# Disc Brakes are coming to road bikes too - Colnago style



## bee (Apr 7, 2008)

Here it comes! The UCI is going to approve disc brakes for road competition. It's just a matter of time. The only question is if the industry (road, that is) will eventually settle on smaller 140mm discs, or 160mm discs.

This is Colnago's entry into the road bikes w/ disc brakes, on display at this years Taipei Bike Show. It great that Colnago decided to do an actual road fork w disc tabs, and not a supertall cyclocross fork w/ disc tabs, thus keeping the frame a true road geometry, and not some quasi cyclocross-hybrid. Behold! :thumbsup:

More pics here:
Tapei show: Colnago launch C59 Disc road bike | road.cc | Road cycling news, Bike reviews, Commuting, Leisure riding, Sportives and more


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## pvd (Jan 4, 2006)

Any disc bike without active front suspension is pretty much garbage. It's cool right now to do it, but it's a pretty lousy bike.

They key here is ACTIVE FRONT SUSPENSION. Passive suspension is definately not adequate to handle the job of supporting the brake load AND provide for a comfortable ride.


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## ohpossum (Dec 19, 2003)

The big deal to me is that Formula have either made their own di2 innards for the levers or are using Shimano guts inside their levers. I'm not sure Shimano will allow Formula to sell either option.


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## Guerdonian (Sep 4, 2008)

Saw this on Cyclingnews this morning
Although i would love disk brakes on my road bike i foresee the following problems:

1. Weight: with super light components the disk brake system would have to be ultra light, which is possible, but currently non existent. Probably requireing small diameter Ti rotors, compact caliper.

2. Integration into sifter/brake lever: Probably a easy switch over with mechanical disk brakes, but for hydraulic the reservoir would have to be integrated into the brake lever/shifter mechanism by one of the "big 3" Sram Shimano or Campy 

3. Front end braking: With a super light weight fork, the forces generated at the caliper could cause some bad things through the bike. Racing rodies see some high speeds, and rapid deceleration. The longer moment arm to caliper location only makes the stresses seen at the steertube higher. Plus what PVD already mentioned.

4. Heat: with a lightweight small rotor, on a bike that is consistently decelerating on a very long downhill the heat buildup will be quite large, causing a lot of fade, or "boiling" of the hydraulic line. Catch 22 of a larger rotor disapating heat better, but adding weight, which is a no no with performance road machines.

The pros would be no more sketchy cork pads on all carbon rims, better breaking modulation, and non of that awful squealing noise when breaking under hard turning (man it scares the crap out of me every time)


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## jay_ntwr (Feb 15, 2008)

I'm excited to see it. It's about time we get rid of half the cables on road bikes too. Seeing that Formula is involved is just icing on the cake.

Now if these guys would start doing hydraulic shifting instead of electronic, we'd be set. Still, the Colnago is cabless and I don't care what the other ramifications are, that's awesome to me. I'm still sort of surprised that the MTB wasn't the first cabless GA release--actually, I suppose the SS is.

The sooner the rim brake is completely obsolete, the better for us all. I don't care if there is a weight penalty either--folks are too crazy about weight at the expense of function.


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## Thor29 (May 12, 2005)

pvd said:


> Any disc bike without active front suspension is pretty much garbage. It's cool right now to do it, but it's a pretty lousy bike.
> 
> They key here is ACTIVE FRONT SUSPENSION. Passive suspension is definately not adequate to handle the job of supporting the brake load AND provide for a comfortable ride.


Am I missing something here? I have both a Salsa La Cruz and a Surly Troll with disc brakes and no front suspension. I have also ridden my Niner SIR9 with a rigid fork. In all three cases, the disc brakes work great. The Salsa is especially nice for bombing San Francisco hills - it takes a lot less lever pressure to slow it down than any rim brake bike I have ridden.


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## smdubovsky (Apr 27, 2007)

Guerdonian said:


> 3. Front end braking: ... The longer moment arm to caliper location only makes the stresses seen at the steertube higher.


