Once you have a basic tool box with metric open wrenches, metric socket set, locking pliers, standard slip-joint, needle nose and water-pump pliers, assorted screwdrivers, ball-peen hammer, hacksaw and whatnot you can start acquiring bike-specific tools.
Cone wrenches are good. You can’t adjust hubs without those thin, flat wrenches that fit the adjusting flats on hub cones. Hence the name. The 16 mm wrench opens bottles.
Next you might consider the fourth hand tool used to hold cables at the desired tension so you can tighten the cable anchor bolt of brake or derailleur. I got the third hand tool, used to hold caliper brake shoes against the rim so that cables can be adjusted, but hardly ever used it after I got a fourth hand. Park makes a fourth hand with a ratcheting lock on it, so you don’t even have to hold onto it once you position it. Lifu and Pedro’s also offer ratcheting models.
My old fourth hand with no ratchet lock has a narrower snout than the new models, so it fits into tighter spaces. That can be handy.
Buy a good cable cutter. I got the legendary Felco C-7 years ago, but Pedro’s has cloned it for less money. I haven’t seen it to compare the quality. The C-7 will cut just about anything, year after year.
Jagwire cloned the Shimano TL-CT 10 cable cutter, which has a crimper for housing ferrules behind the jaws. Park’s CN 10 also has a ferrule crimper. This appears to be an improved update of their older cutter, which I found unimpressive.
Y-wrenches with 8-, 9-, and 10-millimeter sockets come in handy, thought they don’t replace spanners.
Box-open wrenches in a range from at least 8 millimeter through 19 millimeter will be more comfortable than double-open wrenches with a different size on each end. Double up on at least the 17 mm wrenches for three-wrench technique when adjusting hubs. If you have anything old and French you’ll want two 16mm wrenches for those hub locknuts.
A hex-key multi tool is great, but sometimes you want the separate keys, particularly with longer shanks. The Bondhus type, with the ball-end on the long end allow you to spin socket-head hex bolts into place even if you can’t get lined up exactly straight above them. The full set includes everything from 1.5 mm to 10 mm.
Even with the quick-disconnect links in SRAM and other chains, you need a proper chain breaker to cut a new chain to correct length or make emergency repairs in the field. A small tool like the Park Compact is good in the seat pack. A bigger tool with longer handles will be more comfortable in the workshop.
Buy appropriate freewheel or cassette locknut removers to fit your equipment. You’ll want a chain whip to hold the cassette still while you unscrew the lock ring, or to spin off a fixed cog from a hub.
Years ago I bought a set of sliding jaws that fit in a vise so I could clamp a freewheel for disassembly or unthread a fixed cog from a hub after fixing the cog teeth with the pins of the vise insert. I haven’t seen the tool for sale in quite a while, but it may lurk in the back of the United Tool catalog or some other arcane tome. It’s not that important. There are many other ways to loosen a fixed cog, and most of us don’t pull cogs off of thread-on freewheels anymore.
Back in the days of cup-and-cone bottom brackets I bought a flat fixed-cup wrench and lock ring tool, and a couple of varieties of pin spanner to fit adjustable cups. Kingsbridge made a burly tool for installing fixed cups, which I never got around to buying. Now it seems to be discontinued, so I bought a Hozan that seems to be based on the same principle. Machined cylinders thread together, clamping the flat faces of the fixed cup, which can then be threaded into the bottom bracket shell with considerable force, using large wrenches on the flats of the tool.
Because most of us use some form of cartridge bottom bracket, concentrate on the appropriate tool for your favorite brand. These are smaller, lighter and cheaper than the Hozan or
Kingsbridge tools for the old style BB s. Change can be good.
You may find yourself needing Torx wrenches as well. Change can be a pain in the butt.
Get a good, shop-quality crank puller. If you have a hollow-axle BB you need a special puller. You can work around it by inserting something to cap the end of the hollow axle so you can use an old solid-axle puller you might already own.
The latest-greatest Shimano bottom brackets with the outboard bearings call for a completely different set of tools.
Cranks used to come with the appropriate tools, years ago, but that was years ago. Now you have to ask and you should know what you’re asking for. Shimano alone accounts for at least a half-dozen tools in the crank and bottom bracket area. Good luck.
Buy spoke wrenches only if you feel confident messing with your wheels. The round type with multiple sizes makes a good start, but it is not that comfortable to manipulate if you’re doing a lot of wheel work. You have a lot of choices here, but the basic Park set in black, green and red covers the common range of nipple sizes. Pedro’s wrenches offer two jaw shapes in each size wrench, so you can tension a wheel quickly with the U-shaped jaw and increase the tension with the more secure diamond-shaped side of the wrench.
If you really get into wheel work, shell out for the Park TS-2 or a similar shop-quality, self-centering truing stand. Cheesy truing stands waste time and money. You spend a lot of time making up for the imprecision of the stand. I hardly ever use a dishing tool with the TS-2. I do use the T-gauge for checking the alignment of the stand itself.
The Park offset brake wrenches come in handy for aligning caliper brakes and adjusting brake center bolts.
Back in the days of the threaded headset, the home or professional mechanic needed headset spanners. Actually, a big, fat adjustable wrench was good for the top nut, because the fat wrench could hold the thinner headset spanner securely in place on the flats of the top headset race. Park’s HW-2 headset wrench is a thick wrench for 32- and 36 mm top nuts. The jaws have a semi-box shape to hold the nut more securely.
The Campagnolo crank bolt wrench was called the peanut butter wrench because the hungry mechanic could use the handle end to spread the PB on his PB and J at lunch time. That’s another loss to the 8 mm socket-head crank bolt era. Actually, I like the 8 mm bolts, but I was lucky enough to get a Campy peanut butter wrench to keep in my lunch box.
Nowadays, you might want a star-nut setter and a threadless fork cutting guide, in case you decide to slap in a new fork. But where do you draw the line? Buy a headset press? Better by the head tube reamer-facer too, and the crown race setter. Uh oh. You’re way down the slippery slope by then.
You’ll see me downslope ahead of you, in a pile of tools.