Post pics of your bike thread

[Harry Meatmotor]

@hozn 112934 wrote:

This is definitely “rumor-grade” (or rumour-grade, more specifically), but this is probably what vvill was referring to: http://road.cc/content/news/146616-disc-brakes-be-permitted-peloton-2017

100% rumour-grade and even then it’s limited exposure. don’t get me wrong, I think discs will eventually make their way into the peloton, but my guess is that we’re looking at the 2020 season for full requirement.

[hozn]

Well, we shouldn’t have to wait too long to find out.

And luckily this has zero direct impact on my racing “career”.

[jabberwocky]

@Harry Meatmotor 112923 wrote:

I don’t see this happening any time soon. Not that I think it’s a bad idea, but I don’t think the UCI will budge until the vast majority of road bikes sold world wide are disc-equipped. The UCI might be convinced when the only bikes on the sales floor that are still rim brake bikes are the UCI-approved topline models (think, S-works Tarmac, Giant Propel Advanced SL, etc.). For now it’s “lack of standardization something something, need more testing something something…”

I’ve seen several articles recently that said the UCI was pretty close to releasing a decision about them for 2017, and the manufacturers seem to think they’ll be allowed. Who knows. The UCI is the big thing holding them back; the manufacturers want their top end groups to be raced on, so they won’t go disc whole hog until its allowed. But I think it will happen pretty fast once it is. Shimano and Sram both already have extensive experience with disc systems on their MTB groupsets. Contrary to popular wisdom, discs aren’t exactly complicated. They are proven tech in the MTB field. And the advantages (especially once you’re on lightweight carbon wheels) are just too tempting to ignore.

Standardization might be an issue for pros (for wheel changes and such) but its far from insurmountable.

[DaveK]

@jabberwocky 112903 wrote:

This is patently untrue. Good disc brake pads can withstand temps far in excess of anything a bike would exert on them. I raced DH mountainbiking for several years, always on discs, and never once faded a set. These are courses where you would drop thousands of feet in just a few minutes; the rotors would get hot enough to flash any sweat dripped onto them into steam almost instantly, but no braking issues. Rim brakes would never have withstood those forces. Not a million years.

I’m talking about the novice to average rider though dragging their brakes down a mountain instead of hard on the brakes before a turn or an obstacle. You can and will fade disc brakes doing that. And if you do they don’t cool down and come back as fast as rim brakes. A skilled rider can descend far better on discs but I’m thinking about the 90% of riders out there who will drag their brakes the entire way down a mountain.

[hozn]

@DaveK 113090 wrote:

I’m talking about the novice to average rider though dragging their brakes down a mountain instead of hard on the brakes before a turn or an obstacle. You can and will fade disc brakes doing that. And if you do they don’t cool down and come back as fast as rim brakes. A skilled rider can descend far better on discs but I’m thinking about the 90% of riders out there who will drag their brakes the entire way down a mountain.

I think we’d all prefer to experience brake fade than sudden catostrophic failure of the wheel? I certainly would.

I know the basics of descending, but am definitely not a skilled descender (not having descents around here affords little training) and I have never experienced any brake degradation on anything in our region. A friend of mine did the descent down Mauna Kea last year and he did report needing to stop a couple of times to let the brakes cool down as they’d start losing power. That is about as extreme as it gets, though.

[jabberwocky]

@DaveK 113090 wrote:

I’m talking about the novice to average rider though dragging their brakes down a mountain instead of hard on the brakes before a turn or an obstacle. You can and will fade disc brakes doing that. And if you do they don’t cool down and come back as fast as rim brakes. A skilled rider can descend far better on discs but I’m thinking about the 90% of riders out there who will drag their brakes the entire way down a mountain.

Why would discs fade in those circumstances? I don’t have a tremendous amount of experience dragging brakes for a super long period of time, but (for example) racing the steep side at Snowshoe is a several minute descent, and I was on the brakes for a lot of that. I’ve certainly had them get very hot. And I’ve done some loooong descents on the MTB (blue from Hamburg Road to the valley of death in the shed, for example, or Bear Wallow in the GW forest) and never had an issue. I do think the stock organic pads that a lot of discs come with aren’t that great. I generally switch to a sintered pad ASAP. I do run a minimum of a 7″ rotor on all my bikes.

I think any fade on a disc is more a pad compound issue than a brake issue.

