bt

boiling your hydro's on a huge decent can definitely be a life or death thing.

Or maybe you can downshift or use the Jake brake.

Bob Dopolina 

That's pretty rare.

In any case, a rim brake might not fair any better. I've blown tires off alloy rims from excessive heat from braking. Even then that's only happened twice in 30 years and thousands of km of heavy, fast descending.

I've been hit by falling rocks more often than that. In fact, I've struck wildlife more often than that.

Now if I could only hit a pheasant while baking my rotors I'd have lunch.

BigJeff

Or melting rubber pads or rim.

Avispa

Hey Bob, since you are in the business i may ask you. Why have we not seen more carbon wheelsets with evolved brake tracks? It seems Zipp is finally doing something looking at Firestrike. Xentis have been doing their thing awhile. I won't argue that carbon is not great when wet, but it seems this could be bettered.

Avispa

There are many who like Di2/ EPS. But there are also many who use it and still say that for the price difference, it is not worth it.
Keep at same groupset, Super Record EPS and mechanical, DA 9000 and DA 9070.
For the extra you put in, you could get a great wheelset. Ofcourse an electronic groupset is likely to cost more in the long term.
When you have been using your bike and the hooneymoon is over, i think a mechanical rim brake bike is less costly to own.
You need not look to bleed brakes, worry about the small motors that make your gear shiftings.
I mean, we have bike mechanics over here riding MTB, they say it is more hassle changing wheelsets using disc brakes.
A huge Scandinavian dealer brought himself a new Pinarello. He told me he does not shift any faster or better compairing mechanical to electronic. The cost was almost twice going to 9070 from 9000 and according to him, it was not worth it.
What i try to say is, you pay a lot more to buy this and you also (if not doing it yourself) might see that service and maintenance will cost more. Ofcourse everybody decide on there own, but in all honesty. Many people buy what is represented for them and if they learn this is what you should have, they buy it. Ofcourse marketing is demanding that UCI allows disc brakes and electronic. Many people just want what pro uses. Looking at weight weenies ideal components and bikes, you are getting more and more away from it when you introduce disc.
You need the bike to be reinforced and it will gain weight and it will also end up with drag that is almost double of rim brakes.
Just imagine for awhile that brake tracks on carbon rims were redesigned for better wet braking. Better heat dissipation and i think we could have a strong contender to disc brakes in all weather and all climates. We need to see that it is money behind all this. I have never said that it is not about money selling bikes. But if you look at two things here. Drag numbers and weight. It is just wrong direction. You can't possibly say that disc brakes won't demand more maintenance. Also, if you look at the latest super bike frames, they are very skinny at the seat stays and end of chainstays. This is won't work with disc brakes. The extremely light forks and now lately, they become more drop shaped, you can't have this when you use disc brakes. What i try to say that in many ways we have evolved design in frames and now all of a sudden, with disc brakes, this will not work. I have used disc brakes on a race hybrid and that worked well, but we talk much more weight here also.
I truely get it, this requires an all new bike and it is about money.

bt

disc brakes are coming and you'll like it!

good day to you sir!


I SAID GOOD DAY!

UnfilteredDregs

What a giant load of strawman BS.

What ISN'T SIMPLE about a disc brake? You have a remotely actuated caliber and braking surface. Just like a RIM brake. Except it's a discrete system that is far more impervious to the rigors of the road. That is succinct improvement.

I don't want to hear the nonsense regarding weight and aerodynamics... Rim brakes have reached their apex design wise and disc brakes are only beginning to become mature for road bikes. With the advent of simple self adjusting hydro systems the feel is sublime versus any cable actuated system. Hydraulics have been around since the founding of Mesopotamian civilization. Complaining about hydraulics is as ridiculous as complaining about lubrication, ball bearings, etc..

Brake track "treatments" is the typical making a silk purse out of a sow's ear scenario. Brake tracks are ridiculous simply because they immediately impose a limited lifetime upon the wheel. Take away the brake track and a well built wheel, one of the most expensive components of a bike, has a far greater lifespan. Rim brakes have been a limiting factor in wheel development for quite some time simply because of the compromises employed in order to accommodate such primitive nonsense. It makes perfect sense to separate the braking mechanism from the rim.

Self adjusting electronic shifting will be a far more elegant a solution in the long run versus all the voodoo imposed by stretch associated with mechanical cable systems and the nonsense we know as friction. I'm adjusting my shifting every 3 weeks or so because of physical variables, it doesn't bother me but it is a fact and a great many people don't want to dig into the mechanical side of the picture, they just want to ride.

