actuated, consensus and feedback is plentiful to say that, in general, they're "better" than rim brakes.

But the OP's question was whether to choose between cable or hydo discs

The question being asked to each of us (for which there isn't a good or bad answer):
"Are the advantages worth :
a) the cost
b) the possible increased difficulty to solve a problem on the road (and decide the likelyhood in one's particular case)
c) the risk, although statistically very limited and which happens in well identified situations in which proper handling can prevent it?"

Different people, different answer.

It wasn't the question but go on then I'll play.

I'm not really in to play so I'll leave it there. You've (and others) made your point well and it's all good to me.

The cost for me is to change bike, not only the price difference of the brakes themselves (the original poster was asking in the context of a new purchase). Again, this was my point: we have different starting points. I would never give the advice to anyone to choose rim vs disks (or other way around) but only wish to expose different POVs.

AS far as c) is concerned, someone answered that already correctly. There are risks in long descents if braking not done properly. Then again there might be also with rim brakes. I don't pretend to give the ultimate answer.
I tried to express that I thought there was enough information for everyone to make their decision.
I understand that some forum members think choosing rim brakes is only about conservatism and that the risks aspect are overdone. It might be so but I have personally no judgement to make on either choice.

reohn2
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Re: hydraulic disc brakes v cable disc brakes

Postby reohn2 » 9 Feb 2020, 6:21pm

Angstrom wrote:
reohn2 wrote:
Angstrom wrote:I don't think the discussion about discs is about how good they are. Wether hydros or cable actuated, consensus and feedback is plentiful to say that, in general, they're "better" than rim brakes.

But the OP's question was whether to choose between cable or hydo discs

The question being asked to each of us (for which there isn't a good or bad answer):
"Are the advantages worth :
a) the cost
b) the possible increased difficulty to solve a problem on the road (and decide the likelyhood in one's particular case)
c) the risk, although statistically very limited and which happens in well identified situations in which proper handling can prevent it?"

Different people, different answer.

It wasn't the question but go on then I'll play.

I'm not really in to play so I'll leave it there. You've (and others) made your point well and it's all good to me.

The cost for me is to change bike, not only the price difference of the brakes themselves (the original poster was asking in the context of a new purchase). Again, this was my point: we have different starting points. I would never give the advice to anyone to choose rim vs disks (or other way around) but only wish to expose different POVs.

AS far as c) is concerned, someone answered that already correctly. There are risks in long descents if braking not done properly. Then again there might be also with rim brakes. I don't pretend to give the ultimate answer.
I tried to express that I thought there was enough information for everyone to make their decision.
I understand that some forum members think choosing rim brakes is only about conservatism and that the risks aspect are overdone. It might be so but I have personally no judgement to make on either choice.

Fair play to you,I take your point.
BTW,I wasn't trying to be facetious,sorry if it came across that way,Ijust trying to to get to the to reasons for your post.
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Biospace
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Re: hydraulic disc brakes v cable disc brakes

Postby Biospace » 9 Feb 2020, 6:46pm

Is there some common agreement that proven cable disc brakes and proven rim brakes both provide good braking for laden touring, and that each has their own personal preferences and according to use/circumstances for each design?

Strengths of cable operated discs:
Work better than rim brakes in wet and muddy conditions
Create less muck in the wet
No chance of popping a tube if severely overheated
Low weight and small size means it's easy to carry a spare disc

Strengths of rim brakes:
~½kg less mass
Up to 10% less drag than disc systems (cited as 10-15% less for bikes without luggage)
Larger cooling area compared with discs
Symmetrical and smaller stress and strain loadings through the f&f allow for better damping of road vibrations

I think we're all aware of how easy it is to overheat a brake through dragging, rather than releasing fully and reapplying?

It'd be wonderful if there were an affordable and lightweight alternative to wasting all that energy down long descents, but doubt there'll ever be anything which can be effective for bikes on tour.

djb
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Re: hydraulic disc brakes v cable disc brakes

Postby djb » 10 Feb 2020, 12:10am

another potential thing against hydros is extreme cold and seal problems.
I have read of bicycles having this problem, and I presume its about the fluid and well below 0c temps. Obviously our cars dont have an issue with DOT brake fluid, and as a Canadian whose cars live sometimes in -30, -35c temps, its not an issue, but I have heard of bike hydro disc problems.
I once had a motorcycle that after being stored in an outdoor shed for the winter, had seals go, and I always figured it was because I had had that motorcycle on the track at times and probably boiled the brake fluid a number of times, and there must have been water that got in the system, and then froze at -35c and screwed some seals...who knows.

No matter, coming back to touring. As someone who would like one day to do South America, I know that below freezing temps can happen at high altitudes in the Andes, so just one less thing to worry about / have a potential issue with my touring bike.
This would also apply to a bike in Canada, even if you stored it on your back porch or something--although I admit I dont have personal experience iwth this problem, and would need to get the proper info about the diff types of fluids used in hydro discs.

it is logical though that there are hydro brake systems that dont have this problem, given how common these braking systems are on fat bikes and whatnot that get used in the winter.....so maybe I'm all wrong on this.....I suspect it comes down to the actual fluid used...and maybe as simple as quality of seals etc

scottg
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Re: hydraulic disc brakes v cable disc brakes

Postby scottg » 10 Feb 2020, 12:33am

Morzedec wrote:But then, I'm old-fashioned, as are all my bikes.

