Disc road bikes - your opinion

[Froze]

Originally Posted by new_rider

Common sense FTW.

The level of hyperbole is getting insane. Disc brakes are to rim brakes what the computer is to an abacus?!? Some of you guys are getting really desperate.

Originally Posted by swampy1970

Some of us "old" guys have braked from 180mph to very slow in a damn short space of time on good disk brakes on a 400lb motorcycle. Rim brakes would never ever provide that level of performance.

The hyperbole is real - disk brakes beat the **** out of rim brakes. Period, end of story. All that is needed is for a common standard (disk size, caliper mounting location etc) to be set and let the real fun begin.

Just don't expect this to be on bikes where aero is important though... Everywhere else - there's no contest.

No disk don't beat the schit out of rim brakes, you can't use a motorcycle or a car for comparisons because the speed is dramatically different than a bike. I use to live in California and raced the mountains all over Southern CA (including many very hot days, this is So Calif after all!) using nothing but rim brakes as all the rest of us did and millions before us and after us, and none of us ever had a reason to complain about braking. And the very unscientific thought that disk brakes can stop you faster on a bike is complete and utter nonsense. Unscientific I said? Yes, that's right because braking on a bike is completely dependent upon pads, tires, road conditions and rider weight, in other words adhesion, once those adhesion limits have been reached and the tires lock up it doesn't matter if you're using disk or rim, they both will stop (if all the conditions are the same) in the exact same distance. A lot of you guys are buying into new technology and all the hype that marketing can put into it. Like I said before though, if you are riding in snow and mud conditions then disk brakes are better otherwise you're wasting money.

I heard this same **** before about dual pivots vs single pivots and a bike can stop a lot faster with dual pivots, it was all nonsense because it's all about tire adhesion.

By the way disk brake pads wear out faster than rim pads I just learned.

And here is a VERY INTERESTING article I just found from probably the worlds foremost tandem maker in all of this: http://santanatandems.com/Techno/UnderstandingBraking.html

 

[swampy1970]

It is all about tire adhesion but you try locking up your back wheel when going slow, it's easy. Try it at speed and you have to work at it... Dual pivots stop faster. People have tested it and measured it. I would fully expect that a properly installed disk brake system would beat a properly installed rim brake in both stopping distance from a high speed or in modulation. Eecycleworks did a test a few years ago and noted that a Dura Ace 7800 would stop a 150lb rider and bike from 40kmh in just over 6 meters on a flat road. Most top end dual pivots were in the low 7 meter range, Camapg record skeleton, single pivot, just over 8 meters. The rest of the single pivot designs were worse, some requiring almost 11 meters - that's a huge difference. If you're racing or flying down a hill at speed, those couple of meters can matter, especially if you left braking a "bit late" or underestimated how tight a corner was. Rumor had it that the tried testing the Campag Delta brakes but the State of Nevada wouldn't close down the very long straight sections of Hwy50 required to stop from 25mph with those brakes...

 

[new_rider]

The pink elephant in the room is the ever increasing percentage of obese and even grossly obese cyclists these days.

I'm not talking about a 6' 220 lb guy with 20 extra beer gut pounds. I'm talking about riders who are 300 and even 350 lbs.

There's a weight class of riders who are not just fat, but mega-fat. People who take up a seat and a half on an airplane, or who can't see their own feet when they look down.

The US road bike segment is getting really strange: I'd say the modal rider is a recreational rider who is 60 years old, male, 250+ lbs, who nonetheless wants the lightest bike possible and is willing to spend up to $8K and sometimes more to get it.

These "technologies" don't emerge in a vacuum: they're in response to the strangely skewed road bike demographic that has emerged over the past 20 years.

 

[new_rider]

You're wrong again, as usual. This time, you try to make the argument that disc brakes are better than v brakes and dual pivot by citing a study which shows that dual pivots are more powerful than single pivots. Your brain is so fried from alcohol you can't even think straight.

