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it's not 'long descents' per se that create heat. It's dragging your brakes a lot, which requires lots of corners one after the other in short succession (or just bad technique).
Most alpine descents are mainly freewheeling (or even pedaling) on straights then braking into hairpins. You only brake into the hairpins, then you're off the brakes for all the straights.
(or just bad technique).
Also something relevant to dentists but not to Julian Alaphillipe.
He should have stayed at Ineos then where he could ride a heavy rim-braked bike that is prone to cracking and incapable of avoiding walls
But then again the best offer on the table / the only team that would pay his no doubt ridiculous wage demands was ISN, with their shit "heavy", "flexy" disc braked monstrosity of a road bike 😀
Also something relevant to dentists but not to Julian Alaphillipe.
Who rides a Spesh Tarmac SL7 with discs and is one of the best descenders in the Pro peleton.
Weight is less important if you aren’t racing up long climbs above 5%. Even less when you’re 90kg rather than 58kg.
If you take a look at this video, the weight thing isn't even an issue as for example Ritchie Porte's Trek Madone with discs is near as damn it the same weight as Adam Hansen's rim braked Ridley
GCN's 2019 bike weighing video
Fins wont dissipate heat instantaneously.
Obviously not, but the system will run cooler after a few seconds of braking, which is likely to be significant. The fins on the pad will help keep the calliper cool (although not the braking surface), and the fins on the disc will help it cool down a lot quicker between braking efforts.
Most alpine descents are mainly freewheeling (or even pedaling) on straights then braking into hairpins. You only brake into the hairpins, then you’re off the brakes for all the straights.
Descending AdH many years ago, I noted several riders repairing punctures caused, I assume, by blowouts from dragging their caliper brakes and overheating the rims.
I had quite significant brake fade on my front disc brake (Hope RX4) recently, caused I think because I was following a bus down a long descent and was dragging my brakes on the straights. Obviously this didn't pose any risk of a blowout though.
Who rides a Spesh Tarmac SL7 with discs and is one of the best descenders in the Pro peleton.
Seem to recall his brakes locking up completely in a race last year.
You aren’t Pogacar
I am Fatej Podgacar
it’s not ‘long descents’ per se that create heat. It’s dragging your brakes a lot, which requires lots of corners one after the other in short succession (or just bad technique).
I suspect that pro riders racing down road descents is a different game to amateurs out having a bit of fun off road. Their speeds on descents are frightening, they'll be bleeding off serious speed into hairpins. Braking from 40 mph to 20 will generate three times the heat as braking from 20 to zero. DH and enduro MTBs run huge rotors and bigger calipers because a few hundred grams is worth the reliability of heavier brakes. Pro roadies have to build their bikes down to the weight limit and will also be concerned over aero, so they want the smallest, most aerodynamic brakes possible.
As far as technique goes, I agree as far as people dragging their back brake because they are too scared to use the front goes, but pro racers expect to be able to race their gear hard and have it work. If they find that dragging their brakes makes them faster, the team needs to give them brakes that can deal with that.
This reminds me of touring car racing in the 1980s, when old style production cars like the V12 Jaguars were superceded by homologation specials like the BMW M3 and Sierra Cosworth. The old Jags were heavy, but they couldn't fit bigger brakes because they couldn't fit bigger wheels and tyres. I remember seeing Tom Walkinshaw or Win Percy or someone pitting and the brakes were on fire. It took the mechanics a couple of minutes to get it all cooled down and fit new rotors and pads. The TV commentator asked the team why they didn't drive the car within the limits of the brakes, and the response was that the drivers just expected the engineers to build a car that they could drive flat out for the whole race.
Same goes for pro racers on mountain descents. The team needs to give them brakes that they can abuse and not have to worry about overheating.
Descending AdH many years ago, I noted several riders repairing punctures caused, I assume, by blowouts from dragging their caliper brakes and overheating the rims.
On one of the descents in the Etape du Tour, there were people popping tyres all over the place. I wondered what it was initially - thought someone might have put tacks on the road - but it was just an insanely hot day, a very steep descent and a definite mix of skill levels.
I was on aluminium Mavics (the Exalith coating) so thankfully less of an issue for me but I was wishing for discs that day.
He's perhaps less concerned about the power and more just the irritation of the noise or the fact that it works when setup and then doesn't or doesn't in certain circumstances.
My commuter has an annoying habit of un-sorting itself out WRT to discs. All setup perfectly, first ride fine, second ride (wet) now not fine. Not rubbing enough to really slow the wheel, but there's a ching, ching, ching, noise. Why? What's now different?
Not rubbing enough to really slow the wheel, but there’s a ching, ching, ching, noise. Why? What’s now different?
