OK, so this may be somewhat stupid, but I'm a bit puzzled. I'm a beginner mechanic and I've done some work but nothing with wheels.

My wheels were fine, brake pads are fairly new (Kool-Stop Salmons) and braking was fine. Then, last week, I had a flat tire. I fixed it at work but on the ride back home I noticed a dragging sound. One brake pad was dragging on the front rim. At home, I readjusted the front wheel until it looked right and didn't drag when I spun the wheel with my hand. I didn't give a second thought to it. I didn't ride for a few days (travelling) but when I rode in to work this morning the dragging sound was back! Sure enough, the wheel was dragging on the same pad.

After fiddling with the wheel it seems that no matter what I do I can't get the rim to center between the brake pads. There's no wobble, it just always leans on the same pad. Since the pads are fairly new and haven't worn down yet, the barrel adjuster is all the way in, leaving the largest space between the pads and the rims. The only thing that actually seems to move the pads far enough away is the little brake release lever but if I release that, braking is very poor.

Bike is an '07 Specialized Allez. Alexrims S500 rims.

Is the wheel centred? if not, and you put it in the opposite way round to the way it was installed originally, that will be your problem.

jimc101, what do you mean by "centered"? That's what I am trying to achieve by fiddling with it as there seems to be 1mm or so of free play once the wheel is in the fork dropouts.

I am installing it in the same direction so that the tire tread is facing the same (correct) way on both front and rear.

By the way, the flat was on the rear tire, not the front. I did not remove the front, except after noticing the drag.

The wheel should have been centered, i.e. the rim in line'd up with the center of the hub when it was built, if it is dished sightly to one side, and the brakes are setup to compensate for this, then putting the wheel back in, the opposite way, will mean that the brakes need to be re-set, or will rub. This has nothing to do with tire rotation.

Suggest that it probably time to take it to a LBS if you can't id what the issue is.

I believe that it is centered. I have ridden many miles without any problems with this setup. That's the strange thing here, nothing has changed! I didn't touch the front wheel after the flat, I just noticed the problem then. Before that, there was definitely no issue.

Could I have damaged the fork dropouts somehow or the fork itself? I go over some rough roads and big potholes with the 23mm tires and the front wheel has non-overlapping spokes.

I will fiddle with it some more. Further suggestions are appreciated. I'd like to avoid the LBS if at all possible since the LOCAL bike shops are not that great and I don't have a car available to drive the bike to a good one.

Did you maybe mis-align the calipers when you were changing the tire? You could have knocked them out of center. Check that.

Barring that, you said your barrel adjuster is all the way in. You could loosen the brake cable at the nut, thread the adjuster out, and tighten the whole thing back up, if you want to actually be able to use that adjuster.

Well, the flat wasn't on this tire but I will check anyway. Do I check this by sight and feel or is there a special procedure?

Sorry I'm a bit mixed up here. It's all the way in since the pads are like new. When the pads get worn down, I will loosen the barrel adjuster to bring the pads closer. That all seems right, why would I need to do anything with the adjuster?

The front axle should be fully seated in the fork drop outs (when fully seated the front wheel should always land in the exact same place unless, as noted above, you flip the wheel around). Then center the brake caliper (usually a 14mm or so wrench between the fork and caliper). Spin the wheel and you should be good.

Caliper brakes dragging could be caused by a number of things. Some of these things, others have mentioned. But here's what I usually go through:

1. Is the front wheel centered in the fork and resting on the dropouts? If not, I loosen the front QR and press down on the stem holding the bike vertically, and retighten the QR. Then squeeze the front brake. Is it centered?

2. If centered and the calipers are still chronically dragging, I check the brake center bolt for snugness to make sure the brake is on relatively tight to the fork, and then I find a 13 or 14 or sometimes 15mm cone wrench and slide it carefully onto the center bolt flange. On older brakes, single pivot, this flange has groove cut onto the face and holds the caliper spring, and has flat sides for centering the brake. On newer dual pulls, this is a star flange with no groove. If you have an anodized brake, you may want to pull a small bit of masking tape on top before you use a metal tool to do the centering. If the entire caliper set can pivot, you can simply use the cone wrench and center the brake roughly. If too tight, loosen the brake center bolt/nut, hold the calipers centered and retighten and keep pressure on the cone wrench to prevent the calipers from pivoting while tightening. This gets the rough adjustment. For fine adjustment, there should be a 2mm allen bolt near the side pivot point on dual pivot calipers. This does the fine centering. If you've already maxed this in or out, I recommend you screw this adjuster so it's midway, and repeat the above bulk recentering procedure. Now squeeze the front and it should stay centered.

3. Okay, you went for a ride, and a few miles down the road, you're dragging again. Check the cable routing and how you've radiused the housing from the handlebars down. A chronically short or long cable or one that impacts some other protrusion on the bike (e.g. something dangling off the handlebars) can cause the cable to pull and pivot the entire brake. Brifter cables, if improperly routing can also cause abnormal brake pull and pivot the front brake out of alignment. This most often happens at stops or trying to trackstand at lights when one turns the handlebars to extreme angles not seen during normal riding or cornering. In this case, I re-route and replace/re-cut the housing and re-install the front cable.

4. If the above three things don't work, I recommend a deer/hunting camera in the garage set for infrared and motion detect. This checks for gremlins, goblins, careless dopey kids or spouses who may have a vehicle door or some other way to knock your bike near the front brake in a regular way. And this will cause the brake to go out of whack regularly. Yeah, I know the probability is low, but believe you me.... I've been there and wonder were the heck those paint chips on my front fork were coming from... As we're talking vintage, mint, Bridgestone steel bikes. Don't get me started...

I just check it by sight.

I like my adjuster to start near the middle so I can adjust it either way, but if you like it all the way in, no worries. I am really anal about where the pads are and I adjust them often.

OK, I think I've solved this. I believe the caliper was misaligned. I just gave it a little tug in the opposite direction, it moved, and now the rim is equally distant from both pads. There is no more dragging. I'll see if it lasts throughout the ride home.

Should the caliper be loose enough to move with a tug or should I tighten this when I get home?

I still don't know how this could have happened. Maybe at some point I had removed the wheel and hit the caliper wouldn't the problem have manifested itself earlier?

Thanks for all the help.

Tighten caliper bolt.

Cool, now tighten it down so it doesn't move.