Viewing 40 posts - 1 through 40 (of 65 total)
  • Mechanical disc brakes, yes or no?
  • Ajoten
    Free Member

    Yonks ago I had a Kona Dew with cable discs (2004?), which stopped so badly it was in the shed more than on the road. Terrifying. I’m currently musing on a cyclocross bike, but modern low end (i.e. affordable by me) ones all seem to have these mechanical ones, and I’m extremely loath to risk it.

    Was my original bike just a bit duff? Has technology moved on enough in the intervening decade to be confident of such brakes these days?

    Andrew

    davidjey
    Free Member

    They’re still a bit hit and miss, but I’ve never had a terrifyingly bad set. Any bikes in particular you’re looking at? What brakes do they have?

    jekkyl
    Full Member

    2nd hand hydro brakes aren’t expensive.

    Avid BB7’s seem to get good reviews

    Bream
    Free Member

    Technology has certainly moved on but in my opinion cable disc brakes are simply just not great. Loads of people run them and are happy but for me I’d only buy hydraulic. Main reason being lever feel, with hydraulic you can 1 finger brake and needs little force. With cable you often need a hand full and great force, plus cable/system stretch which often means long lever travel and even going to the bars before you lock a wheel. And then you have the single sided pad actuation with most of the cable disc brakes, another weakness and pain to take care.

    So for me no.

    I’ve just taken off a pair of FSA CX Expert calipers and gone Shimano hydraulic, the difference is another world, in all ways. The negative is that buying hydraulic cost more, but for me it’s definitely worth it.

    psycorp
    Free Member

    Cable are nowhere near as good as hydro. I have cable on my Saracen road bike and don’t really like them, but I only paid £400 for it new so beggars etc….

    jimdubleyou
    Full Member

    Mrs Dubleyou has them on her x-bike, but came from a pretty crappy BSO so hasn’t complained.

    IIRC, they are BB7s.

    I wouldn’t trust stopping my mass to cable disks.

    ajantom
    Full Member

    I run Shimano, Hope and Avid BB7s on different bikes. All slightly different feel, but when well set up they all work equally well.
    A lot of issues people have with mech discs are (imo anyway) down to setup. They take a while to dial in, but once done they just work until it’s time to change pads.

    Del
    Full Member

    here
    and here
    anyone who reckons you need a full hand to get cable brakes to work, or just thinks that they’re crap across the board, just hasn’t used a set that have been set up properly.
    all you’re doing is altering the method of transferring the force applied by your finger to the caliper. if the losses involved were that significant then cables would be rather useless for changing gear with, wouldn’t they?

    Ajoten
    Free Member

    Thanks all for your input. Sounds like my fears might be well-founded.

    @jimdubleyou, good point re mass. At 90kg I should probably bear this in mind…

    @ajantom, set-up is one of the reasons why my old bike was off the road so much. Must have gone back to LBS thrice to be looked at.

    Should I assume though that cantilevers are mostly going to be better than cable discs?

    13thfloormonk
    Full Member

    Interesting, usually these threads are mostly pro-cable disc with a few legitimate or otherwise detractors.

    I’ve had two sets of Avid BB7s, which both performed great with not too much attention (i.e. I didn’t do anything fancy with outers, but did follow Avid’s instructions re: calliper set up). Lever feel is perhaps marginally ‘rougher’ than hydros but still plenty of power and one finger breaking.

    I noticed pad wear more on long wet descents, once or twice I had to adjust at the bottom but that could have been down to newish pads that hadn’t bedded in. For a CX bike I wouldn’t be as concerned unless you plan to ride it like an MTB down long, muddy, brake-y descents.

    Like the look of the TRPs, if only because you can use Shimano pads with them and Shimano metal pads are my favourite pads for long life and not too much noise in the wet.

    Cheap cable discs are the work of the devil though, Would only go Shimano CX77, Avid BB7 or BB5 if I could be bothered with the tinkering, or TRP.

    whitestone
    Free Member

    @Bream – some mech disk brakes now have dual pistons – the TRP Spykes for instance. Unlike hydro systems they aren’t self-adjusting so you do need to keep an eye on that side of things. I’ve the Spyres on my CX and they work more than well enough.

    Does depend on what sort of riding you do of course: DH and Alpine trails then definitely hydro; pootling round Centre Parks or similar then mech disks are more than adequate.

    FunkyDunc
    Free Member

    I’ve got BB5 and BB7 on my CX.

    They are ok, not as powerful as hyrdos, and need readjustment every so often.

    If a bike comes with them, not the end of the world, but I personally wont be buying them again, next bike will be hydro. Better performance, less faffing.

    ajantom
    Full Member

    Definitely not! Discs will be much better than cantis, especially if it’s wet or muddy.

