For once I agree with Lenard Zinn - Road disk shortcomings

Discuss light weight issues concerning road bikes & parts.
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sugarkane
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by sugarkane

I bet disks don't make it to the evo 6s, the mclaren venge or the other flag ship models any time soon

It's marketing aimed squarly at MAMALs, more snigger worthy bikes on the road :roll:

Hopeful the Uci drags their feet hey..

by Weenie


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Ramjm_2000
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by Ramjm_2000

Zen Cyclery wrote:...why not simply swap it with a 5mm shift housing? This will allow for maximum braking power. ..


Excellent Idea!

ricerocket
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by ricerocket

sugarkane wrote:Am I :roll:


I don't understand your schizophrenic argument. First you say that "all rims wear out with enough sand/rain/dust", and then you say "my wheels last forever". So what's your stance here? Or are you flip flopping when it's convenient? :noidea:

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sugarkane
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by sugarkane

I said things wear out if you use the hell outa them.. That's just a given. Ride in the rain all,the time with lots of sand and dirt on the road and you'll destroy the whole wheel set pretty fast. I'd say in these ideal conditions for using disks the hubs will be the first thing to pack it in

What's 30000kms to you...? To me it's around 3 years of riding plus or minus 2-3 months. Forever? please don't put words into my mouth.


As for riding in the rain goes I've ridden in the rain 3-4 times in the last 10 months and ride 2-300kms per week. Not a real big issue where I ride to be honest.

Disks might make you feel a bit more secure In riding your bike down a hill but getting around the corner at the bottom qucikly still requires balls not disk brakes
They are not going to make you a better bike handler, but they will make your bike heavier and look a lot more like a MTB :thumbup: :up:

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maddog 2
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by maddog 2

I'm sorry but disks won't make you a better descender. Better tires, skills, and less fear wiil.


have you tried discs sugarkane?

I agree that discs won't make you a better descender. That's clearly an argument no one is trying to make.

But they are definitely faster than rim brakes, dry and wet. I know. I have them.

Maybe the roads I ride are significantly different to the ones you ride. Round where I am the tarmac is often poor quality and the descents are short and steep. Better power, modulation, control and feel all add up to more speed.

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by roca rule

Sugar Kane makes an interesting point. With fatter tubes, fatter tires, higher spoke counts, disc brakes, wider q factors, taller head tubes, beefier stems, wider spacing, the only difference between a 29 er hard tail and a road bike souls be the fork.

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sugarkane
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by sugarkane

maddog 2 wrote:
I'm sorry but disks won't make you a better descender. Better tires, skills, and less fear wiil.


have you tried discs sugarkane?

I agree that discs won't make you a better descender. That's clearly an argument no one is trying to make.

But they are definitely faster than rim brakes, dry and wet. I know. I have them.

Maybe the roads I ride are significantly different to the ones you ride. Round where I am the tarmac is often poor quality and the descents are short and steep. Better power, modulation, control and feel all add up to more speed.



How are they faster? Heavier, more rotating mass?

I used to race production 250 gp class motorbikes as a young man and was at my most competitive in the wet.. I would still ride around the outside of you any day and any conditions. I just think its over complication on a system that works pretty darn well already. Carbon wheels are getting better, brake pads and brake tracks are been improved massively every year, why not allow the perfection of the much lighter and more elegant system road bikes have now... There is still plenty of work to be done with brake pads and the brake tracks been used..

To get maximum performance out of road bike disks it's going to take time and lots of trial and error.. What's good for MTBs is not what's going to be the best for road bikes. Give me some f1 style carbon rotors and magnesium calipers, Kevlar braided hoses and I'll start to pay attention. As it is (good) rims brake setups have enough power to overwhelm any tires on the market.. You Want to see proper performance increases with disks then we are going to need (softer)better tires.. Will you be happy to pay $100 or more for a tire that will last 500-1000 kms?

If you really want a MTB with drops get a cross bike :twisted:

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Wingnut
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by Wingnut

sugarkane wrote:To get maximum performance out of road bike disks it's going to take time and lots of trial and error..


No sh#t, Sherlock...

How is this dissimilar from mtb discs in the begining? Heavy and marginally more effective than cantilevers, many pros stuck with cantilevers due to the weight issues and where are they now...
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airwise
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by airwise

Sugarkane - you didn't answer the question.

