Disc road bikes - your opinion

Discussion in 'Road Cycling' started by AyeYo, May 2, 2014.

  1. AyeYo

    AyeYo Member

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    This seems to be the trend in 2014 and will likely gather steam going foward. Personally, I just don't see the point. Here's how I see it...

    Pros:

    - Better all weather stopping (machined surface rim brakes already work just fine in the rain and I don't ride my road bike in the mud, i.e. nearly useless benefit)

    - Better modulation



    Cons:

    - Heavier

    - Heavier wheels needed

    - Heavier fork needed

    - Very limited rim options

    - More complex/more hassle

    - More expensive

    - Less aero

    - Lack of standardization

    - Heat dissipation on long decents is questionable

    - Hard to avoid drag when used with QR



    Am I missing something? Looks like a very high price to pay for better brake modulation. It's a bike, not a car - laser precise brake modulation doesn't seem to be important enough to offset all the negatives. Yet in spite of this, it appears we will have discs whether we want discs or not.

    Anyone disagree? If so, how do you see the cost/benefit playing out?
     
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  2. CAMPYBOB

    CAMPYBOB Well-Known Member

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    Maybe Campy will integrate an anti-lock braking system into the EPS system. shimaNO counters with carbon-carbon-ceramic rotors. SRAM engineers come up with a Power Dome conical drum with twin leading shoe technology.

    I doubt there will be any better compatibility with disc setups than current BB's, cassettes, seatpost diameters, headset types, spoke length, etc.

    It's interesting technology, but I'll let others do the Beta testing.
     
  3. OldTimer79

    OldTimer79 New Member

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    When I bought my Trek 7.3 last year I test rode the disk brake version too. Didn't seem I stop any better and the disk brakes seemed a lot noisier. So I bought the 7.3 with regular brakes.
     
  4. Volnix

    Volnix Well-Known Member

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    For a commuter sure...
     
  5. new_rider

    new_rider New Member

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    So many faux upgrades in the industry. Noisy, poor braking ultra expensive carbon wheels, heavy disc brakes with a gazillion cons, battery powered shifters, compact double cranks.

    So many "solutions" for problems that never existed.
     
  6. AyeYo

    AyeYo Member

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    Hey now, don't throw compact cranks on that list. Some of us less fortunate (read: no cycling ability) need them to go up anything more than an ant hill. I recently went from 12-30 to a 12-27 on a compact and just did a ride with 6,200ft of climbing yesterday, now I'm trying to remember why I switched from the 12-30. Talk about granny gearing. Otherwise I agree with you though. I think that stuff is all about getting people to buy more stuff they don't actually need. There's minuscule value in some of it, but I think the marketing departments are doing 98% of the selling, not the performance numbers.
     
  7. maydog

    maydog Well-Known Member

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    I have a mechanical disc brake cross bike and I am happy with it. Here are the advantages as I see it:

    1. Brakes work consistently in all weather. Calipers, cantilevers and the like can cake with ice and snow becoming useless. Sand can stick to pads in the rain and make a nice abrasive for those expensive rims.
    2. Much better modulation and braking on long mountain descents.
    3. No finicky pad installation issues
    4. Much longer pad wear
    5. Doesn't wear away the rim
    6. Easy wheel removal
    7. No brake rub when stomping hard on the cranks
    8. Not affected by wheel trueness

    I'd argue against disc brakes being complex. Their operation is simple, on par with calipers. Also why would rim options be limited? Discs depend only on the hub. Finally, I think that standards for discs are pretty well established.

    I like having options

    They are a good choice for a mountain, cross, commuter, rain or winter bike. If I lived near mountains, I would be happy to have a disc equipped road bike. Stopping or even slowing 100+kgs on a long downhill is a lot to ask for some rubber pads.

    For typical sport road riding, traditional calipers are currently a more elegant solution.

    wikipedia has a suprising lengthly discussion of bicycle brake systems:

    http://en.wikipedia.org/wiki/Bicycle_brake#Disc_brakes
     
  8. Volnix

    Volnix Well-Known Member

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    They say that quick release and disc brakes dont mix very well...