“Shouldn’t my new tandem come equipped with a shiny pair of disc brakes?”
Actually, no…
What’s missing is the simple realization that a bicycle’s rim brakes are, in fact, disc brakes. Rim brakes have always been disc brakes. When cars and motorcycles were fitted with disc brakes, they caught up to the braking efficiency bicyclists had known for a half-century.
But, you might ask, aren’t motorcycle-style disc brakes more powerful?
Surprisingly, no. The engineers at Shimano and Avid (companies that produce both types) have confirmed Santana’s test results. Even the newest and most powerful bicycle disc brakes haven’t yet caught up the power of the best V-style (or linear-pull) rim brake.

Quote:
Originally Posted by swampy1970 .

It is all about tire adhesion but you try locking up your back wheel when going slow, it's easy. Try it at speed and you have to work at it...

Dual pivots stop faster. People have tested it and measured it. I would fully expect that a properly installed disk brake system would beat a properly installed rim brake in both stopping distance from a high speed or in modulation. Eecycleworks did a test a few years ago and noted that a Dura Ace 7800 would stop a 150lb rider and bike from 40kmh in just over 6 meters on a flat road. Most top end dual pivots were in the low 7 meter range, Camapg record skeleton, single pivot, just over 8 meters. The rest of the single pivot designs were worse, some requiring almost 11 meters - that's a huge difference. If you're racing or flying down a hill at speed, those couple of meters can matter, especially if you left braking a "bit late" or underestimated how tight a corner was.

Rumor had it that the tried testing the Campag Delta brakes but the State of Nevada wouldn't close down the very long straight sections of Hwy50 required to stop from 25mph with those brakes...

 

[new_rider]

Originally Posted by Froze

And here is a VERY INTERESTING article I just found from probably the worlds foremost tandem maker in all of this: http://santanatandems.com/Techno/UnderstandingBraking.html

Thanks froze. As I said before, I've been test riding bikes with mechanical disc brakes periodically over the last 10 years. The article confirms my anecdotal impressions that mechanical discs are inferior to v brakes and dual pivots.

 

[AyeYo]

Originally Posted by new_rider But, you might ask, aren’t motorcycle-style disc brakes more powerful?
Surprisingly, no. The engineers at Shimano and Avid (companies that produce both types) have confirmed Santana’s test results. Even the newest and most powerful bicycle disc brakes haven’t yet caught up the power of the best V-style (or linear-pull) rim brake.

Again, this information is completely unsurprising to anyone that understands braking systems. There are only two factors that determine how well a braking system works: how much brake force it is capable of generating and how well it handles heat.

The total brake force is a function of the leverage (rotor/rim/drum) diameter, clamping force, clamping area, and friction coefficient of the system. We don't even need math to determine that this win goes to rim brakes, based purely on the torque advantage provided by using the entire rim as a disc.

Heat handling ability is a function of the thermal mass of the system and ability of the system to dissipate built up heat. Again, with no math necessary, the obvious winner is the rim brakes with the many times larger thermal mass and surface area of the rim vs. a tiny disc.

Dry weather braking is a no-contest win for rim brakes. So is overall braking power and heat handling ability.


What's also interesting in that article is that it brings up the point about rim brakes BEING disc brakes. This is true. If we remember the issue of rotor size and torque, using the rim as the disc (if possible, it's not possible on a car or motorcycle so don't bother citing them) is obviously ideal. Ever seen a high-end sports car? They have discs so large they take up all of the available room inside the rim. If you want bike discs that truly do out perform rim brakes, rotor diameters are going to have to go up significantly. If you read the articles about the development of road discs and are capable of reading between the lines, it's obviously that manufacturers aren't developing superior systems. They're working hard to develop adequate systems that don't fail on big hills and they're having a hard time with it. We already have that. They're called rim brakes.

 

[new_rider]

I really like the overall direction that road bikes have taken over the past 24 years or so. Compact geometry, more standover, longer top tubes, taller head tubes, a more upright ride, dual pivot brakes, shifting without taking your hands off the bars, generally lighter bikes, wider gear ranges, slightly wider tires, are all great ideas.

I could certainly quibble about STI design, and I would like to see triples more widely available (I just don't like the 16 tooth jump on chainrings with compact cranks), and a few other things, but generally speaking, the road bike segment has become far more practical for most users.

