Mavic brake set up help needed
 

Hi Guys, trying to set up the brakes on ex RMO 1992 Gitane, fitted with Mavic brakes which I believe are re-branded Dia-Compe? Anyway, adjust the centering via the main rear bolt, brake a couple of times and they then go off center - what do I need to do?

Thanks, Dan.
https://cimg3.ibsrv.net/gimg/bikefor...0a41f7a5e1.jpg

That's a very cool bike!

Take a look at this diagram of a Mavic brake. Mavic Technical Manual Update! ~ tears for gears

The main post (part no. 451 015) has two faces or flat sides. Once the brakes have been tightened, use a flat cone wrench (probably 13mm) and center the brakes. The brakes should also have a washer with knurled edges between that post and the brake bridge/fork.

The Mavic brakes were rebadged Modolos. There were a few types. Can't remember what came with the starfish cranks. Could you post a close up?

First, verify that the star washer is there. That bites into the fork and brake and keeps the post centered in position. Second, make sure all pivot points and spring contact points are lubed.

Without further info, I'd guess that either the main pivot bolt is too tight, or the star washer is missing.

To adjust the conventional sidepull type with a lock nut and adjuster nut (as in diagram above), you adjust it kind of like hub bearings so that the caliper arms move freely but with no play. Then make sure the adjuster nut and outer locknut are locked (tightened against each other).

If this is one of those Modolo/Mavic brakes with a single adjusting nut, those can be a PITA to adjust, and this could be the problem. Easy to make them tight and bind. I can't recall the exact procedure since I haven't adjusted one in decades, but IIRC you kind of have to factor in the actual fastening nut on the back as part of the adjustment of the pivot bolt. Perhaps someone who's worked on these more recently than me can fill in the details. Basically the goal is the same as before; the caliper arms should move freely, but with no play.
Starting to come back to me. If it's this type, there's a flat I think behind the spring mount block. This essentially becomes the adjusting nut. Jiggle/adjust with this flat and the front allen bolt. When you tighten the brake onto the frame ithe mounting bolt locks it down. This may make it bind, in which case you have to go back and forth till everything is tight but still moves freely.,

Hmmm.... those actually look like the rebadged Dia Compes not the Modolos. Maybe the OP can post better pics of the brakeset? BTW, there were recent posts in this forums discussing centering the rebadged Dia Compes. Maybe a quick forum search can bring that up?

Maybe they are the Dia Compe / Mavic 451. Aren't these the ones that come with the ZAP stuff? I can't tell from that pic. VeloBase.com - Component: Mavic 451


https://cimg7.ibsrv.net/gimg/bikefor...637cb42e91.jpg

Here's a link for those if that's the case. They are a little different since they use an internal spring. Mavic 451/Suntour Superbe Pro/Dia Compe BRS500 Instructions ~ tears for gears

One more thing that can affect the pad's centering about the rim would be the cable housing length going from any cable housing stop point on the toptube.

From the photo I'd say it looks normal though.

Yep, those are the ones - pic attached of them fitted (we forget how easy it is to set up a brakeset with a little grub screw adjuster each side...)

Thanks, Dan.

https://cimg2.ibsrv.net/gimg/bikefor...07cc97bdb2.jpg