    I was talking about initial setup – take a bit of time getting the pad distances and angles set up, and all you then ever have to do is turn the red dial to make up for pad wear.
    I’m 90kg or so with kit, and have BB7s on a Surly Krampus. They stop me plenty good enough!

    twisty
    Full Member

    Should I assume though that cantilevers are mostly going to be better than cable discs?

    I wouldn’t assume this, my experience of road cantis is that they are rubbish compared to cable disks or v brakes, this is Tiagra level cantis though.

    What I have gleaned is that disk brakes work just fine as long as they are not crap disk brakes and they are set up with suitable brake cable outers.

    I wouldn’t trust stopping my mass to cable disks.

    More massive people need more massive brake disks. Disk size is more important than cable/hydro AFAIK.

    amedias
    Free Member

    Cable disks can be fine, and can be the equal to hydros, the problem is that crap cable brakes are crap, not because they are cable, but because they are cheap crap.

    A basic cheap hydro will 99% of the time be better than a cheap cable disc, but decent cable discs like BB7s and Spyres, and some of the posher Shimano options, set up properly with decent cables can easily rival a decent hydro*.

    There’s plenty of people on here who either run both hydro and cable on different bikes, and some that have even swapped FROM hydro to cable and are happier for it.

    There’s also more to a brake than just it’s immediate power. Power, serviceability, reliability, ease of adjustment, robustness, heat capacity and how it deals with it, failure modes, on trail fixability, potential for contamination etc. Some of those other aspects mean more to some people than others so horses for courses and all that.

    In summary, decent cable brakes will be fine if you set them up and look after them (same as hydro really…) but if you don’t get on with them then there’s cheap Hydros available to swap to.

    *

    I wouldn’t trust stopping my mass to cable disks.

    hydraulic you can 1 finger brake and needs little force. With cable you often need a hand full and great force

    ^ think about those comments for a moment, cos they come up a lot, not to mention that I have configured BB7s before that were too fierce (and broke a disc mount off a fork), it’s not about the intrinsic system type, it’s about the specific system.

    Hell, back in the mid 00’s I was using BB7s on my trials bike, because they were better and more consistent than the Hope and Hayes options at the time, and more robust. The one thing you don’t want on a trials bike is a brake that lacks power or can’t be modulated properly!

    The amount of force your finger can apply is the same regardless, it’s your finger after all.

    (Assuming equal disc size) The amount of that force that gets exerted on the disc and how well it stops you are governed by three things:

    1 > leverage/piston ratio between lever and calliper
    2 > the performance of the brake pad/disc interface
    3 > losses in the system

    Point 1 is mostly null as you can alter piston sizes and lever ratios and actuation arm sizes etc. so you can achieve the exact same result from hydro or mechanical so one isn’t automatically better.

    Point 2 can be nullified too as you can use the same pad compounds in either system, however cheap brakes often come with cheap pads too, compounding the perceived difference in system types.

    Point 3 is the issue, not at the lever as cable and hydro levers can be built equally stiff, pretty much the same with callipers except for the tiny losses in flex in a cable actuation arm and friction in actuation mechanism, but these are tiny.

    This leaves the cable… even the crappiest hyraulic lines do a damn good job of getting the force from one end to the other with minimal losses, cables can be much more variable. A decent cable, installed correctly, with compressionless outer, nice squarely cut and filed ends with good interfacing surfaces does this job pretty damn well too, an that’s the key.

    Cheap flexy outer, badly cut ends, dodgy interface surfaces/angles and poor setup are what kill the performance of cable discs. And most manufacturers, especially at the cheap end don’t commit the necessary time and money to getting that bit right.

    ton
    Full Member

    long term user of avid bb7 here. anyone who say’s they are not as good as hydro’s has A. never used them, or B. never set them up correctly.

    got them on both of my bikes at present, and as a 20 stone rider, i kind of know if a brake is good or not.

    Del
    Full Member

    Alpine trails then definitely hydro;

    balls. fitted BB7s to my 5 specifically to take to the alps, lift assisted and uplifted.
    i don’t ‘do DH’, so wouldn’t comment on that application specifically, though i have ridden DH trails in wales, and also the french, italian, and swiss alps, and muddled through OK.
    common wisdom has it that cable disk brakes aren’t any good though, and the majority are always correct, right? 😀

    ghostlymachine
    Free Member

    Poor cantis are useless.
    Poor cable discs are useless.
    Poor hydros are barely functional.

    Good cantis, well set up, on decent rims, with decent pads/cables etc will be as good as average cable discs. But can be variable.

