UCI expected to approve Road Disc Brakes for 2016

Discodan
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Re: UCI expected to approve Road Disc Brakes for 2016

Postby Discodan » Tue Sep 19, 2017 6:56 pm

fat and old wrote:
Shouldn't the weight of the disk be included when comparing? You don't exactly remove the brake track from a wheel when checking the rim brake version, disks are essentially the brake track aren't they? Overall weight of the wheel/braking surface is apples with apples?


Depends if you include that in the weight of the overall groupset or not. To my mind it doesn't make much of a difference as the disc is very centralised around the axis of rotation (the axle)

If you go back to my original point that triggered Comedian's rant about wheel weight, it was about refuting the performance impact about the additional rotational inertia of a disc. I didn't say a disc wheelset would be lighter but that a disk rim would be. If you took a disc and a rim brake wheelset of identical weight, the disc wheelset would accelerate faster, and feel like a lighter wheelset, because of its lower rotational intertia. Because a disc wheelset requires additional mass at the hub and spokes but less at the rims it becomes hard to compare the two.

I would be willing to bet that even though a Roval CLX wheelset weighs an extra 50g for the disc version, that it would accelerate faster; It's starting to get too hard now. Wouldn't it be easier if we all just settled on the fact the discs are far superior and anyone who still rides rim brakes is a fun-hating luddite?
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Re: UCI expected to approve Road Disc Brakes for 2016

Postby Duck! » Tue Sep 19, 2017 7:12 pm

warthog1 wrote:That is a point I hadn't thought about. When you remove braking force from the rim and move it inboard to the hub will greater forces be imparted to the spoke bed where it meets the rim, or are the forces still there on a rim brake? The bike is slowing either way, does cross lacing resolve it and that's it?
Will it mean more material needs to be placed there offsetting the losses from the removal of material at the brake track?
Apparently not from the example above.

There's no additional force on the rim from disc brakes, because the bike is essentially hung by the spokes regardless of the brake type used. On a rim-braked wheel the two points of friction, those being the brake and the ground contact, are acting on the same part of the wheel, so there is minimal rotational force going through to the hub. With any form of hub braked wheel, whether that's a disc brake, a drum brake or a coaster hub brake, the force from the brake needs to transfer through the spokes to the rim, which if radially-laced creates a twisting motion of the hub in the wheel. This "wind-up" would result in poor brake feel, and a significantly higher risk of spoke breakage. Crossed lacing braces against this torque, and is exactly the same reason why rear wheels are cross-laced to transfer drive torque.
I had a thought, but it got run over as it crossed my mind.

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Re: UCI expected to approve Road Disc Brakes for 2016

Postby warthog1 » Tue Sep 19, 2017 7:48 pm

biker jk wrote:
warthog1 wrote:
MichaelB wrote:
Just glad I didn't buy the last Propel, as I'd be feeling ripped off by my extra 15W that it takes to pedal at a speed I can't typically get to !!!


You'll need to read Alex Simmon's comment to place that 15w figure in perspective. It appears to be heavily on the marketing side of factual.


Speaking of marketing bs, don't you own a Zipp wheelset? :lol:


Yeah I know they have the lamest of lame marketing but yes they are fast. :lol:
The cheapy ribble alloy is faster than the cervelo if I put them in it and the cervelo wears nomal aluminium clinchers.
Haven't ridden the cervelo or the zipps for about 6 mnths though. They may well be wasted on me now.

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Re: UCI expected to approve Road Disc Brakes for 2016

Postby biker jk » Tue Sep 19, 2017 8:18 pm

warthog1 wrote:
Yeah I know they have the lamest of lame marketing but yes they are fast. :lol:
The cheapy ribble alloy is faster than the cervelo if I put them in it and the cervelo wears nomal aluminium clinchers.
Haven't ridden the cervelo or the zipps for about 6 mnths though. They may well be wasted on me now.


I don't doubt that deeper rims are faster, just that Zipp uses marketing gimmicks like dimples which do nothing (see from 10.12 in the video below).


