Here's the thing nobody tells you about cycling fitness: it doesn't matter. Not when you're standing on the hard shoulder with a flat tyre, a chain hanging off the chainring, and 45km between you and your car. Every watt of FTP, every marginal gain, every perfectly structured training block — completely irrelevant if you can't fix the basic mechanicals that will, at some point, happen to every rider.
And they will happen. Not might. Will.
I've had Craig Geater on the podcast — head mechanic at Team Jayco AlUla, 20-plus years working on WorldTour bikes — and one thing he said stuck with me. The pros don't fix their own bikes. They have a team car, a neutral service motorbike, and a mechanic who can swap a wheel in eight seconds. You don't have any of that. You have a saddle bag and your hands. Which means, in one very specific way, you need to be more mechanically competent than a WorldTour rider.
The good news: the skills you need are not complicated. They're learnable in an afternoon and practicable anywhere you have a bike and a floor. But you have to actually learn them, not just assume you'll figure it out when the time comes. Because you won't. Not with cars passing at 80mph and rain coming down sideways and your hands too cold to work a tyre lever.
These are the essential mechanical skills. The ones that separate riders who fix it and carry on from riders who sit on a grass verge waiting for a lift home.
Inner tube puncture repair: the skill that rescues more rides than any other
This is the big one. The mechanical you will deal with more than any other across your entire cycling life. And yet — and this still baffles me — a huge number of experienced riders cannot do it quickly or confidently.
Here's the step-by-step. Learn it, practise it at home, and then practise it again.
Step 1: Get the wheel off
Shift into the smallest cog at the back before you stop. This makes rear wheel removal significantly easier because the derailleur is out of the way. Open the quick release or thru-axle, and if it's the rear wheel, push the derailleur body backwards as you drop the wheel out. Flip the bike upside down or lean it against something solid — whatever keeps it stable and off the ground.
Step 2: Remove the tyre and tube
Deflate the tube completely. Hook your first tyre lever under the bead about 10cm from the valve, clip it to a spoke. Hook a second lever another 10cm along in the same direction, then slide it around the rim to unseat one side of the tyre completely. Pull the tube out, starting from the side opposite the valve, and pull the valve through last.
Step 3: Find the cause
This is the step most people skip, and it's why they puncture again 3km later. Run your fingers carefully around the inside of the tyre, feeling for thorns, glass, or wire. Check the rim tape. If you can't find anything embedded in the tyre, inflate the old tube slightly and listen or feel for the leak — its position tells you where to look in the tyre. A puncture on the inner rim-side usually means a rim tape issue or a spoke poking through.
Two small holes side by side — a snake bite — mean you were running too little pressure or hit something hard. That's not a tyre problem. That's a pressure problem.
Step 4: Install the new tube
Put a tiny amount of air in the new tube — just enough to give it shape. Tuck the valve through the rim hole first, then work the tube into the tyre all the way around, making sure it's sitting inside the tyre and not pinched under the bead anywhere. This is where most people cause their second puncture. Take your time. Check that no tube is visible between tyre and rim all the way around both sides.
Step 5: Reseat the tyre
Start opposite the valve. Push the bead over the rim with your palms, working in both directions towards the valve. If it gets tight near the end, push the already-seated tyre bead into the centre channel of the rim — that's the deepest part, and it creates slack. Avoid tyre levers for reseating if you can, because they can pinch the tube. If you absolutely must use one, be extremely careful.
Step 6: Inflate and check
Before you fully inflate, push the valve up into the tyre and pull it back down. This prevents the tube from being trapped under the bead near the valve — a very common cause of blowouts. Then inflate to your target pressure, spin the wheel, check it sits true, and reinstall.
The whole process, with practice, takes four to five minutes. Time yourself at home. Get it under five minutes. Then do it with cold hands and wet tyres, because that's what it'll be like when you actually need it.
Tubeless tyre repair: it's not puncture-proof and you need a plan
Tubeless tyres are brilliant for reducing punctures, but they are absolutely not puncture-proof. The sealant inside handles small holes — thorns, glass fragments, anything up to about 2-3mm — automatically. You'll often not even know it happened until you see a small streak of sealant on the tyre after a ride.
But here's where it gets really interesting: when the puncture is too big for sealant, you need to act fast and you need to know what you're doing.
Plug kits
A tubeless plug kit — Dynaplug, Stan's DART, or similar — is the first line of defence for holes that sealant won't seal. These are rubber-coated strips or pointed plugs that you push directly into the hole from the outside of the tyre without removing the wheel.
Find the hole. You'll hear air hissing or see sealant bubbling. If the tyre is still holding some air, leave it inflated — the pressure helps the plug seat. Push the plug tool into the hole firmly, twist slightly, pull the tool out, and the plug stays behind. Trim any excess sticking out. Spin the wheel and check. Most plug repairs hold permanently — I've ridden plugged tyres for thousands of kilometres.
If one plug doesn't seal it, try two side by side. If two plugs won't hold, you're beyond plug territory.
Sealant top-up
Sometimes a tubeless tyre just needs more sealant. It dries out over time — typically every 3-6 months depending on conditions — and if you haven't topped it up, there might not be enough liquid inside to seal anything. Carry a small bottle (60ml is plenty) and add it through the valve core using a syringe or the bottle's nozzle. Remove the valve core with the tool on your valve cap or multi-tool, add sealant, replace the core, inflate, and shake the wheel to distribute.
