|Look what Morati did.||hummu|
Oct 1, 2002 12:57 PM
|And if they did it to a road bike, it would be a no-brainer for the cross bike. This is from a store in Switzerland. Check it out . |
Oct 1, 2002 1:29 PM
|Looks nice, and I bet they stop pretty. HOWEVER, and this is not to sound like a retrogrouch, but I doubt any of you MTB'ers has thought about this angle:
Why would I want 2 knife-edged disc blades spinning at high speed exposed to my (or my competitors') bare legs supposing I was in a pack crash? This is why Spinergy Rev-X were eventually banned unless they have the edge protectors on. I have literally seen a rider crippled by a Rev-X in a crit.
Just a thought, this may be a reason beyond the weight weenie factor why roadies have been so slow to adopt disc technology.
Oct 1, 2002 1:58 PM
|Dunno, sounds like kind of a weak argument. Think about the danger posed by a large chainring when the chain is on the inner ring. That's bigger than a disc rotor AND it has sharp teeth!
Personally, I think discs would be overkill on a cross bike except in really wet, muddy conditions. Skinny cross tires just can't handle that much braking power.
As for the Spinergy, they're still legal for time trials. Check the UCI rule book, it's Article 1.3.018. It says nothing about sharp edges. Instead it requires wheels to pass a "rupture test" and gives a list of wheels that passed the test and thus are legal for mass start events. Spinergy isn't on the list but it's not because they failed the test. This rule went into effect in 2002 and Spinergy had already decided to cease production of the Rev-X and didn't bother to submit a pair for testing.
Another interesting tidbit from the UCI book is that cross tires can't be more than 35mm wide.
Oct 1, 2002 2:41 PM
|legal for TT, not mass start. Last time I checked the vast majority of RR and cross races were mass start. I know it's kind of a crazy argument but so is "no forward facing projections". There's also a reason an official will check to make sure you have your bar end plugs in prior to every crit. Ever seen what happens to a roadie's thigh when they crash on an unplugged bar and get a core sample taken?
The chainring isn't spinning at a high rate of speed like a wheel with sharp edges on it (that includes a disc). If the chain is on the inner ring, you might not be falling onto the chainring at high speed either. I don't know about the ones on the bike pictured above, but the disc rotors on my SO's Hayes equipped MTB are much, much sharper than my chainrings. He's cut his fingers on them simply putting the bike away.
Oct 1, 2002 3:59 PM
|Believe me, a chainring can definitely hurt. Take a fall in criterium sometime. I still have a nasty scar on my leg from a spill over 15 years ago in a crit.|
Oct 2, 2002 10:15 AM
|chainring.....try a broken crank arm (from a MTB race a few years back) I tried to sell the scar to Nike and they wouldn't buy|
Oct 1, 2002 4:03 PM
|rev x legal in a TT cause ya can't hurt anyone else. Discs more exposed than chainring as overlap is usually wheel to wheel or mid frame (leg). I understand the ruling. Also we keep forgetting what this is going to be like shouldering a dozen or so times an hour. Discs are heavy
plus I'm an admitted retro grouch
|Oh no!||peter in NVA|
Oct 1, 2002 1:32 PM
|Now I have got to start saving. How do I justify another bike. Looks great!|
|re: Look what Morati did.||dlbcx|
Oct 2, 2002 5:26 AM
|Chris Kelly was racing on one of his bikes with discs a few years ago. Guess it was one of his prototypes. Also, he had some type of pivot system for suspension.|
|Grouch away - it's only a matter of time...nm||Eager Beagle|
Oct 2, 2002 5:49 AM
Oct 2, 2002 6:06 AM
|On a road bike, you don't need that kind of stopping power. How many times in a race have you had to abruptly and quickly slow down (other than avoiding a crash)? Generally, you are only feathering the brakes. Same with CX racing. I agree, in wet and/or muddy conditions, disc brakes would be a plus, but in those conditions, your speed is generally slower, so increased stopping power is not that necessary. It's just more weight to carry and more things to go wrong mechanically in my opinion.
