Hydraulic v mechanical disc brakes - fat tyres

BetterIwas
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Hydraulic v mechanical disc brakes - fat tyres

Postby BetterIwas » Tue Mar 24, 2015 12:52 pm

I am looking for new bike. I presently have a flat bar Merida with hydraulic discs. Happy with them.

Looking for drop bar relaxed geometry bike with discs.

I know hydraulic are supposedly better than mechanical but is it lack of fade or are they just better. Is it just overegging the cake ?

Some of the bikes I am looking at have mechanical discs (Apollo & Cannondale).

I live in a hilly area and sometimes the roads are damp.

I use 700x32 tyres (Durano Plus) - my thinking is that I trade some 10% of speed for better braking performance. Am I correct or just talking out of my hat ?

Thanks

Calvin27
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Re: Hydraulic v mechanical disc brakes - fat tyres

Postby Calvin27 » Tue Mar 24, 2015 1:55 pm

Hydro discs are heaps better for modulation. It feels more immediate and the pressure is easier to control . There is no cable friction or stretchy you can feel (yes even the best set up cables are no match) On road bikes the noticable impact is about double. Road brake cabling has more complexity than mtb so you really feel the difference.
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Duck!
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Re: Hydraulic v mechanical disc brakes - fat tyres

Postby Duck! » Tue Mar 24, 2015 3:33 pm

As above. Hydros are far better at transferring input effort to the brake due to virtually zero mechanical drag through the system. Ultimately this means you can achieve the same or even greater braking power for less physical effort. Hydros are also self-adjusting for pad wear, so the feel is consistent until the pads are worn, while mechanical (cable) brakes need periodic adjustment due to pad wear & cable stretch.
I had a thought, but it got run over as it crossed my mind.

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rifraf
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Re: Hydraulic v mechanical disc brakes - fat tyres

Postby rifraf » Tue Mar 24, 2015 10:10 pm

No opinion on hydro really as I've never tried them.
I know how to change a cable and I figured on my touring bike BB7's made a lot more sense for me personally.
Absolutely love my BB7's compared to V-brakes though.
I remember listening to forum member Aushiker lamenting having hydraulic brakes on his Giant XTC mountain bike when he lost pressure on them whilst on the Munda Biddi I think it was.
Anyway, somewhere where plenty of braking was necessary but he was unable to fix in the field to his great inconvenience.
When he got home he promptly tossed the hydro's and replaced them with BB7's.
Sold me on the idea of cables :)
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MichaelB
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Re: Hydraulic v mechanical disc brakes - fat tyres

Postby MichaelB » Wed Mar 25, 2015 9:16 am

Until I recently rode a bike with cable discs (polygon Helios C6) I would have said hydro by miles. But now I'd have to temper that with, depends on he cable calipers.

The Polygon had the Shimano 517, and they did really well, in terms of power and feel. Not as good as hydro, but still pretty damn good.

If you have the budget and capability, go Hysro, but if budget constrained , go cable BUT God quality calipers

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baabaa
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Re: Hydraulic v mechanical disc brakes - fat tyres

Postby baabaa » Wed Mar 25, 2015 10:28 am

and then you need to think do you really need disc brakes for the odd damp road. Worth reading this which while aimed at gravel bikes runs pretty true with why we are seeing so many discs about.
http://g-tedproductions.blogspot.com.au ... d-and.html" onclick="window.open(this.href);return false;
been using mech discs since 2007 and still not sure that I really need them on the road. My canti and caliper braked bikes still stop and start the same as a bike should and with 32 mm tyres you will be able to stop well with any brake if it is adjusted correctly. In really wet day to day and even week to week commuting I do like the lack of rim wear that discs offer.

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Re: Hydraulic v mechanical disc brakes - fat tyres

Postby Calvin27 » Wed Mar 25, 2015 10:46 am

Performance aside - the big appeal of discs for me is not chewing through your rims! Yes - that means gravel roads where fine dust and other crap gets into your rim braking surface. A rotor costs from $20 - far cheaper than rebuilding a wheel + rims.

but that's just me who only washes their bike twice a year, even the MTB (drivetrain gets a lot more love though).

I think part of the problem in the 'do you really need disc' argument is the crossover between disciplines. Roadies ride very different to MTBrs even long after they have switched codes. for example guitar ted in the blog is talking about discs being overkill for even gravel rides. Well that depends on what you'd call a gravel ride. a gravel ride could mean a hard pack flat trail or something more extreme like dirty gran fondo. Big difference but somehow people still use the same term 'graveller'. I'd guess most people would prefer discs for the gran fondo, but most would be happy with even caliper brakes on hard pack.

Me and my mates have 'rain hail or shine ride days' and I can tell you those with rim brakes are constantly bickering when the weather man decides to roll dice. On those days, I can honestly say I do not see any road bikes out there - so my point is, if you don't ride in those conditions, you don't need discs.

The point is whatever a canti/caliper brake can do a disc can too - the reverse is not true.

Disc bikes are now not commanding a significant premium over calipers/canti so if you're buying a new bike wouldn't you rather buy the more capable one?

