Bike Forums - Trek 520, Old vs New

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Originally Posted by 3speed (Post 16513355)

Again, the advantages of disk has nothing to do with brake force.

And, yet, that is overwhelmingly the main selling point.

Quote:

Originally Posted by 3speed (Post 16513355)

That said...
I honestly don't mean any disrespect here - I've read Many of your posts in the past and I know you have lots of knowledge, but on this subject I think you could continue to learn about the new aspect of it. If nothing else, disk brakes seriously do offer better modulation. The system lends itself to it from a mechanical aspect. Disk brakes just aren't as grabby, so you can adjust the braking force more subtly.

No disrespect taken.

As I said above, I have just about every brake set up currently on the market. I regularly switch from a hub mounted disc brake equipped mountain bike to a cantilever equipped road bike. I even have a bike where I can directly compare disc and v-brakes. I just don't experience any changes in the ability to modulate the pressure that I can assert on the brake system. The v-brake (rear brake) isn't any harder or easier to control than the front (hub mounted disc). Nor have I ever found a rim brake to be particularly "grabby".

I am also not new to using hub mounted disc brakes. I've been using them on mountain bikes since 2003. If there were anything special about them, I'd have noticed by now.

Quote:

Originally Posted by 3speed (Post 16513355)

As for your hydraulic being very on/off, I'd recommend somehow adjusting them or perhaps it's a poorly designed set. I'm not sure. They would be very powerful, so you can't go just grabbing and squeezing the lever like you have to on non-disk brakes, so keep that in mind, but they should offer a very wide range of braking force.

The model of hydraulic brake I have is well know for being grabby. Numerous posts on MTBR suggest changing the pads for organic pads or using one side organic and the other sintered on each caliper. And, as hydraulics, there is no adjustment you can do. One of the advantages of (some) mechanicals is that you can adjust the fixed pad and/or moving pad sides of the caliper to center the brake and adjust for wear. Hydraulics don't have that adjustment since they are self adjusting.

I've also had this discussion with another mountain bike rider who had the same complaint on his hydraulics which were a different brand. He also felt that the brakes were very touchy and grabby. To me, a brake that is touchy, grabby and requires a very light hand isn't an example of "good" modulation. It's just the opposite.

Quote:

Originally Posted by 3speed (Post 16513355)

Also, that you said all of your brakes are at wheel lock by the half travel point of the lever gives an indication of how you set your brakes up. You probably also have fairly strong hands and use more hand strength vs. mechanical leverage to stop when compared to others. Not that there's anything wrong with that, but it's opposite of the idea behind disk brakes. It's like driving a modern car vs. an old classic with no power brakes. If you grab a hand full of disk brake like you would regular brakes, you are going to go straight from no brakes to wheel lock. Just like if you're used to driving a car without power brakes and then hop in a 2014 Honda, you're going to lock the wheels and come to a screeching halt the first time you try to stop.

I get what you are trying to say but disc brakes on bikes are nothing like the difference between power brakes and non-power brakes in cars. As you said above, the advantage of the hub mounted disc brake isn't in the power.

When adjusted properly, a hub mounted disc brake will have the same kind of lever pull that I run on all of my brakes. They have to or they don't function properly. If you detune a disc so that the lever won't engage like most rim brakes I've seen, the brake won't function. You can try it yourself. Put a lot of slack in the cable so that the lever doesn't engage until half travel and you'll find you can't stop.

Quote:

Originally Posted by 3speed (Post 16513355)

If you look up Sheldon Brown's article on "the geometry of cantilever brakes" and scroll to the "feel vs. function" section, that will perhaps better explain what I'm saying in terms of why the way you use brakes is so different from the idea behind disk brakes and why you aren't seeing their modulation benefits.

Sorry but I don't agree with Sheldon Brown. I've never found a "spongy" brake to stop better. He's just plain wrong. If you don't believe me, detune a mechanical disc like I suggest above. It won't stop you better. It won't stop you at all.