UCI expected to approve Road Disc Brakes for 2016

[Alex Simmons/RST]

Isn't the 2018 Giant Propel only available with disc brakes? I hear it's 15 watts faster than the old rim brake model.

Sorry if this is just me being humour impaired or a dumb mech eng but "15 watts faster" ? Less power required at stated speed?

Richard

Yes, 15 watts less power needed at 38.6kmh and 85 cadence.

That would be nonsense. For that to be the case, they must have significantly different specifications such that it's not a like for like comparison.

[Duck!]

Wind tunnel testing revealed that the airflow is already disturbed by the time it gets to the brake, so there is actually very little increased drag there. Refining other areas of the frame, in particular the head tube/down tube/fork crown interface had a much greater effect on the bike's aerodynamic profile than the brakes.

[warthog1]

They've been allowed in the pro-tour. Kittel won a few stages of the TDF on them. Campy has got on board. It's old news now, next new thing that challenges the very fabric of our society please. Maybe a reduction in weight limits to 6.55kg ?

Yeah I know they are trialing them. I thought it was a lay down misere they would be taken up due to marketing pressure from the manufacturers.
Maybe they don't all have a disc option to push yet. I'd have thought so though.
Is the wheel change issue with different axle standards a PITA that is stopping uptake?
I guess in a handful of years caliper brakes will be gone from racing anyway.

Actually...trial or allowed? What's the difference according to UCI? I don't get that? Is there some sort of TUE that has to be lodged prior to starting?

I've got no idea how the cardigan wearing pipe smokers operate

[Alex Simmons/RST]

Wind tunnel testing revealed that the airflow is already disturbed by the time it gets to the brake, so there is actually very little increased drag there. Refining other areas of the frame, in particular the head tube/down tube/fork crown interface had a much greater effect on the bike's aerodynamic profile than the brakes.

Link please.

[andrewjcw]

Wind tunnel testing revealed that the airflow is already disturbed by the time it gets to the brake, so there is actually very little increased drag there. Refining other areas of the frame, in particular the head tube/down tube/fork crown interface had a much greater effect on the bike's aerodynamic profile than the brakes.

Link please.

https://cyclingtips.com/2017/08/giant-p ... ils-price/

[Duck!]

^^ Thanks, that was exactly what I was going to refer to. It should be pointed out, extracted from the article, that the wind tunnel and its staff are not owned by Giant, but are independent and used by other manufacturers in the bike industry. Only the pedalling dummy used in the tests is Giant's property.

The old Propel was very slick in basically a straight headwind, at yaw angles of 5 degrees and less, but lost efficiency at greater angles. The new frame's revised tube shapes are slightly less efficient at or near zero-yaw, but much better at greater angles, thus improving its overall aerodynamic efficiency.

[Comedian]

They've been allowed in the pro-tour. Kittel won a few stages of the TDF on them. Campy has got on board. It's old news now, next new thing that challenges the very fabric of our society please. Maybe a reduction in weight limits to 6.55kg ?

Yeah I know they are trialing them. I thought it was a lay down misere they would be taken up due to marketing pressure from the manufacturers.
Maybe they don't all have a disc option to push yet. I'd have thought so though.
Is the wheel change issue with different axle standards a PITA that is stopping uptake?
I guess in a handful of years caliper brakes will be gone from racing anyway.

We've been through this.. but the reason why they aren't already ubiquitous in pro cycling is because they are slower - for everyone other than the sprinters for whom it makes no difference.

I've been watching and sniggering as all the disc led sleds are released. Indeed it's looking like rim brakes will survive as a "performance" option.

Yes sir, your $5000 giant weights just a sliver under 9kg with bottles and cages...

https://cyclingtips.com/2017/08/giant-p ... ils-price/

[warthog1]

We've been through this.. but the reason why they aren't already ubiquitous in pro cycling is because they are slower - for everyone other than the sprinters for whom it makes no difference.

I've been watching and sniggering as all the disc led sleds are released. Indeed it's looking like rim brakes will survive as a "performance" option.

Yes sir, your $5000 giant weights just a sliver under 9kg with bottles and cages...

https://cyclingtips.com/2017/08/giant-p ... ils-price/

I'm in a bit of a bind here.
I may have been known to hang a bit of poo on steel is real retro grouches in the past
Looks like I'm destined to be a rim brake retro grouch

[AUbicycles]

If you are concerned about aerodynamics on your disc brakes, don't worry, I've got you covered.

At Eurobike, this is one of the things I spotted and I assume that we will see a market for aftermarket disc brake covers (fresh out of the 3D printer or handmade Carbon Fiber.... because it has to be light.).

Triathletes will be first movers though safety of the covers will be interesting, a nice little bit that can get knocked and then chewed up while riding.