Anyway, OP is asking between hydro and cable discs so I don't see why the 'do you need disc brakes' needs to come in at all.
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Re: Hydraulic v mechanical disc brakes - fat tyres

Postby BetterIwas » Wed Mar 25, 2015 3:36 pm

Thank you for the assistance.

I was understating it a bit when I said "damp" - I mean from wet roads to pouring down when I commute (I will be going from a 10k commute to an 18k commute soon). Do not plan to ride in rain but sometimes it happens - probably 10 times last year. If it saves one fall then the extra expense is worth it to my thinking. .

Whilst a variety of views I understand that hydro are generally better but mechanical can be serviced. Think I will go the hydro.

Thanks

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Re: Hydraulic v mechanical disc brakes - fat tyres

Postby mikedufty » Wed Mar 25, 2015 6:00 pm

I think the best thing about hydro is they self adjust. The worst thing is they have no manual adjustment, so when the self adjusting goes out of whack you are stuck with it.
Cables are probably better for field repairs and bodging, but mostly the hydro's are OK.
I've had one which has some sort of failure where it builds up pressure if parked in the sun. Needs an 8mm spanner to bleed a little fluid out to release properly.
I've had another where the master cylinder has started to fail, so it would always be a bit soft unless you pumped it at the start of a ride. Still continued working like that for sometime, and when I replaced the lever/master cylinder it only cost as much as a cable lever.
The repairability of a cable only really counts if you carry a spare cable with you. Hydros do seem to fail more gradually. The system in principle is tremendously more reliable than cables. Look at the km cars and motorbikes do on hydro systems with virtually no maintenance. On bikes there is more emphasis on getting the weight down and you seem to lose some of that.

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Re: Hydraulic v mechanical disc brakes - fat tyres

Postby zero » Thu Mar 26, 2015 3:06 pm

mikedufty wrote:I think the best thing about hydro is they self adjust. The worst thing is they have no manual adjustment, so when the self adjusting goes out of whack you are stuck with it.
Cables are probably better for field repairs and bodging, but mostly the hydro's are OK.
I've had one which has some sort of failure where it builds up pressure if parked in the sun. Needs an 8mm spanner to bleed a little fluid out to release properly.
I've had another where the master cylinder has started to fail, so it would always be a bit soft unless you pumped it at the start of a ride. Still continued working like that for sometime, and when I replaced the lever/master cylinder it only cost as much as a cable lever.
The repairability of a cable only really counts if you carry a spare cable with you. Hydros do seem to fail more gradually. The system in principle is tremendously more reliable than cables. Look at the km cars and motorbikes do on hydro systems with virtually no maintenance. On bikes there is more emphasis on getting the weight down and you seem to lose some of that.
I have a set of deore hydros (granted deore is a price/feature group, not a lightweight group) that have required basically bleeding and wetting of the front seals once in 9 years to cure sticking. If I was at say the Mont, I'd be able to fix it between laps but truly would not expect to. The bike does all my offroad riding, offroad racing, and most of my wet commuting - its up to about 35,000 kms.

Plenty of people have had cable failures with cable discs, where as I would typically expect my hydro failure mode to be sticking and dragging but still functional. Obviously with lines and calipers of any type, you get what you pay for.

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Re: Hydraulic v mechanical disc brakes - fat tyres

Postby biker jk » Thu Mar 26, 2015 3:36 pm

zero wrote:
mikedufty wrote:I think the best thing about hydro is they self adjust. The worst thing is they have no manual adjustment, so when the self adjusting goes out of whack you are stuck with it.
Cables are probably better for field repairs and bodging, but mostly the hydro's are OK.
I've had one which has some sort of failure where it builds up pressure if parked in the sun. Needs an 8mm spanner to bleed a little fluid out to release properly.
I've had another where the master cylinder has started to fail, so it would always be a bit soft unless you pumped it at the start of a ride. Still continued working like that for sometime, and when I replaced the lever/master cylinder it only cost as much as a cable lever.
The repairability of a cable only really counts if you carry a spare cable with you. Hydros do seem to fail more gradually. The system in principle is tremendously more reliable than cables. Look at the km cars and motorbikes do on hydro systems with virtually no maintenance. On bikes there is more emphasis on getting the weight down and you seem to lose some of that.
I have a set of deore hydros (granted deore is a price/feature group, not a lightweight group) that have required basically bleeding and wetting of the front seals once in 9 years to cure sticking. If I was at say the Mont, I'd be able to fix it between laps but truly would not expect to. The bike does all my offroad riding, offroad racing, and most of my wet commuting - its up to about 35,000 kms.

Plenty of people have had cable failures with cable discs, where as I would typically expect my hydro failure mode to be sticking and dragging but still functional. Obviously with lines and calipers of any type, you get what you pay for.
Thanks for describing your experience. I have been thinking about a disc brake road bike and wondered about the reliability of hydraulic versus cable disc brakes. While I have been on a few rides when somebody broke a gear cable I've never observed a broken brake cable. It's good to know that hydraulic brakes are so reliable.

