Front disc brakes and wheel alignment
 

I recently (3 weeks ago) bought a Giant Roam3 and the disc brakes rub when the wheel is centered and mounted in a vertical position. The only way I can mount the wheel so it doesn't rub is to tilt the wheel which to me seems mechanically faulty. Shouldn't the front wheel be vertical or as close to vertical as mechanically possible and align with the brake? Is this acceptable? It seems to me that the front wheel should not have to be tilted, or uncentered in order for the disc brake to align. Thanks for any advice!

You should be able to re-center the caliper by loosening the caliper mounting bolts and adjusting it. It's not particularly difficult.

The wheel should be fitted into the fork FULLY. The best way to do this is installing the wheel while the weight of the bike is resting on it. Get the wheel into the fork (don't worry about brake rotor rub for now). Ensure the tire is pretty much centered at the top of the fork (telling you that you have it in the fork straight). Now tighten the quick release skewer correctly (instructions here). Only then, after you have the wheel centered securely in the fork, can you then go after the brake caliper alignment (instructions here).

After you're sure the wheel is firmly the the dropouts and the QR is cinched down, put the bike into a stand and loosen the brake caliper bolts, spin the wheel and see if there's a way you can position the caliper by hand so that you don't hear any rubbing. If you find a position where you hear no rubbing--hold that position and have a friend or family member pull on the brake level while you tighten the bolts back up and see if that eliminates the dragging. (There is a inexpensive tool that's easily obtainable, the Hayes feeler gauge, that I like to insert between the brake pads and rotor before the lever gets pulled and the bolts tightened--although sometimes this isn't essential). Sometimes it takes two or three times to make this work.


If you can't find a position where there's no rubbing with a loose caliper, you probably will need to remove the brake pads and inspect whether the pistons are properly retracting. I've used q-tips with rubbing alcohol to clean the pistons and pressed them back in using the Park piston press tool--which is also inexpensive.


Usually doing these two steps is enough for me to eliminate the rubbing--at least for awhile. I like disk brakes on my cross bike--but they aren't totally hassle free.


I'm not sure about the quality control as a relatively inexpensive mech brake set and wheel, but the rotor/wheel trueness should be looked at if you can't solve the problem. Of course there are tons of videos that explain these processes--it's how I learned enough to keep the brakes from driving me nuts.

I had the same problem with my cross trails.

I mounted the wheel, making sure it was properly seated in the dropouts. I then loosened the caliper mounting bolts. This let the caliper move around a bit. I then squeezed the brake lever. While maintaining pressure on the brake lever, I then tightened the mounting bolts. Next, I adjusted the stationary pad away from the disc just enough to see daylight between the pad and the disc.