Crankbrothers M19 Review: What Holds Up After Real Miles

Two and a half years ago I had one genuinely bad day on the bike, and the climbing was not what did it. An 80 mile loop out past Chino Valley left me with a sore lower back, a rear flat I fought for twenty minutes in the sun, and a wrong turn on the way home that added six miles I did not have in me. When I got to the garage I emptied the seat bag onto the bench and looked at what was actually in there. A loose handful of Allen keys held together with a rubber band. A patch kit. Two plastic tire levers. No chain tool at all. That pile of loose keys is why this review exists, and it is why I bought the Crankbrothers M19.

I am Walt Dunmore, 67, and I taught shop in a high school for 31 years before I retired at 62. I ride one bike: a steel touring bike with a 9 speed drivetrain, rim brakes, and 32 mm tires with tubes and Presta valves. A long day for me is 50 to 70 miles on the roads around Prescott and Chino Valley, twice a week from spring through fall, and I am good for about 4,000 miles a year. The Crankbrothers M19 came in the first week of March about two years ago, in the same order as four other things I had been putting up with far too long. I paid for all of it myself. Nobody sent me anything to review, and I have put roughly 8,000 miles on the tool since.

How I've Used It

The M19 lives in the seat bag, not in a jersey pocket, and that was a decision I made in the first week and have never revisited. It measures about 3.5 by 2 by 0.5 inches folded and weighs 175 grams. That is not heavy in a bag, but it is noticeable behind your back on a hot climb. In the bag it just sits there, and I have never once heard it rattle.

On the road the Crankbrothers tool has come out maybe a dozen times in two years. A seat post clamp bolt that worked loose on the washboard stretch of a county road. A bottle cage bolt I could hear and could not ignore. A brake pad that had crept over and needed to go back where it belonged. A spoke that had wound up and needed the spoke wrench before the wheel got worse. In every one of those cases the tool did the job at the roadside in under five minutes, and the side grips gave me enough to hold that I could put real torque into a 4 mm hex without my hand sliding off.

At the bench it does the same jobs a full tool roll does, just slower and with less leverage. I still keep proper shop tools on the wall for anything that needs a real pull. What the M19 changed is the number of times I walk from the bike to the wall and back. That sounds like a small thing. Over two years of twice a week riding it has added up to a great many saved trips across the garage.

Here is something I did not expect. Because the tool is right there and takes ten seconds to open, I now put a hand on the crank bolts and the rack bolts before a long day instead of after something starts rattling. A dozen small tightenings over two years is cheaper than one stripped bolt on the shoulder of a highway.

The flat I fought in the sun that bad afternoon is still the reason tire levers live in my bag, and the M19 did not change that and was never meant to. I want to be clear about it because the listing photo makes the tool look like it covers everything. It covers the bolts, the spokes, and the chain. The tire is my job.

What's Folded Into It

The list matters more than the shape. Crankbrothers puts hex wrenches in 2, 2.5, 3, 4, 5, 6, and 8 mm on the M19. Spoke wrenches in 0, 1, 2, and 3. A Phillips number 1 and number 2, a flat number 2, open wrenches at 8 mm and 10 mm, and Torx. A chain tool, listed as compatible with 8, 9, 10, 11, and 12 speed chains. The body is chromium-molybdenum steel on a centre drive layout, so the two halves open like a book and the bit you want is the one facing you. It carries a lifetime warranty, which I have not had occasion to use.

For my bike specifically, the 4, 5, and 6 mm hex keys cover the seat post clamp, the stem bolts, and the brake hardware. The 8 mm open wrench fits the pedals. The spoke wrench has saved one wheel from becoming a long walk. My drivetrain is 9 speed, well inside the range of the chain tool, and the same tool would still work on the 11 speed bike my riding partner Ed rides.

An honest count of what I have actually touched in two years: the 4, 5, and 6 mm hex keys, the number 2 Phillips, the spoke wrench, and the chain tool. The 2 and 2.5 mm, the Torx, and the 10 mm open wrench have never come out of the body on my bike. That is not a complaint. The extras add almost nothing to the weight and they are there for the next bike, or for the partner whose hardware is not set up like yours.

What it does not have is worth saying out loud, because people assume a tool this size covers everything. It has no tire levers and no pliers. I still carry two plastic levers and a spare tube in the seat bag, and I still carry a patch kit. If you buy this expecting to leave the levers at home, you are going to have a bad afternoon on the shoulder of a road.