Italian brand Tred who do a lot of custom and one-off bikes with 100% local framebuilding and assembly


Parlee Cycles have brilliant looking bikes, but that is just a front for technical excellence (as they say).

On a related topic, I would have expected to see the brand react with rounded edges to the disc brakes as opposed to the menacing steak-knife layered steel and aluminium razors. But the reality is that a disc brake is just as dangerous as a chain ring in an accident.

[Duck!]

We've been through this.. but the reason why they aren't already ubiquitous in pro cycling is because they are slower - for everyone other than the sprinters for whom it makes no difference.

You got actual evidence, or just more of your regressive technophobic hyperbole?

Yes sir, your $5000 giant weights just a sliver under 9kg with bottles and cages...

https://cyclingtips.com/2017/08/giant-p ... ils-price/

It's a well-established fact that aero bikes are heavier than "normal" road bikes, regardless of brake type. Those broad tube profiles, plus the typical target of making them more rigid inherently require more material, which of course is weight. If you care to look at the weight comparison chart in the article properly - yes it's weighing framesets, not complete bikes, but still relevant - the heaviest frameset tested is a rim-braked model.

They've been allowed in the pro-tour. Kittel won a few stages of the TDF on them. Campy has got on board. It's old news now, next new thing that challenges the very fabric of our society please. Maybe a reduction in weight limits to 6.55kg ?

Yeah I know they are trialing them. I thought it was a lay down misere they would be taken up due to marketing pressure from the manufacturers.
Maybe they don't all have a disc option to push yet. I'd have thought so though.
Is the wheel change issue with different axle standards a PITA that is stopping uptake?
I guess in a handful of years caliper brakes will be gone from racing anyway.

Not all teams have equipment sponsors; quite a few have to buy their groupsets, and at the top-level the disc options have often been limited in availability. If you look closely, there are some teams still using 9000 Dura-Ace a year after the release of R9100. Additionally, not every frame manufacturer will have race-oriented disc-braked frames yet, particularly the Europeans who seem to be holding out a more traditionalist approach.

[warthog1]

Not all teams have equipment sponsors; quite a few have to buy their groupsets, and at the top-level the disc options have often been limited in availability. If you look closely, there are some teams still using 9000 Dura-Ace a year after the release of R9100. Additionally, not every frame manufacturer will have race-oriented disc-braked frames yet, particularly the Europeans who seem to be holding out a more traditionalist approach.

Fair enough.
Is there an accepted axle standard yet?
Is replacing a wheel from neutral service in a time pressured situation an issue with hydraulic discs?

[g-boaf]

They've been allowed in the pro-tour. Kittel won a few stages of the TDF on them. Campy has got on board. It's old news now, next new thing that challenges the very fabric of our society please. Maybe a reduction in weight limits to 6.55kg ?

Yeah I know they are trialing them. I thought it was a lay down misere they would be taken up due to marketing pressure from the manufacturers.
Maybe they don't all have a disc option to push yet. I'd have thought so though.
Is the wheel change issue with different axle standards a PITA that is stopping uptake?
I guess in a handful of years caliper brakes will be gone from racing anyway.

We've been through this.. but the reason why they aren't already ubiquitous in pro cycling is because they are slower - for everyone other than the sprinters for whom it makes no difference.

I've been watching and sniggering as all the disc led sleds are released. Indeed it's looking like rim brakes will survive as a "performance" option.

Yes sir, your $5000 giant weights just a sliver under 9kg with bottles and cages...

https://cyclingtips.com/2017/08/giant-p ... ils-price/

I think the disc brake Propel will be a very quick bike overall. When I went overseas with my heavily modded Giant SL3, far from making it as light as possible I ended up changing some components and making it 400g heavier. Different wheels (wider alloy wheels), different RD, and a different cassette.

Which was no great problem as I got 2kg lighter before I left by riding more and not eating rubbish food.

Even though the lightest carbon wheels would have been nice on those huge and very steep climbs, they would have been crap on the first day in the pouring rain - no stopping power.

You can only go so far with light bikes and going uphill fast, the rest was down to descending very fast and taking the corners as close to the limit as possible.

Snigger all you like at heavier bikes, but not all of the elite riders use the absolute lightest bikes. Even the smaller riders, you'd be surprised to see what they run. There are other considerations.

9kg isn't all that bad for an aero bike. My Cervelo P5 is 8.5kg with hydraulic rim brakes..

[Comedian]

Snigger all you like at heavier bikes, but not all of the elite riders use the absolute lightest bikes. Even the smaller riders, you'd be surprised to see what they run. There are other considerations.

9kg isn't all that bad for an aero bike. My Cervelo P5 is 8.5kg with hydraulic rim brakes..

