Next, two-stage designs. There are two types of hand pump. HV (high-volume) pumps, ones that pump a lot of air but don’t have a lot of pressure, which are used for mountain bikes. The Lezyne Alloy Drive is a high-volume pump. Then there are HP (high-pressure) pumps, which pump a small amount of air but can inflate to very high pressures and are used on road bikes. Our top pick is a high-pressure pump.

Otherwise, this tool should serve the average commuter well. Specifically, we think you’ll find the size 4, 5, and 6 hex keys, extremely common sizes in bicycles, very helpful. They’ll adjust seat-post heights or let you remove the saddle entirely, or tighten a loose stem that’s always rattling apart. The Phillips head will tighten loose bolts on shoe cleats or the rear derailleur. The most common use for the torx would be adjusting disc brakes if you have ’em.
Writer Peter Flax, the former editor-in-chief of Bicycling magazine, rode over 1,000 miles and tested 15 tools for our full-length guide to multi-tools, and he concluded the Topeak Mini 9 is the best for casual cyclists. It’s tiny, it’s light, it’s easier to get some leverage with than other tools that have different designs. It’s not meant for serious wrenching on your bike, but it’s good for on-the-fly adjustments.
Nice, helpful, friendly. Central location. Good bikes (I had two over two days.) Bikes had a water bottle cage (some places don't do that!) Provided helmets if needed (I didn't) and a one-sided pannier containing a decently strong but not super-heavy cable lock and a patch kit. Only quibbles: 1) The owner helping me with getting my bikes seemed to 'drop me' for too long when someone else walked in. He should have said to them, after asking what they were in for, that 'I'll be with you as soon as I'm finished with this person.' So I had to wait a little longer than desired, but not bad. 2) On my second day, the pannier bag fell off and got lost after I stopped for lunch, which required locking up the bike somewhere, so I took the bag into restaurant and re-attached it using the two velcro straps on the rear rack. I've used many panniers before, thought I did it correctly. But apparently I did not. So I paid $55 (cost) to replace everything in bag and bag. In hindsight, I wished I'd put a bungee around bag straps to really secure it to bike. PROBABLY MY FAULT. 3) Bring a second lock to lock quick-release front wheel, as decently strong but not super-heavy cable lock isn't long enough for both wheels and frame.I had a second cable lock.
A wrench that fits the hub nuts:   If your bike has quick release front and rear wheels, you don’t need this, but if you have an internal hub on the back, such as the NuVinci, a wrench that fits is a great idea.  99% of the time, this is a 15mm wrench, but you should check your bike.   A 6 inch adjustable wrench can also work, but it will be heavier, and when using an adjustable wrench, you do need to take more care to not round over the nuts.   A fixed wrench is the best choice.    Some multi-tools have a 15 mm wrench built in, but again, if you have limited hand strength, something with more leverage is a great idea.
Modern bottom brackets use a sealed bearing type construction that keeps water and debris locked out, so they seldom go wrong. Maintenance is impossible so they need replacing when they do wear out. Older style cup bottom brackets need to be re-greased every now and again, and occasionally will need to have their bearings replaced. There are a lot more teeth on the chainring cogs than those on the rear cassette, so need changing less regularly. Cranks usually a solid one piece construction so there is not much to go wrong.