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Mechanical disc brakes are toilet!

My wife just bought a new bike with disc brakes but they're Avid BB5s or something and they are utterly rubbish. I've got one bike with unbranded calipers that are better than than these, despite trying to dial slack out of them. 

My only experience of discs has been Shimano hydraulics on MTBs and they will but you over the bars quick sharp. These mechanical things feel like trying  brake with 2 pieces of stale bread or something. You get what you pay for I guess. 

If you're new please join in and if you have questions pop them below and the forum regulars will answer as best we can.

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18 comments

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ashtons99 | 4 years ago
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Don't buy Shimano ones. They are proper 5h1te, I binned them after trying to adjust them time after time. I lost all braking one day....scary. I invested in 105 hydraulic and they are light years apart 

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sizbut | 4 years ago
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BB5 basic.

BB7 better but pain to keep adjusted for full bite. 

Spyre, same braking force as BB7 but much easier to keep good braking (occasional tweak of the cable adjust as the pads wear down). 

Hy-Rd brilliant best of cable operated world. Serious step up of braking force over the others. 

Yes, pad have to be properly bedded in.

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martinkiely | 4 years ago
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Another point is that mechanical disc brakes work best with compressionless outers and decent cables - recently swapped out the cables on my (new to me) Pinnacle Arkose and the difference was massive (TRP cables if you are wondering). Even with the cheapo Tektro Mira calipers, the improvent was huge. A pal of mine uses TRP spyres on his gravel bike and he feels they are pretty impressive - and hes a big guy - 6'5"! - and is quick with it, so don't just discount them out of hand. As a comparison, he rides a rim braked road bike and has several MTB's as well (which are all hydraulic braked) so he knows what all the different options feel like. Yep - hydraulic are better (arguably, in most situations), but cable disc brakes can be very good, and you can still use your existing brifters etc, if changing over, without going to the expense of hydraulics.

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bumble | 4 years ago
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fwiw, i really rate *all* the mechanical discs i've got/used.

avid bb5's - yup, really good, the manual pad-adjuster is handy. 

spyres - nicer, lighter feel, i prefer a hard, crisp bite point, and these feel a bit more nuanced (maybe i could say 'flexy', but that's not quite the right word)

shimano r317 - i love these, so much i've even bought some spares, just in case i want to build another bike in a few years. They've got a nice hefty / crisp lever feel, and great performance.

i've no idea what some people are doing to their brakes so that they need adjusting every couple of days. 

 

 

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shutuplegz replied to bumble | 4 years ago
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bumble wrote:

fwiw, i really rate *all* the mechanical discs i've got/used.

avid bb5's - yup, really good, the manual pad-adjuster is handy. 

spyres - nicer, lighter feel, i prefer a hard, crisp bite point, and these feel a bit more nuanced (maybe i could say 'flexy', but that's not quite the right word)

shimano r317 - i love these, so much i've even bought some spares, just in case i want to build another bike in a few years. They've got a nice hefty / crisp lever feel, and great performance.

i've no idea what some people are doing to their brakes so that they need adjusting every couple of days. 

 

 

 

Agree. I don't understand the problems people are having!

 

I chose cable discs over hydraulics when speccing/building my commuting bike. The single acting calipers like the BB5s/7s do take a bit more setting up but the TRP Spyres I use are essentially fit and forget. I adjust pad clearance once or twice a year just to suit winter versus summer riding conditions - something you can't do with hydraulics. At the same time I am probably also accounting for pad wear without conciously making this adjustment.

 

I find modulation with any type of disc brake better than rims, in any conditions (other than brand new blocks with perfectly clean rims!), but especially so in the wet.

 

Pad choice (or contamination) can be a significant factor though. I once replaced the TRP pads with a cheaper aftermarket brand - they were clearly harder and squealed less in the wet but gave very graunchy/unpleasant lever feedback and braking felt underpowered and 'wooden'. I put some TRP pads back in. Poor pad/block choice/condition can obviously affect hydraulics and rim brakes aswell though.

 

I have hydraulic discs on my 'best' bike as overall I prefer the feel of them at the lever but from past experience hydraulic discs on an all-weather commuting bike are more maintenance heavy than cable discs and have no 'adjustability'.

 

Whether I am riding my rim braked bike or my cable or hydraulic disc braked bikes, I can still lock a wheel up if I am not careful.... If you can't do this then they probably aren't set up at all well!