Have you ridden a bike with discs?

From your posts it would appear not.

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sugarkane
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by sugarkane

Hybrid roadie/commuiter with disks.. Yup, MTBs yup..

$10000+ road bike with disks no..

airwise
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by airwise

So that's no then.

Most of us haven't. Closest I've got is 20km descents on a cross bike with Force, 23c tyres and BB7's.

Of course rim brakes will always be lighter but if you want to descend quickly for 10km, you really don't want a super light and unaerodynamic bike in the first place.

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prendrefeu
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by prendrefeu

airwise wrote:Of course rim brakes will always be lighter but if you want to descend quickly for 10km, you really don't want a super light and unaerodynamic bike in the first place.


While I agree that disc brakes may make braking easier/better for many riders (note the use of 'may' and 'many') - I'll need to dig into your statement there.

First, name a 10km descent, paved, on this planet, that is at a greater avg gradient than 6%. Shorter descents? Sure. That long? I haven't heard of one.
At 6% it really isn't necessary to hit the brakes much, if at all. Honest question, I'm interested. Maybe I need to move to Switzerland. :mrgreen:

I do know of a few 4km descents at 17-18% (continuous), but those are quite rare and rim brakes haven't been a problem at all on those.

Second, if you want to descend quickly I agree "super light" may not be of benefit, however the term 'unaerodynamic' would apply to the disc brake more so than the rim brake bike. Therefore a quick descent would most likely be equal, if not more possible, on a rim brake bike.
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VNTech
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by VNTech

There are half a dozen 10km+, 6%+ climbs within riding distance of where I sit right now in the French Alps. There are just as many within riding distance of my house in Boulder. 6% is quite shallow, and 10km is not that long. Just today I descended for 16km at an average grade of 6.9%. http://app.strava.com/rides/19665099

More importantly, though, they all have tons of corners. So you brake quite a bit regardless of skill or grade, unless you want to fly off a cliff.

Seriously everyone, stick with the good arguments about weigh, aerodynamics, neutral support, etc etc. Trying to argue that discs won't be better purely in terms of function (that is, slow you down faster in a more controlled manner in more varied conditions) is just absurd, and makes you look a bit daft. Of the myriad arguments against going disc, that is simply not one of them.

Further, the argument that better brakes don't allow faster descending is disproved by literally every wheeled sport in existence, including cycling. Again, this is not an argument anyone should be making. What you CAN argue, though, is that other factors may outweigh this benefit. That's completely rational, and largely true at least for now.
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eric
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by eric

I just did a 13.5 mile 6.2% descent in the eastern Sierras after a race, and there'll be another tomorrow.

Where I live there are a lot of long steep descents, and they have a lot of tight corners.

Strong well modulated brakes that don't overheat the rims would be great. But right now the weight penalty is too high, especially considering that the current brakes work reasonably well. Stronger brakes would make for faster descending because you could leave the braking for later, spending more time at speed. But the difference is small. In the amateur races I do we don't often have steep long technical descents so a small improvement in descending speed due to better brakes would not be much of a competitive advantage. Not worth adding a couple pounds to the bike.

I could see pro bikes using discs some day, especially if the current UCI weight limit remains. The rest of the bike could be made light enough to compensate for the added weight of discs and still stay close to the limit.

by Weenie


airwise
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by airwise

My average descent would certainly be steeper than 6% and go on for at least 10km Pren - I guess our perceptions are influenced by where we ride to a degree.

I haven't ridden the road in Ca so can't really comment (when I was there I was very much a mountain biker).

Over here the amount of braking will of course vary enormously depending on the confidence of the rider. I rarely touch the brakes on anything less than 10% except when hitting them hard for sharp turns. Some people I ride with are on them almost all the time.

With regards to the aerodynamics I'll wait and see first. I note that Trek and others claim big aero gains from removing the rear caliper from the airflow. Likewise for Ridley & BMC for the front. It seems there are positives as well as negatives to the employment of discs. The profile of rims will be totally free so gains can be expected there without transitions to braking surfaces. A fork that encloses the front disc will add what, 50g, to the weight of the bike?

One day I hope we'll all have an enclosed drivetrain/disc brake assembly really tidying up the airflow - after all isn't it remarkable that we are riding around on carbon wonder bikes with exposed gearing and derailleurs after all these years?

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