    From:

    http://sheldonbrown.com/disc-brakes.html

    Quote:
    • A front disc brake caliper behind the fork blade generates a powerful force tending to loosen a quick release and pull the wheel out of the fork. Special hub and fork designs are needed to surmount this problem.



    Was that ever true and caused alterations to the design? Or was it never true?
     
  9. new_rider

    new_rider New Member

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    This is a pretty weak list of pro's.

    About 90% of the perceived disadvantage of rim brakes is due to the quality of the PAD. Get some higher quality pads such as kool stops or aztecs (usually at a miniscule $20 for 2 pair front and rear) and the power and modulation improve exponentially over standard generic brands such as tektro.

    1. I generally don't ride in the rain, so I can't answer that question. Disc brakes would not encourage me to ride in the rain, either.

    SHOULD you be riding in the rain? If you think that disc brakes will stop just as well in the wet as in the dry, it may encourage you to ride faster. If you ride faster, you may compromise your safety.

    Disc brakes may stop better but it may ironically encourage you to ride in a more dangerous manner. Not a very good trade-off in my opinion.

    2. I've ridden 50 mph on road descents and never had a problem with modulation or braking power with dual pivots with standard pads, on less than ideal stock matrix rims.

    3. Setting up pads on disc brakes can be just as 'finicky' as rim pad installation, which itself I don't find to be very complex or finicky.

    4. I've used soft rim brake pads for years and years and years with little wear to the pad or rim.

    5. See 4 above.

    6. If you think removing a wheel from a frame with rim pads is 'difficult,' you have no business riding a bike.

    7. Seriously?

    8. I rode a bike with a slight warp in the front wheel -- braking power was still very good. Plus, there are these things called truing stands....

    ---

    How about the CONS of discs?

    1. add a FULL POUND of weight to your ride. That uber light 15.5 lb road bike is now a pedestrian 16.5 lbs. You spent $5K more to shave 1 lb. off the frame? Money wasted with disc brakes.

    2. are DANGEROUS if you crash (feel like getting sliced with a ginzu knife?--avoid disc brakes pal)

    3. FAR MORE expensive.

    4. offer little advantage in dry conditions, which account for the vast majority of rides

    5. IMO esthetically ugly: rim brakes are small, and neatly tucked away. Disc brakes especially on a road bike scream: POSER!

    6. Pro riders, who ride 2 to 3X as fast as recreational riders, reject them in unison. Surely, the "additional control" would serve riders who regularly ride 28 mph in a pack would not be lost on such riders?
    Oh wait, rim brakes work extremely well already.


    tl: dr, get some kool stop pads. Save a TON of money and weight.
     
  10. AyeYo

    AyeYo Member

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    This I don't find surprising. In the messy world of cross racing, it's no surprise that disc brakes are common. The same goes for MTBs.

    However, I'd also like to address a few specific points...

    Quote: 1. Brakes work consistently in all weather. Calipers, cantilevers and the like can cake with ice and snow becoming useless. Sand can stick to pads in the rain and make a nice abrasive for those expensive rims.

    I don't see this applying to road bikes, especially race bikes. No one in their right mind is out on a $5,000 road bike in the snow or ice. Road sand is definitely an issue, but some pads like Kool Stops have wiper areas to help that, plus, again, who is taking a road bike with expensive rims out in the rain often enough to justify all the cons?


    Quote: 6. Easy wheel removal

    I don't see how it's any easier than a rim brake. Most decent quality rim brakes have some method of quick release. My 105 brakes are as simple as rotating a knob 1/4 turn and the wheel is free.