Lol... And I got laughed at so hard... When I had a titanium bike that was 200 grams heavier than the featheriest carbon climbing bikes. They said "We couldn't possibly entertain the thought of a bike that's 200 grams heavier! That would be unthinkable!". That was when the bike industry wanted to sell you a light bike.

Nowadays - they want to sell you all a disc aero bike and yes- it's 2kg of marketing heavier but that's all good!

We've been through this.. but the reason why they aren't already ubiquitous in pro cycling is because they are slower - for everyone other than the sprinters for whom it makes no difference.

You got actual evidence, or just more of your regressive technophobic hyperbole?

Lol! Damn how much of that Giant Coolaide have they been feeding you??? It must be strong stuff.

I've noticed Froomy doesn't seem to be rushing to discs. I bet if he (and all the others) thought it would help them win they would be on it!

I note that even Giant are selling rim braked bikes specifically for climbing so they don't nobble their teams. This also strikes me as strange because I thought we were all going to gain on the descent with out disc brakes (and then some) that we lost lugging them all up the climb?

Climbing is certainly a notable feature of the pro race calendar for 2017, with intense stages in the Giro Rosa and the action at La Course shifting to the mountains and the Col d'Izoard. The reveal on this bike is perfectly timed, and the Liv Sunweb team is set to give the bike its racing debut in the Giro Rosa over the next few days.

"With this new model, climbing won't be a problem," commented the brand manager for Liv Cycles. "I like climbing. It reflects the reality of life. You gain what you work hard for. I find on this bike I feel comfortable, and can follow a smooth tempo."

[/quote]

http://www.bikeradar.com/au/women/gear/ ... ide-51383/

[Alex Simmons/RST]

Wind tunnel testing revealed that the airflow is already disturbed by the time it gets to the brake, so there is actually very little increased drag there. Refining other areas of the frame, in particular the head tube/down tube/fork crown interface had a much greater effect on the bike's aerodynamic profile than the brakes.

Link please.

https://cyclingtips.com/2017/08/giant-p ... ils-price/

So it's not a like for like comparison. That was evident at the very start of the article:

The biggest story of the new Propel is that it’s only available with disc brakes. As of right now, there is no rim brake model.

[g-boaf]

Snigger all you like at heavier bikes, but not all of the elite riders use the absolute lightest bikes. Even the smaller riders, you'd be surprised to see what they run. There are other considerations.

9kg isn't all that bad for an aero bike. My Cervelo P5 is 8.5kg with hydraulic rim brakes..

Lol... And I got laughed at so hard... When I had a titanium bike that was 200 grams heavier than the featheriest carbon climbing bikes. They said "We couldn't possibly entertain the thought of a bike that's 200 grams heavier! That would be unthinkable!". That was when the bike industry wanted to sell you a light bike.

Nowadays - they want to sell you all a disc aero bike and yes- it's 2kg of marketing heavier but that's all good!

Your titanium bike was probably a lot heavier than the lightest carbon climbing bikes. I mean, heck, I've got one here now that is extremely light and it has no super special components on it other than the wheels. And it isn't even a small size frame. However it is illegal as it is less than 6.8kg. And there are others out there in the region of 4.5kg or less.

There are certainly light enough disc brake bikes out there. Focus does one at 7.6kg for the 56cm version, there are others around too that are lighter than that, light enough to make stuff all difference. I don't have any disc brake bikes and I won't be getting one soon, but I think they will eventually take over.

It must be said that even rim-brake versions of the Propel aren't exactly light weight machines. I did look at getting one and the thing was quite a tank of a bike. Which I knew it would be anyhow.

If I go overseas again next year, I'd be tempted to rent a disc braked bike instead of taking one of my own bikes.

[Kev365428]

If you are concerned about aerodynamics on your disc brakes, don't worry, I've got you covered.




Parlee Cycles have brilliant looking bikes, but that is just a front for technical excellence (as they say).

The Parlee one will never get UCI approval as it's purely an aerodynamic fairing and serves no other purpose.
However, stranger things have happened I suppose.

Kev.

[Comedian]

Snigger all you like at heavier bikes, but not all of the elite riders use the absolute lightest bikes. Even the smaller riders, you'd be surprised to see what they run. There are other considerations.

9kg isn't all that bad for an aero bike. My Cervelo P5 is 8.5kg with hydraulic rim brakes..

Lol... And I got laughed at so hard... When I had a titanium bike that was 200 grams heavier than the featheriest carbon climbing bikes. They said "We couldn't possibly entertain the thought of a bike that's 200 grams heavier! That would be unthinkable!". That was when the bike industry wanted to sell you a light bike.

Nowadays - they want to sell you all a disc aero bike and yes- it's 2kg of marketing heavier but that's all good!