Call me a retro-grouch, but why not leave well-enough alone?
Oct 2, 2002 8:12 AM
|"Call me a retro-grouch, but why not leave well-enough alone?"
I have some very retro tendencies as well. I prefer cantis to v-brakes, I run drops on my MTBs, I prefer tubulars to clinchers for cross, I still think non-aero brake levers feel better, my touring bike still has a Brooks, etc, etc.
I also doubt I'll ever have discs on any of my cross bikes unless I move to Seattle.
That said there are soooooo many things wrong with your statement. If everyone had that attitude we'd all still be riding single speed bikes, wearing itchy wool shorts, and cycling shoes with nail on cleats.
I've no problem with people trying new things (like discs on cross bikes) so long as I'm not the guinea pig being forced to ride it. Fortunately, there's enough diversity in cycling that this doesn't happen. I remember when V-brakes first came on the scene and everyone screamed that there'd be no more cantilevers. Now I look on cyclocrossworld.com and see 8 (!) different sets of cantilevers for sale. People have also lamented the death of the steel hardtail yet there's a HUGE number of builders out there making steel hardtails. Not only that but the quality of steel tubing today well exceeds anything that existed when the steel hardtail was at its peak.
Oct 2, 2002 10:10 AM
|I gotta agree, even though I'm a bit of a grouch I do appreciate all technological advances even if I choose not to use them. I think discs would be good on a cx / adventure bike, it just doesn't make sense in a race. I've never seen a cx track with really gnarly hills.
Viva la Difference! Viva La Steel Hardtail! Viva la Single Speed!
can't say viva La Wool Jersey as I'm allergic to wool.
|Maybe a little overstated...||greg n|
Oct 2, 2002 10:27 AM
|O.k. so I guess it was eventually going to happen -- disc brakes on road/cx bikes. And yes, I can appriciate techno advances even though I have no use for some of them.
I was merely stating my opinion on why I thought it was unnecessary to have the stopping power of disc brakes on a road or CX bike. So I guess they're not for me. But I'm sure there are plenty of people out there who'll jump all over them.
And I agree, Viva La Steel hardtail. And viva la steel frame in general.
|Maybe a little overstated...||wspokes|
Oct 3, 2002 2:52 AM
|Remember what Albert Einstein once said, "it has become appallingly apparent that our technology has surpassed our humanity!"
I am a retro grouch that just has to come out and say it. I am entitled to my opinion and I feel the Immorality...is fugly! just my opinion. I can see why others might find it beautiful but I just don't like it. I love lugged steel beauties. I have never been into cookie cutter frames. Peace
|Maybe a little overstated...||atpjunkie|
Oct 3, 2002 10:36 AM
|here's another thing. Disc brakes slow and stop the wheel from the center out, which causes extra torque on the faster rotational area (rim). This torque puts undo stress on the spokes and nipples. This is also why most disc hubs demand you run your spokes 3x and heavy gauge. So you will be forced to run 32 or 36 spoke wheels laced 3x most likely with unbutted 14's or 15's. This is more additional weight to add to the disc, caliper etc... and once again think of shouldering that a dozen or so times.|
Oct 3, 2002 11:30 AM
|Yes, discs put additional stress on spokes and nipples; however, I've been racing on my current disc MTB wheelset for 3 years without ever breaking a single spoke. Yes, the wheels are each laced 3X; however, I'm using DT Revolution (15/17g) spokes, not straight-gauge 14s or 15s, and I am using aluminum nipples, not brass. A properly built disc wheel can use light-weight spokes and nipples without any issues.
Oct 3, 2002 3:10 PM
|that also depends on your weight and riding style. What will easily stop someone at 130 won't for someone 230. Use alloy nipples with King disc hubs and you void the warranty. I think I'll trust CK.
Remember also that a 700 C wheel is larger than a 26" MTB wheel which increases rotational torque on the nipples. I'm sure your system works but as a Clydesdale I wouldn't run it for myself. I can break 15/17s in a good sprint.