Probably, the wet conditions lubed the piston seals (with water). The pistons reset themselves with very minimal clearance to the disk. That's how disk brakes auto adjust. A "ching, ching, ching" noise without dragging means they are perfectly adjusted.
On one of the descents in the Etape du Tour, there were people popping tyres all over the place. I wondered what it was initially – thought someone might have put tacks on the road – but it was just an insanely hot day, a very steep descent and a definite mix of skill levels.
I was on aluminium Mavics (the Exalith coating) so thankfully less of an issue for me but I was wishing for discs that day.
In my case, it was about 6am on the way down to the start of La Marmotte, so it was still cold. I guess you generate some serious heat, which perhaps combined with poor technique and carbon rims only has one result.
I know from comparing my brakes to a friends that ice tech rotors make a big difference in rotor temperature and that is for mtb rotors without the extra vanes and fins.
As previously mentioned the issues associated with dragging brakes won't affect pro riders, yes they're braking hard but they have time between those hard stops with no braking and high airflow to allow brakes to cool sufficiently. They would also have the option of running larger discs on alpine stages if they felt it necessary.
I find the argument between rim and disc funny in that I'm still on rim brakes that are around 8 years old having never changed the pads as I barely brake riding locally so discs seem a pointless upgrade, if I were riding big hills frequently then I'd definitely want the added power of discs.
TBF, I am wondering why his disc brakes are “rubbing all the time” do road discs do that?
Most road disc brakes aren't put through what Froome will put them through.
Surprised he’s not looking into how stiff the stem is for a few more watts! 🤔
Shimano GRX 810's are servo wave which gives you the bigger pad clearance and more power.
Will the new Dura race have servo wave?
I guess you generate some serious heat
An 80 kg rider/bike on a 130 m vertical descent will generate about 100 kJ of heat that needs to be dissipated. That's enough energy to heat 1 kg of steel by about 250 degrees C. A pair of 6" rotors weighs roughly 250 g, so those would reach over 1000 degrees if they didn't have airflow to cool them. Steel melts at about 1 500 degrees, so riding down the Alps generates enough heat to literally melt steel rotors if the heat isn't dissipated.
I honestly call BS on the whole thing. He sounds like someone stuck in a mindset and needing to vent. Because high end bikes can come in way under the 6.4kgs weight is never going to be an issue and in terms of aero in the real world ie not wind tunnel the width of your rims and body habitus makes the effect of 160mm or even 140 mm discs just about irrelevant. He's understandably going to take a while to get used to a new setup but I believe he will likely be faster on this bike overall than without discs. Maybe he just can't get over the move from an F12 to what the advertising gurus would want us to believe is simply less of an F1 car?
I just think it's funny how nobody is willing to accept that one of the fastest road racers in the world maybe just doesn't need or particularly like disc brakes, it's like some sort of weird cult where someone has finally publicly said that they're just not that keen on kool-aid 😎
I believe he will likely be faster on this bike overall than without discs
How will they make him faster overall? You're going to say something about late braking into corners aren't you...
I just think it’s funny how nobody is willing to accept that one of the fastest road racers in the world maybe just doesn’t need or particularly like disc brakes,
This reminds me of Alex Zanardi in F1. He just couldn't get on with carbon brakes so the Williams team tried to run steel brakes for him, which didn't seem to help. F1 teams use carbon brakes because they are better overall, drivers have to adapt to that. Froome's problems with disks seem to be that they are unfamiliar and he wants to stay with what he's used to. Disks have more consistent performance when its wet and can dissipate heat better than rim brakes. The weight penalty is irrelevant and the other issues seem to come down to hiring a mechanic who can set them up properly.
Been riding ultegra disks for the best part of 4 years on my road bike. I've experienced a lot less rubbing on that than on my mtbs.
I like discs on road bikes. Some people don't.
I like angel delight. Some people don't.
🤷
I just think it’s funny how nobody is willing to accept that one of the fastest road racers in the world maybe just doesn’t need or particularly like disc brakes, it’s like some sort of weird cult where someone has finally publicly said that they’re just not that keen on kool-aid 😎
I kind of agree here. What gets me is that he doesn’t even say he doesn’t like them - he’s just acknowledging one of the shortcomings in the technology.
Here's Alex Dowsett a bit more upbeat about his new bike.
I just think it’s funny how nobody is willing to accept that one of the fastest road racers in the world maybe just doesn’t need or particularly like disc brakes
The thing is Chris Froome is without doubt an amazing grand tour rider, but with all due respect, he's not winning races because of his exceptional bike handling and braking skills, is he? Plus he's happy enough to use oval chain rings despite them being more prone to dropping the chain, so he's possibly not the man to turn to for unbiased opinion on bike set-up. What works for him, may not be so good for someone else.