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Cmonsta | 4 years ago
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Anyone looking at this thread, I did buy the GTP calipers, they are awesome, 10/10 now I can pop the back wheel braking from 40kph.

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CXR94Di2 | 4 years ago
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I bought a genesis Day One with mechanical brakes.  Understanding that they would likely be poor, my god they were shite. 

I immediately ordered a full set of shimano Di2 levers and calipers.  Instant perfect performance with nice ergo hoods being di2 and the bike being single speed.

I ordered my hydraulic full brake system from german website, significantly cheaper than elsewhere. I had to shorten hoses and swap left to right being foreign wrong setup  4

 

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barongreenback | 4 years ago
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Hate my mechanic disc brakes on my winter bike. Ironically I have hydraulic on my Summer best bike. Will definitely be replacing them this Autumn with 105 hydro. 

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alansmurphy | 4 years ago
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Only reinforcing the above but if you get the cheaper end of the bike market in terms of brakes, you're going to feel it.

 

I have mechanical discs on one winter bike and cable hydraulics on the other and the difference in huge. Then i bought an e-mtb with hydraulics and wow, it really loves to stop - but then it is a lump with huge grippy tyres too!

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theslowcyclistxx | 4 years ago
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A lot depends on the installation. I have the bb7sl and the performance is decent. After having researched a lot, however, my best bet for the best breaking mechanical disc brake (far better than any normal mechanical system, according to users) is juin tech gt - which I have just received (so cannot report on performance yet). They seem very light and well made though.

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Cmonsta replied to theslowcyclistxx | 4 years ago
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casperradil wrote:

my best bet for the best breaking mechanical disc brake (far better than any normal mechanical system, according to users) is juin tech gt - which I have just received (so cannot report on performance yet).

Heya did you like the GT calipers? I'm looking at getting a pair and I got severe sticker shock with the price. I'd imagine they're probably the best mech disc brake out there but what's your findings with yours?

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Awavey | 4 years ago
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I've got spyres mechanical discs on my bike & I thought they were toilet when I first had them,it was only when I swapped pads to something half decent, that they actually worked as good as decent rim brakes,they'll never be as good as hydraulic & you have to keep on top of the constant adjustment as they wear else you'll just find you are grabbing a handle full of air

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Joe Totale | 4 years ago
3 likes

Rim brakes - Great

Hydraulic Disc Brakes - Great

Mechanical Disc Brakes - The worst of both worlds. You have the extra half a kilo weight of disc brakes but none of the extra stopping power or modulation that hydro disc brakes give you.  They're a hell of a lot more faff in terms of maintenance than the above two systems, note the commentor above saying they need adjusting "every couple of days". 

They're an evolutionary dead end and will probably go the way of cantilever brakes soon. 

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Rod Marton | 4 years ago
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For every type of brake there are good ones and bad ones, and BB5s are not one of the good ones. I swapped mine for a pair of Spyres and the difference was remarkable.

Having said that, you can quite probably improve things with a better set of pads.

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antigee | 4 years ago
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BB5's aren't great (in my opinion see end) disc brake pads take a bit of bedding in and heating up whatever hydraulic or cable  - worth googling for best way but my  summary is down a long hill and drag them after picking up speed x 3 to 4   - out of the box not impressive but will grow to love them in the wet other than their noisy howls and the need to adjust every couple of days 

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Jimthebikeguy.com | 4 years ago
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They all take proper setting up to really get them in the sweet spot, but some are certainly better than others. The problem with the avids is that only one pad moves, so the static piston has to be set very close to the rotor by aligning the caliper very carefully... Then the moving piston needs winding in so you get plenty of bite. Otherwise all that happens is the rotor just gets flexed.

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huntswheelers | 4 years ago
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Spyres are great mechanical calipers and Avid can be found the sweet spot...if it's a new bike then get it back into the workshop to get it sorted. I have many coming in here hydraulic and mechanical citing poor performance....but down this way there is little need for discs ( you can all argue the disc /rim debate) and many have glazed disc pads...swap out with softer pads...bingo it's okay.... It does vary area to area but like I say if it's new....get it into the mechanic

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Xenophon2 | 4 years ago
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You indeed get what you pay for but I used to ride with a pair of Spyres and they were very good, on par  with the very top end rim brakes in terms of performance and the latter wore out my rims right quick. 

Hydraulics are better but come with their own drawbacks where maintenance is concerned.

Are you certain they're mounted correctly?

 

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