With a good multi tool, you're ready for anything that goes wrong with your bike. Here's what to look for and a selection of some of the best you can buy.
Multi tools vary from simple folding hex key sets, to all-singing, all-dancing widgets that'll do everything but the washing up.
There are two schools of thought when it comes to multi tools. You either go for one that has the absolute minimum of bits to fix things that are likely to go wrong with your own bike, or you carry as versatile a tool as possible so you can help out others too. But what bits are available?
Also known as Allen keys, these hexagonal tools are the core of most multi tools. You usually need a minimum of 6, 5 and 4mm sizes, but it's worth carefully inspecting your bike for smaller ones in hard-to-find spots like brake lever and spring tension adjusters.
You may have an 8mm hex head lurking somewhere too, like the back of your pedals or the bolts holding your cranks on. Because an 8mm hex tool is large and heavy, multi tools usually have a sleeve round a smaller bit to fit the larger size.
Check your derailleur adjustment screws and make sure your multi tool has the right screwdriver bit, usually a small flat-head or cross-head driver.
Once only found holding disc brake rotors in place on mountain bikes, Torx screws are becoming more common on road bikes because they are harder to round out than Hex heads. The most common application is chainring bolts, which usually need a T30 tool, while brake rotor bolts are T25.
Few things can stop you dead in your tracks like a broken chain, rare though it is. We wouldn't try and repair a 10- or 11-speed chain in the field; it's a fiddly job that needs care and a good quality chain tool. Better to carry a joining link for field repairs, but you'll still need a chain tool to dismantle the old link.
Some multi tools include tyre levers, either moulded into the body of the tool or as separate parts that clip together in your bag. These tend to be a bit shorter than standard levers, so make sure you can remove your tyres with them. It'd be a bit embarrassing to find they're not up to the job in the middle of nowhere.
If you ding a wheel or break a spoke you'll need a spoke key to set things right, especially with low-spoke-count wheels where a broken spoke can distort the wheel so much it won't pass through the frame. If you've got wheels with non-standard spokes like Mavic's or Shimano's, look for a tool with a matching spoke key
If you're taking off into the wilds for multiple days, then a knife is a handy thing to have, so some multi tools come with short blades.
What follows is a selection of the best-reviewed multi tools from road.cc but we're sure you'll have your own favourites — tell us about them in the comments.
You get five essential tools here in a simple fold-out tool. It's nicely made, very easy to use and cheap enough that you won't get too upset if you lose it or it doesn't come back from being loaned to a friend.
Tools: 4, 5, 6mm hex keys, T25 Torx, cross-head screwdriver
Gooj stands for Get Out Of Jail, and while you might not want to find this multi tool in a cake, it's got a great selection of bits for dealing with on-road mechanical mishaps, and the price is a bargain.
Tools: Chain tool, spoke wrench sizes 1, 2, 4, 3 Shimano and Mavic, T25 Torx, Philips screwdriver, flat screwdriver, two tyre levers, 2, 2.5, 3, 4, 5, 6, 8mm hex.
This tidy, light tool incorporates a pair of tyre levers into its body, includes enough tools to cover most jobs and even has a hook to help hold a chain together as you join it.
Tools: Allen keys 2/2.5/3/4-2/5/6/8mm, Torx Bit T25, Phillips & Flat Head Screwdrivers, Spoke keys 15g/14g, Chain Tool, Chain Hook, Tyre Levers
We like these tools from Fabric. They're compact, well-made and tough, withstanding even our tester, who confesses "I break things". Even the Sixteen's chain tool proved resistant to Gander abuse, and the selection of tools in each unit is sensible.
The Crank Brothers M17 comes with the standard range of tools that you would expect. All of the tool bits are hi-ten steel, so they should last. They're fairly short too, which should reduce the chance of a tool bit twisting and snapping off. The downside is that they might be a little short for some fiddly operations but we've had no trouble.
Tools: chain tool; spoke wrench sizes #0, 1, 2, 3; 2, 2.5, 3, 4, 5, 6, 8mm hex; Phillips #2 screwdrivers; flat #2 screwdriver; 8mm & 10mm spanner, T25 Torx
A top quality multi tool that packs a lot of features into a very small space, leaving more room in your pack or pocket for gels and energy bars. Good value too.
Tools: chain tool; tyre lever; 2, 2.5, 3, 4, 5, 6mm hex keys; T25 Torx; Phillips #1 screwdriver; flat screwdriver; 8, 9, 10mm box spanners; 3.2, 3.3, 3.5mm spoke keys
The Unich Stepless Rachet Multi Tool Wrench is a multi-tool that looks a bit like a CO2 inflator – compact enough to carry for beside-the-road adjustments, with an unusual ratchet giving instant engagement. It houses a good selection of durable bits, providing most of the tools you're likely to need while out on a ride. It's a pleasure to use, although its design means there's no chain tool.
Unich says that the patented design of the ratchet mechanism is a key advantage for when you're working on hard-to-access parts of your bike.
A conventional ratchet has a certain number of engagement points (just like a freehub), and this means you can have a few degrees of rotation before you start to loosen or tighten the fastener you're working on. Here, a miniature clutch mechanism means there are effectively infinite starting positions. Compared with using a fold-out multi-tool, this makes it much less fiddly to access bottle cage bolts, for example. For any bolt where you've got a very limited space and hence less than 60 degrees of rotation, it's a real benefit.
If you're worried about Torx bolts coming loose, the Lezyne SV10 has you covered with both T30 and T25 bits for chainring bolts and disc rotors respectively, and comes in a stretch leatherette pouch to protect it.
Tools: chain tool; 2, 3, 4, 5, 6, 8mm hex keys; T25 and T30 Torx; Philips screwdriver.
Multi tools tend to be roughly the same design – think Swiss army knife but for bikes rather than camping. Fabric, though, has bucked the trend with its Chamber Multi-tool, creating a ratchet tool that functions as a multi tool – and does so very well. The heads sit inside the chamber of the tool. Imagine double-sided extended drill bits sat in a holder that roughly resembles a revolver barrel. These function through the ratchet element that sits at the top of the tool.
Tools: 2, 2.5, 3, 4, 5, 6 & 8mm hex keys; SL3, SL5, PH1, PH2 screwdriver; T10 & T25 Torx
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Our official grumpy Northerner, John has been riding bikes for over 30 years since discovering as an uncoordinated teen that a sport could be fun if it didn't require you to catch a ball or get in the way of a hulking prop forward.
Road touring was followed by mountain biking and a career racing in the mud that was as brief as it was unsuccessful.
Somewhere along the line came the discovery that he could string a few words together, followed by the even more remarkable discovery that people were mug enough to pay for this rather than expecting him to do an honest day's work. He's pretty certain he's worked for even more bike publications than Mat Brett.
The inevitable 30-something MAMIL transition saw him shift to skinny tyres and these days he lives in Cambridge where the lack of hills is more than made up for by the headwinds.