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Re: UCI expected to approve Road Disc Brakes for 2016

Postby warthog1 » Tue Sep 19, 2017 9:14 pm

biker jk wrote:
I don't doubt that deeper rims are faster, just that Zipp uses marketing gimmicks like dimples which do nothing (see from 10.12 in the video below).



Meh, I suspect you are right. They were less than 1/2 price NRS neutral spares with naff all use.
I'd just buy the wiggle prime wheels now if they weren't reduced price.
I'm 48 now and I can't see myself needing aero anything anymore really :( lol

How lame is the "speed weaponry" slogan :lol:

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Re: UCI expected to approve Road Disc Brakes for 2016

Postby MichaelB » Wed Sep 20, 2017 8:34 am

Hahaha, love all the comments re the marketing, especially from Giant.

Their statement has so little fact and so little meaning that it is useless. It gives a single data point (no doubt the best one) for a single and very specific set of conditions in a wind tunnel (not the real world), with a pedalling manikin (not a real person), at a very specific speed (38.6km/hr), at a very specific cadence (85) and no details on what the yaw angle is or even frame size, bike setup (stack & reach, in drops or on hoods, rim type & size, tyre size etc, etc).

One step out in the real world and every variable changes every second, so those '15W' will vary all over the place.

(AT) warthog1 - Speed weaponry is not anywhere near as lame as the marketing BS behind 'biomimicry' ......

Anyway, back to discs being approved. When is the UCI going from Trial to full use approved ?

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Re: UCI expected to approve Road Disc Brakes for 2016

Postby Alex Simmons/RST » Wed Sep 20, 2017 10:44 am

It's reasonable to criticise marketing departments (and hence Brands) for manipulating or misrepresenting wind tunnel data.

But I wouldn't be so quick to criticise the wind tunnel methodologies used to ascertain the data. Obviously one would like information on the tunnel, process and personnel involved but wind tunnels have been and are excellent tools to assess aerodynamic properties of cycling equipment and cyclists and have been demonstrated to reliably predict actual performance in "the real world". That's because the physics or air flow doesn't magically change just because you make measurements in a tunnel.

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Re: UCI expected to approve Road Disc Brakes for 2016

Postby biker jk » Wed Sep 20, 2017 11:11 am

Alex Simmons/RST wrote:It's reasonable to criticise marketing departments (and hence Brands) for manipulating or misrepresenting wind tunnel data.

But I wouldn't be so quick to criticise the wind tunnel methodologies used to ascertain the data. Obviously one would like information on the tunnel, process and personnel involved but wind tunnels have been and are excellent tools to assess aerodynamic properties of cycling equipment and cyclists and have been demonstrated to reliably predict actual performance in "the real world". That's because the physics or air flow doesn't magically change just because you make measurements in a tunnel.


Hambini Engineering disagrees.

Speed tests are often conducted at 40km/h (50km/h in the latest bikeradar test), they do this because if they did this at a lower speed, there would be insufficient difference between the best wheel and the worst wheel to justify the horrendous price difference. The average "good" rider will probably be going at 35km/h (air density will affect this), most club riders are at 28km/h. At these "mortal" speeds a NACA aerofoil is quite effective because it's side to side vortex shedding is limited. A toroidal aerofoil is really only good in completely steady state conditions such as a wind tunnel. Out on the road which is where it matters, there are various bits of road furniture that upset the airflow coming onto the rider - technically this is called transient analysis.
Items such as lamp posts, a passing car, a hedge all affect the airflow. Another factor which nobody seems to have commented on is when a rider is going full gas, their bike tends to rock slightly from left to right, only by a few degrees but this upsets the oncoming airflow. An aerofoil which sheds fewer vortices during this process will be more aerodynamic.

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Re: UCI expected to approve Road Disc Brakes for 2016

Postby andrewjcw » Wed Sep 20, 2017 11:39 am

Are you guys serious? It's a first ride report in a cycling magazine, not a bloody scientific journal. The logical take away is that, as we already knew, the aerodynamics arguing of rim vs disc brakes is silly and diversionary. Of course it doesn't matter if it's 15 watts or 12 watts or what the exact testing protocol or sample number or yaw or p value is.