    However, the real issue is wheel installation. With the rim brakes, I just crank the QR down, rotate that level back into position I'm good to go. On my 8.4DS with hyrdo discs, I put the QR on, spend five minutes dicking around with it trying to get the disc centered properly, then end up busting out the multi tool to loosen the caliper and recenter it over the disc... EVERY time I have to the put the wheel on (which is EVERY time I ride because I have to take the wheel off the get the bike in my car). It never fails that no matter how hard I crank it down, if I stomp the brakes hard enough, the caliper and/or QR axle will shift just enough to start rubbing again - time to get back off the bike and readjust. Long story short - rim brake equiped road bike is out of the car and ready to go in <10 seconds and I never worry about the brakes again. Disc brake equiped hybrid bike takes five minutes to get situated and needs to be readjusted damn near every time I stop. This is a known issue with discs and QRs. Want to avoid it? Now you need through axles... more weight, cost, and complexity to fix something that isn't broken. Worth it on a MTB or CX bike, not worth it on a road bike.


    Quote: 7. No brake rub when stomping hard on the cranks

    Not sure that I've noticed this before, I'll have to pay better attention next time. I don't think my wheels are that noodley though.



    Quote: 8. Not affected by wheel trueness

    True, but why would you be riding on a bent rim to begin with? Also, let's not forget that they ARE effected by rotor trueness. In fact, just last night my friend dinged her rotor taking her CX bike out of the car, which was enough to bend it slightly. I had to spend five minutes trying to bend it straight (enough) by hand so that it wasn't seizing when going through the caliper. A rotor is a lot easier to accidently bend than a rim, especially during transport and handling. Better hope you're strong enough to rebend it by hand or that's going to be one difficult (or brake-less) ride.
     
  11. maydog

    maydog Well-Known Member

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    Apparently you guys haven't read my full post - I said that road brakes are a more elegant solution for sport road riding.

    I like having options - if the manufacturers want to offer and improve disc brake technology, I am all for it.

    I have done mountain descents with a good 20 minutes on the brakes still averaging 40+ mph on calipers it was a scary experience. Similar descents on using discs were alot less dramatic. Needing to control the speed of a combined mass of 110+ kgs down a 10% grade, my preference is for discs. Lighter folk get more braking benefit from the wind and need to dissipate a lot less energy so it may be a non-issue for them and a non-issue for 99% of the riding I do.

    I purchased my cross bike of ebay in really rough shape. The front rim was fubar, I trued it up the best I could and am still riding it after a couple of seasons. The true is still not perfect, but it does not matter since if have discs.

    People may not take their $5K road bike out in the snow or ice, but I used to regularly take my $500 bike out. I'd ride a entry level or intermediate road bike with discs as a daily driver, commuter, rain, group ride - do everything bike.
     
  12. new_rider

    new_rider New Member

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    What is sport road riding? I've never heard of the term.

    ---

    What type of calipers were you using and what pads? There are major differences in single pivot vs dual pivot vs center pull, at different price ranges and of course the quality of PADS makes an enormous difference.

    ---

    I've used 105 dual pivots with stock pads on house brand trek matrix rims on 50 mph descents and felt very confident in my braking.

    I've even ridden 35+ mph on a crappy bike with steel rims. I felt perfectly secure using calipers on descents.

    There's a good chance that your braking technique was poor to non-existent. And that's a major problem with a lot of cyclists. They have poor technique and rely on their technology to bail them out when they make stupid decisions.

    Standard calipers with quality pads can modulate VERY WELL and of course can lock up your wheels instantly if you try. The rest of the equation is the rider: do you tuck your weight backwards on descents? Do you scrub speed periodically so that you are in control? Do you have good technique when cutting through corners?

    I cannot refute your subjective state of mind, but rim brakes with the ability to lock up wheels instantly have more than adequate power and have a very linear modulation feel when adjusted properly, and are equipped with high quality pads.

    ---

    As I said before, my front rim was dented and damaged within the first few weeks of ownership and could not be perfectly trued. Braking performance was still very good: not much different than when the rim was undamaged.

    A $500 bike if spec'ed with discs, is going to be spec'ed with crappy disc brakes. Simple as that. You might as well save the money and weight and get rim brakes. Spend an extra 20 on kool stops and have equivalent performance on a lighter, less expensive bike.