I dont think so. The stresses within the fork legs are quite different but the stress at the steer/headtube should be the same. Draw a FBD. A disc simple relocates (and changes magnitude) one of the vectors. They still have to sum to a zero moment. Modern deep 'aero' fork blades like those pictures should be more than enough to cope w/ the different forces.


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## rockcrusher (Aug 28, 2003)

Guerdonian said:


> Saw this on Cyclingnews this morning
> Although i would love disk brakes on my road bike i foresee the following problems:
> 
> 1. Weight: with super light components the disk brake system would have to be ultra light, which is possible, but currently non existent. Probably requireing small diameter Ti rotors, compact caliper.
> ...


I think in this day and age of min UCI weight limits and bikes regularly shattering that and having to add weight back to the frame with powermeters, weights on the frame etc, it seems that weight is less of concern on discs on road bikes.

I agree that to get the discs accepted by the masses there needs to be a hydraulic integrated lever but this will be coming because CX is usually a mess, mud, snow and water and even the best cable system can be stymied by getting that goop in the caliper arm. Hydraulics won't have that problem so they will deliver them to the pros.

I think with a lot of the asymmetric layup we have been seeing with carbon accounting for the braking forces without messing with the ride of a fork shouldn't be a problem. If they an account for the asymmetry of the drive train they can get disc brakes.

Shedding the heat shouldn't be that big of a problem, shimano has cooled pads now and a carbon material rotors would make a lot of sense on a road bike. Not carbon fiber but carbon ceramic coatings like in the automotive high end.

Just my thoughts on the topic. I give discs on a road bike a thumbs up if only for not having to mess with the brake to swap in a tire and for being able to ride with a slightly tweaked wheel (provided it will bypass the frame).


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## Guerdonian (Sep 4, 2008)

smdubovsky said:


> I dont think so. The stresses within the fork legs are quite different but the stress at the steer/headtube should be the same. Draw a FBD. A disc simple relocates (and changes magnitude) one of the vectors. They still have to sum to a zero moment. Modern deep 'aero' fork blades like those pictures should be more than enough to cope w/ the different forces.


Yep, didn't think it through about the wheel torque to disc torque magnitude change, was simply thinking Force moved down on fork = larger moment. Hehe, my college engineering courses are getting rusty.



rockcrusher said:


> I think in this day and age of min UCI weight limits and bikes regularly shattering that and having to add weight back to the frame with powermeters, weights on the frame etc, it seems that weight is less of concern on discs on road bikes.
> 
> I agree that to get the discs accepted by the masses there needs to be a hydraulic integrated lever but this will be coming because CX is usually a mess, mud, snow and water and even the best cable system can be stymied by getting that goop in the caliper arm. Hydraulics won't have that problem so they will deliver them to the pros.
> 
> ...


Touche, solid on all points! I changed my mind, they are a good idea, which makes me want them even more. Sounds like a few years from now the switch will happen. As you hinted i think it will be cyclocross driven, and then a jump over into road.


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## G-reg (Jan 12, 2004)

I wonder where disc size will settle out. I really like my 140s, even on a mtb, but I ride in ND/MN. I made a front post mount for a 140 and still had good modulation, could still lock the front with one finger through a BB7. And that's great for short hard applications like ND "MTB" or cyclocross. You are putting the hurt on the pads and disc for sure, but not really putting much heat into the system. 

Now if I visit the homestead in CO, and find myself chickening out on a looong unfamiliar road descent I can see needing the mass of a bigger rotor for heat dissipation alone. *EDIT* Oh and 135mm rear spacing? Are the weight weenies going to really have low spoke counts on narrow hubs?


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## JaquesN (Sep 14, 2009)

If you build a fork stronger on one side, it's also going to flex less. So you either overbuild both sides or you have a fork with one more flexible side and one less. 

This seems like a loss for road bike feel, as well as for simplicity.