Unfortunately, the industry is whiffing big time on a few developments:

1. disc brakes: I have yet to try any that worked as well as conventional brakes. Far more expensive and much heavier.

carbon wheels: extremely expensive, not any lighter and far noisier than conventional wheels. As another poster has mentioned, if your tires are 'too wide' the aero 'advantage' is completely negated.

battery shifting: dumb. You're screwed if your battery runs dry. Enjoy your fixie. Completely unnecessary for the rear, and a stronger spring would serve just as well for the front. Plugging your bike into an electrical outlet every night is just goofy.

I'm also not crazy about the 'crash and dispose' carbon parts and frames which are in vogue now. But that's a wave that's washed over the entire industry, so no amount of criticism is about to make a difference there.

I'd give the industry a B or B+ in road bike development in the past quarter century. Much of the progression is logical and practically useful. But some of the duds are simply embarrassing.

 

[swampy1970]

Originally Posted by AyeYo


Again, this information is completely unsurprising to anyone that understands braking systems. There are only two factors that determine how well a braking system works: how much brake force it is capable of generating and how well it handles heat.

The total brake force is a function of the leverage (rotor/rim/drum) diameter, clamping force, clamping area, and friction coefficient of the system. We don't even need math to determine that this win goes to rim brakes, based purely on the torque advantage provided by using the entire rim as a disc.

Heat handling ability is a function of the thermal mass of the system and ability of the system to dissipate built up heat. Again, with no math necessary, the obvious winner is the rim brakes with the many times larger thermal mass and surface area of the rim vs. a tiny disc.

Dry weather braking is a no-contest win for rim brakes. So is overall braking power and heat handling ability.


What's also interesting in that article is that it brings up the point about rim brakes BEING disc brakes. This is true. If we remember the issue of rotor size and torque, using the rim as the disc (if possible, it's not possible on a car or motorcycle so don't bother citing them) is obviously ideal. Ever seen a high-end sports car? They have discs so large they take up all of the available room inside the rim. If you want bike discs that truly do out perform rim brakes, rotor diameters are going to have to go up significantly. If you read the articles about the development of road discs and are capable of reading between the lines, it's obviously that manufacturers aren't developing superior systems. They're working hard to develop adequate systems that don't fail on big hills and they're having a hard time with it. We already have that. They're called rim brakes.

Do you understand braking systems? I think not judging by the above diatribe. Explain then how my FZR1000 with it's puny 320mm disks up front would brake with so much force you'd struggle to keep yourself from being launched over the front of the bike on concrete - and that's braking from 100+mph with a total weight of about 650lbs (bike and rider).

 

[swampy1970]

Originally Posted by new_rider
I really like the overall direction that road bikes have taken over the past 24 years or so. Compact geometry, more standover, longer top tubes, taller head tubes, a more upright ride, dual pivot brakes, shifting without taking your hands off the bars, generally lighter bikes, wider gear ranges, slightly wider tires, are all great ideas.

I could certainly quibble about STI design, and I would like to see triples more widely available (I just don't like the 16 tooth jump on chainrings with compact cranks), and a few other things, but generally speaking, the road bike segment has become far more practical for most users.

Unfortunately, the industry is whiffing big time on a few developments:

1. disc brakes: I have yet to try any that worked as well as conventional brakes. Far more expensive and much heavier.

carbon wheels: extremely expensive, not any lighter and far noisier than conventional wheels. As another poster has mentioned, if your tires are 'too wide' the aero 'advantage' is completely negated.

battery shifting: dumb. You're screwed if your battery runs dry. Enjoy your fixie. Completely unnecessary for the rear, and a stronger spring would serve just as well for the front. Plugging your bike into an electrical outlet every night is just goofy.

I'm also not crazy about the 'crash and dispose' carbon parts and frames which are in vogue now. But that's a wave that's washed over the entire industry, so no amount of criticism is about to make a difference there.

I'd give the industry a B or B+ in road bike development in the past quarter century. Much of the progression is logical and practically useful. But some of the duds are simply embarrassing.

Both Shimano and Campagnolo offered very nice triple chainset groups.