[vvill]

I thought this was interesting, from Lennard Zinn:

Quote:

The kinetic energy of the bike and rider is four times bigger for the same guy when he goes twice as fast on his road bike as on his MTB. It does beg the question of why road rotors are smaller than MTB rotors and how big a concern boiling fluid might be on a road bike.

http://velonews.competitor.com/2015/04/bikes-and-tech/technical-faq/technical-faq-road-discs-and-tire-pressure-on-wide-road-rims_365759

[mstone]

@jabberwocky 113228 wrote:

Why would discs fade in those circumstances? I don’t have a tremendous amount of experience dragging brakes for a super long period of time, but (for example) racing the steep side at Snowshoe is a several minute descent, and I was on the brakes for a lot of that. I’ve certainly had them get very hot. And I’ve done some loooong descents on the MTB (blue from Hamburg Road to the valley of death in the shed, for example, or Bear Wallow in the GW forest) and never had an issue. I do think the stock organic pads that a lot of discs come with aren’t that great. I generally switch to a sintered pad ASAP. I do run a minimum of a 7″ rotor on all my bikes.

Remember, this is for roadies (who are so fixated on weight that they’ll spend money on titanium bolts to save a fraction of a gram). We’re not talking about thick 7 inch rotors, we’re talking about gossamer-thin 5 inch rotors. That’s just not much mass to dissipate the heat, so the temperature will rise fast. Add the fact that the road biker is probably going substantially faster than the mountain biker before applying the brakes, and the fact that energy increases with the square of the velocity…you’ve got more energy to dissipate into a system that can’t dissipate as much energy. Get hot enough and you can boil your brake fluid or cook your hub bearings. It’s not common, but it is a concern. (You could argue that blowing a tire is a similar concern on a rim brake, and equally rare, but we’ve got 100 years of experience with that and not so much with road discs.)

For a commuter, discs are a no-brainer. For a go-fast bike, I just don’t get it.

Really, though, the biggest problem I have with discs for non-utility bikes is that you need to beef up the fork & wheel so much to handle the higher stress of the disk brake that you end up with a heavy & dead front end. No gracefully curved low-trail forks with road discs. I guess the solution is road shocks?

[hozn]

@mstone 113489 wrote:

Really, though, the biggest problem I have with discs for non-utility bikes is that you need to beef up the fork & wheel so much to handle the higher stress of the disk brake that you end up with a heavy & dead front end. No gracefully curved low-trail forks with road discs. I guess the solution is road shocks?

This is often cited as an objection to discs on road bikes, but has not been born out by the production road-disc wheelsets or forks. Yes, road disc wheels will have at least 24 spokes in front and spokes will be crossed, instead of 20h radial (Ok, some people do run 20h [crossed] disc-brake wheels, but that does seem insufficient). And most road disc hubs are still MTB hubs, so they tend to be burlier/heavier. But building a sub-1600g road disc wheelset is easily doable and affordable; my 45mm carbon wheelset is less than that — and I suspect I overbuilt those with 28 spokes. There are an increasing number of dedicated road disc rims that are coming as light or lighter than the rim-brake equivalents, by dropping the reinforcements otherwise present for braking. E.g. the 40mm Novatec rims with (claimed) 410g weights. Or the Ryde Spring rim is another example of the disc-brake version being lighter than the rim-brake version.

And disc-brake forks can be found sub-400g (e.g. the Whisky 9 is claimed 375g). A little heavier. Maybe a little stiffer, sure, but I’d much rather have a stiff frontend on the race bike.

Personally, I like consistent, powerful, and predictable stopping on my go-fast bike.

[mstone]

@hozn 113502 wrote:

This is often cited as an objection to discs on road bikes, but has not been born out by the production road-disc wheelsets or forks. Yes, road disc wheels will have at least 24 spokes in front and spokes will be crossed, instead of 20h radial (Ok, some people do run 20h [crossed] disc-brake wheels, but that does seem insufficient). And most road disc hubs are still MTB hubs, so they tend to be burlier/heavier. But building a sub-1600g road disc wheelset is easily doable and affordable; my 45mm carbon wheelset is less than that — and I suspect I overbuilt those with 28 spokes. There are an increasing number of dedicated road disc rims that are coming as light or lighter than the rim-brake equivalents, by dropping the reinforcements otherwise present for braking. E.g. the 40mm Novatec rims with (claimed) 410g weights. Or the Ryde Spring rim is another example of the disc-brake version being lighter than the rim-brake version.

Sorry, didn’t mean “heavy” in the sense of mass. I don’t know what anything on my bike weighs. Nor am I a racer by any means. My bikes divide into “utility” and “fun”. What I’m looking for in a fun bike is a little liveliness/springiness, and that’s not compatible with a disc fork. (If a disc fork isn’t rigid you’ll end up with severe brake steering–the fork blade that the brake is mounted on will end up flexing more than the other one, turning the wheel–if not catastrophic failure.) I understand that the racing world never turned down more stiffness, but that just seems horribly uncomfortable to me.

