The Great Disc Brake Swindle?
Comments
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The same way people managed with wood rims and cork brake blocks. People use what's available at the time. :roll:
You may have used cork brake blocks but I never did.
What I'm saying is that I never had a "oh sh*t!" moment due to crap brakes before these new-fangled disc brakes. I'm quite happy to go back to caliper brakes on my next choice of bike.Cannondale Trail 6 - crap brakes!
Cannondale CAAD80 -
What I don't think has been discussed in this thread are three important advantages of disks unrelated to stopping ability. Firstly your wheels do not get coated in the disgusting mixture of rim and brake material which when the fairy strikes mean you, your clothes and your pristine white bar tape get covered in grey gunk which never comes out completely. Secondly, you don't have to open your brakes to get the wheel out, then find that your new super duper wide rim and 25c (plus) tyre combination mean you have to deflate the tyre slightly. Thirdly, and this may or may not be an advantage, your wheels last forever.0
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Ride in regularly in rain = get discs
Don't = don't.0 -
[url=http://www.bikeradar.com/forums/viewtopic.php?p=19745876#p19745876]tommytranquillo[/url] wrote:There are indeed lots of threads about this, but like all forum threads they quickly degenerate from polite discussion to entrenched positions and name-calling. My point was that, for the first time, certain industry insiders were breaking ranks. That's what interests me, not the debate about whether disc brakes are any good or not.
Quite agree, Tommy. Anyone who questions disc brakes (or di2) on this forum opens a hornets' nest. People who have come to road bikes from mountain biking love their disc brakes and are evangelistic in their desire to get everyone using them. People who have used rim brakes on road bikes for years without problems get shirty at being lectured to. The result is often childish abuse from both sides of the debate.
As you rightly say, the interesting thing here is the fact that industry insiders are starting to question whether disc brakes are so great for bikes with skinny tyres.
Richard Hallett, in particular, has written a very well argued appraisal of the pros and cons of disc brakes on road bikes - a welcome contrast to the uncritical puff pieces which appear in most magazines. As the former technical editor of Cycling Weekly and an award-winning frame builder and bike constructor, he's got the credentials.
For those who haven't read his full article in the Oct/Nov issue of the CTC magazine Cycle, he doesn't slag off disc brakes, just questions whether they are right for all road bikes. He concludes by saying "there are a couple of situations where discs undoubtedly win on road: when using deep-section carbon clincher rims, which are susceptible to heat build up and tyre blow-off, and for all-weather commuting ..."
Strangely enough, the only two people I know with disc-braked road bikes (steel and titanium) are elderly CTC types! I've never seen a lightweight carbon road bike with disc brakes on the road nor a gravel bike. But then I do live in the wilds of Shropshire and fashion trends take time to reach us.0 -
[url=http://www.bikeradar.com/forums/viewtopic.php?p=19745876#p19745876]tommytranquillo[/url] wrote:There are indeed lots of threads about this, but like all forum threads they quickly degenerate from polite discussion to entrenched positions and name-calling. My point was that, for the first time, certain industry insiders were breaking ranks. That's what interests me, not the debate about whether disc brakes are any good or not.
Quite agree, Tommy. Anyone who questions disc brakes (or di2) on this forum opens a hornets' nest. People who have come to road bikes from mountain biking love their disc brakes and are evangelistic in their desire to get everyone using them. People who have used rim brakes on road bikes for years without problems get shirty at being lectured to. The result is often childish abuse from both sides of the debate.
As you rightly say, the interesting thing here is the fact that industry insiders are starting to question whether disc brakes are so great for bikes with skinny tyres.
Richard Hallett, in particular, has written a very well argued appraisal of the pros and cons of disc brakes on road bikes - a welcome contrast to the uncritical puff pieces which appear in most magazines. As the former technical editor of Cycling Weekly and an award-winning frame builder and bike constructor, he's got the credentials.
For those who haven't read his full article in the Oct/Nov issue of the CTC magazine Cycle, he doesn't slag off disc brakes, just questions whether they are right for all road bikes. He concludes by saying "there are a couple of situations where discs undoubtedly win on road: when using deep-section carbon clincher rims, which are susceptible to heat build up and tyre blow-off, and for all-weather commuting ..."
Strangely enough, the only two people I know with disc-braked road bikes (steel and titanium) are elderly CTC types! I've never seen a lightweight carbon road bike with disc brakes on the road nor a gravel bike. But then I do live in the wilds of Shropshire and fashion trends take time to reach us.
