Thank you Don. Although I am not a bike mechanic, I have been riding bikes for a very long time with all sorts of brakes (I remember the being thrown forward by my pedals trying to brake as well as the first mtb cables that looked like logging cable). When dry, well adjusted rim brakes (most designs / of good quality construction, installation and maintenance) are super stoppers. Also you can take a canti brake fork that is shuddering and stop the shudder with an install of the old horseshoe shaped stabilizer that bolts onto canti bosses. It works. But I have to say well designed, installed and maintained disc brakes are just amazing. I have just spent another winter riding in all sorts of conditions using mostly disc brakes. In my opinion the disc brake not only slows and stops better than rim brakes, but is so consistent compared to rim brakes, safe bike operation is greatly enhanced. I knew SRAM had the Hydro road disc coming and was not surprised when I heard it. I personally believe it will not be that many years when there will be more bikes equipped with disc brakes produced than with rim brakes. Like any technology, it is expensive at first, but as time goes on, the production costs come down so more people have access.
For something like Road racing or Cross the difference between a wheel with rim or disc brakes will become a non issue as most racers at the pro level either have another bike available if there is a problem or a mechanic that is so well trained a wheel can be changed in seconds.
I could say my old 57 Chevy was such a great car because of the overall design or I could do all the maintenance. That would just be my opinion and not have that much to do with fact. Looking at that car now, it may look cute, but is also a very inefficient machine compared to modern vehicles.
Disc brakes are one of the best additions to bicycles I have experienced in my life. They are an example of how mtb technology via motorcycles has moved toward road bikes as have the tapered head tube. The great thing about Avid mechanical is they might be considered toward the low end of the disc gene pool, but they are like the old Chevy in one important respect. They are competitively priced as well as easy to install, adjust and maintain. Even if hydraulic disc brakes on road / cross bikes become common, mechanical will (in my opinion) the brake of the masses. Disc brakes have already changed rim design. Nothing stays the same. Including the fact that rim brakes do work.
ron
From: don person
Sent: Monday, April 16, 2012 8:51 PM
To: john
Cc: OBRA remailer
Subject: Re: [OBRA Chat] 'cross brake question
John,
SRAM has production hydro road disc brakes coming in a few months.
There is nothing wrong with BB7 Road calipers and road STI levers. I have been running them on my mtbs since the road caliper came out. I like the performance better than the BB7 mtn caliper and long pull levers. Have never had issues with the levers bottoming. PLENTY of power with the modulation (I prefer not to fit over the bars). Quiet 98% of the time, too.
I would also take cantis any day over any brake with a Travel Agent. Was never able to get the TAs to hold adjustment for an entire ride. Just not worth the trouble.
-shiggy
On Monday, April 16, 2012, john wrote:
"hydraulic road disc brakes "
Doubtful. I have been running disc on my commutter bike for a year now or so. And am convinced their only advantage is that your rim doesn't get ruined. So in most places in the country/world where road cyclists don't even know what fenders are, rims don't wear (or wear incredibly slow..) , like in the gritty with lots of stops and hills northwest..
So then what is their advantage ? there is none: more weight, more force/stress on wheels and frames, and not necessarily better braking...
Now granted not ruining rims is huge advantage and I think worth it, but my experience is that they don't stop as well as good rim brake setup. And need pretty constant adjustment (which thank god is easy enough..) My front BB7s, in the rain/wet, also squeal to high heaven and scare the bejesus out of other cyclists, way way way beyond the noise ever created by the any rim / brake pad combination i have used... ( I think it has more to do with my overall system stiffness, since squeal / chatter is nat'l frequency situation... tried a couple other pads to no avail, metallic pads are next? and possibly a steel adapter... a different disc? )
Ok yes the modulation is great, but when you really need that extra lock-em-up slide the front tire /nearly flip, it's not there, and I've almost become a trunk monkey a couple times. Ok so I can set them up with a bit of drag, with of course better braking, but chose one: great brakes or no drag, you won't get both, at least not with the current designs(road BB7** ).
I think some drag is of course OK with your big downhill rig, but I would think totally unacceptable if taking a couple minutes out of your time trial ;-) ! Ok the drag is at least at a smaller diameter, so not as much drag torque, but still, it drives me nuts to have something dragging. Of course you can go to a bigger disc. But tradeoff is heavier, not as true, which means more clearance and thus either drag or not as good of brakes.... and the tiger chases tail. Ok decrease tolerances, but this hard for something that may get routinely heated dull brown and is expensive or heavier..
BTW, just in case they didn't teach this at UBI (and if they didn't, i would ask for refund ;-) :
The reason linear / v-brakes are better is because the cable tension is half (given equal hand force). Thus your cable stretch and cable housing compression is halved. (remember the huge MTB cables and housings that we use to have before v-brakes?). So it was quite good idea. Less force in the cable, thus less cable stretch = more responsive brakes, and also less weight because less stiffness required, win-win by design alone.
Another issue with bicycle brakes is too much mechanical advantage. Granted they have to work with 12 year old hand I suppose, and granted old time brake pads might have been left wanting, but I think now they need to design in some ability to adjust your mechanical advantage (like some mtb levers where you can increase or decrease the distance from pivot to cable pull..).
**The same problem that plagues canti's also plagues road mechanical discs: too much cable tension resulting in too much cable stretch and one runs out of brake lever movement. Obviously the front isn't much of an issue since cable length is short (cable spring rate being E*A/L). An upgrade for my discs will be to go to MTB bb7's and then run either long pull road levers or a "travel agent" converter. I may even further decrease my mechanical advantage (as I did on my tandem rear brake) so that I am assured of not bottoming out my brake lever and in getting proper brake pad pull-off !!
Now what happened to ceramic rims ??
All of this because I am building low count spoke wheels with tubeless... (i just can't bare to scratch up those fancy light stans rims... ) But I am saving money on not buying tubes !
(I can't even imagine carbon rims... i guess that's the real market for disc brakes.... )
Even better i suppose I buy one of those skidding tires with the extra rubber and install an old time paddle brake (or whatever they called them, foot brake??) that comes right down on the tire. the tire is a wear part anyway, use it like it is !
On Mon, Apr 16, 2012 at 3:40 PM, Rick Johnson wrote:
On 4/16/2012 3:34 PM, john wrote:
Maybe someday the bike industry will progress to having all brake levers be "linear pull".
We'll have hydraulic road brakes long before that happens...
Rick Johnson
Bend, Oregon
Every revolutionary idea seems to evoke three stages of reaction...
One, it's completely impossible.
Two, it's possible, but it's not worth doing.
Three, I said it was a good idea all along.
Arthur C. Clarke
--
Don Person (shiggy)
http://mtbtires.com
http://titusti.com
http://shop.on-one-usa.com
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