Carbon wheels are lighter. If you can't tell the difference between wheels like Zipp 202's or any of the Lightweight wheels and even a set of svelt alloy rimmed wheels with GEL280's then you don't even have a basic concept of weights.

Battery shifting. If I rode lots in the mountains every day I'd have Di2 in an instant with remote shifters on the bar tops. For a TT bike they'd be ace - I remember how much of a pain in the ass it was with bar ends on tri-bars when you were out of the saddle and wanted a different gear. Charging every night? You get about 1000 miles to a charge - if you ride on the flat and don't change often then obviously you'll get more.

Crash and dispose carbon frames? You obviously bring the fail on this one... unsurprisingly. Calfee Design (originally carbonframes - the company who supplied bikes to LeMond when he won the 1990 Tour) will repair a carbon frame for less than a repair to a typical steel frame at a custom builder. Calfee also do Di2 retrofits. There are a good number of companies that'll repair carbon. Good luck getting aluminum repaired.

 

[swampy1970]

Originally Posted by new_rider
The pink elephant in the room is the ever increasing percentage of obese and even grossly obese cyclists these days.

I'm not talking about a 6' 220 lb guy with 20 extra beer gut pounds. I'm talking about riders who are 300 and even 350 lbs.

There's a weight class of riders who are not just fat, but mega-fat. People who take up a seat and a half on an airplane, or who can't see their own feet when they look down.

The US road bike segment is getting really strange: I'd say the modal rider is a recreational rider who is 60 years old, male, 250+ lbs, who nonetheless wants the lightest bike possible and is willing to spend up to $8K and sometimes more to get it.

These "technologies" don't emerge in a vacuum: they're in response to the strangely skewed road bike demographic that has emerged over the past 20 years.

You are the pink elephant in the room. The topic gets tricky and you move onto something else.

 

[Froze]

Originally Posted by swampy1970

Do you understand braking systems? I think not judging by the above diatribe. Explain then how my FZR1000 with it's puny 320mm disks up front would brake with so much force you'd struggle to keep yourself from being launched over the front of the bike on concrete - and that's braking from 100+mph with a total weight of about 650lbs (bike and rider).

Sure can, it's called tire adhesion to the road. However I can do the same thing, in fact I could launch myself over if I wanted to on any of my bikes build from 84 till 2013 and none have disk brakes.

 

[Froze]

Originally Posted by new_rider
I really like the overall direction that road bikes have taken over the past 24 years or so. Compact geometry, more standover, longer top tubes, taller head tubes, a more upright ride, dual pivot brakes, shifting without taking your hands off the bars, generally lighter bikes, wider gear ranges, slightly wider tires, are all great ideas.

I could certainly quibble about STI design, and I would like to see triples more widely available (I just don't like the 16 tooth jump on chainrings with compact cranks), and a few other things, but generally speaking, the road bike segment has become far more practical for most users.

Unfortunately, the industry is whiffing big time on a few developments:

1. disc brakes: I have yet to try any that worked as well as conventional brakes. Far more expensive and much heavier.

carbon wheels: extremely expensive, not any lighter and far noisier than conventional wheels. As another poster has mentioned, if your tires are 'too wide' the aero 'advantage' is completely negated.

battery shifting: dumb. You're screwed if your battery runs dry. Enjoy your fixie. Completely unnecessary for the rear, and a stronger spring would serve just as well for the front. Plugging your bike into an electrical outlet every night is just goofy.

I'm also not crazy about the 'crash and dispose' carbon parts and frames which are in vogue now. But that's a wave that's washed over the entire industry, so no amount of criticism is about to make a difference there.

I'd give the industry a B or B+ in road bike development in the past quarter century. Much of the progression is logical and practically useful. But some of the duds are simply embarrassing.

I actually agree with all this mostly. The carbon thing is going to be a very emotional debate because so many people have embraced it so there better not be anything bad about it, so I won't go there to keep the tension down.

