Brake pad adjustment tips?

rice rocket · #1 03-05-2011, 09:50 AM

I'm apparently horrible at this. I cannot dial out the mush in the system (unless I'm overlooking something else as well?).

The trailing edge of the pad seems to contact the rim first, and as I add more pressure, I can see the whole thing pivot. The pad holders don't really have toe adjustment on them.

What am I doing wrong here? It's a used brakeset (Ultegra 6500 levers and brakeset), should I pickup a set of Dura-Ace pads and start all over?

eddief · #2 03-05-2011, 10:09 AM

if you loosen the pad holder/brake shoe fixing bolt then the whole holder usually pivots on a conical washer thingy. That thingy should allow you to adjust the toe in or out of the pad. No?

In the tech doc below, number 16 shows bolt and conical washer.

http://techdocs.shimano.com/media/te...9830728758.pdf

If you adjust and things still feel like mush, maybe your housing is crimped, old, too long. Need a new cable. Or you need to pull some cable so the pads start out closer to the rim.

rice rocket · #3 03-05-2011, 10:31 AM

The BR-6500 holders don't have a conical washer, it's just a flat washer. The conical ones only came on 6600 and later. I can see the brake arm move another 1-2mm after the pad contacts the rim.

Do shops normally carry the fixing bolt/washer (assuming I need a longer bolt to accomodate the conical washer), or are they sold w/ the pad set?

I'll tear and down and check the cables tonight.

eddief · #4 03-05-2011, 10:55 AM

that the 6500 brakes do not have the conical washer. for the conical washer to work, the brake shoe would also have to have a rounded surface where it meets the conical washer. otherwise the pivoting would not be able to pivot.

maybe one of those times when a real LBS smart person would be able to assist. in old days we used to "bend" in the brake arms with a crescent wrench applied to brake arm flat where the shoe is attacached. not recommending, just remembering.

Wilkinson4 · #5 03-05-2011, 11:05 AM

Toe in!!! Or Toe out??? Interesting post on the net!

"I always hear people say you should set your rim brake pads with "toe-in". Even the masters say it. The problem is that they are all WRONG. Technically, you want toe-out on brake pads, hear me out.

Everybody thinks of toe-in when they are standing over their bike looking down at the brakes and wanting the front(with respect to the bike) of the pads angled in. This is the wrong reference system. The leading edge of the brake pad is the toe, and the trailing edge is the heel. What you have to realize is that it is the leading edge with respect to the rim, not the bike. The bike does not rub against the brake pads, the rim does. This means that the leading edge of the brake pad is the one that the rim rotates into which happens to be the one at the rear of the bike.

If you want quiet brakes, you want the trailing edge to contact the rim first. This means that you want toe-out."

mIKE

eddief · #6 03-05-2011, 11:09 AM

you've turned my world upside down. that was really smart...and I mean it. not joking. never thought of it that way.

OP may want new shoes anyway:

http://aebike.com/product/shimano-ul...r6606-qc30.htm

mandasol · #7 03-05-2011, 11:57 AM

I've got a set of 7700 brakes and the setup looks pretty similar to what you are describing for the 6500. There isn't much toe adjustment on them as far as I can tell, so if that is what you are looking for go for newer design vs. upgrading to 7700.

fjaws · #8 03-05-2011, 01:58 PM

Quote:

Originally Posted by Wilkinson4

Even the masters say it. The problem is that they are all WRONG. mIKE

No disrespect, but I'm with the "masters" on this one. Toeing as you suggest will tend to force the leading edge of the pads away from the rim as the trailing edges grip the rim and are pulled slighly forward. The traditional toeing method, as illustrated on the Park Tool website (with illustrations as to orientation) will do exactly the opposite and pull the trailing edge of the pads into the rim and give you maximum pad contact and stopping force.

oldpotatoe · #9 03-05-2011, 02:16 PM

Quote:

Originally Posted by rice rocket

I'm apparently horrible at this. I cannot dial out the mush in the system (unless I'm overlooking something else as well?).

The trailing edge of the pad seems to contact the rim first, and as I add more pressure, I can see the whole thing pivot. The pad holders don't really have toe adjustment on them.