Is 15 watts exaggerated and probably best case? Yeah, probably, as any good marketing team would swing results. But we also know it's very unlikely to be an outright lie or that the reality is that the last model was in fact more aerodynamic, Giant (and every other manufacturer) has a lot more to lose than gain by such stupidity.

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Re: UCI expected to approve Road Disc Brakes for 2016

Postby kb » Wed Sep 20, 2017 1:21 pm

jasonc wrote:http://road.cc/content/news/154249-first-ride-stunning-new-focus-izalco-max-disc-road-bike
The new Focus Izalco Max Disc comes with the claim of being the world’s lightest production disc-equipped road bike, and with a SRAM Red-equipped model coming in at 6.8kg for a size 56cm, it nudges the Specialized S-Works Tarmac Disc I tested last year off the top spot.

I ride with a friend who has one of those. 48cm though so light enough :-)
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Re: UCI expected to approve Road Disc Brakes for 2016

Postby Alex Simmons/RST » Wed Sep 20, 2017 2:53 pm

biker jk wrote:
Alex Simmons/RST wrote:It's reasonable to criticise marketing departments (and hence Brands) for manipulating or misrepresenting wind tunnel data.

But I wouldn't be so quick to criticise the wind tunnel methodologies used to ascertain the data. Obviously one would like information on the tunnel, process and personnel involved but wind tunnels have been and are excellent tools to assess aerodynamic properties of cycling equipment and cyclists and have been demonstrated to reliably predict actual performance in "the real world". That's because the physics or air flow doesn't magically change just because you make measurements in a tunnel.


Hambini Engineering disagrees.

Speed tests are often conducted at 40km/h (50km/h in the latest bikeradar test), they do this because if they did this at a lower speed, there would be insufficient difference between the best wheel and the worst wheel to justify the horrendous price difference. The average "good" rider will probably be going at 35km/h (air density will affect this), most club riders are at 28km/h. At these "mortal" speeds a NACA aerofoil is quite effective because it's side to side vortex shedding is limited. A toroidal aerofoil is really only good in completely steady state conditions such as a wind tunnel. Out on the road which is where it matters, there are various bits of road furniture that upset the airflow coming onto the rider - technically this is called transient analysis.
Items such as lamp posts, a passing car, a hedge all affect the airflow. Another factor which nobody seems to have commented on is when a rider is going full gas, their bike tends to rock slightly from left to right, only by a few degrees but this upsets the oncoming airflow. An aerofoil which sheds fewer vortices during this process will be more aerodynamic.


The point about air speed is reasonable, which is why I much prefer to provide aerodynamic comparisons as differences in CdA since that is independent of air speed* (across the range of typical cycling speeds / Reynolds numbers).

Yet when we attain analysis from both wind tunnel and field testing, we find close agreement between them. This is not news, it goes back to at least the 1990s in published work which ultimately resulted in a validation of the mathematical model of road cycling power. Indeed the real world results were so good, it was recognised that when field testing with a quality power meter (and good process and analytical technique) it was possible to attain resolution as good as quality wind tunnels.

That's probably because all of the small transient factors have a tendency to average out. It's rare that such things create a bias of any significance in the results.

You can do CFD analysis as way to model various scenarios as well.

The aerodynamics testing I do is with the rider actually riding their bike.

As an example, theoretical models, CFD analysis, wind tunnel testing and field testing of riders riding in close proximity to each other result in the same aero outcomes for both leading and trailing riders.


* there are some interesting specific cases where this might not be the case, e.g. strategic use of trips on an object of a particular size and shape (like an upper arm) at cycling speeds where CdA may not be independent of Re. In any case, the same impacts are measurable in the field and in a tunnel.

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Re: UCI expected to approve Road Disc Brakes for 2016

Postby Comedian » Thu Sep 21, 2017 12:59 pm

warthog1 wrote:Thanks Nobody.
I think I've asked the question before and braking forces imparted on the wheel are lower than the force applied by irregularities in the road surface.

Yes, and the tricky bit is - and this is the thing that all the disc advocates either refuse or unable to understand.. moving the braking moment forces so much lower means that the fork has to be massively stronger. Pretty much all of the compliance in the front end of a road bike comes from the fore and aft movement of the fork. To make matters worse - the forces are asymmetric (Ie they act differently from side to side). So, if you don't want unwanted steering effects under strong braking you've got to make the fork **really** strong.