    Also, you can ride a bike with rim brakes in the ice or snow, but you'll be far more likely to ride more slowly and cautiously and therefore MORE SAFELY with rim brakes.

    Extra braking power is only more important if you insist on riding faster. An insistence upon speed in the snow or rain increases the odds of an accident where traction and visibility are often severely compromised.

    Then again, there's always some knucklehead who insists on beating the red light or crossing those train tracks before the warning light....
     
  13. AyeYo

    AyeYo Member

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    Have there been any actual tests done to compare the heat dissipation ability of rim brakes on aluminum rims vs. disc brakes? I'd be interested in seeing that. While rim brakes have to deal with the tire heating issue, a rim has an astronomtically larger amount of mass to absorb and dissipate heat than a tiny, thin rotor. I'd be willing the bet the maximum temperatures are far, far higher for disc brakes. The tiny rotor is also then dumping that huge amount of heat into the hub and fork.

    I think one of the common misperceptions about braking ability (and this holds very true in the automotive world) is that it's limited by the brakes. Any brake system powerful enough to lock the wheels cannot be improved upon for single stop braking ability. Braking distance in a car is limited solely by tire grip, and in the case of a bicycle, by weight transfer and the point at which you go flying over the handlebars. What can be improved upon is heat dissipation, which will help in maintaining that braking ability in subsequent stops - which brings us back to my above question. Even in 50mph descents, I've never felt that my rim brakes couldn't have locked the wheels if I really wanted them to. So when I read articles talking about how discs are going to improve stopping distances or how rim brakes and disc brakes can't race together because of different stopping distances, I can't help but laugh.

    One area discs certainly could help is with horrible braking carbon rims... but then have you negated the aero advantage of the rim?
     
  14. CAMPYBOB

    CAMPYBOB Well-Known Member

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    Quote by Maydog:
    "I like having options - if the manufacturers want to offer and improve disc brake technology, I am all for it."

    Same here. A good option IMO. I won't be their Beta tester, though.

    shimaNO, SRAM and Magura had to recall product. Think I'm jumping all over that sweet 1000 gram disc-compatible carbon frame and matching fork? No way in hell. Not yet.

    When the cracking carbon stops and the brakes stop getting CPSC tickets I'll look into them for road use. The technology behind discs is awesome and I think we'll all be on them...eventually.
     
  15. maydog

    maydog Well-Known Member

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    Cycling, also called bicycling or biking, is the use of bicycles for transport, recreation, or for sport.[1] (wikipedia)
    Sport cycling or cycling for sport would be the latter of the three. It is typically characterized by competition against another or a timed event.

    Am I being insulted because I claim that one brake technology offers some advantages to another? The is plenty of literature that says the same and the manufacturers are placing their stake in the technology. If I had poor braking technique, I would have needed to be airlifted off of that mountain.

    If the switch to disc brakes makes the manufactured have to beef up their forks and frames - good. I am pretty beefy myself and stronger components will benefit me more than my flyweight cycling partners.

    I have good pads and well adjusted brakes, underway I can neither lock up my wheels using calipers nor the mechanical disc brakes. The sliding friction of a tire is proportional to the coefficient of friction and the force normal to the interface (the weight over the wheel). The force from the braking system is constant; it does not increase for a larger load. A lighter rider may be able to skid on a given surface, but a heavier rider may not. Think about it, what has more friction a rubber tire on clean dry asphalt with 100 pounds of force between them or smooth rubber and smooth aluminium with whatever force the cable or lever will support. If your brake pads are lasting years and years - they are not working very hard are they? I go through a few sets of brake pads a year.

    As an experienced winter road rider, I always want the option to have braking power. Going downhill on an slippery slope is not the place you want to find out that you have no means of controlling your speed. Pro riders have to slog through Ice and snow sometimes.

    I was asked to provide my opinion and experience which I did and now I am bashed for it? I have no need to justify my experience or engage in name calling. It is sufficient to say that people who design, bicycles for a living, for a paycheck, people with engineering and scientific backgrounds see a future with the technology.