Happy days,


Old fashioned would be spoon or rod brakes, maybe coaster brakes.
Rim brakes are new fashioned foreign rubbish compared to rod brakes, harummphhh.
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m-gineering
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Re: hydraulic disc brakes v cable disc brakes

Postby m-gineering » 10 Feb 2020, 7:49am

djb wrote:another potential thing against hydros is extreme cold and seal problems.
I have read of bicycles having this problem, and I presume its about the fluid and well below 0c temps.


It seals becoming hard and starting to leak, Sram for instance had a massive recall after their new shiny kit failed at the first cyclecross when temps were a bit down. Cables can freeze up nicely though, but fixing that is low tech
Marten

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

iandusud
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Re: hydraulic disc brakes v cable disc brakes

Postby iandusud » 10 Feb 2020, 8:59am

Horses for courses: I have bikes with caliper brakes, V brakes, cable discs and hydro discs. They all work well. IME hydro discs on a mtb is a no brainer as they offer fantastic power and modulation and they work well in the wet and mud. If they present a problem they can be sorted out when I get home. I would not want them on a touring bike. I have spent much of my life repairing and servicing bikes (mostly professionally but also in a bike recycling charity) and have spent more time than I would like servicing hydraulic brakes (Bleeding them is a very straightforward procedure but they can present all sorts of niggley problems. They are great when they work well but can also be pain when they don't. The issue of overheating hydraulic fluid would also steer me away from them for a touring bike. Also they are vulnerable to damage, particularly the hoses. If was building up a new touring bike I would go for cable discs for the stopping power and simplicity of servicing/repair on the road. And although slightly off topic I would fit bar-end gear shifters for the same reason.

Just my 2d, Ian

reohn2
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Re: hydraulic disc brakes v cable disc brakes

Postby reohn2 » 10 Feb 2020, 9:05am

Biospace wrote:Is there some common agreement that proven cable disc brakes and proven rim brakes both provide good braking for laden touring, and that each has their own personal preferences and according to use/circumstances for each design?

Strengths of cable operated discs:
Work better than rim brakes in wet and muddy conditions
Create less muck in the wet
No chance of popping a tube if severely overheated
Low weight and small size means it's easy to carry a spare disc

Strengths of rim brakes:
~½kg less mass
Up to 10% less drag than disc systems (cited as 10-15% less for bikes without luggage)
Larger cooling area compared with discs
Symmetrical and smaller stress and strain loadings through the f&f allow for better damping of road vibrations

I think we're all aware of how easy it is to overheat a brake through dragging, rather than releasing fully and reapplying?

It'd be wonderful if there were an affordable and lightweight alternative to wasting all that energy down long descents, but doubt there'll ever be anything which can be effective for bikes on tour.

A couple more for the plus side of discs:-
No rim wear with discs.
A disc equipped bike can still be ridden with an effective brake even with the rim wildly out of true(providing the wheel will turn through the frame or fork),not so with rim brakes

Do rim brakes really offer 10% less drag than discs?
I'd need some scientific proof of that before accepting it to be true
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Biospace
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Re: hydraulic disc brakes v cable disc brakes

Postby Biospace » 10 Feb 2020, 11:49am

I chose four significant benefits of each system, of course there are plenty more smaller benefits on each side. For me, feeding larger and lob-sided forces into something as finely engineered as a good bike, especially given these forces act in a way to pull the front wheel out of the fork, more than balances the benefits of brakes which keep a bike cleaner in wet weather and which wear down the braking surface of many thousands of miles.

From https://road.cc/content/feature/213876- ... ind-tunnel,
"We've measured a 16% increase in wheel drag between a disc-braked wheelset and a standard wheelset", Jean-Paul told us. "We performed a direct back to back test of the Zipp 303FC in standard version and disc brake version, for our own competitor comparison purposes. That 16% is a constant offset in the performance curve across the entire cross wind angle range."

djb
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Re: hydraulic disc brakes v cable disc brakes

Postby djb » 10 Feb 2020, 1:35pm

Re more friction, I reckon for us slow as molasses tourers, the wind resistance thing is pretty much null.
Actual disc rub certainly can be an issue, I know with my qr bike one has to be careful, as the clearance between rubbing and not rubbing is very very small, and if one is inattentive or has bad eyesight, rubbing issues will occur.

With my mechanical system, I carefully adjust the pads to not be too close, and I prefer lever engagement part way through travel to get more leverage, just like I do with rim brakes, but we are taking small amounts here. Bonus is that I'm sure never to have disc rub.

Hydro setups don't allow this, so perhaps there is more rubbing going on, and maybe more as calipers get older and dirtier...?

Certainly disc setups are more finicky than rim wheels, and requires one to learn all this stuff, which can be a challenge and again, depends on if you are mechanically inclined etc.