Hence, all compliance is lost in the front, which is I suspect why we're seeing systems like the specialized "headshock"

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Re: UCI expected to approve Road Disc Brakes for 2016

Postby Comedian » Thu Sep 21, 2017 1:11 pm

jasonc wrote:http://road.cc/content/news/154249-first-ride-stunning-new-focus-izalco-max-disc-road-bike
The new Focus Izalco Max Disc comes with the claim of being the world’s lightest production disc-equipped road bike, and with a SRAM Red-equipped model coming in at 6.8kg for a size 56cm, it nudges the Specialized S-Works Tarmac Disc I tested last year off the top spot.


LOL :mrgreen:

As far back as 2013 the same bike from the same manufacturer... That's progress for you...

The top specced Izalco Max 0.0 weighs a claimed 5.4kg for a size 54, built up with SRAM Red 11, DT Swiss RRC carbon wheels and Schwable One tubular tyres and THM Fibula carbon brakes.


http://road.cc/content/news/87814-focus-izalco-max-and-chrono-max-launched

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Re: UCI expected to approve Road Disc Brakes for 2016

Postby MichaelB » Thu Sep 21, 2017 2:12 pm

Note, my highlights

Comedian wrote: ..... moving the braking moment forces so much lower means that the fork has to be massively stronger. Pretty much all of the compliance in the front end of a road bike comes from the fore and aft movement of the fork. To make matters worse - the forces are asymmetric (Ie they act differently from side to side). So, if you don't want unwanted steering effects under strong braking you've got to make the fork **really** strong.

Hence, all compliance is lost in the front, which is I suspect why we're seeing systems like the specialized "headshock"


The fork has to be constructed differently to accept different forces in different areas, yes. But terms like, 'massively' and '**really**' are just bollocks I'm afraid.

You are obviously anti-disc, and that's fine, but when you raise falsehoods and exaggerations, that's just stoopid.

Compliance is not 'lost' just because a fork has a disc brake mounted to it.

Ant the blue highlighted statement is just utter rubbish.

I really don't know where you get some of your assertions and understanding from.

If you don't like discs, fine. I couldn't care less, but using unfathomable arguments to support that dislike is just weird ....

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Re: UCI expected to approve Road Disc Brakes for 2016

Postby biker jk » Thu Sep 21, 2017 2:34 pm

Comedian wrote:
jasonc wrote:http://road.cc/content/news/154249-first-ride-stunning-new-focus-izalco-max-disc-road-bike
The new Focus Izalco Max Disc comes with the claim of being the world’s lightest production disc-equipped road bike, and with a SRAM Red-equipped model coming in at 6.8kg for a size 56cm, it nudges the Specialized S-Works Tarmac Disc I tested last year off the top spot.


LOL :mrgreen:

As far back as 2013 the same bike from the same manufacturer... That's progress for you...

The top specced Izalco Max 0.0 weighs a claimed 5.4kg for a size 54, built up with SRAM Red 11, DT Swiss RRC carbon wheels and Schwable One tubular tyres and THM Fibula carbon brakes.


http://road.cc/content/news/87814-focus-izalco-max-and-chrono-max-launched


You're talking bs again. The comparable bike is the Izalco Max 3.0 which weighs 6.2kg versus 6.8kg for the disc brake model. That 600 gram weight penalty is about the average for all brands.


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Re: UCI expected to approve Road Disc Brakes for 2016

Postby warthog1 » Thu Sep 21, 2017 3:18 pm

Comedian wrote:Yes, and the tricky bit is - and this is the thing that all the disc advocates either refuse or unable to understand.. moving the braking moment forces so much lower means that the fork has to be massively stronger. Pretty much all of the compliance in the front end of a road bike comes from the fore and aft movement of the fork. To make matters worse - the forces are asymmetric (Ie they act differently from side to side). So, if you don't want unwanted steering effects under strong braking you've got to make the fork **really** strong.