As I understand it, he also raised the question of physics and claimed that spokes and forks would break when subject to repeated braking. A claim that others on the internet find difficult to accept, scientifically. Does anyone have a link?My blog: http://www.roubaixcycling.cc (kit reviews and other musings)
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Don't have the link, Bender, but Hallett states that discs "require a stiff wheel with tangential spoke lacing to resist brake torque" and says "the frame and fork must be built to take the loads imposed by the calliper". He says these loads are "about four times the magnitude of those imposed by rim brakes for the same braking force since a 700c rim is roughly four times the radius of a 160mm disc rotor". He doesn't make any statements about spokes breaking.
He argues that it is "unwise to mount disc callipers to a conventional steel fork unless the blade is beefed up to suit". Hallett says that "frame builder and disc brake pioneer Chas Roberts found that regular tapered blades would crack in front of the calliper mount as brake torque tried to bend the tip backwards." Hallett points out that Surly, Kona and Salsa have recalled steel forks in recent years and adds that strengthening blades on the disc side "inevitably diminishes the resilience and springiness for which steel road forks are renowned."
He also describes, under the heading Red Hot Rotors, how overheating poses a greater issue for road bikes than mountain bikes which themselves have suffered complete loss of braking power in downhill events such as Megavalanche. "At 60mph, a cyclist has nine times the kinetic energy of a cyclist travelling at 20mph and slowing an 80kg bike and rider from 60 to 20mph in three seconds generates 8.5kW, which heats the disc to as much as 500C depending on front/rear brake usage. By comparison, an aluminium rim might only reach 90C in short bursts of braking", says Hallett.
I've personally not always agreed with what Hallett has said in articles over the years, but feel that this piece is definitely thought-provoking.0 -
Those example you quote are extreme and won't be encountered by 99% of riders 99% of the the time. In those situations it is just as likely that a rim brake used just as carelessly would result in a tyre burst - I'm not sure which situation is worse. Riding within limits and proper braking technique would eliminate these issues.0
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I think disc temps is the key concern worthy of note, but why is he comparing disc temps under continual braking to rim temps under short bursts of braking??? Only reason I can think of is to deliverately skew the results and mislead... And as such, his primary valid point is diminished if he has not discussed it in an unbiased way.0
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I think disc temps is the key concern worthy of note, but why is he comparing disc temps under continual braking to rim temps under short bursts of braking??? Only reason I can think of is to deliverately skew the results and mislead... And as such, his primary valid point is diminished if he has not discussed it in an unbiased way.
Exactly0 -
I think disc temps is the key concern worthy of note, but why is he comparing disc temps under continual braking to rim temps under short bursts of braking??? Only reason I can think of is to deliverately skew the results and mislead... And as such, his primary valid point is diminished if he has not discussed it in an unbiased way.
I don't think you are right. Hallett could have worded it better but he talks about braking for three seconds with discs when going from 60 to 20. My understanding is that his "short bursts" phrase refers to a similar time scale when using rim brakes.0 -
I wouldn't mind a bit of brake drag, it would make it a lot easier to rest the bike against the wall when I shut the garage! My new winter bike (with disks) has ludicrously free running wheels.
They grumble a bit when you drag them on long (a UK long so actually short) descents but my bike with rim brakes does as well. I blame my braking style, I seem to have sub-consciously adopted a draggy style on descents over about 5% gradient.
And it is staying really clean.0 -
All brakes work by converting kinetic energy into heat (and a bit of noise) - it's the same amount of energy (give or take small differences in weight) whether it's a rim or disk brake so it's how quickly the rim or disk dissipate the heat, the disk would have a lower heat sink capacity due to size but a higher tolerance to temperatures vice versa for the rim brake.0
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Braking from 60mph to 20mph in three seconds is quite an achievement. Most riders never get near 60mph on a road bike or a mountain bike. This is just a pointless speculation about something that will never happen. If it did mountain biking would be littered with casualties. I descended from the top of a 3000ft mountain off road down to sea level at speed with no braking issues.0
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[url=http://www.bikeradar.com/forums/viewtopic.php?p=19746507#p19746507]Arthur Scrimshaw[/url] wrote:All brakes work by converting kinetic energy into heat (and a bit of noise) - it's the same amount of energy (give or take small differences in weight) whether it's a rim or disk brake so it's how quickly the rim or disk dissipate the heat, the disk would have a lower heat sink capacity due to size but a higher tolerance to temperatures vice versa for the rim brake.
I agree, Arthur. I don't have any experience of discs on road bikes but I've ridden a lot of motorbikes up and down the Alps and heat dissipation is the key to maintaining braking power. Even with engine braking, I've experienced disc brake fade. Bigger discs dissipate heat better - which is why I question whether tiny 140mm rotors are really suitable for high mountain descents on road bikes. Even disc enthusiast ugo.santalucia of this forum is now asking about finned rotors after cooking his brakes in the Etape du Dales. His rotors were glowing and he lost braking power at the bottom of Buttertubs pass.0 -
Ride in regularly in rain = get discs
Don't = don't.