The Chain Tool Earned Its Keep Once

In two years and about 8,000 miles I have needed the chain tool on the road exactly once. A rivet on a worn chain started to let go on a Saturday ride north of town, and I limped to a wide gravel pullout and broke the chain there. It took me about fifteen minutes, most of it spent working out which way the pin wanted to feed, and it got me home. That single use is worth more to me than everything else on the tool combined, because without it I would have been walking the last eight miles in cycling shoes.

It is also the fiddliest thing on the tool, and I will not pretend otherwise. The pin driver is small, and with cold hands in October it takes me two or three tries to get the pin seated where I want it. The side grips help a great deal, but there is no way around the fact that a folding chain tool is a compromise against a proper bench tool. Do the job once a year at the bench with bare hands and you will be fine. Do it in the rain at 40 degrees and you will be out there a while.

The advice I would give anyone buying this is to practice at home before you need it. I broke a worn chain in the garage on a Tuesday afternoon the first spring I owned the tool, just to see how the pin fed through, and that practice is the only reason the roadside job went as fast as it did. Ten minutes at the bench with good light teaches you more than any instruction printed on a package.

Two Years of Wear

Chromoly steel does what chromoly steel does. The edges where the two halves rub against each other have polished themselves smooth, and every hex key still fits its bolt without rock or slop. I have not had a single fastener round out on me, which was a weekly event with the loose keys in the rubber band. The pivot has not loosened. This tool has spent two monsoon seasons in a bag that gets damp, and I have not found a spot of corrosion on it anywhere.

The side grips are still grippy enough that I can use the tool with a light glove on, which matters more every year. My hands are not what they were at 40, and a tool that demands bare hands in cold weather is a tool I leave at home. The Crankbrothers tool has never made me do that. The folded size has not changed and the halves have not developed play. The honest version is this: it looks used, and it works exactly the way it did in the first month.

I keep a small notebook in the garage and I mark down anything that needed attention after a ride. Looking back through it, the tool has been noted maybe thirty times across two years, and not one of those notes says anything worse than tight, cleaned, or adjusted. For a piece of steel that lives outdoors half the year, that is a good record.

Where It Falls Short

The size is the first thing. At 3.5 by 2 by 0.5 inches folded it is a bag tool, full stop. I tried it in a jersey pocket for one ride and spent the entire day aware of it against my back. That is not really a flaw, it is the trade you make to have a chain tool in the same body, but it does mean you need a seat bag or a frame bag to carry it properly.

The second thing is the chain tool again. Fold-ups are always a compromise there, and this one is no exception. The third is that there is no torque reference anywhere on it. On steel touring hardware that is fine. On anything carbon, or on a stem with a number stamped in newton meters, you should not be guessing with a folding tool. I own no carbon parts and do not plan to, so this costs me nothing. It will cost somebody.

The last thing is not a fault of the tool so much as a fault of the category. Crankbrothers makes an M19 and a smaller M17 and a bigger M20, and standing at a screen trying to pick between them is harder than it needs to be. My own rule is simple now: buy the one with the chain tool if you ride far from home, and skip the rest of the comparison shopping.

The chain tool came out of the bag exactly once in 8,000 miles. That one time was worth the whole tool.

Who This Is For

This is for the rider who does long days alone or in a pair, on roads where a mechanical means a long walk back. If your bike is 8 to 12 speed, if you run rim brakes or mechanical disc brakes, and if you want one object in the seat bag that handles the bolts, the spokes, and the chain, the M19 does all of it without asking you to think about it. Riders past 50 who have started doing bigger days will get more out of it than they expect, mostly because it removes the excuse to skip the roadside fix and push on with something loose.

If your hands have gotten weaker and your grip is not what it was at 40, the side grips are the part you will notice most. I can get a 5 mm bolt properly snug with a glove on, and I could not do that with the loose keys I used to carry, because there was nothing to hold onto. That is a small design detail that changes how useful the tool is for a rider in his sixties on a cold morning.

Who Should Skip It

Skip it if you ride tubeless and expect a multitool to help you seat a tire, because this one has no levers and no pliers and will not get you there. Skip it if you work on carbon fiber and need torque values, because nothing on this tool tells you how hard you are tightening. Skip it if you want something for a jersey pocket on short rides, because it is more tool than a pocket wants. And if you already carry a full fold-up set that has served you for years and has a chain tool on it, you do not need to replace it just because I like mine.

Ed carries a Park Tool IB-2 and it has been fine for him for close to a decade, so I am not going to tell you the tool you already own is wrong. The fold-up category is crowded and most of it works. What I can tell you is what I know from my own seat bag over two years with the Crankbrothers M19: nothing has loosened, nothing has rusted, no bolt has rounded, and the one time the chain let go I got home under my own power. That is the whole case for it, and it is enough for me.