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Re: Hydraulic v mechanical disc brakes - fat tyres

Postby Calvin27 » Thu Mar 26, 2015 4:21 pm

I think the repair-ability of cable vs hydro is overstated. It will rarely happen. If you're touring, yes, it's important. If racing, if either develops any failure, race over - or you're coming last anyway.

The benefits of cable over hydro in failure mode though are:
- Can swap caliper easily so that you have at least a front brake
- Can do some diy cable changes (i.e. cut rear cable to fit front)


Generally hydros are reliable enough not to worry about them but cables will work until their very last moment before ultimate failure. Brake heating will cause poor braking with cables but can be catastrophic with hydro. Leaks will end a hydro brake very soon but cables can run even in the worse condition and setup. But having said that, if you're running 5+year old hydros and don't care to test the condition before a race, then either you are not serious enough about racing to warrant concern (i.e. apart from nc, not much impact) or you are taking a risk.

I should probably add to hydro sti shifters are not easy to retrofit with the newer internally cable routed bikes. A hydro line does not fit in the hole!
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Re: Hydraulic v mechanical disc brakes - fat tyres

Postby mikedufty » Thu Mar 26, 2015 7:33 pm

I can't see why swapping the rear caliper to the front in an emergency wouldn't work with hydro, you'd just be stuck with the lever on the wrong side, and a lot of excess hose coiled up somewhere.

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Re: Hydraulic v mechanical disc brakes - fat tyres

Postby slaw » Fri Mar 27, 2015 10:24 am

My commute/tourer bike has Shimano Saint hydros. Have done nearly 50,000km in 8.5 years. They have been fantastic.
I replace the pads as needed. I've had a sticky piston maybe three times. Never been bled. Everything, apart from the pads, and including the rotors is original.
Easy to adjust if needed. MUCH easier than V-brakes.

On my MTB I had Hayes hydro which I had to bleed every few months. I replaced them with BB7s when I was going on an OS trip so I'd have fewer maintenance issues. They felt good with quality fully enclosed housings and not too hard to adjust to compensate for pad wear. But one wet muddy race had me adjusting them mid lap as the pads wore down. A team mate had shimano mech brakes and lost all function as the caliper reached the end of its travel. So I've now replaced the BB7s with XT hydros and not had any issues since.

Next roadie will have hydro disc brakes I reckon.

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Re: Hydraulic v mechanical disc brakes - fat tyres

Postby Bentnose » Wed Apr 01, 2015 8:03 am

slaw wrote:On my MTB I had Hayes hydro which I had to bleed every few months. I replaced them with BB7s when I was going on an OS trip so I'd have fewer maintenance issues. They felt good with quality fully enclosed housings and not too hard to adjust to compensate for pad wear. But one wet muddy race had me adjusting them mid lap as the pads wore down. A team mate had shimano mech brakes and lost all function as the caliper reached the end of its travel. So I've now replaced the BB7s with XT hydros and not had any issues since.

Next roadie will have hydro disc brakes I reckon.
This is basically exactly what I went through except I bought SLX hydro. I remember completely stripping and rebuilding my BB7's after a race when I was stopping every 10 minutes to adjust them, next race I did i had the same issues, needed another rebuild, threw them in the bin and bought hydro, no issues since and much more powerful.
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Re: Hydraulic v mechanical disc brakes - fat tyres

Postby Sharkey » Wed Apr 01, 2015 8:31 am

I have a Specialised Stumpjumper that I bought in 2005. It has basic Shimano Deore hydro discs that have been absolutely bullet proof. I have not had to touch them (other than to replace pads) in 10 years of hard riding. They haven't even needed to be bled.

The bike has been rebuilt completely twice in that time. Once it was stripped down, frame sandblasted and powder coated and the other time the rear swing-arm snapped and needed to be repaired. The only original components on the bike are the seat post, handlebars and the brakes. Everything else (fork, shock, derailleurs, wheels etc.) has needed to be replaced and, as mentioned, the frame has had major repairs.

If the rest of the bike was as durable and reliable as the brakes I'd be quite a bit wealthier.

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Re: Hydraulic v mechanical disc brakes - fat tyres

Postby Xplora » Wed Apr 01, 2015 10:33 pm

10 wet rides is not worth going Hydro or Mechanical disc really. Alloy rims will cope with that. Similar to Aero wheels, I will have one ride every 6 months where I dislike the deep profile but outside that? Gimme 808s every day!

I had Shimano cable discs and the braking is no more useful with or without them.

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Re: Hydraulic v mechanical disc brakes - fat tyres

Postby Bentnose » Thu Apr 02, 2015 9:42 pm

I have the CX75 Shimano discs and even in the dry, my 105 rim brakes with Dura Ace pads feel like blocks of wood in comparison. The issue I have with my CX75 brakes is a design issue, I have used up all of my pad adjustment, with plenty of material left, on the rear due to the moving part of the caliper having a long arm that contacts a dead stop if you pull too much cable through, I can maybe manage another 3mm, which won't get me far. This is something that just isn't an issue on BB7's.
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