I've just switched to a front disc setup on my Giant TXC, and am having an issue with the rotor rubbing when pushing sideways on the bars (climbing out of the saddle, etc.). Any hard efforts produce a tell-tale tinging sound.

Setup is as follows:

-Hayes rotor (near-new, straight)
-Shimano BR-505 caliper
-Evo Aprebic carbon disc fork (was stock on Voodoo Limba bikes)
-Circus Monkey disc hub (w/ Velocity A23 rim)

I am familiar with setting up (hydro) discs successfully on MTB. I've backed off the inboard/outboard pads as much as is feasible, tried shimming the caliper, and played with the rotor centering (from dead center to the recommended 2/3rd space to inboard pad), but the rotor is still rubbing under hard efforts.

I suspect the fork might be flexing. Has anyone run into a similar issue with this or another carbon disc fork? Could it be flex in the Circus Monkey hubbub axle or shell?

Any ideas or suggestions would be appreciated. I have the lighter Trigon disc fork on order, but I'd like to get this setup working for now.

Thanks.

I get a bit of disc rubbing on my setup, sometimes. Its a Trigon fork and XTR hydro calipers.

I just have to make sure the caliper is nice and clean and the pistons are free the retract fully, and the disc is centred and unbuckled. If everything is bob on then its okay. It's not a big deal for me though if it occasionally a rubs a bit, it's a minor issue and doesn't actually slow me down in any significant way.

Thanks for the info Maddog. I've managed to largely eliminate the disc rub by repeatedly playing with the centering/pad adjustment on the ground (instead of on the stand). I found that I could induce the flex and rubbing by simply pressing on the bars.

I guess I find the disc rub extra annoying because I had my old mtb set up with XT hydros and no disc rub.

On to the next issue: severe howling when braking hard.

What type of pads are you using?

Stock M06 metal pads that come with the BR-505 caliper.

As far as I know, metal pads (sintered) are known to make more noise than organic (and semi-metallic?) pads.