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## ade ward (Jun 23, 2009)

I also run rigid forks on my 29 er and feel the brakes are great, 
If PVD could explain his comments I would be very interested as far as the tyre is concerned disc brakes are the same as a calliper brake , or haveci missed the point, it wouldn't be the first time

The other part of the braking is that I don't think youvwould be able to run lightweight radial spoked front wheels it will have to transmit the braking torque through the spokes to the rim tyre 

But I am tempted I have seen a few heat affected carbon rims ,


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## Drew Diller (Jan 4, 2010)

ade ward said:


> But I am tempted I have seen a few heat affected carbon rims ,


Wha? Carbon is extremely heat resistant. It's the stuff left over when you burn some wood.It gets used it in F1 cars and jets and whatnot.


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## TigWorld (Feb 8, 2010)

Drew Diller said:


> Wha? Carbon is extremely heat resistant. It's the stuff left over when you burn some wood.It gets used it in F1 cars and jets and whatnot.


The carbon is, but the resins are not. Special (ie. more expensive) temp resistant resins need to be used in carbon rims with a braking track.


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## TimT (Jan 1, 2004)

SRAM already announced a hydro road disc brake option and hydro calipers for road bikes. 
SRAM Red Hydraulic Brakes | The Daily Grind Cycling Journal

Tim


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## Eric Malcolm (Dec 18, 2011)

My personal bike has disc's, I use it with both 26"x 2.1 and 700C x 23 wheels (as the outer diameters are almost the same) on a rigid steel fork, 160mm disc; post mounted. I too do not understand PVD's view as it does not match my experience in the riding of my bike. I consider this the premium way to go, nothing better out there.


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## dbohemian (Mar 25, 2007)

Drew Diller said:


> Wha? Carbon is extremely heat resistant. It's the stuff left over when you burn some wood.It gets used it in F1 cars and jets and whatnot.


TIG world already answered this. Just wanted to add. In fact, most carbon is burnt Rayon fiber so when some of the old timers call it "carpet fiber" that is not too far from the truth.

Carbon or graphite has one of the highest melting temps of all known elements but to use it in brakes and such they use a form called RCC or reinforced carbon in a carbon matrix. No epoxy. Downsides is that it is really expensive and brittle as was demonstrated when the RCC leading edge of the shuttle orbiter failed. So, its not for everything and because of its cost can only be used for Formula Un....


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## Drew Diller (Jan 4, 2010)

GTK, thank you.


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## DWF (Jan 12, 2004)

Discs on road bikes is so frikken' sexy! Come on hydro brifters!!!


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## G-reg (Jan 12, 2004)

I was riding my Salsa Fargoish/monster cross bike last night and I realized something. No matter how well set up a cable disc is, if it's at the end of 6ft if housing with the bends under bar tape, it's going to feel squishy. I like bb7's, but a hydro line would feel great on that long run.


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## customfab (Jun 8, 2008)

The race mechanic in me is dreading disc brake approval by the UCI. Discs certainly have their applications to fill in 'road' riding. But I don't think they are destine for the TDF. Wheel changes are going to triple in time and the slight variations in rotor alignment is going to cause problems as well. Not to mention keeping the rotors straight in the back of a car following a race.


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## james-o (Nov 8, 2010)

pvd said:


> Any disc bike without active front suspension is pretty much garbage. It's cool right now to do it, but it's a pretty lousy bike.
> 
> They key here is ACTIVE FRONT SUSPENSION. Passive suspension is definately not adequate to handle the job of supporting the brake load AND provide for a comfortable ride.


PVD, are you talking about needing/preferring anti-dive links in the fork to avoid brake dive when you talk about supporting the brake load?
If so I'd agree, but I think it's overkill on a road bike hence some suprised reactions to anyone suggesting a disc+rigid bike is garbage. We're used to thinking of 'active suspension' in terms of rear suspension from so many years of FS bikes marketing .

However since spending a couple of years on a rigid MTB, then on a really comfy, well-balanced 29er with big tyres (ie where I don't miss the sus forks at all) I've remembered how sus forks lose control under braking as much as gain it over bumps.

Not wanting to hijack a road bike disc thread, just interested in your comment.


