Whilst every single component in a road is constantly improved, I don’t see any progress in the breaks. On a road bike weight and aerodynamics are more important than when riding a mountain or touring bike. But does it mean that nothing can be improved? I doubt that on long fast descents road bikes have enough breaking power or use the right technology. Certainly on some descents I feel the ride is a bit hairy. As an example take the last Tour – Joseba Beloki crashed due to his rims being totally overheated.
Apparently, the TT bike that Lance Armstrong will ride this year in the tour will include a set of vintage Dura-Ace AX. These breaks (also known as Parapull break callipers) have been introduced by Shimano sometime in the early 1980s. These brakes suppose to be more aerodynamic and provide Lance with some extra efficiency to help him with the battle against his waning power. I can’t see any other component being revived.
Perhaps I am incorrect and more modern road/tri bikes do have much improved breaking systems.
The DuraAce AX brakes (not “breaks”, BTW) are not nearly as good as modern systems. If they were that good, he’d use them on his road bike as well.
Set up properly, a good set of modern brakes are very effective in dry conditions. They are more than capable of exceeding the limits of traction offered by a set of skinny tires. In wet conditions, they are not as good as they could be (eg discs / internal brakes), but are good enough.
Beloki probably didn’t crash because his rims overheated, he crashed because the road surface had partially melted due to the heat and became slick. His tire rolled off in mid-crash.
Beloki probably didn’t crash because his rims overheated
That is correct - Beloki was using Campy carbon rims and I think ceramic brake bads both of which disipate heat much better than alloy rims. More importantly, other than light weight/good strength, another advantage of carbon rims and carbon or ceramic brake pads is that with that rim/pad combination, to a small extent braking action actually improves as the rims/pads heat up.
As was previously mentioned, Beloki did not crash because of his brakes - rough spots/pot holes in the roads on which that state was conducted had been patched within the 24-hours preceding the race and due to the heat of the day, the asphalt was still very soft and had become slippery due to oil/resin in the newly laid asphalt that was pooling on top of the asphalt. Beloki’s line took him directly through the center of one such patch of asphalt and upon hitting the oily patch, his rear wheel momentarily lost traction and when it regained traction, the rear of the bike was in a lateral slide that instantly tore the tubular off of the rim and few riders are going to be able to stay upright once that happens at 70-80 kph!
You are absolutely right. What I wrote regarding Beloki was incorrect. I remember reading somewhere a description of the accident that claimed that it is related to what I have described. But it is obviously wrong.
I found in VeloNews the following text:
“As the VeloNews crew made its way to the arrive in Gap, two hours in front of the peloton, we noticed the hot road (37 degree centigrade air temp) had begun to “weep” oil in sections where recent road repairs had been made. The highly heated road was so slick that it made even the handling of our Volkswagen Passat a bit tenuous in particular corners”.
Apologies for writing breaks and not brakes – bloody computers.
I still believe that at some point we will see the development of road bike disc brakes. When I go from my mountain bike to my road bike there is a huge difference in braking power. You probably could get away with 4 inch rotors (rather than 6-8" mountain bike rotors) and small calipers. The bonus would be that rims could be made lighter without brake tracks and you wouldnt need special pads. The brakes would work equally well in both wet and dry conditions with much better modulation than the carbon rims (Reynolds) that I now use.
The problem is the moment created from having the braking action at the hub. All of the torque generated has to be put to the road via the spokes. Until the spoke count goes up, or at least the spokes getting a lot beefier, I think its braking out at the rim for a while. - E
Disc brakes do not result in lighter rims/wheels. The forces applied to the rim are different but comparable, and the structural requirements for the rim are as well.
You will get a different shape for the rim, but weight is in fact more likely to go up than down, due to the way braking at the hub distributes force to the wheel. Wheel weights will certainly go up overall w/discs (no radial spoking of front wheels, for example.)
I’d love disc brakes on my road bike. I’ve even spent time trying to retrofit oneto my exisitn road bike. It rains alot here in NZ and wet weather braking is an important issue to me since I commute to work, train and race in all conditions (haven’t raced in snow here yet however)
I don’t undertand why people worry about the braking force travelling through the spokes to get tothe wheel/tire. It works on MTB’s just fine. They get some pretty serious speeds going, over very rough terrain intight corners etc. Surely the forces on a MTB wheel while braking heavily must be aboutthe same as a road bike braking?
I think with ridiculously low spoke counts there may be an issue but for a normal wheel (say 24 spokes or above) I think it should be fine.
Get me a road bike disc compatible fork and I’ll buy it. (Cable operated preferred)
I think ceramic brake bads both of which disipate heat much better than alloy rims. More importantly, other than light weight/good strength, another advantage of carbon rims and carbon or ceramic brake pads is that with that rim/pad combination, to a small extent braking action actually improves as the rims/pads heat up.
Carbon rims do not dissipate heat better than aluminum. This is specifically why different brake pads are recommended for use with them. Aluminum dissipates heat very effectively. The carbon retains the heat buildup and literally melts standard brake pads during extended braking. This does cause standard brake pads to become extremely “grabby” on carbon rims. You lose good brake modulation and control. You also go through standard brake pads quickly.
As mentioned in other posts, none of the caused the Beloki crash.
An improvement in road brakes was the development of dual pivot brakes for more braking power. I also agree that current brakes have sufficient stopping power to the point that you would need more tire on the ground to effectively use more anyways.
There have also been some lightweight brakes, although not dual pivot (less stopping power, but lighter ~180grams as I remember).