The weird thing about bike technology is that the 80's SIS system shifts faster than the newer STI stuff, I know this because I have both, in fact the STI stuff is about as fast as my older friction stuff!! I find the biggest hinderance to electronic shifting is the reliability issue and the cost to repair when things go wrong. And now with wireless coming out and everyone will jump on that bandwagon, will it make it almost impossible to find a battery or a wired derailleur or brake lever for the "older" electronic systems in 5 years? Again the manufactures will force you to spend more money to buy something to replace the obsolete stuff they made just 5 or so years prior. We already know that the STI stuff only lasts about 20,000 miles, yet people all yell: "yippe what great stuff, mine lasted 20,000 miles!"...BIG DEAL...my old Suntour Superbe friction components have over 160,000 miles and not one problem other than an occasional adjustment. Ok, there was one problem, the band on the front derailleur snapped when it had about 140k miles on it but I had a identical brand new replacement in storage.

And talking about brake pads, I have the Suntour Superbe pads made by Scott-Mathauser if I remember correctly which later went on to become Kool Stop, but the pads were a salmon colored and would not only last a long time but stop faster than any other brand. I got about 30,000 to 45k miles on a set of pads! I'm only on my 5th set and they're in almost new condition and I still have a set in storage so I'm set for a long time to come. But disk brake pad will only last about 1200 miles tops and some reporting as little as just 50 miles due to bad weather, and these pads cost around $25 for a pair when the rim pads cost just around $10?!?!? And rotors last only around 3 years which cost another $20 or so. People don't realize the cost of this stuff before they buy so they think, oh cool I got disk brakes until about a few miles later and they have to replace the pads. They do the same thing with vehicles too, I knew a guy who bought a new Dodge 1 ton truck back in 07 with duallies with some sort of weird rim size and the cheapest tires he could find for it cost $2800 for all 6, he was so ****** he sold the truck! Chrysler's 8 speed transmission will supposedly cost about $6,000 to rebuild when the time comes! It pays to investigate how much stuff will cost when repair time comes so your not in shock when you have to pay through the nose or pay all the time.

 

[AyeYo]

Originally Posted by Froze
Sure can, it's called tire adhesion to the road. However I can do the same thing, in fact I could launch myself over if I wanted to on any of my bikes build from 84 till 2013 and none have disk brakes.

Pretty much this. The limiting factor in automotive and motorcycle braking distance is not the brakes, it's the tire grip. Any brake capable of locking the tire (which is basically any brake installed a road worthy vehicle) cannot be improved upon for single stop braking distance - that distance is entirely dependent on available grip. The limiting factor in bicycle brakes is weight transfer and the point at which you're thrown over the bars - I said this earlier in the thread. People think brake power determines stopping distance, this is not true. High performance cars and motorcycles have larger rotors to improve heat dissipation and maintain reliable stopping during repeated, heavy use. They have larger, multi-piston calipers for additional thermal mass (which goes back to the previous point) and also for additional rigidity and reduced caliper flex, which improves brake feel (aka modulation) and consistency (not braking distance).

 

[CAMPYBOB]

Swept area of the brake is also a function of the stopping force it can generate and a hydraulic disc can be designed to offer more swept area.

That said, I can still generate enough stopping for to throw any good bike into a skid or catapult myself over the bars. MORE braking will enable me to do this slightly quicker I'm guessing...modulation and all that hype be damned.

A even Campy's Delta brakes have won multiple Grand Tours and Classics/Monuments. They have more than enough stopping capacity to keep a professional racer in the leader's jersey. Riders mounted on them beat all those fancy stiff sidepulls that 'supposedly' offer some advantage in stopping. Maybe those guys needed less braking...not more?

Of course, with any brake and a sufficiently talented fool, you'll find idiots kissing houses by underestimating the coefficient of friction vs. braking distance divided by skill (or lack of skill).

 

[swampy1970]

Originally Posted by Froze
I actually agree with all this mostly. The carbon thing is going to be a very emotional debate because so many people have embraced it so there better not be anything bad about it, so I won't go there to keep the tension down.