Oct 4, 2002 3:40 AM
|Common sense should always be used when spec'ing spokes, nipples, rims, hubs, lacing, etc.
Agreed, much depends on the rider's weight and riding style. However, simply because the rider is using disc brakes does not automatically mean that he/she should be using straight-gauge spokes.
A teammate of mine is 185lbs and rides very, very agressively on demanding and technical rocky and rooty singletrack. He is also using DT Revolution spokes with aluminum nipples on his MTB disc wheelset and he has not had any issues either.
|....oh, and where did you read that alloy nipples void King warranty?||SS_MB-7|
Oct 4, 2002 8:51 AM
|....oh, and where did you read that alloy nipples void King warranty? I just read through my "King DiscGoTech Instructions" and there was no mention of nipples. There is reference to skewers, spokes and lacing patterns.
|....oh, and where did you read that alloy nipples void King warr||atpjunkie|
Oct 4, 2002 9:21 AM
|have older set of CK MTB Disc hubs, came with the instructions, said 3x /Brass Nipples. I'll double check this weekend. Spoke preference is strictly mine. I'm almost 6'5" and 230 so I have 45 lbs on your 185 lb friend. You are right, definitely rider pref. Funny I don't think mine mentions skewers. Will have to check.|
|You and I are on completely different ends of the wheel requirements spectrum...||SS_MB-7|
Oct 4, 2002 9:40 AM
|Well, you've got ~100lbs and ~1 foot on me (I'm 135lbs and 5'6") so our wheel building choices are on completely different ends of the spectrum.
Ya, here's what King has to say about skewers:
"Chris King hubs are designed to be used in conjunction with quick-release skewers. It is recommended that the skewer develop a minimum of 1100 lbs of clamping force when set. For best performance, use a steel skewer. Titanium skewers are not recommended for sue with front or rear suspension."
|You and I are on completely different ends of the wheel requirem||atpjunkie|
Oct 4, 2002 9:57 AM
|I believe that, as a Clydesdale I never use titanium anything. People think of it as strong but it actaully has a "snapping" point where torque causes the metal to shear. It is why most mfr's only recommend Ti Skewers, BB axles and Pedals to riders under 165 and is supposed to be replaced yearly.
I've broken some of the "strongest" steel BB's so Ti is off my diet. I'm an ex rower, football player so my height, weight, strength puts a lot of torque on my parts.
5'6" 135 hmmm let me think........August of my 13th year.
In one year from ther I was 6"3" 18o. There went my dreams of being a cyclist.
Oct 2, 2002 9:05 PM
|The main advantage of discs brakes over rim brakes is not necessarily power but smoothness - especially in mud and sandy grit. I've also heard disc brakes will last longer in those types of conditions.|
|discs and skinny tires||jpre|
Oct 3, 2002 1:15 AM
|Has anyone had experience with brakes being too strong for skinny tires and it causing problems? I would have thought as long as modulation was good, brakes strong enough to skid a tire would be ok.|
|discs and skinny tires||flyweight|
Oct 3, 2002 8:13 AM
|We put some V's on a cross bike for a customer at their insistance and against our best advice. The brakes were like a light switch - on or off and little in between. I rode a cross bike equipped with Avid mechanical discs around the parking lot and found it was much better though still nothing like a decent set of cantis. Also thought it would be way too easy to lock up the brakes and put the bike into a skid.
One other problem with V's is that they generate too much power for the lighter weight seatstays found on many cross bikes. Our customer discovered this the hard way when his V-brakes caused the seatstays to rotate inward to the point that the brake studs snapped off the frame. He claimed the frame was defective but we refused to submit it for warrantly pointing out that:
1) We warned him not to use V's when he bought the bike.