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## TigWorld (Feb 8, 2010)

I think what PVD is getting at is that it is impossible (or perhaps extremely difficult) to build a rigid fork that gives a comfortable, compliant, vibration absorbing road ride (like you get with a quality carbon fork), and then have that fork also stiff enough to handle the single sided torsional forces from a brake caliper attached at the hub end of the structure.


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## james-o (Nov 8, 2010)

If so, it's odd to suggest that any disc-braked bike without springs is garbage. 

If passive suspension refers here to fork flex, yeah it's harder to balance the comfort and the stiffness needed for the brake but it's not impossible, people seem to manage more complex stuff with carbon. Or at least claim to.


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## Guerdonian (Sep 4, 2008)

During my monthly browsing of B.R.A.I.N. I came across this: 
Bicycle Retailer and Industry News

"Hydraulic rim brakes for the road are not new; Magura's HS77 and Mathauser hydraulic rim brakes were on the market about 20 years ago. But Magura's release of a new line of hydraulic rim brakes and SRAM's announcement that its hydraulic road brakes will arrive by fall signal a big change.

Shimano's 16 patents and patent applications in the area of road hydraulics-brakes, levers and hydraulic plumbing hardware-were published in 2011 (covered in this month's Tech Briefs column, page 24). Given this activity, it's probably safe to say it will join Magura and SRAM in offering roadies hydraulic options.

While hydraulic rim brakes do nothing to mitigate braking issues with carbon rims, their power and modulation will be welcomed by many. Plus, their obvious technological benefits make hydraulic brakes an easy showroom sell, depending on pricing."

No mention of disk, but hydraulic integration to the road world is well on the way already....


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## Guerdonian (Sep 4, 2008)

A bit more on the subject: Bicycle Retailer and Industry News

"But there remains wariness among some about whether discs make sense for the road (even ignoring the fact that the UCI still bands them in international competition). Cervelo co-founder Phil White told BRAIN that road discs can heat up and fade, or fail altogether, on long descents. He favors hydraulic rim brakes, which Cervelo is already using on its time trial bike courtesy of a new design from Magura. SRAM also is working on a hydraulic rim brake and integrated shifter.

American Classic founder Bill Shook told BRAIN on Wednesday that discs are a bad idea for the road. The brake rotors would need to be made larger to handle the heat, but larger rotors would add weight that roadies would reject, he said. Heat build-up from a long descent would not only lead to fading or failure; it would heat up the hub, possibly even causing the hub bearing seat to expand. To Shook's mind, the only upside for disc brakes on the road is that they would eliminate the braking and reliability challenges faced by the makers of all-carbon clincher rims."


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## jay_ntwr (Feb 15, 2008)

Guerdonian said:


> American Classic founder Bill Shook told BRAIN on Wednesday that discs are a bad idea for the road. The brake rotors would need to be made larger to handle the heat, but larger rotors would add weight that roadies would reject, he said. Heat build-up from a long descent would not only lead to fading or failure; it would heat up the hub, possibly even causing the hub bearing seat to expand. To Shook's mind, the only upside for disc brakes on the road is that they would eliminate the braking and reliability challenges faced by the makers of all-carbon clincher rims."


I don't know how many guys on here build wheels as well, but I refuse to build the AC disc hub for anyone over about 140lbs anymore because it sucks so badly and even then, there are better hubs for those folks. AC doesn't seem to be in a position to talk intelligently about disc brakes IMHO.

You'd think with all these guys talking about the gloom and doom that hydraulic disc brakes don't work on airplanes, F1, daily drivers or even, get ready..... bicycles. It reminds me of this on the scale of alarmist attitudes by folks that probably don't fully understand the problem:

Has the Large Hadron Collider destroyed the world yet?

someone register should:

havehydraulicdiscbrakesonroadbikesruinedtheentirebicycleindustryyetandkilledeveryonethattriedtorideabikedownahill.com


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## jay_ntwr (Feb 15, 2008)

*This sums it up with humor*

UCI to ban disc brakes on all caravan vehicles


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## Adam_M (Aug 8, 2008)

customfab said:


> The race mechanic in me is dreading disc brake approval by the UCI. Discs certainly have their applications to fill in 'road' riding. But I don't think they are destine for the TDF. Wheel changes are going to triple in time and the slight variations in rotor alignment is going to cause problems as well. Not to mention keeping the rotors straight in the back of a car following a race.