Nothing is overcomplicated here.

In the end you'll have a far simpler machine in terms of maintenance requiring less downtime for adjustments, etc.. and more time to ride.

bt

wow!

Bob Dopolina 

What do you mean by evolved!

Manufacturers have been working with resins that have higher transition temps for a while now. Brake pad manufacturers have also been working on reducing temps while increasing braking performance.

Claims from various brands vary and some seem unrealistic but progress has been made. It may be possible to use resigns that would eliminate the issue entirely but then it becomes about cost. Considering the fact that all the carbon used by the entire industry is equal to an airbus or two and scale becomes a factor.

Bacciagalupe

Avispa, I'm not really finding your argument all that persuasive.

Electronic shifting generally requires less maintenance than mechanical, as you don't need to adjust the derailleurs, and the cables are less fussy. I find it hard to believe that it's harder to plug in a battery once a month compared to the upkeep required by mechanical drivetrains.

For disc, we've already seen MTB almost completely switch to hydraulic disc. For example, Trek sells 98 models of mountain bikes. 16 models use linear pull brakes, 4 use mechanical disc, and 76 use hydraulic disc. Why would this be the case, if disc was such an utter nightmare to maintain? I.e. yes, I can seriously tell you that disc brakes don't require more maintenance, and that people are recognizing the benefits of this (relatively) new technology.

As to carbon rims, manufacturers have been doing lots of R&D, and coming up short. There's only so much they can do about physics and the nature of the materials. I for one don't think disc will ever be as aerodynamic as rim brakes. However, there's lots of situations where aerodynamics take a back seat, and one of those is wet or muddy conditions, cobbles, or rough roads.

Again: It is screamingly obvious that bike manufacturers are not waiting for the UCI, and most bike purchasers don't give a crap about the UCI. Most of them have no clue what the UCI is in the first place. Even among that group, if you live in the Pacific Northwest where it rains frequently, odds are you're going to want a brake system that is more reliable and consistent in that environment. If the UCI banned discs forever and ever, manufacturers will still offer them as long as people want to buy them.

As to the idea that it is "all about money," I find such borderline-conspiracy thinking to be a bit absurd. If you buy a Trek MTB, and the brakes need more frequent maintenance, how does Trek profit? They don't. The brakes are mostly made by other companies (Avid, TRP, Tektro, Hayes etc) and the service is done largely by independent bike shops. Trek doesn't see one thin dime from any extra maintenance, in fact they'd get a bad rep for selling unreliable equipment.

More importantly, it is ultimately the customers who are in charge. Competition is intense, and no company wields enough market power to force consumers to buy things they don't want to buy.

Schwinn, for example, was the biggest bike brand in the US in the 70s, but failed to keep up with the popularity of MTB bikes in the late 70s and early 80s. Smaller bike companies exploited the opportunity, not by shoving MTB's down anyone's throats, but by offering what people wanted. There were other factors that led to the demise of Schwinn, but missing out on the MTB was certainly a factor.

No one can afford to shove unwanted products down the throats of consumers. No one wants to be a Schwinn. No one benefits by selling inferior equipment.

grolby

Even with brake track treatments, there's still the fundamental physical problem of carbon fiber rims having a much higher heat capacity than aluminum or steel, and that leads to problems with heat management. Despite the scare stories about boiling hydraulic fluid, this is essentially a solved problem for road discs - they test these things by dragging brakes down the Stelvio, for crying out loud. The most common type of heat-related brake failure is boring old brake fade, i.e. glazed pads, and rim brakes are much more vulnerable to this than discs. Especially with CF rims, where there's simply nowhere for the heat to go but into the pads. There's a lot more room to design heat management into a disc system than a rim caliper system, and when things do get too hot it's still safer because you at least don't have to worry about blowing a tube from overheating.

There's obviously no need to run out and switch to discs tomorrow, so the sowing of fear via extreme technical ignorance is not just obnoxious, it's totally uncalled for. It's absolutely true that there are many people who will have no need for disc brakes. It turns out that they're under no obligation to buy them.

