Just getting into the bike repair world and have a few bikes that need maintenance on hubs, bottom brackets and headsets. The bikes are an 86 Trek 830, 95 Trek 930, 97 Trek 6000 and a mid 90's Specialized Hardrock. Can anybody suggest what size cone wrenches to buy. I'm guessing that Park would be the way to go in terms of brand.

No one can say what sizes you factually have, cone wrench wise. Many might speculate, as I can too. 13mm, 15mm cover the vast majority of cones on Asian made loose balled hubs, with an open wrench serving the lock nuts. but there are exceptions of 14, 16, 17 and even 19 that I've seem. The only way to be factually sure is to measure your cones, easiest done with a cone wrench acting as a gage.

Go into your LBS and ask them to "measure" then buy the right sizes from that shop. Andy.

Even working within the Shimano family of hubs I've needed 13, 14, 15 and 17 mm cone wrenches and one hub that required two 14 mm wrenches. Generally, the locknuts have been accessible to a conventional 17 mm open end or box wrench but some have required a cone wrench.

A full set. You need a full set. I need a full set. We all need full sets.

Make that two sets so one can counter turn cones or lock nuts for fine adjustments. Andy.

Note: It's not unusual for the cone to have two different flat widths 90 degrees offset from each other, 13 and 15mm, so you can use either size wrench. Some lock nuts are like this as well.

I agree with HillRider that even recent, mainstream Shimano hubs are all over the map for wrench sizes. In addition to the nominal flat sizing, some hubs are very picky about wrench thickness. I have encountered at least one hub where a full-size Park "pro" wrench couldn't fit in the space behind the locknut face (many of their hubs leave the locknut face round, probably to maximize contact area with the dropout, and just mill a narrow slot in behind it). As a result, I now also have a collection of the Park double-ended wrenches, which seem to be thinner and don't have the fancy anti-rust coating. They're also stubbier and so can't generate (or withstand) as much torque, I would imagine, but are fine for what they're used for.

So I would say you really can't have too many cone wrenches, but do switch up on brands and styles to maximize flexibility.

In the past few years, the only one I've used is a 15 for my pedals. As other have said, it depends.

It is worth having nice wrenches, and for times you need them, sometimes you need two.

Places I used to use various sizes:
Threadless headsets - none needed for me now.
My hubs - use 5mm allen keys, now I need two of those.
BB - special tool.

It might be handy, but I can generally make do with one cone wrench plus standard wrenches, or a standard adjustable wrench.
Maybe 2 for common sizes (13,14,15), and one for the rest.
Or a mix of single and double ended wrenches.

As can I make do. But when you get use to more/better tools and have faster/finer methods you want to suggest them to others. Hence my suggestion to be able to counter adjust two cones (or two lock nuts) after the close but not just right initial adjustment. Andy

I lock one side, then do the fine adjustments on the other side with locknut about 75% tight. Thus one cone wrench plus one open end wrench.

I do occasionally need to loosen and readjust, but always getting better.

A lot depends on OP's goals. If just one bike, then figure out what that bike needs, and get minimum functional set. On the other hand, if he is servicing dozens or hundreds of bikes, go for the deluxe set with doubles or triples of everything.

Agreed. Andy

The more tools you have, the more tools you'll use. The right tool for the job and all. So many times I have seen a nice bike that looks like a rodent was chewing on certain the nuts and bolts. You will find yourself doing more and more on your bikes with the right tools. Keep your "bike tools" together. They are specific tools for specific tasks. They become more valuable every time you use them. (Get a pedal wrench.)

Thanks for the help everybody. Ended up buying one of each size from 13 to 16 and will buy more if necessary.