    Maybe they will read this thread or you can write them a letter to convince them otherwise.
     
  16. danfoz

    danfoz Well-Known Member

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    Since you've already offered the opinion that bike racing is stupid, we can assume that you don't race or tt. It's an odd sentiment however to knock riding fast under adverse conditions and then brag about 50mph descents. If you approached the topic of cycling in general with an open mind, maybe you'd gather that suggesting another riders component choice being unnecessary based on your needs is about as folly ridden as them suggesting your equipment should be based on their needs.

    One example... one problem compact cranks can alleviate is a smaller jump between gears when needing shorter (lower) gearing. I.e if a course offers a section with a significant grade but enough flat section where a rider may miss out on having an 18, between their 17 and 19, especially if that rider prefers the shorter jump between low gears on a 23t or 25t vs. a 27t cassette because that riders optimal cadence at or close to redline is more efficiently served in a certain ratio, a compact may offer the solution.

    Another... if an elite rider is competing in a time trial against other well equipped riders, deep section carbon wheels may offer an advantage over similarly profiled alloy rims which if going much beyond 50mm deep may become a liability over a course with steep gradients and switchbacks. Probably not an issue for weekend warriors or competitors in the lower tiers, but as a rider advances, the delta in fitness decreases and equipment choices start to matter more. Your needs/wants vs. their needs/wants.

    One more... electronic shifting. This one would escape a non-competitor completely as the biggest benefit to having a low torque shifting option (an electronic button) which minimizes handlebar input during a field sprint at 37mph, and available in an alternate location (like on the drops), increases both safety and efficiency. Your needs/wants, theirs...

    All the above... products of bike racing, and a free market. Your adequate 105's? Trickle down from race technology and a free market. Think they had 105's in Mao's China. No. That's a poor comparison, but they probably didn't have Campagnolo, Weinmann, or Mafac either. No bike racing, no free market, no way. But they had a shitload of cheap 3spds that the Commissar of Transport probably thought entirely adequate for anyone wanting to ride a bike. They didn't stop so good but that's no problem because it's entirely impossible to ride them faster than 15mph. Not a fan of bike racing, who cares. A fan of the free market? I don't really care but I'm sure glad for it. It means someone with the ingenuity to create a product, and a market for it, is limited only by their thoughts and capacity for hard work. Without European bike racing in the first three quarters of the century, then racing in America during the fourth quarter, and our collective free markets, the best we'd likely have are those crap 3speeds. Like porn drove the technology behind the high speed internet of today, bicycle racing drives the technology behind the splendid bikes we now see on the road, even those steel "10 speeds" with box section rims, downtube shifters, and single pivot brakes that many of us deem entirely adequate to ride fast on. We may not need, want, or like porn or bike racing, but we like high speed internet and nice bikes, at least folks visiting cycling forums on the internet probably do.

    Trickle down, great for bike parts, maybe not so good for economics.

    For the record, I will never ride disc brakes. For my needs calipers do just fine, plus I find them aesthetically repugnant.
     
  17. new_rider

    new_rider New Member

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    I'll have more to say later, but you are speaking of supposed, theoretical advantages of specific "technologies" which real world experience demonstrates are both completely unnecessary and often universally rejected by elite racers, unless they are forced to adopt them by sponsors.

    Remember that the top pros rejected INDEXED SHIFTING. They had no use for it. It's a bit ridiculous to say that they NEED or even WANT electronic shifting now.

    Electronic shifting has been around for oh, 20 + years. How many pros and teams adopted electronic shifting in that time? ZERO. I repeat. ZERO. It was useless.

    These are fake upgrades with serious disadvantages and minimal benefit. I still wish I could find quality mtb thumbshifters at a decent price.

    As far as offering choice, yes, I wish the industry did offer choices. I want the choice to use high quality affordable thumb shifters on my mtn bike. I can't because component manuf. don't offer them anymore. I'm stuck with trigger shifters.