Hence, all compliance is lost in the front, which is I suspect why we're seeing systems like the specialized "headshock"


You would think they'd be a bit less compliant true.
I better shutup about that however given my hx of posting youtube clips showing compliant steel forks bending. lol

I think that disc braked bikes will take over once an axle size and type becomes std.

I might buy one in another 5-10 years.Prob not.
Braking aint a big issue for me pedaling is.
I hate riding in the rain. So if I know it's going to rain I either dont ride or take a short cut.
Rim brakes work fine for me for my riding.

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Re: UCI expected to approve Road Disc Brakes for 2016

Postby Arbuckle23 » Thu Sep 21, 2017 6:48 pm

warthog1 wrote: once an axle size and type becomes std.


Yep, it's still a dogs breakfast at the moment.

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Re: UCI expected to approve Road Disc Brakes for 2016

Postby Discodan » Thu Sep 21, 2017 7:26 pm

biker jk wrote:
You're talking bs again. The comparable bike is the Izalco Max 3.0 which weighs 6.2kg versus 6.8kg for the disc brake model. That 600 gram weight penalty is about the average for all brands.



Correct, the other way of looking at it is the weight-weenie special Izalco Max Disc they built with tubs, THM gear etc was 'under 6kg' so once again 600g heavier than the rim brake WW special
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Re: UCI expected to approve Road Disc Brakes for 2016

Postby g-boaf » Thu Sep 21, 2017 9:45 pm

Comedian wrote:
jasonc wrote:http://road.cc/content/news/154249-first-ride-stunning-new-focus-izalco-max-disc-road-bike
The new Focus Izalco Max Disc comes with the claim of being the world’s lightest production disc-equipped road bike, and with a SRAM Red-equipped model coming in at 6.8kg for a size 56cm, it nudges the Specialized S-Works Tarmac Disc I tested last year off the top spot.


LOL :mrgreen:

As far back as 2013 the same bike from the same manufacturer... That's progress for you...

The top specced Izalco Max 0.0 weighs a claimed 5.4kg for a size 54, built up with SRAM Red 11, DT Swiss RRC carbon wheels and Schwable One tubular tyres and THM Fibula carbon brakes.


http://road.cc/content/news/87814-focus-izalco-max-and-chrono-max-launched


What exactly do you intend to do with a 5.4kg bike? Tape some spanners to it every time you want to race it? Ultra light weight brakes... Hmm, no thanks. I know those Focus bikes well, I've seen many Izalco Max frames being built up for a race team and they are very, very nice. But once you are at 6.8kg there is really no point in going for more.

If you really want light, get yourself an AX Lightness Vial Evo Ultra at 4.4kg, at a massive price.

I'd like to have a go at a high end disc brake road bike though.

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Re: UCI expected to approve Road Disc Brakes for 2016

Postby andrewjcw » Fri Sep 22, 2017 10:18 am

http://www.bikeradar.com/au/road/news/a ... kes-50852/

Pro conti team apparently going to disc only bikes with 1x for 2018...

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Re: UCI expected to approve Road Disc Brakes for 2016

Postby Comedian » Fri Sep 22, 2017 1:41 pm

MichaelB wrote:Note, my highlights

Comedian wrote: ..... moving the braking moment forces so much lower means that the fork has to be massively stronger. Pretty much all of the compliance in the front end of a road bike comes from the fore and aft movement of the fork. To make matters worse - the forces are asymmetric (Ie they act differently from side to side). So, if you don't want unwanted steering effects under strong braking you've got to make the fork **really** strong.

Hence, all compliance is lost in the front, which is I suspect why we're seeing systems like the specialized "headshock"


The fork has to be constructed differently to accept different forces in different areas, yes. But terms like, 'massively' and '**really**' are just bollocks I'm afraid.

You are obviously anti-disc, and that's fine, but when you raise falsehoods and exaggerations, that's just stoopid.

Compliance is not 'lost' just because a fork has a disc brake mounted to it.

Ant the blue highlighted statement is just utter rubbish.

I really don't know where you get some of your assertions and understanding from.

If you don't like discs, fine. I couldn't care less, but using unfathomable arguments to support that dislike is just weird ....