The weird thing about bike technology is that the 80's SIS system shifts faster than the newer STI stuff, I know this because I have both, in fact the STI stuff is about as fast as my older friction stuff!! I find the biggest hinderance to electronic shifting is the reliability issue and the cost to repair when things go wrong. And now with wireless coming out and everyone will jump on that bandwagon, will it make it almost impossible to find a battery or a wired derailleur or brake lever for the "older" electronic systems in 5 years? Again the manufactures will force you to spend more money to buy something to replace the obsolete stuff they made just 5 or so years prior. We already know that the STI stuff only lasts about 20,000 miles, yet people all yell: "yippe what great stuff, mine lasted 20,000 miles!"...BIG DEAL...my old Suntour Superbe friction components have over 160,000 miles and not one problem other than an occasional adjustment. Ok, there was one problem, the band on the front derailleur snapped when it had about 140k miles on it but I had a identical brand new replacement in storage.

And talking about brake pads, I have the Suntour Superbe pads made by Scott-Mathauser if I remember correctly which later went on to become Kool Stop, but the pads were a salmon colored and would not only last a long time but stop faster than any other brand. I got about 30,000 to 45k miles on a set of pads! I'm only on my 5th set and they're in almost new condition and I still have a set in storage so I'm set for a long time to come. But disk brake pad will only last about 1200 miles tops and some reporting as little as just 50 miles due to bad weather, and these pads cost around $25 for a pair when the rim pads cost just around $10?!?!? And rotors last only around 3 years which cost another $20 or so. People don't realize the cost of this stuff before they buy so they think, oh cool I got disk brakes until about a few miles later and they have to replace the pads. They do the same thing with vehicles too, I knew a guy who bought a new Dodge 1 ton truck back in 07 with duallies with some sort of weird rim size and the cheapest tires he could find for it cost $2800 for all 6, he was so ****** he sold the truck! Chrysler's 8 speed transmission will supposedly cost about $6,000 to rebuild when the time comes! It pays to investigate how much stuff will cost when repair time comes so your not in shock when you have to pay through the nose or pay all the time.

I don't see the materials side of things being an emotional debate. Whatever material is "best" for the job is what matters. The application even changes based on event type.

If your STI is slower than SIS then you need to set it up properly. As soon as you release the lever after hearing the click the gear should change instantly. If it doesn't there's something wrong.

STI only 20,000 WTF? Now you see why I look after my own stuff...

The guy who bought a 1 ton truck - did he need to buy a 1 ton truck for hauling/towing or was it a "fashion" purchase. If the latter then he's just a ****. LOL. You shouldn't need to replace a transmission ever. The only caveat to transmission life is the changing the fluid when it needs to be changed - and with the correct fluid. Mopar vehicals NEED mopar transmission fluid - and only mopar transmission fluid. When it needs to be changed is the key - if you tow then it'll be sooner than it would be if you just have a track and haul two kids and a significant other.

 

[swampy1970]

Originally Posted by CAMPYBOB
Of course, with any brake and a sufficiently talented fool, you'll find idiots kissing houses by underestimating the coefficient of friction vs. braking distance divided by skill (or lack of skill).

... coefficient of friction reduced by cow-**** and diesel

If wasn't so much as a kiss...

 

[swampy1970]

Originally Posted by Froze
Sure can, it's called tire adhesion to the road. However I can do the same thing, in fact I could launch myself over if I wanted to on any of my bikes build from 84 till 2013 and none have disk brakes.

That wasn't the question I asked. I was being told by "Mr Brake Expert" above that puny small disks couldn't generate sufficient force to brake like that... 600+lbs on 320mm disks seems to work damned well. The 250mm rotors on the Mazda Miata that I won a regional SCCA title on braked plenty good enough to stop the 2,068lb (wet - without driver) Miata really effing well. Larger rotors were allowed by the rules but a marginally larger brake rotor would have really only offered better heat dissipation in a situation were I didn't need it. Smaller brake disks mean less rotating weight and the pads I used preferred a bit a heat.

If anyone tells me that a rotor that's only 70mm smaller can't stop a bicycle in short order is going to get laughed at.

If you talk to folks that have Volagi bikes you'll hear nothing but glowing praise for the brakes in both extra stopping power and modulation. I haven't ridden one at speed but they seem great in a parking lot.