    Good cables discs, well set up and looked after with good compressionless cable outers are as good as average hydros.

    kilo
    Full Member

    I have used cable (Haynes)cable / hydro combined (juin tech) and sram hydro. I found the cable to involve much more faffage than the others. Cable hydraulic combo were good and pretty fit and forget and provided better stopping, they are still on my spare cx bike. The sram have been completely fit and forget and the best working. I ride my cx er on longish runs rather than race and do reasonably technical descents on it

    epicsteve
    Free Member

    BB7’s are decent but hydro’s are better. I used to use BB7’s on most of my bikes but all of them have hydro’s now.

    whitestone
    Free Member

    Just looking on CRC and the TRP Spyke is £80 per end for caliper only, the BB7 is £75 per end again caliper only whereas the XT is £70 per end for caliper, hose and lever. On that basis I’d go for the XTs.

    amedias
    Free Member

    BB7’s are decent but hydro’s are better. I used to use BB7’s on most of my bikes but all of them have hydro’s now.

    And yet there are people who (if they see this thread) will pop on here and claim the exact opposite.

    FWIW, I’m one of those people that has cable on some bikes, hydro on others, and somehow I still mange to not die when swapping between them.

    forums eh, can’t trust em 😉

    1-shed
    Free Member

    BB7 work just fine, want to buy my bike in the for sale section?

    craigxxl
    Free Member

    I have BB7’s on my PlanetX XLS and they have been faultless. Plenty of modulation and with 160mm discs I’m still able to lock up front or rear if I want and over 90kg of Ajoten. Yes they need a bit on manual adjust to compensate for pad wear that you wouldn’t need to do with Hydraulics but it’s no deal breaker as it’s very simple to do.
    The limit of the BB7’s isn’t in the brakes themselves but the available grip of the tyres.

    ton
    Full Member

    the power of a bb7 used with 200mm disc is far superior to any hydro set up i have ever used, including shimano saints.

    if i ever went back to hydro’s it would be saints that i would buy.

    kcr
    Free Member

    I used BB7s for about 9 years of commuting. They were much better than rim brakes, but more fiddly than hydro to get setup correctly. For me, their big failing was that they didn’t stand up to winter conditions, and quickly corroded and started sticking.
    I am now using TRP HyRds, which are a big improvement. Better feel, better braking and self adjusting. I will upgrade to full hydro eventually, but expect to be running on 9 speed for a few more years.

    jimdubleyou
    Full Member

    Ok, so what I’m getting from this thread is that I’m a brake snob and shouldn’t rule out a bike with cable disks (esp. BB7s) as long as I learn to set them up properly.

    craigxxl
    Free Member

    whitestone – Member
    Just looking on CRC and the TRP Spyke is £80 per end for caliper only, the BB7 is £75 per end again caliper only whereas the XT is £70 per end for caliper, hose and lever. On that basis I’d go for the XTs.

    The brakes are for a CX bike so the XT’s won’t really work with drops and BB7’s are less than £45 each end which makes them a bargain for performance/£.

    jamiep
    Free Member

    BB7 Road are £45 a pair on ebay (with adaptor and bolts, without discs)

    whitestone
    Free Member

    @craigxxl – I have BB7s on my On-One Pompetamine, generally they’re fine. Two “problems”: 1. I found that winter grit/salt meant they need a complete strip down and clean each spring (a spring clean?). 2. The Pompetamine has an Alfine hub so chain wear meant that I needed to adjust the position of the rear caliper on a fairly regular basis, about once a month. This is only a problem for hub gears or single speed setups though.

    I certainly wouldn’t avoid a bike because it had cable brakes (2 out of 3 of my disk brake bikes are cable) – I’ve got a Singular Puffin rolling chassis heading my way and I’m undecided on whether to fit cable (TRp Spykes) vs hydro brakes (Shimano SLX) as it’s mainly for winter use and, true to interweb forum law, opinion is divided on which is better.

    craigxxl
    Free Member

    I have BB7s on my On-One Pompetamine, generally they’re fine. Two “problems”: 1. I found that winter grit/salt meant they need a complete strip down and clean each spring (a spring clean?). 2. The Pompetamine has an Alfine hub so chain wear meant that I needed to adjust the position of the rear caliper on a fairly regular basis, about once a month. This is only a problem for hub gears or single speed setups though.

    Moving the caliper so the pads are in contact with the disc would be the same regardless of cable or hydraulic so not really an issue as you are still undoing the same 2 bolts moving the caliper back and re-tightening.
    Never had a problem with winter salt and grit but I do tend to give my bikes regular cleaning and maintenance so may have prevented the issue occuring

    tillydog
    Free Member

    The TRP Spyres on my bike rusted up in a couple of months of summer riding 🙁

    They needed to be dismantled and (carefully) greased, following a guide that someone posted on here, as the manufacturer considers them non-serviceable (and obviously for dry use only, as there was no grease in the mechanism). The pad adjusters rely on a bit of thread-lock not to back off…

    They work just about OK, but I would avoid in the future.

