Disc Brakes — Hydraulic vs. Mechanical?

[Judd]

@Dan K 160651 wrote:

Greetings All –

Stepping up from my 5 year-old Jamis Coda Sport this Fall. Staying with the Coda (love the steel), upgrading to either the Comp (which has mechanical discs), or the Elite (which has hydraulic discs).

In terms of hydraulics vs. mechanicals, looking for opinions regarding both performance and upkeep (frequency and cost).

Thanks in advance!

I thought about this question a lot tonight as I rode on wet pavement with cheap mechanical brakes that are in need of adjustment. The thought occurred to me that I wouldn’t drive a car without power brakes so I probably shouldn’t ride a bike without power brakes either.

[Birru]

The heart-in-the-throat interval when you first squeeze the brake levers in the wet is far, far shorter for sure.

[peterw_diy]

@Judd 160676 wrote:

I wouldn’t drive a car without power brakes so I probably shouldn’t ride a bike without power brakes either.

Good news, Judd, you’re nowhere near as heavy as you seem to fear. 👍

Bad news, your engine is weaker than an old Karmann Ghia. 🤷

[hozn]

Yeah, there are people still using rim brakes out there (!); heck, I’d still take low-end mechanicals over rim brakes. But in general, I’m willing to spend extra for better brakes. I’ve never regretted having brakes that were too powerful and linear in delivery of stopping force; I’ve certainly regretted having brakes that were crappy or brakes that didn’t work as well in the wet. I’ve also regretted having tires that didn’t grip well in wet conditions, so there are certainly other factors in stopping safely.

(I do sometimes regret using sintered metallic pads on my commuter when their piercing scream [when wet] startles pedestrians.)

[huskerdont]

@hozn 160658 wrote:

On road (drop-bar) bikes the difference is HUGE to me. Road BB7s or TRP Spyres offer quite inferior braking compared to their MTB counterparts, IMO. And the road hydraulic systems are much better at stopping.

On the MTB, I’m not sure the difference in stopping power is necessarily as huge; I’ve had BB7s that were setup *really* grabby using fancy housing, etc. But the modulation and control of the hydro brakes on MTB is a *lot* nicer. At least, this is true for the Shimano SLX brakes I have on my MTB now. Being able to feather the brakes into turns without anything grabbing is really, really nice. I would never go back to mechanicals for that reason alone. But maintenance with self-adjusting pads is also a lot nicer / less frequent.

I’m starting to see the difference in disc brakes between a MTB and and drop-bar bike. On my mountain bike, the BB7s offer more stopping power than any other brakes I have. Yet on my drop-bar, the TRP Spyres aren’t anywhere near as good as the BB7s on the MTB. I had not realized this was a thing before, but if I had to do it again (I’ve already upgraded, to the Spyres), I’d consider hydros for the drop-bar bike, even though I swore off hydros the first time a system developed a leak on my old MTB. I’m no engineer so I don’t know why there’s such a difference, but no doubt smarter folks could explain it.

[Judd]

@huskerdont 160684 wrote:

I’m starting to see the difference in disc brakes between a MTB and and drop-bar bike. On my mountain bike, the BB7s offer more stopping power than any other brakes I have. Yet on my cross, the TRP Spyres aren’t anywhere near as good as the BB7s on the MTB. I had not realized this was a thing before, but if I had to do it again (I’ve already upgraded, to the Spyres), I’d consider hydros for the cross bike, even though I swore off hydros the first time a system developed a leak on my old MTB. I’m no engineer so I don’t know why there’s such a difference, but no doubt smarter folks could explain it.

I found some guys that can explain it:

https://youtu.be/_-agl0pOQfs

[hozn]

@huskerdont 160684 wrote:

I’m starting to see the difference in disc brakes between a MTB and and drop-bar bike. On my mountain bike, the BB7s offer more stopping power than any other brakes I have. Yet on my cross, the TRP Spyres aren’t anywhere near as good as the BB7s on the MTB. I had not realized this was a thing before, but if I had to do it again (I’ve already upgraded, to the Spyres), I’d consider hydros for the cross bike, even though I swore off hydros the first time a system developed a leak on my old MTB. I’m no engineer so I don’t know why there’s such a difference, but no doubt smarter folks could explain it.

Yeah, I was similarly surprised at the performance, compared to BB7s on my MTB, when I switched my ‘cross bike from mini-v to mechanical disc. The TRP Mini-V that I had probably did just as good a job of stopping — as long as it was dry. I started with [road] BB7s; they were pretty lackluster. I upgraded to Spyres which were maybe a bit better, but mainly I preferred the way Spyres have dual caliper (i.e. adjust with barrel adjuster).

I think a lot of the difference is the shorter cable pull on road bikes. I’ve certainly run the same cables & housing as on the MTB, but behavior was quite a bit worse.

But, yeah, once I upgraded my commuter to hydro, I really disliked riding my road bike (with Spyres). So I eventually upgraded that one too.

You might want to check ebay for Hy/Rd calipers. I noticed one set that just sold for $80 which isn’t bad at all. People say those offer a nice upgrade to mechanical calipers — obviously w/o needing new levers. (But probably not quite as good as full hydro.)

[huskerdont]

@Judd 160685 wrote:

I found some guys that can explain it:

https://youtu.be/_-agl0pOQfs

Magic. Miracles. That’s your explanation to everything!

(I was listening to Miles Davis before I clicked on that link, btw, so thanks for the v. odd transition.)

