edscott.

You also have to consider the frame. Classic geometry, as in the bike shown previously, allows only up to 23 mm, which is fine for my 63 kgs.

big john

They're anti-lock.

noodle soup

The Northshore of Chicago is known for their high speed descents.

For you, discs are overkill. Even I my local area, no one needs them. 30 miles from Phoenix, and it’s not pancake flat.

DiabloScott

Serious question - do they work so well that you don't even think about their being wet? With rim brakes in the rain I just adjust my thinking and technique to accommodate for what I know will be reduced performance - how much less accommodation would I be making with discs?

kingston 

There's one hill on Sheridan road but they closed it to bikes in the 80's claiming too many bike crashes. True story.

Cyclist0108

Having lived on that road (in my early youth), I find that ... remarkable.

tyrion

I certainly think less about wetness affecting braking with discs. Water is simply less of an issue than it used to be (with rim brakes). Like everyone, I became acclimated to being able to brake later with discs.

Hard to quantify it, but you definitely notice it.

HTupolev

Depends on what you call "classic." Most road bikes from the early 80s and before can fit at least 30s with healthy clearance.

tomato coupe

What current side pull caliper brakes will accommodate 40mm tires?

kingston 

Tektro R559

noodle soup

Do you want to compare the braking of Tektro R559 side pull brakes, to Shimano hydraulic discs?

AlanHK

I care. I recently got my first bike with hydraulic brakes, a used one I thought was a bargain, and have had so much hassle and expense getting the brakes working that I am pulling out my hair. For rim brakes all I needed was a 5 or 6 mm hex key and a 10mm spanner. Replace the cable and pads every few years for pocket change. Spit on a tissue to clean the rim and pads if they get oily from the road.
For hydraulics I had to buy the absurdly expensive Shimano oil, tubes, syringes, and then give it multiple transfusions to replace the fluid. Then replace the expensive brake pads. Then spend hours polishing and tweaking the rotors to make them flat. Then get a new expensive lockring to secure the rotor. Then get a lockring tool to attach it it. Align the brakes. All the time being paranoid about getting a drop of oil on the pads and poisoning them.

If you have a team and a sponsor to handle all that, no problem. Or if you are a yuppie and just take it to the shop and pay $100 for servicing whenever, no problem. For some of us, it is something we care about.
I'm sure bike dealers love them, more money up front and steady stream of income to maintain them.

If I was setting up a bike, I might use disk brakes to get the admittedly better wet weather performance. But definitely cables, not oil. Hydraulics are such a pain and expense to maintain. I think now probably why the original owner got rid of it, easier to by a new bike than fix. Everything else I got tuned up in an hour.

kingston 

Irrelevant. I've ridden that bike on every big hill within 300 miles of Chicago, many of them at night in the pouring rain, and haven't crashed into anything yet.

noodle soup

You could do that with a coaster brake.

kingston 

Agree and I could lay down some sweet skids too.

tomato coupe

If you're riding a road bike with those brakes and 40mm tires, I think the extra weight of disc brakes would be insignificant.

kingston 

Totally insignificant. That bike weighs over 40 pounds loaded for a brevet.

Seattle Forrest

Fair enough. You can buy a road bike with disc brakes and 30+ mm tires though, pre built and ready to test ride though. Hundreds of different models. I'm just saying the idea that discs can't be better because tires are what's important for traction - that doesn't take into account the fact that in practice discs give you more choices for tire size. I don't think bigger is necessarily better and we should do be riding 10,000 mm tires. And I recognize that not everybody needs discs, but I don't have any control over what Trek sells, so it doesn't matter what I understand.

tomato coupe

A lot of people drove cars with drum brakes their whole lives without crashing, but that doesn't mean automobile drum brakes are as good as automobile disc brakes.

HTupolev

An extra pound has a roughly equivalent performance impact on a 17lb bike as on a 30lb bike.

kingston 

I have a bike with drum brakes too. Also perfectly adequate for riding around the north shore.

tomato coupe

Sure, but if you're riding a 40 lb bike, it's would be pretty silly to argue that the increased weight of disc brakes is a significant issue.

tomato coupe

Have you crashed into anything with them? If not, would you then conclude they are as good as rim brakes and disc brakes?

kingston 

That would be silly. The reason I don't have disks on that bike is because they are unnecessary and the frame was built for sidepulls.

kingston 

I have never crashed that bike so I conclude that drum brakes are good enough and they are infinitely less maintenance than any other kind of brake.