elcruxio

I only use compressionless housign on my 29er. It doesn't work with drop bars so I use regular jagwire housing on touring bike. Won't go back to Shimano housings if i can help it.

I actually move the actuator arm just a tiny bit to get the slack off the brake cable. it doesn't affect clearance but makes the brake feel just a little bit crispier.

About the hydro and easier braking. I have to concede that hydro brakes offer a more accurate brake feel than mechanicals. But the BB7's are still so good I've seriously started questioning the importance of hydraulics in various applications in my own use. I put mech discs on my 29er for the winter season and haven't taken them off. I don't know if I will take them off. If I need more power I'll put in a larger disc but I've done quite nicely with a 180mm rotor on my 29er and 160mm rotor on my touring bike, and other pavement bikes.

mtn.cyclist

I use TRP Spyre mechanical discs on my Specialized AWOL. I went with mechanical for what I think is easier field repair and service. It's easy to change a cable or replace the pads but I don't want to be faced with fluid issues when I'm out somewhere. These brakes work very well. Powerful stopping, good feel, easy adjustment, which they don't need often. I find them less finicky than BB7's.

fietsbob

4 tourists sent their bikes ahead All LHTD, all with mechanical discs .. most with too much pad to disc adjustment looseness..

LBS takes them in and assembles them for a fee..

alan s 

I've never heard anyone say mechanicals were equal to hydros in the amount of braking power with the same hand force. Not saying it isn't true, but this has not been my experience. Hydros are far superior fin every aspect over any mechanicals I have ever tried, but I certainly haven't tried them all. It is possible older model hydros and newer model mechanicals are closer.

GeoKrpan

It used to be that hydro was not all that much better than cable but things have changed. I have some old hydro that were single piston, now they are all twin piston. Funnel bleeding really helped too. Hydro now make cable feel stone age.

djb

And as most of us have ridden using rim brakes for decades, to me anyway, mechanical being not as strong as hydros is still a moot point, as from my very limited experience with mechanical discs in a mtn bike situation, they aren't shabby.

jeff400650

I am learning a lot from this thread. But what are "compressionless housings"?

elcruxio

My hydro discs have all the bling newer shimano's have, ie. funnel bleeding, servo wave, dual piston etc. because they are in fact pretty new. 2014 model I think. BB7's are 2013 and 2015 models.

Then only brake that I've had that has been substantially more powerful than both the current Shimano hydro and avid bb7 was the legendary Magura Gustav DH brake. And that brake was old. Could have stopped a goldwing probably.

elcruxio

Jagwire for example makes a kevlar reinforced brake cable housing that uses the same technology as shifter housings. Instead of having a slightly compressive spiral steel wire on the housing reinforcement, it has wires that travel paraller with the brake cable. The kelvar keeps the housing from bursting as the force inflicted on the housing is pretty big. It makes for a crispier more accurate brake feel, and supposedly increases power. I mainly use them for looks reasons but brake performance is increased as well. Don't work with certain drop bar, brake lever and bar tape combos (a very tight wrap or very tight double wrap is a no no)

djb

I don't follow NASCAR so I don't know the tire pressure thing there, given the oval situation re braking. Ic can only relate my little experience with motorcycle racing, we'd set pressures cold 10% low to account for pressure increase when running on track, or pressures would be too high and less traction. I know this is done in most motorsport and can cause issues with restarts, because of lower pressures and temps than ideal.

elcruxio

I've broken a tube because of a too hot rim. Don't know whether it was because of too much pressure due to heat or due to the rim getting so hot as to damage the tube. I burned my fingers on the rim though.

alan s 

So is it your opinion that hydros offer no advantage over mechanicals? If so, why then so many hydros out there and mechanicals pretty much relegated to retrofits and lower end bikes?

fietsbob

You are noticing what you want to see , and ignoring what you want to ignore ..

It Happens a lot in that most Political of US Cities. you have been well Trained..

elcruxio

Nice strawman there. It's easy to beat an argument you made up yourself.

What I'll say is that hydraulics offer some definite advantages to mech discs. But for me those advantages are not really that relevant for touring context.

BB7's and shimano servo wave hydro's offer almost the same power. The shimano's are more precise and naturally have less lever drag (because fluid you know) but are also not nearly as reliable.

Self adjusting pads are nice but considering I do daily checkups on our bikes on tour it's a nonissue. And having to check the brakes frequently also tells me about pad wear, which might otherwise be forgotten.

Since I moved away from quick releases noise has stopped being an issue. Hydro's and mechanics make the same amount of noise on my bikes and only when wet/cold. After a quick drag they're quite and purring again.