 

[AyeYo]

Originally Posted by swampy1970

That wasn't the question I asked. I was being told by "Mr Brake Expert" above that puny small disks couldn't generate sufficient force to brake like that...

If anyone tells me that a rotor that's only 70mm smaller can't stop a bicycle in short order is going to get laughed at.

I never said any of that. What I did say is that the massively larger diameter of using a rim vs a brake disc gives rim brakes the stopping force advantage. If disc brakes couldn't stop a bike, they wouldn't exist. What I was combating is the repeated claims of "disc brakes offer more stopping power" - they don't. And "disc brakes handle heat better" - they don't.

Also, don't forget that there's a significant difference between a Miata and a bicycle: the Miata has twice as many rotors, which means comparing rotor size is meaningless. Also, cars can get away with smaller discs because clamping force is part of the braking force equation. Cars have leg actuated brakes which are vacuum assisted, which means both more travel and many, many times more force on the actuation arm - which then gets converted through the mechanical advantage of the hydraulic system to many thousands of pounds of claiming force. That's a little more difficult to get out of a bike with a lever that has 1/4" of travel and is actuated by two unassisted fingers.

 

[swampy1970]

A brake lever with 1/4" of travel. What bicycle do you ride? Your measurements seem as confused as New Riders concept of weight.

The Miata may have twice as many rotors but it's also a wee bit heavier. The last time I checked my Cannondale was 15.6lbs, Ridley 16.8lbs and the Miata I raced was 2,068. A stock 94 Miata is closer to 2,400lbs.

Vacuum assist doesn't change the travel of the pads. It may allow the change in design of the brake system but given you only need a few mm of movement you're barking up the wrong tree here. My friends UK spec Lotus Elise ran with no vacuum assist and didn't suffer because of it. My 3700lb 67 Camaro may run without vacuum assist on a Wilwood brake setup. The current booster runs too close to the valve covers of the aftermarket big block and makes it a pain in the ass when the valve covers need to come off for a valve adjustment.

Your argument was that rim brakes offer more usable stopping power - which they don't. They certainly don't offer better modulation.

Mmmmm, running double disks up front... Oooooh, that'd be fun and a cause for much conversation.

Heat. Heat per se isn't usually a big issue when looked at for a bike with alloy rims. You can melt brake blocks and you can pop a tire off a rim on long technical descents but that is an exception rather than the norm but it does happen. I have a hill that is steep enough to heat my rims to a "too painful to hold" level. I make a point of not racing down that hill, which is a shame as it'd be ace fun to do so. They even used to make a "tape" that insulated the inner tube from excessive heat... You don't see them too much these days but I know a few people that have used them in the past. If you read the tech docs that come with carbon rims from companies like Zipp and Reynolds they'll tell you how to deal with and clean pad glazing caused by excessive heat.

This thread has conveniently forgotten that a lot of people these days ride on carbon rims.

Modulation seems to be an issue too. I don't recall back in the days of alloy rims Pro's falling off like Lemmings on a regular basis every time that two specks of rain fell from the sky.

Another benefit would be not having to run with your quick release open if you're swapping from 19mm wide rims on training wheels to 28mm wide rims like Zipp 303's - if opening the QR actually lets you open the brakes that much! Imagine the Pro's riding Roubaix on 303's and getting a wheel from the Mavic bike on Arenberg and even with the QR closed not getting any pad contact on the rim and hence no braking. LOLz.

If you get the rotors toasty then you'll suffer a bit of brake fade. In a car you can melt the grease right out of the hub bearings, which is why you don't use plain jane grease in the hubs of a car that's going to the track... On a bicycle I don't see that happening due to their being less work involved. If you consistently ride on descents where the rotors get hot - change the pads for ones that like heat. Last time I checked, there were no tires made for descents where excessive rim temperature caused a rapid rise in tire pressure to dangerous levels.

I used to train and race a lot in the rain and as such I used to go through several sets of pads per year why is on a par of what I'd expect a disk brake system to use. Even if they offered different pad compounds for disk brakes I'd probably always go for the ones that offer best modulation and initial bite for the conditions involved. Similarly I always used Conti GP4000S because I feel they offer the best ability to keep my ass off the tarmac when riding fast. I don't care that they wear out faster than Gatorskins for example. My ass is worth more than a $20 savings on buying an inferior tire and likewise my ass deserves the best performing brakes I can afford. Plus the higher end stuff is much more fun to pull apart and rebuild.