Bob Dopolina 

Yeah, I'm not sure who you're addressing here. I completely agree. I mean we are the folks selling disc specific carbon rims so I think we are committed to the idea.

grolby

Nailed it, Baccialupe. The complaints that hydraulic discs are too "fussy" and "high-maintenance" are among the most infuriating, as they can only be uttered by someone who has no actual knowledge of hydraulic discs or how they work. Hydros require one specialized maintenance task, which of course is bleeding the brake fluid. It's specialized mostly in that it requires specific tools (what else is new) and fluid. Bleeding needs to be performed, under typical conditions, once or twice annually. Beyond that and of course the initial setup, hydraulic brakes require practically no maintenance at all. The pads are even self-adjusting. Hydraulic disc brakes didn't take over in MTB only because they are more powerful, though of course they are, but also because they are easier to live with and require much less periodic maintenance than either cable discs or linear pull brakes.

grolby

To be clear: I was expressing agreement with you. I'm addressing your critic, Avispa.

woodcraft

From riding my mtn bike, I have actual knowledge of hydraulic disk brakes, & I understand how they work. I find them fussy & high maintenance.

Worth it for stopping power and allowing less rim trueness, but easier to live with & less maintenance? Not.

- Noisy
- Pads wear quickly in wet/dirty.
- Pads expensive
- Bleeding $ at LBS

IME, compared to rim brakes, replace pads 2x as often (or more) at 2x cost, adjust (bleed) 2x as often- either w/ special kit & technical instructions, or at cost/ time at LBS.

Not hating on hydraulics, but let's don't pretend that a more complex technology is simpler.

cruiserhead

What are you running?
I have no problem with hydro XTR
and pads are no more expensive than rim brake pads
bleeding is easily done at home

I agree hydros take more aptitude to maintain but they are simple.

Disc brakes don't have to be hydro either.
THere are plenty of good cable disc brakes and currently equiped as such on many road/urban bikes.

It's easy to get trapped into an all or nothing argument, but that's not reality.
Even with this relatively new road tech, there are choices.

woodcraft

Shimano XT. Also have & have had mech disks.

Just countering the idea that
"they are easier to live with and require much less periodic maintenance than either cable discs or linear pull brakes."

dalava

I can see you've been in Taiwan for too long

bt

lol

Avispa

Now we have two views of the matter. Fine by me.

grolby

Ah. So you think that boiling hydraulic fluid happens more often than glazing brake pads? Ok.

Avispa

Exactly my point!
A rim brake works directly on the rim and the attached tyre; a disc brake applies a potentially large torque moment at the hub. The latter has two main disadvantages:

1. The torque moment must be transmitted to the tyre through the wheel components: flanges, spokes, nipples, and rim spoke bed. Engineering for this moment inevitably leads to a heavier wheel.
2. A front disc brake places a bending moment on the fork between the caliper anchor points and the tip of the dropout. In order to counter this moment and to support the anchor points and weight of the caliper, the fork must be thicker and heavier.

The heavier fork and wheels compound the weight disadvantage of the brake assembly itself.
Disc brakes are sensitive to lateral play or "slop", so careful manufacture and adjustment is required. Hub bearing wear is an issue with disc brakes.

Electronic derailleur servo motors may be great, but my consideration was/ is that they're still motors and what cost is there to repair these if something happens.
All i am really trying to say is, you offset weight savings and implement more things that will be prone to cost money.
What is it to argue about really?

I just read that we need more bicycle mechanics that has education as bike are becoming more advanced. Hell, my buddies at work told me, why don't you look for such a job. People can argue back and forth and i did really not intend to argue. All ofcourse invest in what they want. Yes i agree that brake systems like discs may have more benefit in some climates.
I personally want a bike to be light and simple, but some may want the electronics and discs, which is OK by me.
I know the bike store work shop earn more on these clients than me.

Bob Dopolina 

^^^ Your data regarding weights is out of date. Look at ALL the new disc brake road bike being offered by every major bike manufacturer on the planet and get back to us.

Willbird

Most of my disk brake experience is with cars and motorcycles, but bicycles too enjoy a long life in the hands of users, and hydraulic disk brakes when they get some years on them have some problems that can be a pita to figure out.
The people who get paid to work on them will no doubt learn the ins and outs of making a 20 year old brake caliper work again just like I did the one on my 1972 honda 750 :-).....there are some nuances to the system that are not self explanatory :-)......one being the engineered extra width to the seal groove .....that can fill up with "stuff" in 10 years of use.....new seals will not fix the situation of the piston not retracting, only mecanically removing the "stuff" so the seal can move in the groove as intended makes it work right again :-).

my new road bike I'm getting in 2 weeks has mechanical disks.....which seem simpler than hydraulics :-)

Bob Dopolina 

I don't understand this idea that somehow hydro discs are new fangled and full of mystery. How many years and how many MTB have been sold with similar systems that have been ridden for hundreds of thousands hours under much harsher conditions?

If they've passed that test I am pretty confident that they will be just fine on the road.