Disc brake maintenance

[bongoman]

Hello

I've been commuting to work on a Marin Toscana for about 18 months now, roughly 60 miles a week but lots of stop start through city traffic.

The bike on the whole has stood up well and I'm very happy with the purchase. The only issue I have is with the cable disc brakes.

Every 4 to 6 weeks the disc brakes start to lose their effectiveness and I need to take them into a cycle shop to get them adjusted. This is obviously an inconvienience, and a costly one at that so I'd like to know how to align them myself.

Now I know that obvious problems could be:

1) The brake pads have worn down
2) The cable has stretched so needs tightening

I've tried tightening the cable and I'm told the disc pads are fine.

The guy in the cyle shop that the problem was that they had "lost their alignment".

I've no idea where to start on aligning my disc breaks, do any forum members have any tips, web links or books that I can look at?

As it stands today if I pull the front brake to it's max, I can still pedal with ease... Just after it came out of the shop pulling the brake half way would lock the wheel which is what I want.


If I'd known the disc brakes were going to be such high maintenance I'd have probably gone for the Specialized Tricross instead, but if I can master disc break alignment I think I should be ok.

Matt

 

[jimboalee]

[QUOTE 1235532"]
What brakes are they? Disc brakes are generally pretty easy to adjust, but some are easier than others.
[/quote]


This is true. For their FIRST adjustment, get a LBS to do it, as you have. Some brake caliper adjustment screws are assembled DEAD TIGHT ( bad tolerance ) or assembled with 'thread lock' in the factory.

Most maintenance sheets for brakes are on the manufacturer's website.

 

[fixedfixer]

I have a Marin Toscana. The brakes are Avid BB5's. Take a look at the Avid website there are clear easy instructions for making the adjustments. Because you can only adjust the inboard pad they need a bit more frequent tweaking than the BB7's where both pads can be adjusted.

So you could 'up grade' to BB7 or just follow the instructions on the web to keep the performance tip top. Having said that, some forum users report that BB7's can be a faff as well.

 

[NormanD]

Slacken the two bolts that hold the brake caliper to the brake mount adapter (should be the two bolts to each side of the caliper and not the bolts attaching the it to the frame) slacken enough so you have free and easy movement of the caliper.  

Now have a friend or family member hold the brake leaver in (for the brake you're working on) so the brake is applied (this will aline the caliper to the disc) now tighten the two bolts while the brake is still applied ....done!

Now spin the wheel to make sure there's no binding, make small adjustment if required.
Also if the pads become polished due to use, you can grind the face off them with a sheet of sandpaper, hold the pad side down on the sheet and just make a few circles so it grinds a thin layer off the face of the pads, you can also roughen up the disc face the same way.

 

[byegad]

BB5s are well known for needing regular adjustment. I had them on my Kettwiesel and swapped them for BB7s. Same disc so only the calliper to change, I did it myself. The BB7s work better as they have larger pads and are easily adjusted as both sides have a quick adjust on them. I got 1000 miles out of the BB5 pads on one side before they needed replacing, the BB7s have covered over 3000 miles on the same pads and still going strong, they also need lower hand pressure to get a given braking force and they don't drag for no reason.

 

[bongoman]

Thank you for the help here. I used the xmas break to do a bit of servicing on my bike and finally sorted my brake problems.

For any other users that may be interested, on the BB5 there is a big red disc - I used a screwdriver with a star shaped head to give this disc a couple of turns (clockwise) and now my brakes are back to being sharp and responsive.

I cycled in this morning and enjoyed it as I could crank up the gears again safe in the knowledge that my breaking distance is reasonable.

I guess the brakes themselves slowly unwind, hense the need to give them a quick tune up every now and again?

Anyway, I'll see how the maintenance goes, if it becomes a faff then I'll probably either go for BB7s or more likely - get some cantilever brakes fitted!

As a small point of interest, I notice Marin have stopped shipping the Toscana with disc brakes and reverted to a cantilever brake - could this be due to the high maintenance of the BB5 disc brakes in the model I have?

 

[Zoiders]

You just adjusted for pad wear.

Same as with a rim brake.

 

[HJ]

Thank you for the help here. I used the xmas break to do a bit of servicing on my bike and finally sorted my brake problems.

For any other users that may be interested, on the BB5 there is a big red disc - I used a screwdriver with a star shaped head to give this disc a couple of turns (clockwise) and now my brakes are back to being sharp and responsive.

I cycled in this morning and enjoyed it as I could crank up the gears again safe in the knowledge that my breaking distance is reasonable.

I guess the brakes themselves slowly unwind, hense the need to give them a quick tune up every now and again?

Anyway, I'll see how the maintenance goes, if it becomes a faff then I'll probably either go for BB7s or more likely - get some cantilever brakes fitted!

As a small point of interest, I notice Marin have stopped shipping the Toscana with disc brakes and reverted to a cantilever brake - could this be due to the high maintenance of the BB5 disc brakes in the model I have?

Once set up BB7 are very easy to maintain. I suspect the reason Marin reverted to a cantilever brakes has more to do with cost cutting to keep the bike at the price point...