What am I doing wrong here? It's a used brakeset (Ultegra 6500 levers and brakeset), should I pickup a set of Dura-Ace pads and start all over?

That brakeset and pad had no conical washer, no way to adjust toe in/out.

Take out the pad and gently bend the caliper arm.

mpetry · #10 03-05-2011, 02:49 PM

You know, the problem you're having might lie somewhere else. One of the things I've found with brake installation is that the setup on the cables and housings is critical to getting enough braking authority. If the cable housings are mushy or not seated properly, the brakes will feel mushy and will never stop well.

At the very least take the housings out and inspect them. Make sure the ends are square and not distorted. You can trim off a couple MM and file them square, removing the burr. I touch mine to the bench grinder.

Then install the housings, make sure they are seated in the ferrules, and do a trial installation of the cables and brakes. Squeeze the brakes against the rim (or a wood block) and note how much the lever travels after the pads are in contact. If you're getting "significant" lever travel once the pads contact the rim, you're not going to get good braking authority anyway, it's like a mushy brake pedal. The lever should feel VERY solid. If it doesn't, then it's time to replace housings and inner wires.

It's even more critical on centerpull brakes, where you have less mechanical advantage.

Mark Petry
Bainbridge Island, WA

oldpotatoe · #11 03-05-2011, 02:52 PM

Quote:

Originally Posted by mpetry

You know, the problem you're having might lie somewhere else. One of the things I've found with brake installation is that the setup on the cables and housings is critical to getting enough braking authority. If the cable housings are mushy or not seated properly, the brakes will feel mushy and will never stop well.

At the very least take the housings out and inspect them. Make sure the ends are square and not distorted. You can trim off a couple MM and file them square, removing the burr. I touch mine to the bench grinder.

Then install the housings, make sure they are seated in the ferrules, and do a trial installation of the cables and brakes. Squeeze the brakes against the rim (or a wood block) and note how much the lever travels after the pads are in contact. If you're getting "significant" lever travel once the pads contact the rim, you're not going to get good braking authority anyway, it's like a mushy brake pedal. The lever should feel VERY solid. If it doesn't, then it's time to replace housings and inner wires.

It's even more critical on centerpull brakes, where you have less mechanical advantage.

Mark Petry
Bainbridge Island, WA

Please, PLEASE, NO FERRULES into STI or shimano brake levers!!

Or Campagnolo either after 2002. Pet Peeve number 201.

mpetry · #12 03-05-2011, 03:30 PM

Peter -

OK, so I read that and rushed off to check my bikes! The good news is no ferrules - mostly - but what about this spot - seems like the housing would be pretty sloppy without 'em, don't you think ? I believe the Campy housing kit comes with ferrules on this piece of housing.

What I probably should have said was that the cable housings should be properly seated in "whatever they are supposed to be seated in" be it lever, frame cable stop, or brake arm.

I have found that dressing up the housing ends restores crisp shifting or braking "feel" - after months or years the ends get mushed over or whatever and there's some slop.

Just trying to help out the OP who was clearly stuck.

Mark Petry
still ridin crappy old record-10 on
Bainbridge Island, WA

eddief · #13 03-05-2011, 03:34 PM

what did potatoe mean? i don't use ferrules for the gear cable at the lever connection point. Nor do i use them where the housing hits the brakes. but do use them everywhere else on all of my STI bikes.

neiltron · #14 03-05-2011, 04:04 PM

What's the issue with ferrules going into levers ?

I have a pair of Mavic SSC brakes with Yokozuna brake/shifter housing and my brakes are very strong, have a great feel and are easy to modulate. No mushy feeling, and the price for the fancy housing was worth it IMO.

oldpotatoe · #15 03-05-2011, 04:20 PM

Quote:

Originally Posted by eddief

what did potatoe mean? i don't use ferrules for the gear cable at the lever connection point. Nor do i use them where the housing hits the brakes. but do use them everywhere else on all of my STI bikes.

No brake Ferrules in shimano STI or ERGO LEVERS. Yes der ferrules in shimano and Campagnolo 1992 thru 2008. Please, no brake ferrules in STI either, they goon up the housing and get stuck in there. but YES ferrules for der housing.