2) Seatstays are designed to be light and flexible for comfort and are not designed for the forces created by v-brakes.
|A Real Data Point||peter in NVA|
Oct 3, 2002 2:39 PM
|Thats very interesting you still found cantis better than the Avid discs. I was told that disc mounts would not work on the thin steel tubing of my cx and currently you need 135mm spacing for disc hubs- so that means a new bike with maybe stiffer seat stays and fork. Sounds like we're not quite there yet, but I feel someday thats what I'll probably have!|
|A Real Data Point||flyweight|
Oct 3, 2002 2:56 PM
|Well you need 135mm hubs simply because nobody makes disc hubs in anything other than 135mm (yet, I'm sure that will change)
I'm a bit skeptical about the thin tubing argument. I've seen disc tabs on scandium aluminum bikes and those tubes are thinner and more flexible than any steel tube. It is possible that heat of TIG welding onto an already assembled rear triangle could cause damage. Disc tabs mount very close to the dropout/seatstay weld and adding a disc tab could force you to reheat an already welded section. Today's thin steel tubes don't hold to that sort of treatment. (this is also why most modern lightweight steel bikes are no more repairable than an aluminum bike - something the old school steel purists don't like to admit!)
|Thats what I am afraid of.||peter in NVA|
Oct 3, 2002 3:03 PM
|If you heat the stays for the tabs, the dropouts will fall off and the original alignment will go out the window.
Even if repairablity was true, I would never admit it myself-everyone needs an excuse for a new bike!
|a couple of thoughts on those avid discs.....||TWD|
Oct 3, 2002 3:46 PM
|As I read your post a couple of thoughts came to mind.
First are you sure the pads were bed in? Before the Avid pads bed in they won't even produce enough power to skid the rear tire. In my experience from running the Avids on my mtb for about a year and a half, it takes at least one long ride with some good downhills to get them fully bed in and working properly.
Second thought that hit me, is that one of the big advantages of the Avid mechanical discs on mountain bikes is that you can fine tune the feel and modulation a lot if you are running speed dial levers. You can set them up really grabby or far more modulated depending on your preferences. You obviously won't have that option with road levers.
All that said, I'd still probably consider discs on my next cross bike (not that I'm planning on getting a new one anytime soon). Mainly since I ride my cross bike all winter long in the Pacific NW. Rim brakes in general don't cut it for the type of riding that I do in the winter (wet, gritty, long downhills), which is the reason that I switched to discs on my MTB in the first place. I got tired of wearing through two sets of rims/year.
Now, if we're talking about cross racing on relatively flat dry courses, I'd agree discs probably are overkill. And for road riding....I'd think they would be even more overkill. Then again I don't ride my steel road bike in the rain anyway. That's why I have two mountain bikes and a cross bike.
It has taken a quite a while for Disc brakes to evolve and and catch on in the MTB community to the point that they are pretty mainstream.
Judging from the creative responses to the origanal post, It doesn't sound like discs will become "mainstream" for cross unless the manufactures really push it to try to market their cross bikes as the ultimate do anything kinda bike.
Just my $0.02.
|re: Look what Morati did.||SandiaSS|
Oct 6, 2002 1:37 PM
|Okay, two things, first how does one actuate hydraulic brakes with Campy ergopower levers? Is there some kind of external slave cylinder that is cable actuated?
Secondly, and this applies more to road than cross, many of the top pros, and amatures with deep pockets, are moving to full carbon rims which have marginal braking in the dry and almost none in the wet (just ask Jan Ulrich). Disc brakes would be an optimal soulution to this problem, one can use a very lightweight all cabon rim (which could be made even lighter without having to engineer in braking surfaces) and still have better all weather braking than rim brakes.
Lastly a well designed disc brake is not too powerful, it really is "just right". Seriously, when you apply the brakes in your car or on your motorcycle, how often do you lock the wheels up? My guess would be almost never, because the brakes are engineered for that specific application, just as a road or cross specific disc brake would be.
Just my opinion, Michael
|Those are Hope XC4 disc brakes.....||SS_MB-7|
Oct 6, 2002 4:23 PM
|....and I seem to recall Hope having a hydraulic/cable master-cylinder. |