cubewheels

I have used rim and disc brakes, both mechanical. In my experience, stopping power is just the same in dry conditions.

But I think I'm going with discs from now on. Can be more finely modulated and safer to use in wet conditions - unless you live someplace where it never rains and you'll probably be better off with rim brakes. Safety is the consideration for me and 2nd with our local road conditions - mixed dry, wet, and always dusty/gritty. My bike with rim brake has significant rim wear now due to road grit.

Sy Reene

I get the rim wear argument, but a bit of googling tells me that disc brake pads on average are good for about 800 miles, and a pair of rotors for about 3 disc pads. Basic math is therefore about $150 every 2500 miles (2 rotors plus 6 disc brake pads)? Is this accurate and/or how does this compare to the mileage (and therefore replacement frequency and cost) impacts to rims plus rim brake pads?

WhyFi

LOLWTFBBQ - no, that's not right. I get more than 5x the miles out of a set of pads. Still haven't worn a set of rotors to the min thickness.

Troul 

mechanical failure, installation error, brake happy freds, cheap parts & neglect of maintenance all may cause premature wear, but that is a low number for an average. Glad my average is not near that low, but it wouldn't change what I prefer to has for brakes.

tomato coupe

Where in the world do you get those numbers? I get at least 10x that mileage.

tomato coupe

FYI materials don't "gas off" they "outgas." Gassing off is what old people with crazy ideas do.

Carbon fiber bikes get hot in the sun unless they're black? Okaaaay ....

Koyote

When you go on these rants, no one -- NO ONE -- agrees with you. Does that tell you anything?

Kapusta

800 miles?

Are you talking road biking or mountain biking?

KPREN

The guys with rim brakes in our summer bicycling group don't need a bell to warn pedestrians. All they have to do is grab some brake. The squealing instantly makes pedestrians jump off the multi-purpose path. The sound just screams Wal Mart bike even though their bikes are not big box store bikes. No thanks. I will stick with my hydraulic disk brakes. I don't need a marketing guru to tell me that.
I don't know much about the new hydraulic rim brakes, maybe they are way better but I can't see stopping over 300 lbs going down hill with rim brakes.

rydabent

My trike has about 15000 miles on it from new. I have never changed the disc brake pads. I bought a couple of sets several years ago, when I get an indication they need changing. 800 mile on a set of pads is ludicrous.

rydabent

Doesnt bother me a bit. Some one has to be right.

rydabent

I have seen and touched a couple of Wright Bros steel bikes. they are now around 120 years old. Put a set of tires on it and off you would go. Do you honestly think that you could do that in 120 years with a CF bike built today. I say it would be so brittle it would shatter in a thousand pieces when someone tried to get on.

I offer this analogy. I help friends work on old cars. The plastic electrical plug are extremely brittle and prone to breakage. Remember the lions part of the weight in a CF bike is plastic.

indyfabz

That’s why he does. Cut off its food supply.

cubewheels

I ride all the time in heavy volume vehicular traffic in and the outskirts of the city with many steep hills, ~1,500 elevation gain per ride involving tons of braking at relatively high speeds from 20 to 40 mph

But I'm getting over 3000 miles per brake pad on the front brakes (even more mileage with rear brakes). My disc brake pads are sintered metal type, bottom end, dirt cheap China made units as the rest of the braking system. They have been trued and bedded perfectly.

If I only ride in very light traffic and open roads all the time way outside the city, I bet I could possibly get up to 10,000 miles per disc brake pad. Rotors looks like they could last 4x brake pads and rotors are dirt cheap anyway (at least, the ones I'm buying).

And I'm only using a $20 mechanical disc braking system.

tomato coupe

How many people on this forum do you think are concerned about their bike lasting for 120 years? If that's your main criterion for selecting a bike, you might want to look into granite.

Troul 

I'd want about a decade before the frame starts to have issues.

70sSanO

I do. I can here it now....

”Here’s your great-great-great-grandpa’s bike.”

”What are those?”

“The Smithsonian says they’re rim brakes. They squeeze the rim with enough force to stop the bike.”

”Eek. I’m not getting near that thing.”

John

tomato coupe

"Why do the footrests move?"

Eric F

You seem to think all plastics react the same to time and environment. Fact: They don't.

Based on your opinions and conclusions, there's no way a 50+ year-old plastic-handled screwdriver should still be unusable. Yet, I have a bunch of them that I continue to use on a regular basis, and they show no signs of failure any time in the foreseeable future. In fact, I recently used one as a kind of chisel, and hit the end of the handle hard with a framing hammer multiple times. You might be shocked to hear that the handle didn't shatter on impact. Sorry, man. Your plastic analogy fails.

There is actually a current thread on BF that includes info about the ratio of CF fibers to resin/epoxy in a CF matrix for bicycle frames. Not surprisngly, the numbers don't match your guess. There's actually multiple bits of info in that thread that shoot holes in some of your other CF conclusions.

