Linear-pull Brake Adjustment

Apr 26, 2010
212
2
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Shimokitazawa
#1
Hi everyone. I posted a while back about having a really hard time sourcing Avid brakes in Japan. I finally got them through Chain Reaction and they've been every bit as sweet as I had been led to believe. Unfortunately, I noticed that the front set was gradually shifting to the left. I take the wheel off every night when I get home in order to store the bike inside. To my knowledge, the brakes and fork have never been bumped or otherwise knocked out of alignment. However, when I put the wheel on this morning, the right brake pad was touching the rim. No amount of adjusting gave me any gap between pad and rim. Eventually I had to give up and ride my other bike in to work.

I don't know a ton about bike mechanics, I'm learning as I go, but I tried everything I could think of to get some clearance but no dice. I realize most of the riders on here are roadies and don't deal with linear-pull brakes, but if anyone has any advice I would appreciate it. Attached are pics of the set up.
 

AlanW

Maximum Pace
Jan 30, 2007
1,214
435
103
Tokyo
#2
Look near the pivot where the brake bolts to the frame. There should be a small Phillips head screw or allen screw there, pointing across the bike. This will adjust the spring tension of each arm. Loosen the one on the left brake and tighten the one on the right brake.
You can also just set (bend) the spring rods behind the brake arms for coarse adjustment then fine tune with the adjustment described above.
Also check the pivots are not binding and grease the pivot if necessary.

AW.
 
Apr 26, 2010
212
2
38
Shimokitazawa
#3
Thanks Alan. I had adjusted the small spring tension adjustment screws before, but only on the side giving me trouble. I though it was just somehow changing the distance of the brake pad from the brake arm, moving it closer or farther from the rim (and doing this independently of the opposite arm)! I realize now that this is so very much not the case. Thanks for cluing me in to the fact that it is actually adjusting the spring tension... therefore it stands to reason that adjusting one side will affect the other. I hadn't realized this. I chucked the wheel on just now and adjusted both sides and it evened out perfectly.

Thanks for your help!
 

FarEast

Maximum Pace
May 25, 2009
5,528
538
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Yokohama
#4
Also looking at your photo it looks like the arms are to far out as well, V-Brakes should stand almost vertical to the fork, take a look at the image below Avid have a nice flat section on the inside edge of the brakes this should be near to vertical:

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The when set up properly the brakes move horizontal to the rim and not at an upward angle.
 
Sep 2, 2009
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#5
Ghetto it;

Unlatch the spring on the back of the brake on the side that is too close to the tyre, bend it out a bit, and then put it back in place.

I learnt that trick when I used to work in Halfords when I was 16 years old; what could possibly go wrong!

>EDIT; and yeah, what FarEast said - your arms are way too far out. There appears to be too much cable between the top of both arms, and it is sagging which indicates that it is not set up properly. If you like a bit of play in your brakes, I am sure you can set that up in the brake levers, instead of doing it down on the brake itself... What levers are you running?
 
Apr 26, 2010
212
2
38
Shimokitazawa
#6
Yeah, I always thought it looked a bit sloppy. Initially Pro-Tech set them up... and unapologetically broke my shifter in the process, then Nalsima tuned them, but they're a roadie shop. I'm not sure how many linear pull brakes come their way. I'll have a look at it tonight and see if I can get those arms straight.

I'm using Cane Creek Drop-V levers in order to mate the brakes with drop bars (apparently this is not commonly done).
 
May 22, 2007
3,595
1,422
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Kawasaki
halffastcycling.com
#7
I learnt that trick when I used to work in Halfords
Oxymoron du jour.

Lost count of the times I've heard from colleagues: "I bought it in Halfords just before I came out, and they set it up for me". Deathtraps all. Last one had both springs from the front QR on one side ("It's a bit wobbly"), and zero grease in the rear wheel hub ball race ("It makes a funny noise").

So glad that I can do maintenance in my air-conditioned office.

--HF Mike--
 

AlanW

Maximum Pace
Jan 30, 2007
1,214
435
103
Tokyo
#8
The width of the arms is set by the width of the rim + clearance between the rim and the pad + the thickness of the brake pad + any spacers you have between the arm and the pad.
The spacers/washers are also the adjustment mechanism for the angle of the brake pad relative to the rim. There should be one convex and one concave washer each side of the arm. This allows you to move the brake pad when the pad fixing bolt is loosened.
For your setup, make sure the thinnest washers are on the inside of the brake arm, the side nearest the rim. You only need one concave and one convex so if there are additional spacers on the inside (which there may be, looking at your photo), shift these to the outside. Adjust the brake pad so it's square on to the rim when looking from the front, doesn't overhang the rim, and has a little bit of toe-in when looking from the top (i.e. front of pad hits just before the rear.
I also noticed that the left brake has "R" etched on it and the right brake has "L" etched on it so these may in fact be a rear brake pair.
If you can't bring the brake arms inward it's not really important, as long as the pads are hitting square to the rim and are not catching the tyre at all when they move. You'll lose a tiny bit of brake power but (probably) you'd never notice.

AW.
 
Sep 2, 2009
5
0
0
#9
Oxymoron du jour.

Lost count of the times I've heard from colleagues: "I bought it in Halfords just before I came out, and they set it up for me". Deathtraps all. Last one had both springs from the front QR on one side ("It's a bit wobbly"), and zero grease in the rear wheel hub ball race ("It makes a funny noise").

So glad that I can do maintenance in my air-conditioned office.

--HF Mike--
Yeah, I was taking the piss mate. I did, however, used to work in Halfords when I was 16, as well as my local bike shop and did actually learn a lot from the guys who worked in Halfords. This was 15 years ago, mind, and no doubt standards have dropped since I left. :cool: