[gilbertlikesbikes]

So I have been breaking in my new 2010 GF Paragon, and things are going well, with one exception. I have the Avid Elixir 5's with 185mm front / 160mm rear rotors. When breaking, the rear rotor/brake vibrates strongly enough to vibrate the whole rear triangle all the way up to the seat post/seat. It is quite uncomfortable to have these vibrations up in between my legs, not to mention that this shouldn't happen. I have done many pad "break in/bedding" runs, but they still vibrate. I have checked all the bolts on the rotor and the caliper, and they are tight. I have also checked for alignment of the rotor and the caliper/pads. Visually, they seem to be lined up and parallel. I have also reseated the rear axle a few times to make sure it is up in the hanger and seated correctly. It is.

Does anyone have any ideas as to what is causing this and what I can to do fix it?

 

[AZ]

Have you re centered the caliper ?

 

[gilbertlikesbikes]

No I have not.

How do I do that?

 

[AZ]

Loosen the caliper bolts so the caliper can move . Gently apply the brake and hold while tightening the caliper bolts . It can take a couple of try's so be patient . Good luck .

 

[neex]

Loosen the caliper bolts so the caliper can move . Gently apply the brake and hold while tightening the caliper bolts . It can take a couple of try's so be patient . Good luck .

It helps to load the wheel also and tighten one bolt at a time before loading again. In other words, if you hold the brake lever tightly and rock the wheel back and forth before tightening the CPS bolt/washers, it seems to center perfectly the first time (it works for me anyway with Elixir CRs).

Good luck.
A.

 

[gilbertlikesbikes]

Sorry for the dumb questions, but which screws are the CPS screws?

There are 2 that mount the caliper to the mount (which then is bolted to the frame), then there are 2 that are in the caliper which look like they go through the caliper to the other side, then there is one screw that I assume is for bleeding, and then finally a sixth screw which looks like it holds the pads in place.

 

[cort]

Sorry for the dumb questions, but which screws are the CPS screws?

There are 2 that mount the caliper to the mount (which then is bolted to the frame), then there are 2 that are in the caliper which look like they go through the caliper to the other side, then there is one screw that I assume is for bleeding, and then finally a sixth screw which looks like it holds the pads in place.

First one ^

Loosen the two bolts that mount the caliper to the adapter (you will see conical washers on both ends of the caliper).

Note:

A lot of rear vibration issues have surfaced with the new Avid Elixer brakes. No one seems to know why (one theory is that the pad catches the leading edge of the rotor), nor is there a solution other than installing Avid G3 Solid Sweep rotors (heavy) and new organic pads. The good news is that it will all be covered under warranty.

 

[gilbertlikesbikes]

Ok, so I did the caliper recentering thing several times, seemed easy enough. However, nothing changed.

Are you guys saying that the only thing I can do is to try to get the shop to warranty them to get the solid rotors and organic pads?

Are there no other options?

Do you think the vibration would cause any damage to my bike in any way? I ask because it is not so loud as it is annoying. It vibrates up into my groin and feels uncomfortable.

Thanks for the info.

 

[cort]

Gilbert,
Do a search in the brake forum - lots of helpful suggestions on how to silence these brakes. Some seem to work, others - well not so much

I find these seem to help a bit::

1) Disc tabs faced and caliper centered

2) bolts are torqued to spec

3)Both pistons move the same distance (no lazy piston). Clean and maintain them on a regular basis

4) Organic pads instead of semi-metallic

5) Rear wheel on good and tight (same for suspension bolts)


Don't worry about the vibration doing any damage to the bike. It's just annoying and embarrassing for the rider. If all else fails try the new rotor and pads

 

[gilbertlikesbikes]

Thanks for the reply,cort. I have been searching the forums. I will continue.

I'll look into those suggestions. Since these are brand new, I am a bit disappointed. Kinda sucks that such expensive brakes that rank close to the best Avid makes have these issues. Plus they don't seem to be isolated.

 

[permagnes]

Solution for my Paragon

Hi,

This is how i solved the same problem on my Paragon. After trying many of the solutions proposed in this and other treads. (Vibration in rear brake / Turkey sound from brakes).

I realised after reading all the people efforts in changing allmost every part on the brake/rotor/hubs/wheels there must be an other solution. I noticed that by holding my foot lightly towards the triangle in the rear (braking side) the noice stopped. The sound came from the triangle towards the seatpost. As pointed out by many.

Then i thought if I (instead of loosen the braking cable) fasten it real tight to the frame using a little elctro black tape to protect the brake cable and make more contact to the frame the cable would swing in a way that stopped the resonance sound. Fantasic, in my first test ride no sound even in the hardest downhills.

I saw this solution in another tread an everebody overlooked it, including me. Sometimes the easy, is the best. I belive it will work for many.

Then after some rides the noise came back a little, and I saw that the braking cable had became slightly loose. I fasten it and it disapeared.

Then I thought about a permanent solution. My al. frame (GF Paragon) is open in end of frame towards the brake. What if I fillled it with expanding isolation foam (weights nothing, costs 8$) ? Voila permanent solution. Never heard the noice again.

I even think you can use a thicker anti rust paint (on the inside) and it will dampend the vibrations enough for the sound/reconance to disapear. If your frame is not open in the bottom, putting on something on the outside that stoppes the resonance will solve your problem.

Per Magne, sorry for all my spelling/grammar mistakes.

 

[cort]

This had to be done on Trek's first generation Fuel bike's to help stop the brake vibration. It worked nicely but the expansion foam was sure messy - ah the memories!

 

[permagnes]

Hi Cort

Yes, dont use to much foam. Tru it out in å garden hose.

When i read about all the people with this problem I believe it must be a phenomen among many producers.

Per Magne