This reminds me of Alex Zanardi in F1. He just couldn’t get on with carbon brakes so the Williams team tried to run steel brakes for him, which didn’t seem to help. F1 teams use carbon brakes because they are better overall, drivers have to adapt to that. Froome’s problems with disks seem to be that they are unfamiliar and he wants to stay with what he’s used to.
This kind of sensible discussion has no place in a debate about road discs! Get out!
he’s not winning races because of his exceptional bike handling and braking skills, is he
Stage 19 of the 2018 Giro springs to mind. Froome was taking time out of the chasers on every descent after he'd attacked. Roads that were a mix of dry/wet due to snow melt.
Admittedly some of the group behind weren't the best descenders, and they stuck together as a group to give themselves a better chance. But Froome is no mug when it comes to going downhill.
I'm not saying he's the best, but he's far from rubbish.
This kind of sensible discussion has no place in a debate about road discs! Get out!
I’m not saying he’s the best, but he’s far from rubbish.
I didn't say he was rubbish. My point is what works for him works for him. It doesn't mean what doesn't work for him is rubbish, and it doesn't mean he's an expert on brakes. He's an expert at winning stage races.
Now that it's outlawed to sit on the top tube and pedal, will we see dropper posts on road bikes?
If we do, I hope they get banned too.
What's going on with the finish of the down tube on Dowsetts bike? In some shots from that video the bit between the "R" and the head tube looks like it's been dragged across the factory floor.
F1 teams use carbon brakes because they are better overall, drivers have to adapt to that. Froome’s problems with disks seem to be that they are unfamiliar and he wants to stay with what he’s used to.
But a massive proportion of the performance gains/losses in F1 come in the braking phase, not to mention overtakes. I’ll say that again. Overtakes.
If the brakes are quantifiably better but have a different feel then fine, force your drivers adapt. You’ll likely find the most successful ones are pushing for the change and will be eager to make the adaptation.
In cycling the overwhelming proportion of the difference between riders is their climbing (not braking there). Or their aero for breakaways. Or their sprinting. Brakes largely irrelevant for those too.
Yes, there’s a little in it on the descents, yes some riders are better (braver), and froome did a great job on that Giro stage*. But really they’re not really a gain for winning bike races.
But they’re great for losing you bike races. Since the neutral support don’t support disc users, you can be left wanting (like Richie on last years tour, and he was lucky to get back on - mostly because he’s a good bloke and the riders on other teams seem to like him!)
Until you can get a wheel from the neutral support I think they only hurt a rider’s chances.
I should say that I understand they’re a rolling advert, and are paid to ride things. And that I now have discs on all my bikes, and wouldn’t go back. But that I understand that one might not want them on a race bike if you can do more than 6Wpkg.
*biggest issue was the other riders waiting for each other. And not realising that froome was fuelled, motivated and *able* to smash all 80k remaining. I think it’s the best ride in a stage race I’ve ever seen. But that brakes had nothing to do with it!
I find it quite odd that Froome is not in either Paris Nice or Tirreno Adriatico ISN rosters!
^^ Interesting video that.👍
^^ Interesting video that.👍
Yeah, interesting in so much as he is designing and selling his own disc rotors.
Ashima airotor disk look very similar to those campy disks. I had 160mm Ashimas on my Kona race bike and im sure they weren't floating. Never had an issue with them riding in the uk.
How many grand tours have been won on a bike with disc brakes?
How many stage wins have there been at those grand tours by riders with discs? How many one day races? That the one team that now doesn’t use them has good/the best GT GC tactics is nothing to do with the brakes.
That the one team that now doesn’t use them has good/the best GT GC tactics is nothing to do with the brakes.
No, but it somewhat undermines how important discs are on a road bike, this Giro was hardly a clement one and Skineos are known for their marginal gains approach so if there was a performance benefit surely they'd be all over it?
That said, maybe Froome's problems ARE a Swissstop thing. Just bedded in new Swissstop pads and rotors on my gravel bike, now the rotors are wibbling and the brakes are rubbing! Should have stuck with cantis... 😉
Going back a few months I know, but one comment resonated with me
no one wants to pay more for a heavier bike no matter how well it stops no one wants to pay more for a heavier bike no matter how well it stops
I recall paying good money to swap the horrid mechanical discs out for hydraulics on my CAADX a few years ago. CAADX bought to replace a CAAD8 for general wet weather and commuting duties.
More money paid. Weight definitely went up. Stops better? Hell yes if it’s wet.
Of course, I’m not racing. If I was, and at his level I’d not be happy with occasional rubbing. It annoys me at my level.
I do think that a system where clearances are 2-3x larger when pads retracted would be preferable. Lever throw would need to be similar to now though. I remember servo-wave with cable v brakes. Something similar for hydraulics perhaps?