No, a fork doesn't loose compliance because it has a disc brake mounted to it. However, a fork that has a disc brake mounted to it needs to be far stronger. That's what causes the loss of compliance. Do tell me, where else can the compliance come from? Do disc brakes come with a physics exemption? I must have missed the memo!

I have a bike that doesn't have a disc brake that has a very very stiff fork. It's a dog to ride on anything other than a very smooth road. I don't like it - not one little bit. It's only because I have other bikes that have much better forks that I know that I don't have to put up with it - should I choose not to.

Perhaps you should do some reading?

Deflection is flex. All forks do it. A fork with lots of deflection is flexible, and can feel squirrelly or soft for heavier riders, but may be perfectly matched for lighter riders or riders who want a little more comfort. A fork with very little deflection is stiff. A stiffer fork can be jarring over bumps, but often is more precise in handling.


https://www.sheldonbrown.com/rinard/rinard_forktest.html

https://cyclingtips.com/2012/05/whats-in-a-fork/

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Re: UCI expected to approve Road Disc Brakes for 2016

Postby Comedian » Fri Sep 22, 2017 1:53 pm

biker jk wrote:
Comedian wrote:
jasonc wrote:http://road.cc/content/news/154249-first-ride-stunning-new-focus-izalco-max-disc-road-bike


LOL :mrgreen:

As far back as 2013 the same bike from the same manufacturer... That's progress for you...

The top specced Izalco Max 0.0 weighs a claimed 5.4kg for a size 54, built up with SRAM Red 11, DT Swiss RRC carbon wheels and Schwable One tubular tyres and THM Fibula carbon brakes.


http://road.cc/content/news/87814-focus-izalco-max-and-chrono-max-launched


You're talking bs again. The comparable bike is the Izalco Max 3.0 which weighs 6.2kg versus 6.8kg for the disc brake model. That 600 gram weight penalty is about the average for all brands.


Look.. I don't know.. I'm sure you're on it. When you guys said that the lightest production disc brake in the world.. I just googled an older rim brake model. It even had the same group and bigger heavier wheels. I'd love to know where the weight goes.. I asked for it many times in many threads but no one seems to be able to tell me. I just get yelled at for being a heretic.

All I know is that my training bike, a cheap lynskey with durable alloy wheels (30k+) and a powermeter weighs about the same. My mate's caad10 also with power meter and alloy wheels also weighs about the same. Neither bike even gives a nod to weight weenie-dom but both match the top dollar weight weenie disc bike. That's progress.

EDIT: I'll watch the video later
EDIT: I fully expected that not matter what bike I used for comparison someone would think it was somehow different or no applicable. I tried to mitigate that by using the same brand, model, and groupset... but alas...

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Re: UCI expected to approve Road Disc Brakes for 2016

Postby MichaelB » Fri Sep 22, 2017 3:24 pm

Comedian wrote: I have a bike that doesn't have a disc brake that has a very very stiff fork...


So as you point out, the lack of flex/compliance/deflection/etc/etc has NOTHING to do with whether it has a disc or not.

Just because something is strong in a given direction, does not mean it isn't compliant in another. That's called DESIGN. Something a good engineer knows about.

Have a look at some F1 componentry and you'll see what I mean.

No, mass production road bikes do not have the same level of engineering, and nor do disc forks, but they are not all equal. Aside from the fork, there are MULTIPLE sources of compliance such as (and not limited to) tyres (size & construction), rims, spokes, wheel construction, frame geometry, frame stiffness, stem, handlebars, bar tape, oh and I forgot tubes.

Ah crap, just fed the troll again ..... :roll: :|

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Re: UCI expected to approve Road Disc Brakes for 2016

Postby Comedian » Fri Sep 22, 2017 3:47 pm

warthog1 wrote:
Comedian wrote:Yes, and the tricky bit is - and this is the thing that all the disc advocates either refuse or unable to understand.. moving the braking moment forces so much lower means that the fork has to be massively stronger. Pretty much all of the compliance in the front end of a road bike comes from the fore and aft movement of the fork. To make matters worse - the forces are asymmetric (Ie they act differently from side to side). So, if you don't want unwanted steering effects under strong braking you've got to make the fork **really** strong.