Your titanium bike was probably a lot heavier than the lightest carbon climbing bikes. I mean, heck, I've got one here now that is extremely light and it has no super special components on it other than the wheels. And it isn't even a small size frame. However it is illegal as it is less than 6.8kg. And there are others out there in the region of 4.5kg or less.

There are certainly light enough disc brake bikes out there. Focus does one at 7.6kg for the 56cm version, there are others around too that are lighter than that, light enough to make stuff all difference. I don't have any disc brake bikes and I won't be getting one soon, but I think they will eventually take over.

It must be said that even rim-brake versions of the Propel aren't exactly light weight machines. I did look at getting one and the thing was quite a tank of a bike. Which I knew it would be anyhow.

If I go overseas again next year, I'd be tempted to rent a disc braked bike instead of taking one of my own bikes.

Sounds like a good call on the renting a disc bike. Perfect outcome if you don't need one in normal conditions.

Yes.. I agree there were some feathery carbon climbing bikes out there. However.. in the mainstream is where I'm trying to focus on. In my size (large) for a mainstream bike about 6.8kg with relatively normal components was quite common. Frames were about 850 grams or so (stated), and my light Ti bike frame is about 250 more than that.

The heavy Ti bike (the training lynskey) is an eye watering 1.5kg for the frame. What astonishes me though - is it's 7.5kg ready to roll with training alloys (with power tap hub!), bottle cages and pedals. So even built to be a bombproof training bike it's still lighter than the lightest mega dollar disk brake bikes.

I stand by what I've always said though. A couple hundred grams is inconsequential .. but when we are talking 5k bikes that are 2kg heavier than they used to be - that's pretty significant. You would have to work pretty hard to convince me.

[andrewjcw]

http://www.cycling.org.au/News/All-News ... oad-racing

Time for you guys to sign up for racing with your light weight aero rim brake machines and drop all those pros and A graders stupidly going to the slow crappy disc brake bikes. Now's your time to shine!

[Comedian]

http://www.cycling.org.au/News/All-News ... oad-racing

Time for you guys to sign up for racing with your light weight aero rim brake machines and drop all those pros and A graders stupidly going to the slow crappy disc brake bikes. Now's your time to shine!

When you have Froomey we'll talk...

[warthog1]

The UCI protour is advertising for the bicycle industry.
The manufacturers want to sell more bikes.
Industry pressure will be exerted to ensure they are ridden.
Are disc brakes decisively better to race on? Apparently not, as they are available now and they aren't all riding them.
I am a grouch already I just await the retro tag when rim brakes become a rarity.

[Comedian]

The UCI protour is advertising for the bicycle industry.
The manufacturers want to sell more bikes.
Industry pressure will be exerted to ensure they are ridden.
Are disc brakes decisively better to race on? Apparently not, as they are available now and they aren't all riding them.
I am a grouch already I just await the retro tag when rim brakes become a rarity.

Yes - that's the only way I can see discs becoming ubiquitous in the peloton. It will only be if all teams and all riders are running them - because I don't think anyone wants to give their opposition a rim braked advantage. Even if disc bikes can be made to the 6.8 limit - the disc braked bike will still have more rotating mass which people like Froome are known to be very very finnicky about.

At this juncture I can't see teams like Sky who have worked so hard on marginal gains forcing their climbers to ride disc bikes. As I've mentioned.. it looks like rim brakes are going to survive in a "performance bikes" niche so it may well be a marketing advantage to give Sky what they want.

As to being branded a grouch.. that ship appears to have sailed and I can't see it changing unless I come into very large quantity of Specialized/Giant/etc Koolaide(TM).

[warthog1]

As to being branded a grouch.. that ship appears to have sailed and I can't see it changing unless I come into very large quantity of Specialized/Giant/etc Koolaide(TM).

[MichaelB]

..... but the reason why they aren't already ubiquitous in pro cycling is because they are slower - ....

Proof please ?

Not some theoretical wind tunnel dummy or in house commissioned testing, but a direct comparison of a disc/rim brake bike - same model, size etc from the same brand by the same testing mob at the same time.

[kb]

...
Even if disc bikes can be made to the 6.8 limit - the disc braked bike will still have more rotating mass which people like Froome are known to be very very finnicky about.
...

Actually less (where it counts). The rims can be made lighter.

[Discodan]

FFS, how long can this discussion go on for? There's a couple of mainstream disc bikes at 6.8-6.9 (Izalco Max, S-Works Tarmac) so they can be made light but they'll always be a bit heavier than a rim brake model due to the hardware. Take your choice; I'm a weight weenie but I'll happily lug around half a kg more for the reliability and confidence discs give. If you prefer otherwise that's fine but I don't care either way.

Also a 150g disc at 140mm diameter will have little impact on rotational inertia and will be more than offset by the weight reductions in the rims that are now coming through due to lack of brake track and heat dissipation required