That's my take on it too - my dry bike has braking power that I can't ever see me feeling the need to improve.
Having just replaced another pair of rims on my wet/winter bike, however. . .0 -
All my bikes are now disc brake. They are simply better, and I get to ride high end wheels all year round without the rim wearAnd the people bowed and prayed, to the neon god they made.0
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I've been on discs for all bikes for ages. Took the new Supersix out today. Ultegra brakes. Very good, but disconcerting at first.My blog: http://www.roubaixcycling.cc (kit reviews and other musings)
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[url=http://www.bikeradar.com/forums/viewtopic.php?p=19746507#p19746507]Arthur Scrimshaw[/url] wrote:All brakes work by converting kinetic energy into heat (and a bit of noise) - it's the same amount of energy (give or take small differences in weight) whether it's a rim or disk brake so it's how quickly the rim or disk dissipate the heat, the disk would have a lower heat sink capacity due to size but a higher tolerance to temperatures vice versa for the rim brake.
I agree, Arthur. I don't have any experience of discs on road bikes but I've ridden a lot of motorbikes up and down the Alps and heat dissipation is the key to maintaining braking power. Even with engine braking, I've experienced disc brake fade. Bigger discs dissipate heat better - which is why I question whether tiny 140mm rotors are really suitable for high mountain descents on road bikes. Even disc enthusiast ugo.santalucia of this forum is now asking about finned rotors after cooking his brakes in the Etape du Dales. His rotors were glowing and he lost braking power at the bottom of Buttertubs pass.
I think they overheat quicker than rim brakes... on balance I would probably prefer rim brakes to come down Hardknott or Monte Zoncolan.
That said, I would not buy a rim braked bike anymore, for some reason... not sure what the reason is though... could well as shallow as disc braked wheels look coolerleft the forum March 20230 -
I wonder if the internet bike forums had existed when STI levers were invented
rec.bike existed, check the archives if they still exist. I remember lots of "shitmano" barbs back in the day.BASI Nordic Ski Instructor
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[url=http://www.bikeradar.com/forums/viewtopic.php?p=19746507#p19746507]Arthur Scrimshaw[/url] wrote:All brakes work by converting kinetic energy into heat (and a bit of noise) - it's the same amount of energy (give or take small differences in weight) whether it's a rim or disk brake so it's how quickly the rim or disk dissipate the heat, the disk would have a lower heat sink capacity due to size but a higher tolerance to temperatures vice versa for the rim brake.
I agree, Arthur. I don't have any experience of discs on road bikes but I've ridden a lot of motorbikes up and down the Alps and heat dissipation is the key to maintaining braking power. Even with engine braking, I've experienced disc brake fade. Bigger discs dissipate heat better - which is why I question whether tiny 140mm rotors are really suitable for high mountain descents on road bikes. Even disc enthusiast ugo.santalucia of this forum is now asking about finned rotors after cooking his brakes in the Etape du Dales. His rotors were glowing and he lost braking power at the bottom of Buttertubs pass.
I think they overheat quicker than rim brakes... on balance I would probably prefer rim brakes to come down Hardknott or Monte Zoncolan.
That said, I would not buy a rim braked bike anymore, for some reason... not sure what the reason is though... could well as shallow as disc braked wheels look cooler
aren't you on some older cable disk designs? these things are improving quickly.
certainly if my experience last year rolling off the Blorange after watching the Tour of Britain finish at Keepers Pond, on a old MTB with full panniers ie the bike was heavy, lots of braking due to some interesting driving and riding and just weight of numbers so speed varied 30-10 mph think I averaged 20mph ish.
ie with a heavy bike, down for uk at least a long hill with lots of braking no disk fade, they at the bottom when I stopped to adjust one of the panniers out of interest I checked the disks which where tepid, ie not warm let alone hot.
and this is some fairly cheap MTB 160mm etc, the Trance has nicer Shimano disks, I see no reason why road hydraulics shouldn't be equal.
in fairness my only experince of riding down a really big lumps is Mt Teide which at 21miles 5% and no problems with heat on the rim brakes on the hire roadie, though disappointing amount of power but that's in comparison to my mainly disk braked bikes.0 -
I don't see how a more modern hydraulic system would cool quicker than a mechanical/semi hydraulic. Pads are the same, discs are the same, friction is the same.left the forum March 20230
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I don't see how a more modern hydraulic system would cool quicker than a mechanical/semi hydraulic. Pads are the same, discs are the same, friction is the same.
Many of the more modern shimano systems have cooling fins on the pads, and several makes of rotor use fins and incorporate spiders to reduce warping - but other than that, yes you are right.