Hence, all compliance is lost in the front, which is I suspect why we're seeing systems like the specialized "headshock"


You would think they'd be a bit less compliant true.
I better shutup about that however given my hx of posting youtube clips showing compliant steel forks bending. lol

I think that disc braked bikes will take over once an axle size and type becomes std.

I might buy one in another 5-10 years.Prob not.
Braking aint a big issue for me pedaling is.
I hate riding in the rain. So if I know it's going to rain I either dont ride or take a short cut.
Rim brakes work fine for me for my riding.


I tried to think of what would encourage me to buy a disc bike. This was all I had...

- I move somewhere where I needed to ride in the rain more than twice a year. Or something happens and the world looses all the Kickrs.
- I move somewhere so flat that I won't have to deal with constantly dragging heavy bikes up hills.. but hold on.. I really won't need brakes then...
- I move somewhere so hilly that I'm unable to effectively stop with rim brakes. Roll on my shack in the Pyrenees.
- I buy a road bike with tyres big enough to actually use all the extra brake force, and also big enough to replace the lost front end compliance. I'm thinking this would take 30+ but I'm actively experimenting in this area.
- Should I be unable to buy replacement parts for my current bikes. Given the rise of "performance rim braked bikes" I'm pretty relaxed about this one.
- Someone from specialized/giant holds me down and fills me with coolaide... rendering me unable to critically asses the situation.

But hey.. people like riding bikes. People like buying bikes. If you want to buy a disc braked road bike - and that makes you happy then go knock yourself out. But don't hate on me for not wanting one. I ride what I ride because I don't like buying new things just because they're new. I appreciate the world needs consumers though. :|

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Comedian
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Joined: Mon Aug 09, 2010 7:35 pm
Location: Brisbane

Re: UCI expected to approve Road Disc Brakes for 2016

Postby Comedian » Fri Sep 22, 2017 4:00 pm

MichaelB wrote:
Comedian wrote: I have a bike that doesn't have a disc brake that has a very very stiff fork...


So as you point out, the lack of flex/compliance/deflection/etc/etc has NOTHING to do with whether it has a disc or not.

Just because something is strong in a given direction, does not mean it isn't compliant in another. That's called DESIGN. Something a good engineer knows about.

Have a look at some F1 componentry and you'll see what I mean.

No, mass production road bikes do not have the same level of engineering, and nor do disc forks, but they are not all equal. Aside from the fork, there are MULTIPLE sources of compliance such as (and not limited to) tyres (size & construction), rims, spokes, wheel construction, frame geometry, frame stiffness, stem, handlebars, bar tape, oh and I forgot tubes.

Ah crap, just fed the troll again ..... :roll: :|


For the life of me.. I don't understand how you can't understand that stiffening a fork enough for braking forces won't lead to a stiffening of the front end. If that makes me a troll then so be it.

All the other sources of compliance can be changed on any bike. Apart from the fork, and tubes/tyres they are all pretty minor.

Would you believe specialized? When they added a disc - even with the help of McLaren (world leaders in composites) they couldn't get around the problem so they added a mechanical shock absorber to replace the lost compliance. As I said, I've ridden bikes with very stiff forks - and I agree with Specialized (GASP). They aren't very nice to ride on anything other than the smoothest of roads and they are fatiguing on longer rides. All good for crit races though.

For what it's worth - I think the specialized system is a pretty well thought out answer to the problem their engineers knew they needed to solve. Personally - if I really wanted a disc brake road bike I'd try one of them. Fortunately for me - I have nice compliant forks (ENVE) and I don't need disc brakes so I'm all good.

https://www.specialized.com/au/en-au/smoother-is-faster
FUTURE SHOCK
When it comes to compliance, there are two competing schools of thought. In one corner, there's splay. In the other, there's axial compliance. Essentially, splay is the fore & aft movement of the front axle, relative to the frame, as a result of any bending of the frame and fork. Meanwhile, axial (or vertical compliance) can be characterized as the movement of the handlebars, relative to the front axle, as a result of fork, frame, and stem compliance.

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