Again...You have zero idea what you're talking about. Please stop. You're only putting your own ignorance on display.

elcruxio

Those wright brother bikes are probably pretty rusted out on the inside. I wouldn't ride them. Because if we take the nonsensical hyperbolic approach you've been going with I can imagine all kinds of reasons why no frame material is sufficient for bicycle use.

Take steel for example. Steel rusts. And while aluminum oxidizes as well, especially in the presence of chlorine atoms, steel just rust so much worse. When you combine chlorine with aluminum the chlorine atom does its thing oxidizing the aluminum atoms and then it kinda stops. Thus you need more salt for more corrosion. However with steel the chlorine atom doesn't stop. It jumps to the next atom and the next after that causing a chain reaction rusting the steel which eventually rusts the whole frame apart. And you cannot avoid it. Chlorine is everywhere but especially in salt which is found in sweat. So you sweat on your steel bike once and it's gone. Eventually.

Aluminum on the other hand doesn't have a fatigue limit. So you ride it and eventually it will fall apart. There's no avoiding it. An aluminum frame will fail eventually when it's ridden. That's a fact. So don't be so dumb as to ride an aluminum frame.

Titanium can only be welded in vaccuum. So if your frame does break it's pretty much toast.

Wood might be the way to go. But then there's worms and other pests which eat wood. And mold. You cannot win.

But if we consider plastics, there is in fact more than one. And different plastics have different properties. Not all plastics are UV-sensitive. Nylon is. Polyester not so much. Which is weird because most quality tents are made out of nylon... I wonder why that is? Could it have something to do with UV-protective coatings?
So to assume a carbon frame will suffer from UV-light we must first assume that the epoxy used to form the frame is very UV-sensitive. That's not a given though. But if the epoxy is UV-sensitive, it then needs to be uncoated for the UV-rays to get through. If the frame is painted, well then there's no issue is there? Paint can be reapplied if it chips.

As to the concept of "gassing off", there aren't that many plastics that actually do that. Plastic's stability is actually a major environmental issue. They just won't degrade. But I suppose that can happen with some volatile plastics like those that were made in the early days of plastic. The kind you see in old cars. But to my knowledge the epoxies used in carbon fiber production don't vaporize and are actually very stable even in low pressure environments, like airplane for example. Did you know all modern fighter jet wings and chassis are made out of carbon fiber? Well now you know. And a fighter jet has a service life of more than 40 years or so of far heavier use than a bicycle will ever see.

Now if you do respond to this post, feel free to ignore all of the stuff written above. Just respond to this. If you don't I'll know you're trolling and full of it.
Have you ever seen sailboats? What are they made of? Could it be glass fiber? The stuff that is also bound by an epoxy matrix, ie. plastic. Now do sail boats see much sunlight and therefore UV-light? Do sailboats experience demanding conditions?
The sailboat my inlaws own was made in the early 70's. By your logic since it's almost 50 years old it should have disintegrated by now or at least it should be unusable because of the various methods of plastic degradation. It looks like new.

Kapusta

99,99% of 120 year old steel bikes can’t be ridden, either.

My experience with cars is that rusted steel does them in before brittle plastic does.

And how many of those old plastic parts you speak of are modern CF?

You are mistaking a gut feeling for a reasoned argument, here.

Sy Reene

Ok, I referenced quick googling of 'how long do bike disc brake pads last"
eg.
https://prodifycycling.com/bike-disc-brake-guide/

followed by googling 'how long do bike disc rotors last'
https://www.feedbacksports.com/mecha...ce%20schedule.

The writers may well be just quoting lowest denominator (MTB I suppose?). OTOH, a bit more searching and I'm hard-pressed to find anyone stretching lifespan to 8-10,000 miles.

Troul 

the uv sensitive product is likely used for ensuring you will be buying a new one eventually. Planned obsolescence. The other more durable material could be pretreated & sold in its place, but there's no money in that.
CF are words that are generic in meaning, yet used to a specific thing by others.
Kinda touches on the life span of CF. Tried looking for a link that I read a long time ago that provided a short & sweet to it all...
https://www.technewsworld.com/story/76172.html

Troul 

If you search automotive pads, you'll get something of the following:
"average lifespan of brake pads between 25,000 and 65,000 miles...." "though some people will have brake pads last beyond 80,000 miles...." While it's impossible to give an exact number, the 40,000-mile range is the general mileage to keep in mind when planning for vehicle maintenance...."

That is a rather big gap regarding miles for a set of pads, that is assuming it's referring to the front only. Under normal conditions & with commonly designed purpose; Rear pads do not wear as frequently.

As to clarify the point; The expectations for pad & rotor replacement is a "YMMV" greatly. A logical & common understanding of the system may aid in developing what to expect out of brake pad wear.

Dan Burkhart 

As I read this, I can hear the hinterland whos who theme in the background. Only those of us from Canada and of a certain age would get that I think.