I totally agree with the rotor position and keeping rotors straight issues for race teams throwing wheels into cars mid race. Shouldn't be an issue following a race though?

Not sure about the wheel change point anymore. It would have been true last year, but the UCI's new rule about fork modifications which bans filing off the 'lawyer lips' is going to push wheel change times up anyway. Not sure that discs will add anything to that. If anything, the solution here is bolt through forks rather than conventional QRs, as modern bolt through axle systems can be quicker than a QR to do up!

Rotor sizes for road bikes won't be super small. The need to cater for long alpine descents will see 160 or even 180 mm as the standard size, IMO.

I don't buy the weight arguments. As long as the 6.8kg min weight limit applies, there is plenty of scope to accommodate an increase in the weight of the brakes without going above 6.8kg.


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## ohpossum (Dec 19, 2003)

I think we'll just see more bike changes versus wheel changes for the contenders. For the rest of the squibs on a team, they'll end up with slower wheel changes and more effort to get back in the group.


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## TimT (Jan 1, 2004)

I've done plenty of long steep desents on my MTB with out any hub/bearing issues. Its just a matter of time before road bikes come standard with disc brakes.

Tim


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## Mr.Magura (Aug 11, 2010)

dbohemian said:


> Downsides is that it is really expensive and brittle as was demonstrated when the RCC leading edge of the shuttle orbiter failed. So, its not for everything and because of its cost can only be used for Formula Un....


Expensive, most definitively right, but fragile and brittle is an old wives tale.

I have been working a lot with that stuff, and have even made a disc brake for my bike of it.
It works very well, and sports none of the drawbacks the material usually is claimed to have.
The raw material sure has a nasty price tag to it, but I would expect that to change within the next 10 years or so.

Keep in mind, that most people whom talks about that type of composites, have never seen it, let alone used it for anything. 
The degree of misinformation about composites in general, and friction composites in particular, is simply overwhelming.

Magura


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## rockcrusher (Aug 28, 2003)

Mr.Magura said:


> Expensive, most definitively right, but fragile and brittle is an old wives tale.
> 
> I have been working a lot with that stuff, and have even made a disc brake for my bike of it.
> It works very well, and sports none of the drawbacks the material usually is claimed to have.
> ...


All the carbon brakes i have seen have been on racecars and on high end sports cars as options and all have been huge due to the need of the race cars for cooling and stopping power. The one thing I have read is that they have a tendency to be hard cold brakes, needing a few stops to get them to really bite.

How are they for an application that requires them to be so thin? and how is the initial bite for a bike, if you have tested this?

I know for a fact that carbon ceramic brakes would be awesome for mountain bikes, especially those of us that gravity likes a little more (hefty folk). I have burned myself on rotors and have had caliper pump from DOT fluid that has ingested too much humidity from the air between bleeds. Carbon Ceramic brakes should be able to avoid a lot of that, but where does the heat go? I have seen LeMans cars with Carbon rotors glowing in the night laps so they definitely get hot. Is the compound actually able to drop the heat enough that it would be benefit or is this a technology that really isn't suited to anything but TDF road bikes in the hills?


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## Mr.Magura (Aug 11, 2010)

rockcrusher said:


> All the carbon brakes i have seen have been on racecars and on high end sports cars as options and all have been huge due to the need of the race cars for cooling and stopping power. The one thing I have read is that they have a tendency to be hard cold brakes, needing a few stops to get them to really bite.
> 
> How are they for an application that requires them to be so thin? and how is the initial bite for a bike, if you have tested this?
> 
> I know for a fact that carbon ceramic brakes would be awesome for mountain bikes, especially those of us that gravity likes a little more (hefty folk). I have burned myself on rotors and have had caliper pump from DOT fluid that has ingested too much humidity from the air between bleeds. Carbon Ceramic brakes should be able to avoid a lot of that, but where does the heat go? I have seen LeMans cars with Carbon rotors glowing in the night laps so they definitely get hot. Is the compound actually able to drop the heat enough that it would be benefit or is this a technology that really isn't suited to anything but TDF road bikes in the hills?