In tour context however the maintenance of a mech disc is much easier as pad contamination isn't nearly as big of an issue (I've had the caliper leak oil on the pads from three manufacturers), catastrophic failure is easier to fix with basic spare parts one usually carries (spare cable and zip ties) while with hydro's you just can't do anything with even a relatively minor issue. And if there is an issue, like a leak, or sudden air in line etc. you'll likely have a very big unfixable problem in time. Or you can fix it by swapping a caliper or lever or the whole system.

So in my opinion and for me in touring context the slightly better performance and self adjusting pads is not nearly worth the myriad of risks hydraulics have

350htrr

If hydraulic brake systems are so risky and prone to failure, why do basically "all" motorbikes, cars and pickups have them...?

alan s 

Because motor vehicle brakes can be fixed virtually anywhere, whereas fixing your hydraulic bicycle brakes simply cannot be done.

gattm99

That I think is a good point. How powerful, smooth, and awesome your brakes are is nice, but it's a marginal thing. Sure hydros are better, in my opinion the fact that hydraulic hoses offer static performance for years and years, while cables need to be replaced, is their real benefit.

In response to those who seem skeptical of disc brake overheating I can tell you this. It was very freighting because it was like nothing I've experienced on a bike. I've rode a few mountains and I've experienced brake fade on rim brakes while dragging the brake, mainly just to explore the limits. On rim brakes there was a gradual loss of power and a fairly quick return to power after releasing the brake. Even when hot there was still some stopping power. On my discs there was an almost immediate loss of power accompanied by the smell of burnt material and smoke coming from the front calliper. The brake had almost no affect on the bike's speed. I released the front brake and pulsed the rear which was effective to keep speed down but I was still going to fast. WHen I pulled the front again it had cooled enough to work.

This was with Magura Julies and stock rotors with a 250 guy on a Trek Liquid so I was asking alot of the brakes, but if your touring with a load then you may be too. Maybe this isn't a concern with newer rotors or pads with heat sinks?

elcruxio

It's still a slightly different system. Like I've said before bicycle hydro discs are still in the toy category. They are for the most part not as reliable as car hydro brakes. Or when have you last heard of car brakes simply not functioning due to cold weather? Have you ever heard of an epidemic of absolutely non functional car brakes due to slight cold? I haven't but every winter our local forums fill up with discussions about how to make hydro brakes work in cold. And then there's the obligatory threads for hydro disc issues in general as in normal conditions. No such threads for mech discs...

There is one hydro system I might consider for touring. Hope brake with steel braided hose, but you can't get that for drop bars.

elcruxio

Anywhere you get a shop. No shop, no fix. Same with bicycles. But in the context of bicycle touring the next bike shop doing hydro brakes might be a lot farther away than your average auto shop which are usually everywhere.

Also to expand on that, there simply are no parts for hydro brakes, except for full calipers, full levers and full systems. Rebuild kits are exceedingly rare if they're even made and to think you'd find one from the first shop you limp to.... come on... it's difficult to get those when shopping online.
Hope makes a rebuild kit, but that's the only manufacturer I know of that does. Shimano definitely does not so if a part, seal, piston or anything function critical is damaged even slightly the whole caliper/lever needs to be swapped.

350htrr

My Grimeca hydraulic brakes didn't need any "fixing" for the whole 16 years I have had them... Just like all my cars..

350htrr

DOT 3 or 4 brake fluid is what my Grimeca hydraulic brake system uses. Like I said before, 16 years and never a fix needed...

djb

And despite all this, in a touring application, a bit better really isn't an issue or concern weighed against the possible issues brought up. Or we can just look at it from this point of view, use what you want and balance the various details for the areas you will tour in.
And I'm sorry, but despite all this talk, we are not talking racing on a circuit here, we're taking touring, and even in exceptional situations (hairpin descent that goes on for 10 20kms) rim brakes are adequate if you use common sense.
And for all the posturing, how quickly you can get down a real technical downhill will depend much more on your descending, cornering and judgement skills--not to mention how comfortable you are going fast. One person's mental is another person's cruising comfortably....

str

great stuff here, cool.

DropBarFan

Don't motor vehicle brakes have redundancy safety features? Also, some types of racing cars (like short-track) can suffer from "soft pedal" when brake fluid gets bubbles or whatnot. NASCAR racers used to get that fairly often though it seems less common now.

djb

soft pedal, long pedal, spongey feel--can happen in your road car, or a motorcycle , you just need to overwork the braking system and the hydraulic fluid gets too hot. I imagine with mech discs you end up toasting the pads and or the rotor and glazing it, or simply cooking the pad material, just like with a rim brake pad.