    This is just the tip of the iceberg. But the notion that racers are somehow beelining to these new features or that the cycling industry offers "choice" are both notions which are flat out wrong.
     
  18. CAMPYBOB

    CAMPYBOB Well-Known Member

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    Quote by new_rider:
    "Electronic shifting has been around for oh, 20 + years."

    To be accurate, Mavic's system was never fully developed and had a horrible reputation for failing in the rain. Battery life was low and under the best conditions set up and maintenance was demanding.

    As Dan stated, higher level racers can gain an advantage from electric shifting. The cost of these systems are dropping with a Campagnolo Athena Athena EPS group now available for around $1900 (complete group). My guess is that shimaNO will easily undercut that price with the next gen Ultegra and/or 105 level group(s).
     
  19. danfoz

    danfoz Well-Known Member

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    Rain? You mean that weather condition where bicycle tough guys tread, and carbon rims refuse to stop.

    I was just thinking about another improvement which could be deemed unnecessary - clipless pedals. Sean Kelly was the last to go clipless in the pro peleton. I didn't loose my straps till 1991. The main reason behind that was I have EEE width feet and finding a new pair of cleats with drillings to fit was a PITA. Who new a little float was probably better for ones knees, and that someones pride could be spared some bruising when he keeled over at the stoplight in front of a street load pf pedestrians because he was too busy paying attention to the buxom beauty crossing at the light to remember to reach down and loosen his straps <did I just say that out loud?>. Had I been riding on my old leather straps I could have probably wrenched my foot loose and escaped, but alas I had just installed another unnecessary upgrade, new aero pedals with pretty blue nylon straps, which didn't budge a millimeter under duress. Aero savings were negligible but they sure looked fast. Their only benefit was a few more millimeters of cornering clearance. Another completely unnecessary feature, unless of course one raced criteriums and was occasionally prone to pedaling through corners.

    I will admit that I held out as long as possible in indexed shifting, probably because in the early days it wasn't all that great. If I had the $$ I'd love to build a stable of the old bikes I drooled over as a young teenager, all of them would have friction shifters, but I'd never give up my indexed 11spd. Wait, wut!? Why do we even need 11 speeds? Oy vei ;)
     
  20. AyeYo

    AyeYo Member

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    I didn't intend for this to turn into a pissing contest of who can do what with the oldest and most basic equipment. The point here was that I can see a marked difference between disc road brakes and things like electronic shifting, deep section carbon wheels, and compact cranks. The latter items all offer tangible benefits (although sometimes small) with only minor or no downsides. Electronic shifting isn't going to make me go faster, but it'd certainly make for a more slick and pleasent riding experience, plus groups like Record EPS just look amazing and let's admit, there's definite bling factor to the riding hobby. I'd buy it if I was inclinded to spend that kind of money on a slight improvement to my riding experience, but I'm not - someone else is though. Same goes for carbon wheels. Yes they're outrageously expensive and brake poorly (though that's improving), but there is a benefit to them and to the people that can afford them they're great. You can play the "well we don't really NEED that" game until there's nothing left but a direct drive unicycle. Bikes have been around for a long time so there's been a long time to perfect them. Gains going forward will be tiny and might have more to do with improving the experience than increasing speed. Add together many small improvements though and you have a noticable benefit. That's how bike technology has advanced.

    However, the reason I made the thread is because, unlike these other items, I see disc road brakes as a step backward. I see them as a move by the marketing departments to grab copious amounts of new money with new frames, new forks, new wheels, new hubs, etc. - all for no real benefit to the rider. It's a significant standard change that comes with the opportunity to sell riders lots of new, totally unnecessary equipment. For what? Taking a baby step foward in brake modulation while taking large steps backward in many other areas?

    This is a pretty good article on road discs and even includes a Q&A with major manufacturers on the issues with road discs:

    http://www.bikerumor.com/2012/02/14/road-bike-disc-brakes-are-coming-but-will-they-work/
     
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