This thread will answer your questions:

http://forums.mtbr.com/brake-time/homebrew-heat-sink-702878.html

I made carbon pads with heat sinks, and carbon rotors.

In the last pages, I have posted thermographic images of the brake in use.

Lots of pics through the entire thread, showing the inns and outs.

Magura


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## rockcrusher (Aug 28, 2003)

Mr.Magura said:


> This thread will answer your questions:
> 
> http://forums.mtbr.com/brake-time/homebrew-heat-sink-702878.html
> 
> ...


Thanks, I just breezed through it but you pretty much answered all my questions. Why Shimano or SRAM hasn't hired you away to design carbon ceramic brakes is beyond me.

Are you still using the rotor?


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## Mr.Magura (Aug 11, 2010)

rockcrusher said:


> Thanks, I just breezed through it but you pretty much answered all my questions. Why Shimano or SRAM hasn't hired you away to design carbon ceramic brakes is beyond me.
> 
> Are you still using the rotor?


Well, they obviously are unaware of the MTBR forum 

Yes I still run that brake. i am quite happy with it.

Magura


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## Mr.Magura (Aug 11, 2010)

Has any of you seen a road disc compatible fork, besides the Colnago proto?


Magura


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## GTscoob (Apr 27, 2009)

Mr.Magura said:


> Has any of you seen a road disc compatible fork, besides the Colnago proto?
> 
> Magura


A bunch of us on here have disc cyclocross bikes, some even with carbon disc brake forks. This is nothing new, the forks will be the same just with shorter A-C distances.


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## Mr.Magura (Aug 11, 2010)

GTscoob said:


> A bunch of us on here have disc cyclocross bikes, some even with carbon disc brake forks. This is nothing new, the forks will be the same just with shorter A-C distances.


Sorry, that was not a very precise question 

I meant road forks, with shorter than cyclocross A to C. 
I am not aware such is made by anybody at this point?

Magura


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## bee (Apr 7, 2008)

Mr.Magura said:


> Sorry, that was not a very precise question
> 
> I meant road forks, with shorter than cyclocross A to C.
> I am not aware such is made by anybody at this point?
> ...


Yeah, you are right.

Cyclocross forks w/ disc brake tabs - yes in 390+mm A-C
Touring forks w/ disc brake tabs - yes in 378+mm A-C
Road forks w/ disc brake tabs - no, nothing available in 367+mm A-C 

I'm sure you can get a tall cyclocross or touring fork and put it on a road bike, but then you f--- up your road geometry. What would be great is an option for a true road fork with disc tabs in a road-worthy 367 - 370mm axle-to-crown height.


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## Mr.Magura (Aug 11, 2010)

bee said:


> Yeah, you are right.
> 
> Cyclocross forks w/ disc brake tabs - yes in 390+mm A-C
> Touring forks w/ disc brake tabs - yes in 378+mm A-C
> ...


Hmm, seems like a nice next carbon project then.

Just gotta finish up at least one frame first.

Magura


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## Clockwork Bikes (Jun 17, 2006)

On a funny note.


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## 2wheelrider (Feb 20, 2011)

Back in my bike shop days I seems to remember a similar discussion with disc brakes and mountain bikes and look where we are now. I think that the industry will come up with the solutions to the problems and I Iook forward to it. whether or not it is right for top rung pros I'm not qualified to answer but it seems like us in the masses could benefit. Just my opinion but I think I am building my next road frame with disc tabs and 135 rear spacing.


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## thierict (May 30, 2012)

It's exciting to see the development from Disc Brakes on road bikes. Colnago addressed the flex problems by beefing up the frame to cope with the asymmetrical stress. Hopefully the brake manufacturers have also solved the overheating problem; road bikes can be brutal on the brakes due to some long steep descents.


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