In terms of actual weight I’d expect disc rims to be lighter, because they don’t need thick sidewalls.

[jabberwocky]

Dunno, I don’t think modern carbon race forks are especially “springy”, are they? Old steel forks, sure, but your average top end carbon fork these days is pretty damn stiff already. The spoke thing I can see (you need more spokes and stronger lacing to transfer braking loads), but that will be pretty quickly offset by freeing manufacturers to do better rim profiles (as happened in the MTB world; not needing a braking surface lets you optimize strength/weight/aero a lot better).

I do agree that whats out there for road discs is somewhat crippled by the weight-obsession; thin 140mm rotors will not deliver a great braking experience. But thats a very simple solution (put larger rotors on there and suck up the 30 gram difference).

Thing is, this stuff is not exactly experimental. Shimano and SRAM have been doing discs for over a decade in the MTB world. Once the UCI allows them I think the top end groups will switch pretty fast and any issues will be rapidly solved. I’m not gonna guinea pig the first gen stuff, but I won’t be surprised when things move over.

[mstone]

@jabberwocky 113510 wrote:

Dunno, I don’t think modern carbon race forks are especially “springy”, are they? Old steel forks, sure[/quote]

Yes, that’s the thing I’m retrogrouchily complaining about. If you buy into road discs you’ve doomed yourself to a dead ride. I don’t really care if the racers do that (they’re an odd bunch anyway) but it’s a shame to see regular people doing it also and worse when the industry move in a direction that makes it even harder to put together a nice, fun, comfy bike.

[Supermau]

Interesting conversation on disc brakes. I made it a priority on my next bike because I enjoy all season riding and relish in the muck. My 140mm rotors have been great thus far. I wish I could afford another racier bike right now, if I could I’d probably stick with canti’s. At any rate, my new bike is getting dirty and I’m loving it.

[ATTACH=CONFIG]8325[/ATTACH]

[eminva]

Not my bike but my brother’s; he inherited it last night from a friend who is moving away. I am visiting him now in The Netherlands. I think this is an old German brand, Hercules. The rear derailler is Sachs Huret. The shifters are Rival ARS. I think it is from the 1980s.

Liz

[hozn]

@vvill 112924 wrote:

I always thought it was more the other way around – once the UCI approves something (with whatever standards they pick), manufacturers will follow suit. (Having of course already discussed and collaborated on technical issues/standards with the UCI before any official announcement.)

@Harry Meatmotor 112923 wrote:

I don’t see this happening any time soon. Not that I think it’s a bad idea, but I don’t think the UCI will budge until the vast majority of road bikes sold world wide are disc-equipped. The UCI might be convinced when the only bikes on the sales floor that are still rim brake bikes are the UCI-approved topline models (think, S-works Tarmac, Giant Propel Advanced SL, etc.). For now it’s “lack of standardization something something, need more testing something something…”

@jabberwocky 112938 wrote:

I’ve seen several articles recently that said the UCI was pretty close to releasing a decision about them for 2017, and the manufacturers seem to think they’ll be allowed. Who knows. The UCI is the big thing holding them back; the manufacturers want their top end groups to be raced on, so they won’t go disc whole hog until its allowed. But I think it will happen pretty fast once it is. Shimano and Sram both already have extensive experience with disc systems on their MTB groupsets. Contrary to popular wisdom, discs aren’t exactly complicated. They are proven tech in the MTB field. And the advantages (especially once you’re on lightweight carbon wheels) are just too tempting to ignore.

Standardization might be an issue for pros (for wheel changes and such) but its far from insurmountable.

@DaveK 112888 wrote:

I don’t see the point. Discs are heavier, less aero, more expensive, more complex, and just as likely to cook the brakes on a downhill as rim brakes (and slower to come back if you do cook them). As someone who’s been burned (literally) by a disc rotor before I’d also like to not repeat that. The benefits are better initial bite, much better modulation than rim brakes, if you’re running carbon wheels you’ll get better braking all around, more impervious to mud and weather, and there’s no chance of blowing out a tube or a tubular from heat built up in the rim. Looking at the pros and cons I see no reason to run discs on the road or for CX.

They have their place on MTBs, definitely, but that’s it for me.

… And it’s happened! http://velonews.competitor.com/2015/04/bikes-and-tech/uci-to-lift-ban-on-disc-brakes-in-august_366590

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