Interesting also is whether those worrying about heat problems use organic pads, which are less tolerant to heat?0 -
I don't see how a more modern hydraulic system would cool quicker than a mechanical/semi hydraulic. Pads are the same, discs are the same, friction is the same.
Many of the more modern shimano systems have cooling fins on the pads, and several makes of rotor use fins and incorporate spiders to reduce warping - but other than that, yes you are right.
Interesting also is whether those worrying about heat problems use organic pads, which are less tolerant to heat?
I have opened a thread about finned rotors and nobody has been able to say "they are better". That said, I could use them with mechanical systems.
I use semi-metallic... purely sintered ones have a terrible feelleft the forum March 20230 -
I wonder if the internet bike forums had existed when STI levers were invented
rec.bike existed, check the archives if they still exist. I remember lots of "shitmano" barbs back in the day.
For me, the main issue is that disc brakes = new total bikes pretty much.
When ergo levers, or clipless pedals etc came in the cyclist could make gradual changes to existing bikes. Disc brakes mean a new frame/frames and new wheels, probably new groupsets as hydraulic levers are needed. At the same time, the "old" kit will become almost worthless. For many long-established club/racing cyclists with a good collection of frames, wheels etc it's a major issue, and a huge expense. For instance, an established and experienced road racing rider with, say, 3 road bikes (including a winter bike) and maybe 10 pairs of wheels (maybe 3 or 4 pairs of Zipps or the like), could need to spend up to £30,000 to get back on par, and for what - no actual performance benefit (I've never heard anyone say "I'd have won that race if my brakes were better").
I accept that for all weather commuting then there may be a case, but otherwise it's a huge cost to the cyclist, and a huge opportunity for the industry.
By the way, as the UCI is only now agreeing a standard for fork width etc I wonder if there will be equal frustration for "early adopters" when the standard turns out to be not what they are currently running?0 -
I wonder if the internet bike forums had existed when STI levers were invented
rec.bike existed, check the archives if they still exist. I remember lots of "shitmano" barbs back in the day.
For me, the main issue is that disc brakes = new total bikes pretty much.
When ergo levers, or clipless pedals etc came in the cyclist could make gradual changes to existing bikes. Disc brakes mean a new frame/frames and new wheels, probably new groupsets as hydraulic levers are needed. At the same time, the "old" kit will become almost worthless. For many long-established club/racing cyclists with a good collection of frames, wheels etc it's a major issue, and a huge expense. For instance, an established and experienced road racing rider with, say, 3 road bikes (including a winter bike) and maybe 10 pairs of wheels (maybe 3 or 4 pairs of Zipps or the like), could need to spend up to £30,000 to get back on par, and for what - no actual performance benefit (I've never heard anyone say "I'd have won that race if my brakes were better").
I accept that for all weather commuting then there may be a case, but otherwise it's a huge cost to the cyclist, and a huge opportunity for the industry.
By the way, as the UCI is only now agreeing a standard for fork width etc I wonder if there will be equal frustration for "early adopters" when the standard turns out to be not what they are currently running?
He could just buy a Cannonade Synapse Carbon Ultegra disc and some handbuilts and use that for non racing
My blog: http://www.roubaixcycling.cc (kit reviews and other musings)
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Ride in regularly in rain = get discs
Don't = don't.
That's my take on it too - my dry bike has braking power that I can't ever see me feeling the need to improve.
And mine too! Horses for courses. To me, a lot of this sounds like someone saying that it would be silly to buy a Caterham 7 because there's no space for your shopping and no roof to keep the rain off. There's a time for practical purchases and a time for uncompromised fun purchases.Faster than a tent.......0 -
Millar appears to want to start a rant about it on Twitter at the moment.Trail fun - Transition Bandit
Road - Wilier Izoard Centaur/Cube Agree C62 Disc
Allround - Cotic Solaris0 -
The high-disposable-income cyclists leading the charge to discs also lead sedentary lives and have low grip strength compared to the predominantly working-class cyclists of the past. I suspect that plays a part.
Love this part... love it, love it, love it... left the forum March 20230 -
I suspect that some of them may well have stronger wrist strength.The high-disposable-income cyclists leading the charge to discs also lead sedentary lives and have low grip strength compared to the predominantly working-class cyclists of the past. I suspect that plays a part.
Love this part... love it, love it, love it...The above may be fact, or fiction, I may be serious, I may be jesting.
I am not sure. You have no chance.Veronese68 wrote:PB is the most sensible person on here.0 -
The high-disposable-income cyclists leading the charge to discs also lead sedentary lives and have low grip strength compared to the predominantly working-class cyclists of the past. I suspect that plays a part.
Love this part... love it, love it, love it...
the pathetic emo child attitude of the UK cyclist in a nutshell - thank god the rest of the world is nt like them!We're in danger of confusing passion with incompetence
- @ddraver0
