Disc brakes; am I an idiot?

Lewis Moon · #1 01-12-2018, 06:42 PM

So, I got the X-Fire set up and I'm completely underwhelmed with the brakes. Lots of pressure and only a little stop. They're Hayes CX 5s and Ultegra levers. What am I doing wrong?

donevwil · #2 01-12-2018, 06:45 PM

Did you bed/break-in the pads and rotors?

Lewis Moon · #3 01-12-2018, 06:50 PM

UThe bike has about 500 miles on it by the previous owner. I believe he may not have been as into bikes as mybadself. How do you break them in?

donevwil · #4 01-12-2018, 06:57 PM

Hmm, can't imagine them not being broken-in in after 500mi, but I guess it's worth a try. There are probably better videos, but this one covers it.

vqdriver · #5 01-12-2018, 07:00 PM

there's a lot of variables with that set up. it's mech, so cables, housing, cable pull ratio all come into play. on top of the normal pad/rotor bedding. did you buy the bike and build it up yourself or was it complete as it is?

edit: if you bought it complete from someone who isn't as into it as you, then they probably didn't pay much attention to the rotors. first thing could be to simply give the pads a new surface by lightly sanding and cleaning the rotor faces with alcohol to remove any oils/dirt. bedding the rotors is important tho..

Veloo · #6 01-12-2018, 07:00 PM

Regular or compressionless brake cable housing?

Lewis Moon · #7 01-12-2018, 07:02 PM

Quote:

Originally Posted by Veloo

Regular or compressionless brake cable housing?

Regular. I can see where that would help.

Lewis Moon · #8 01-12-2018, 07:03 PM

Quote:

Originally Posted by vqdriver

there's a lot of variables with that set up. it's mech, so cables, housing, cable pull ratio all come into play. on top of the normal pad/rotor bedding. did you buy the bike and build it up yourself or was it complete as it is?

It was complete and the previous owner had it set up by a shop.

vqdriver · #9 01-12-2018, 07:12 PM

yeah, i'd just start with cleaning up the pad/rotor interface. if not already, compressionless housing is in your future. which also means new cables. not terribly expensive and it does help.
i've tried jagwire and the trp housings. either one is fine.

dddd · #10 01-12-2018, 07:17 PM

I felt that I was getting very unresponsive braking from my Shimano mechanical calipers, so substituted a larger rotor size to achieve just enough braking response.

Many mechanical calipers get installed poorly aligned with the rotor, such that much lever travel is lost to flexing the caliper sideways or actually twisting it. Be sure that there is absolutely minimal movement of the rotor as the pads engage, or fix the alignment until this is the case. Some installations will require filing of the mounting surfaces, which is a very time-consuming, iterative process!
Some installations use swivel washers between the caliper and the mounting, and some do not or use these washers only under the bolt head, I kid you not!
Adding these washers where not originally specified may push the pads outward of the rotor surface, causing off-center contact and odd noises, so be sure that the original installation is keeping the pads centered on the disc's friction surface path.
I always inspect caliper alignment and adjustment outside, in the sun, so that there is a bright background that illuminates the gaps to either side of the disc. This visual inspection actually allows for very accurate adjustment of the very small gaps and of the caliper's alignment with the rotor.

simplemind · #11 01-12-2018, 07:38 PM

Hayes are not known for their braking prowess, however what is the pad material that you have? If they're metallic, you could get a lot more power just out of switching to an organic pad. Yes, they wear faster but the benefits outweigh the cons, imho.

Lewis Moon · #12 01-12-2018, 08:01 PM

Quote:

Originally Posted by simplemind

Hayes are not known for their braking prowess, however what is the pad material that you have? If they're metallic, you could get a lot more power just out of switching to an organic pad. Yes, they wear faster but the benefits outweigh the cons, imho.

They're OEM.

ColonelJLloyd · #13 01-12-2018, 09:35 PM

Compressionless housing is key for mechanical discs. Now you know.

On top of that there are lots of variables as have been discussed.

Gummee · #14 01-12-2018, 09:53 PM

One more fun question: are the brakes set up so that the arm is bottoming out on the caliper?

Seen that more than once

M

David Kirk · #15 01-12-2018, 10:47 PM

I would pull the pads and lightly sand them just enough to get a fresh surface and then I would bed them in according to the manufacturers recommendations.

Just riding and putting miles on the brakes will not bed them - in fact more often than not it just glazes the pads and then they will work like crap.

Bed them right and they will work great.

dave