Thursday, February 16, 2012

Brakes, part II...

I thought this deserved a bit more attention than simply a comment to a comment. In reply to the post yesterday about disc brakes on road bikes, Wally had this to say:

"There are bigger two wheeled devices with motors that use disc brakes extensively. So there is knowledge and expertise on proper braking technique and use for fast or slow rides. The bike rumor article only reinforces the role ignorance and common sense plays in making choices. I use disc brakes on my road bikes and I use calipers too. Mine discs are all BB7's and I see no need to change. I personally prefer a well dialed in disc brake bike on the road but have no issue with good caliper brakes either. I've done some hefty descents on my fully loaded Vaya while touring where my speeds were well into the upper 30's and lower 40's and I liked having my disc brakes then."

Good points all. And yes, the set of circumstances with regards to the hydraulic disc failure in the Bike Rumor article are unique. The writer does admit that his choice of parts may not have been the best and I've got to give him props for trying to make current hydraulic technology work on the road. It's my understanding that the TRP set-up he used was initially unveiled in the cross racing arena. The function of a brake during a cross race is much different than during a long, fast descent on the road. The brakes during a cross race are typically applied in a time period measured in seconds. On a long road descent, the brakes might be engaged for a time period measured in minutes.

While I don't necessarily want to be an armchair quarterback, I had some more thoughts on the subject I thought I'd share. Anyone who has ridden both mountain bikes and road bikes - and cross bikes - knows that brakes are used very differently during each discipline. What may work well for one type of bike, may not work for another type because the riding and braking style is different.

Wally mentions that motorcycles use disc brakes with no problem. I don't think it's fair to compare disc brakes on motorcycles and cars to disc brakes on bicycles of any kind. Disc brakes on bicycles are so much more finicky than the brakes on motor vehicles. First, the individual components on vehicles are much beefier. Weight, to a point, is not as much of a concern. Bicycle disc brakes need to be much lighter. The weight of a typical automobile rotor is greater than an entire bicycle. The disc pads and rotors on a bicycle need to be free of contaminants or performance suffers immensely. Spill a few drops of chain lube on your bicycle's disc brake rotor and you might have to kiss the pads and rotor goodbye. That's not a worry on a motor vehicle's brakes.

I've said it before, I'm a huge fan of Avid's BB7 brakes in either their mountain or road configuration. They work great in a wide variety of applications. I'm sure the writer of that Bike Rumor piece would have had no issue had he been using BB7 brakes. He tried something and learned something. Everyone seems to be on a hydraulic binge. Yes, hydraulic disc brakes are used very efficiently and reliably on mountain bikes. Trying to kludge together what is currently available for use on the road may not be the best use of one's time. Both SRAM and Shimano are hard at work developing disc brakes for road bike and I'm sure what they come up with will work very nicely. Heat dissipation is probably the main focus - and light weight. I wonder if the new hydraulic disc brakes for road will find more use on cross or gravel bikes than on pure road bikes.

Okay, I'll give it a break now.

Potts 29er 19

(What's playing: Absolutely nothing. Wow, it's quiet)

6 comments:

Guitar Ted said...

Mike, we were discussing this very thing at the shop today. I agree that whatever Shimano and SRAM come out with will most likely be very good, however, don't you agree that as a system, the entire format of road bikes needs to change along with these brakes?

It was touched on in the Bike Rumor piece as well as your first post- things will have to be engineered to adapt to these new brakes, and I think that is going to upset a very traditionalist apple cart of sorts.

Whatever happens, it is going to be a very interesting ride.

(Nice brake, by the way!)

Trailer Park Cyclist said...

Hey Mike, I too have been listening to the sounds of silence lately and it ain't all bad.

I'm old and I have experienced drum brakes on motorcycles and well remember the advent of first one disc on the front wheel with a drum in back, then dual discs on the front and a disc in back and I also well remember thinking back then that it was all gimcracks and geegaws and nothing to date has changed my mind and now it has been over thirty-five years.

It is all marketing and a lot of the kids here in the trailer park stop their bicycles by reaching back with one foot and stopping their broke-cable-brake walmart bicyles with tennis shoes from goodwill.

It is all about how to spend money and while I like a gorgeous component as much as I like a gorgeous babe (and the thirty-five years +21 have done nothing to change my thinking on THAT subject) I just plain love plain bicycles.

I was enamored of your last ride report and intimidated by your cohorts but weren't most of you guys riding elderly technology?

Did it slow you down? Or, to the point, did any of you have any trouble when it came time to slow down?

Crap man it's just bicycles and once Madison Avenue sics their werewolves onto any market it goes crazy and Schwinn winds up in Walmart and cyclists start bickering about how to stop their bicycles.

Sheldon Brown turned me on to why I don't really need treads on my bike tires but I still run rubber with grooves.

Marketing is a powerful force and sometimes can overcome reality and the physical laws of the universe.

Meanwhile I know I was supposed to send a deposit on that frame but I am broke as ever so try to forgive me. I ain't gonna let it stop me from spewing and meanwhile I just came in from a ride on my '81 Schwinn that as near as I can tell still has the original brake pads on her. I'm serious. Most of the time.

TJ

blackmountaincycles said...

TJ - The fastest guy down the mountain was on a 1970 bike with brakes from 1970. The oldest technology on the mountain. A lot of folks think, falsely, that if you want to go faster, you just take your brakes off. It's the ones with the best brakes who go fastest. And his 1970 Campy Nuovo Record brakes were the fastest that day.

blackmountaincycles said...

GT - Yes, I hope that we finally see some smart standards set forth if the industry is going to develop disc brakes specific to road bikes. I'm quite surprised that mountain bikes still have 135mm spacing. The industry should have changed to 140mm rear spacing for mountain bikes over 10 years ago.

I don't think disc brakes on road bikes will be widely adopted early on and may not take hold for quite a while. But, it will be interesting. Very interesting. I'm sure the big benefactors of this whole thing are the journalists. Plenty to write about coming down the pike.

Wally said...

Mike,
I didn't mean to imply that bicycles with disc brakes and motorcycles with discs were similar, just that some things transfer such as techniques, pad choice, rotor choice, modulation, etc.
For instance, I swap pads on my bicycles far more often than on my motorcycles. Same for rotors. Suspension plays a huge roll in motorcycle braking and with a bicycle you just don't have that. But common sense and proper expectations coupled with a little knowledge goes along way and that may apply no matter which type of brake is used.

Anonymous said...

the technology available today may not be appropriate or even necessary for road bikes yet...but the manufacturers are eager to push them, the big frame makers are tooled up to accommodate them, and they'll be forced on the market soon. interestingly, i suspect that protour bikes would be one of the last places you'll see discs implemented unless the sponsors, (trekalized, etc...) demand it.