The proof is in the pudding - there has to be some data from tests done on MTB's about braking performance similar to the eecycleworks road caliper tests.

 

[new_rider]

Calm down bro. You've been posting non stop on this topic all weekend long, including saturday nights. It's memorial day weekend for chrissakes! Spend some time with your friends and family.

No hate man but you need to get a life. Disc brakes ain't worth getting this worked up over. No one's reading your ten page rants anyway. Sending some much needed love...

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Originally Posted by swampy1970 .
A brake lever with 1/4" of travel. What bicycle do you ride? Your measurements seem as confused as New Riders concept of weight.

The Miata may have twice as many rotors but it's also a wee bit heavier. The last time I checked my Cannondale was 15.6lbs, Ridley 16.8lbs and the Miata I raced was 2,068. A stock 94 Miata is closer to 2,400lbs.

Vacuum assist doesn't change the travel of the pads. It may allow the change in design of the brake system but given you only need a few mm of movement you're barking up the wrong tree here. My friends UK spec Lotus Elise ran with no vacuum assist and didn't suffer because of it. My 3700lb 67 Camaro may run without vacuum assist on a Wilwood brake setup. The current booster runs too close to the valve covers of the aftermarket big block and makes it a pain in the ass when the valve covers need to come off for a valve adjustment.

Your argument was that rim brakes offer more usable stopping power - which they don't. They certainly don't offer better modulation.

Mmmmm, running double disks up front... Oooooh, that'd be fun and a cause for much conversation.

Heat. Heat per se isn't usually a big issue when looked at for a bike with alloy rims. You can melt brake blocks and you can pop a tire off a rim on long technical descents but that is an exception rather than the norm but it does happen. I have a hill that is steep enough to heat my rims to a "too painful to hold" level. I make a point of not racing down that hill, which is a shame as it'd be ace fun to do so. They even used to make a "tape" that insulated the inner tube from excessive heat... You don't see them too much these days but I know a few people that have used them in the past. If you read the tech docs that come with carbon rims from companies like Zipp and Reynolds they'll tell you how to deal with and clean pad glazing caused by excessive heat.

This thread has conveniently forgotten that a lot of people these days ride on carbon rims.

Modulation seems to be an issue too. I don't recall back in the days of alloy rims Pro's falling off like Lemmings on a regular basis every time that two specks of rain fell from the sky.

Another benefit would be not having to run with your quick release open if you're swapping from 19mm wide rims on training wheels to 28mm wide rims like Zipp 303's - if opening the QR actually lets you open the brakes that much! Imagine the Pro's riding Roubaix on 303's and getting a wheel from the Mavic bike on Arenberg and even with the QR closed not getting any pad contact on the rim and hence no braking. LOLz.

If you get the rotors toasty then you'll suffer a bit of brake fade. In a car you can melt the grease right out of the hub bearings, which is why you don't use plain jane grease in the hubs of a car that's going to the track... On a bicycle I don't see that happening due to their being less work involved. If you consistently ride on descents where the rotors get hot - change the pads for ones that like heat. Last time I checked, there were no tires made for descents where excessive rim temperature caused a rapid rise in tire pressure to dangerous levels.

I used to train and race a lot in the rain and as such I used to go through several sets of pads per year why is on a par of what I'd expect a disk brake system to use. Even if they offered different pad compounds for disk brakes I'd probably always go for the ones that offer best modulation and initial bite for the conditions involved. Similarly I always used Conti GP4000S because I feel they offer the best ability to keep my ass off the tarmac when riding fast. I don't care that they wear out faster than Gatorskins for example. My ass is worth more than a $20 savings on buying an inferior tire and likewise my ass deserves the best performing brakes I can afford. Plus the higher end stuff is much more fun to pull apart and rebuild.

The proof is in the pudding - there has to be some data from tests done on MTB's about braking performance similar to the eecycleworks road caliper tests.