I'm pretty new to touring. What should I be checking before going on a three week tour?

I've always been a little mystified about tires. Knowing they're totally worn out doesn't seem too hard. Knowing that they're nearly worn out is harder. How do I tell? I'm running a set of michelin Comfort Contacts that have a few thousand miles on them. I can't tell that they're significantly worn. But rather than just look for signals and not know exactly what I'm looking for I'd like some kind of measurement or specific method to be following.

This bike was brand new in November 2012 so I don't much expect a lot of mechanical wear. But it would be nice to be in the habit of knowing what to look for.

I know myself and given a long list of things to check, I won't do it. I don't love to tinker. I love to ride. But a short list of the most critical things is something I'm looking for. I want relatively easy things to check that might otherwise be missed and especially things that might be particularly difficult to deal with while on tour.

I'm going all over the bike tightening stuff, especially hardware that holds my racks on (Surly Nice Rack). Where would I find some replacement allen bolts that hold my racks & water bottle cages etc? It would be nice to have spares. I don't know if my bolts are different depths. Do I need to remove them all to find out?

How fast do disc brake pads wear out? How do I know if they're near the wear limit? (Avid BB7)

Tires, if you think they have life on them yet, then keep them. A three week tour won't put that much wear on them.

Brakes need to be checked, that is the one thing that if it fails, you learn about it at the wrong time and have a really bad day. I have never run disc brakes, get advice from someone else on what to look for.

Racks and bolts, I suggest putting blue locktite on all rack bolts and if you have a kickstand, those bolts also. A good hardware store like Ace or True Value should stock replacement bolts along with the blue locktite. Yes, they have different depths. I carry a couple spare bolts.

It is very common to forget to check bolts in shoe cleats if you are using cleats, but that is something that you should do. When you first install a cleat, you are compressing some plastic in the sole, that plastic deforms a bit over the next few weeks and the bolts get loose. If you do not retighten them, a bolt can fall out and then you can't release your shoe from the pedal. Over time teh plastic stops deforming and they stay tighter but I check these bolts for tightness every couple of months and carry one spare cleat bolt.

A visual inspection of just about everything else should be adequate. And, if something feels wrong on the bike, try to figure out what that is. It might be something serious or it might just be the way you packed your tent, in which case it is not a problem.

About a week before a 3-week tour, I would put new tires on the bicycle. Leave your old tires as spares in case you need them some time after you get back

If you're concerned about mechanical wear, take the bicycle into the shop for a quick tune-up. And ask your shop about the brakes.

Do you have time to take a class? It's not a bad idea to take an intro bicycle maintenance course, especially one that emphasizes on-road repairs. Your shop might have something like that, or maybe the local cycle-touring club.

I used to make it a point to start long tours with new tires, but have since started just replacing them where ever I am as needed. I found that once I took them off I never used them again and it was a waste of expensive tires. That might mean I have less choices at the time of replacement, but no big deal.

I do the same for brake pads, but if a tour is in the mountains I might carry a spare pair or change them before I get go.

If in doubt you might want to make sure that all of your bearings are OK and not in need of repacking. Maybe also check cables for fraying at or near the ends.

Walter S, A "few thousand miles" in less than four months will mean that a general tune up by the LBS is in order. They'll let you know what's needed for three weeks on the road. You should take a course in basic bicycle maintenance/repair, sometimes offered for free, just to deal with a mechanical in the middle of a wheat field.

Brad

One thing to keep in mind if you are using premium tires. I bought a set of Schwalbe Marathon tires. They lasted me for about five years. In all that time, with no flats I never had to change the tubes. That is, until one day I had a catastropic blow out from the valve stem separating from the tube. Luckily I was on a dirt path when it happened and all I got was a face full of dust and a sore stomach from landing on the handlebars.
That stem will wear out from normal airing of the tire. From now on I'm changing tubes every year.

bring a 3rd tire, just in case.

If you've ridden say 2000 miles and are going to do 1000+ more during the tour, I would replace the chain, even if it isn't worn out to a serious degree. If serious wear occurs during the tour (which seems likely), it might damage the cogs, which would mean you would have to replace those early. The bike mechanic might say the chain is still good or he might advise to have it replaced - I would ask for a new one regardless.

I agree with most of the above. Time for tuneup procedures. and new chain.
Grease what all has loose bearings.
My disc brakes went 10,000 miles, so I doubt you need a pad change but maybe get spare pads since you do high mileage.
Staehpj1 is right about tire changes, especially for the populated states. Otherwise. if the miles are 3,000+ then I would consider putting a new tire on the front and rotate it to the back. As for wear, I have 2 heavy duty tires with over 5,000 miles, SMPs and a Conti TP. I noticed that they do wear a lot faster after the glossy coating is gone. Look for how many little cuts are in the treads.
Spare bolts and cables are a good idea.

Usually threads for rack mount holes and water bottles are 6mm. Try a bike shop and see if you can pick up some up cheaply, but in an emergency, they can be found at hardware stores. Try and get stainless steel if you can, or replace non-plated ones (black) with more corrosion resistant bolts before they get rusty.

I learned the hard way. If there is any doubt about your tires, replace them. Riding with touring load put a lot of stress on tires that could safely commute around town for another year but could fail a few weeks out on tour. Put a drop of Loctite Blue on your rack bolts. Learn that one the hard way too.

Bikes differ on the size of the rack braze-ons mounts. Mine are 6mm and all the other mounts are 5mm.

Unfortunately, with BB7 pads you have to pull the pad put of the caliper and measure the thickness. Replacing the pads is relatively easy and they're pretty light, so I usually just pack an extra set and replacement on the road if necessary.

Most brake pad have wear groves in them. In this case the pads need replacing when the groves cannot be seen when viewed from the top. Also clean metal particle off pads and remove glaze with sandpaper. These pads are in the process of removing the glaze. Some glazing can still be seen of the right side. There are also a couple of metal particles embedded in the pad that need to be removed.

I think mine are 5mm.

The stock Avid BB7 pads don't have wear grooves. Or at least they didn't the last time I bought them. It sure would be nice if they did!