    Switching to hydraulics is expensive, both because of the high cost of hydraulic levers for drop bars, and the need to match derailleurs, etc. to them.

    If you want hydraulics, buy a bike with them on (IMHO).

    whitestone
    Free Member

    My Spyres have been fine in nearly a year (once set of replacement pads so far) with same use and care as with the BB7s. Know what you mean about the adjusters backing off, reading around it seems to be a common problem. American outdoor kit and dry use seems to be a common theme – you’d think they lived somewhere sunny 😆

    @craigxxl I wasn’t meaning that the “problem” was with the brakes themselves just that without a tensioner of some sort you’d be adjusting the brake position on a regular basis whichever disk system you used. Obviously with a derailleur you get the tensioner for free with the jockey arm.

    smiffy
    Full Member

    There has been little mention of the biggest issue for me; cable brakes can’t adjust as you go. I’ve had to crash land half way down a descent with levers back to the bars because of no pad wear take-up, and two minutes later been off again to Talybont with full brakes after winding the pads in manually. I have both cable and hydro on different bikes and I’d advise hydro if you can.

    highlandman
    Free Member

    I’m with Amedias, Ton etc on this; I have a pair of BB7s on our tandem, with 200mm rotors on both ends. When touring fully loaded with a trailer, we probably weigh just over 400lbs and I’ve never had a problem braking single finger, front only on fast fun descents. We don’t hang about; the tandem has frequently exceeded 75km/h and sometimes well over 80km/h. I’ve also got one on the front of my 29er commuting bike, which has also been faultless. There’s no shortage of control for trickling through commuting traffic or when off-road and feeling for traction. Follow the instructions carefully and they’re absolutely grand, plus they will last a whole lot longer than any Shimano hydro up to XT level. At least they don’t wee fluid onto my discs….

    BillOddie
    Full Member

    I have TRP Spyres on my gravel/cx/whatever bike. They are fine but need careful setup, if you adjust for pad wear with the cable barrel adjusters they feel poo.

    amedias
    Free Member

    I’ve had to crash land half way down a descent with levers back to the bars because of no pad wear take-up, and two minutes later been off again

    Anecdotes like that don’t hold much water with me.

    For that ^ to happen the pads must have been worn significantly before you started the descent, with the commensurate affect on lever travel self evident. ie: you should have adjusted them sooner. I don’t believe a single descent could wear enough material off the pads in one run to go from ‘normal’ to levers hitting bar, and if they could then surely the they’d you’d wear the pad to the backing plate on the next descent.

    I can believe that they can go from ‘noticeably worn and in need of adjustment’ to hitting the bar, btu that’s not the same thing and if you decided not to deal with it in advance then on your head be it. All rim brakes have the same requirement and nobody bleats on about that.

    On my commuter/gravel bike/tourer thing with BB7’s I’ve been through one set of front pads in ~3000 miles, rears are half worn. I have to put a click or two on the pad adjuster every 3-4 weeks, hardly a chore.

    Offroad they wear a little quicker, but I check my brakes before I ride regardless of hydro or cable (don’t you?) I can count on one hand the times I’ve started a ride that then required me to then further adjust the pads mid ride, and they were all in the depths of winter in grinding paste, and even then we’re talking 1, maybe 2 clicks of adjustment when I stopped for a breather anyway.

    IMO the ‘they need constant adjustment’ argument is massively overstated or again, a result of poor initial setup.

    if you adjust for pad wear with the cable barrel adjusters they feel poo

    yeah, you shouldn’t really as it alters the position of the actuation arm which affects travel and leverage. That’s why the wheel on BB7s is so good.

    13thfloormonk
    Full Member

    I don’t believe a single descent could wear enough material off the pads in one run to go from ‘normal’ to levers hitting bar, and if they could then surely the they’d you’d wear the pad to the backing plate on the next descent.

    Hmm, I dunno, I’m largely all forcable discs, including the two sets of BB7s I’ve had in the past, but I did do one descent which went from my normal lever set up (admittedly slightly closer to the bar than average, but not massively so) to levers virtually at the bar. This was in the Pentlands which are not famed for massive brake burners, but can get wet and gritty. There were probably lots of other factors at play though, could well have been organic pads that weren’t bedded in etc.

    Point being, it put me off them for MTB use, but not road/CX use.

    amedias
    Free Member

    organic pads

    ah, well that might be related, gritty conditions can burn through organic pads very VERY quickly.

    Sintered all the way when offroad for me, especially on cables as you can’t boil any fluid 😉

Viewing 40 posts - 1 through 40 (of 65 total)

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