[huskerdont]

@hozn 160687 wrote:

Yeah, I was similarly surprised at the performance, compared to BB7s on my MTB, when I switched my ‘cross bike from mini-v to mechanical disc. The TRP Mini-V that I had probably did just as good a job of stopping — as long as it was dry. I started with [road] BB7s; they were pretty lackluster. I upgraded to Spyres which were maybe a bit better, but mainly I preferred the way Spyres have dual caliper (i.e. adjust with barrel adjuster).

I think a lot of the difference is the shorter cable pull on road bikes. I’ve certainly run the same cables & housing as on the MTB, but behavior was quite a bit worse.

But, yeah, once I upgraded my commuter to hydro, I really disliked riding my road bike (with Spyres). So I eventually upgraded that one too.

You might want to check ebay for Hy/Rd calipers. I noticed one set that just sold for $80 which isn’t bad at all. People say those offer a nice upgrade to mechanical calipers — obviously w/o needing new levers. (But probably not quite as good as full hydro.)

I had a bit of a brain freeze and confused two of my bikes. The CX bike still has the lousy Promax brakes, so when I upgrade that one, I probably will do either hyros or the Hy/Rd you suggest. (It’s my rain bike that I upgraded to Spyres. They actually work well enough that I won’t re-upgrade them. It’s just that if I don’t keep them adjusted, sometimes I need to augment the rear brake with the front, especially when wet. Not really a problem, but a touch disappointing compared to the BB7s on the MTB.)

[vvill]

@hozn 160687 wrote:

Yeah, I was similarly surprised at the performance, compared to BB7s on my MTB, when I switched my ‘cross bike from mini-v to mechanical disc. The TRP Mini-V that I had probably did just as good a job of stopping — as long as it was dry. I started with [road] BB7s; they were pretty lackluster.

Agree with both you and huskerdont’s experiences there. My first experience installing my own disc brakes was BB7s on a 26″ MTB and it worked great – especially when towing a kid around. My first time trying stock mech. discs on a CX bike was underwhelming to say the least – I upgraded them to road BB7s upon purchase. I also had mini-Vs at the time, on a different bike, for reference. They certainly stopped well in all conditions, but I did accidentally lock up my rear wheel a few times, and in really cold and/or long descents (specifically, I remember a Cap CX race and a couple of HBR descents) my hands + fingers were too sore/tired to use them as effectively as I would’ve liked – in hindsight, I’m sure hydros would have been nicer. Especially for one of the HBR descents (I crashed). The shorter cable pull makes sense as an explanation.

I’m happy enough to ride rim brakes in non-wet weather situations but now with 3 hydro equipped bikes in the fleet, I don’t see myself ever making another rim-brake based purchase. And I tend to gravitate towards the hydro equipped bikes when choosing what to ride.

[EasyRider]

Another thing that I’m curious about re: disc brakes is the perception of stopping power, and actual stopping power. For example, remember the first time you used V-brakes instead of cantilevers or sidepulls? I do. It was in 2003, on my new Giant Yukon. At least in dry conditions, for the first few weeks, I was very conscious of how easy it would be to lock up the wheel without much hand effort. In that case, there was indeed more stopping power compared to the rim brakes I’d been using.

But, I’m kinda skeptical that my mechanical disc brakes will be more powerful than my rim brakes, if only because the innards of a disc caliper are unknown to me. They are both cable-actuated, but a disc brake forms a shorter lever than does the rim brake, so as I understand it, a disc caliper has gotta squeeze the rotor a lot harder than a rim brake has to squeeze the rim in order to stop the wheel. So there’s a tradeoff there, and I’m wondering if the BB7s will FEEL more powerful than my rim brakes, but not actually be more powerful — at least in the dry conditions I mostly ride. If so, that’s OK. I’m not sure I need or should have more stopping power in dry conditions than I have already. Better brake feel, though, that’s always welcome.

Related — WHY are hydraulic disc brakes are more powerful than mechanicals? Maybe vicegrip or hozn can summarize?

[vvill]

@EasyRider 160695 wrote:

Related — WHY are hydraulic disc brakes are more powerful than mechanicals? Maybe vicegrip or hozn can summarize?

I don’t feel like mech. disc brakes are more powerful than rim brakes – they’re about the same. But they are more predictable in response. Possibly they are easier to lock up too.

Hydros require less effort in terms of pulling on the brake lever, and they modulate a lot better than mech. disc brakes on drop bars. But again, not necessarily more powerful than other brakes assuming they’re well set up.

[drevil]

@EasyRider 160695 wrote:

Related — WHY are hydraulic disc brakes are more powerful than mechanicals? Maybe vicegrip or hozn can summarize?

Watch video from guys way smarter than me:
http://www.cyclingweekly.com/news/product-news/everything-you-need-to-know-about-disc-brakes-202130

[drevil]

@EasyRider 160695 wrote:

Related — WHY are hydraulic disc brakes are more powerful than mechanicals? Maybe vicegrip or hozn can summarize?

Smarter guys than me explain why:

[dkel]

@vvill 160699 wrote:

I don’t feel like mech. disc brakes are more powerful than rim brakes – they’re about the same. But they are more predictable in response. Possibly they are easier to lock up too.

Hydros require less effort in terms of pulling on the brake lever, and they modulate a lot better than mech. disc brakes on drop bars. But again, not necessarily more powerful than other brakes assuming they’re well set up.

My mechanical discs are not noticeably more efficient for braking than rim brakes I use. Most importantly for me, though, discs are way nicer for commuting because they require far less attention during and after riding in crappy weather: they function more consistently, last longer, and make far less mess in the wet and muck.

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