If you hear air escaping around the tyre bead rather than through a hole, break the bead in that area, add sealant directly, reseat it, and inflate quickly. This is fiddly roadside but it works.
When to boot a tubeless tyre
A boot is for sidewall cuts — slash damage to the side of the tyre that neither sealant nor plugs can fix because the hole is in a flexible area that opens and closes as the tyre rotates. We'll cover tyre boots in detail below, but the short version: if you can see the tube or the tyre casing through the cut, it needs a boot from inside. And if the cut is longer than about 20mm, you might be installing an inner tube behind that boot and riding home very carefully at low pressure.
Always carry a spare inner tube even with tubeless. It's your last resort. Remove the valve core from the tubeless valve so it doesn't interfere, seat the tube inside the tyre behind the boot, inflate to a lower-than-normal pressure, and ride gently. You're not racing. You're getting home.
Chain repair with a chain tool: saving the longest walk home in cycling
A broken chain is the mechanical that strands people. A puncture is annoying. A broken chain 40km from your car, in a mobile dead zone, on a back road — that's a long walk in cleated shoes.
The chain tool on a decent multi-tool weighs almost nothing and can save you hours. Here's how to use it.
Identifying the damage
Most chain breaks happen at a link that was already weakened — a stiff link you didn't notice, a link that took a bad shift under load, or one that was damaged by a previous repair. Look at the break. If a pin has sheared or a plate has cracked, you need to remove the damaged section entirely.
Using the chain tool
Place the damaged link in the chain tool's cradle. Line the tool's pin up with the chain pin you want to push out. Turn the handle slowly and evenly — don't force it. Push the pin far enough to clear the outer plate on the far side, but if the tool has a second position for loosening stiff links, that's for a different job. For a break repair, you're pushing the pin all the way through to separate the chain.
Remove the broken links. You want to end up with the chain having an inner link (no protruding pins) on each end, because that's what a quick link connects.
Connecting with a quick link
A quick link — also called a master link or power link — is a two-piece connector that joins the chain without needing to push a pin back in. Thread one half through each end of the chain from opposite sides so the pins poke through the inner plates, then pull the chain taut. On Shimano 12-speed, you'll hear a click. On SRAM, pull hard — stand on the pedals with the brakes on and give it a firm pedal stroke to snap it into place.
The chain is now shorter by however many links you removed. This means some gear combinations — big ring, big cog — might not work because there isn't enough chain. Stay in the middle of your cassette, avoid extremes, and ride home. A proper chain replacement can happen in the workshop.
Carry the right quick link. They are speed-specific. An 11-speed quick link will not work on a 12-speed chain. Check your drivetrain, buy the right one, and tape it to your seatpost or tuck it in your saddle bag.
Barrel adjuster basics: the most underused tool on your bike
Here's the thing nobody tells you about shifting problems: most of them are a quarter-turn fix. Not a workshop job. Not a cable replacement. A quarter-turn of a barrel adjuster that's already on your bike, accessible without any tools at all.
A barrel adjuster is the small threaded cylinder where the gear cable meets the derailleur or the shifter. Some bikes have them at both ends. Turning it changes the effective cable tension without touching the cable clamp or the limit screws.
How it works
Think of it this way. The derailleur positions the chain by cable tension. More tension pulls the derailleur further from the frame (towards bigger cogs at the rear). Less tension lets the spring pull it back towards the frame (towards smaller cogs).
When cables stretch — and they do, especially new ones — the tension drops slightly. The derailleur doesn't quite reach where it should. The chain hesitates on upshifts, rattles between gears, or refuses to engage the biggest cog. Cable stretch is also what Geater talks about: the kind of thing a pro team addresses constantly but amateurs ignore until it becomes a real problem.
The fix
Chain skipping or hesitating when shifting to bigger cogs (easier gears): Turn the barrel adjuster anti-clockwise (away from you, when looking at it from behind) by a quarter-turn. This effectively lengthens the cable housing, which increases cable tension. Shift through the gears. Better? Good. Still not right? Another quarter-turn. Small increments.
Chain overshooting or slow to shift to smaller cogs (harder gears): Turn the barrel adjuster clockwise by a quarter-turn. This decreases cable tension.
Chain rubbing or rattling in one specific gear: Usually a half-turn in the appropriate direction fixes this. If the chain is loud in the middle of the cassette but quiet at the extremes, cable tension is slightly off.
You can adjust barrel adjusters while riding — just reach down and turn. On a group ride, on a climb, mid-race if it comes to that. No stopping, no tools, no drama. Just know which direction to turn.
When barrel adjusters won't fix it
If you've wound the barrel adjuster out more than two full turns and it's still not shifting cleanly, the cable is either badly stretched, frayed, or the derailleur hanger is bent. A barrel adjuster compensates for minor cable stretch. It doesn't fix mechanical damage. That's a workshop job.
Similarly, if the chain drops off the cassette at either extreme — top or bottom — that's a limit screw issue, not a cable tension issue. Don't touch limit screws roadside unless you really know what you're doing, because a wrong adjustment can put the chain into the spokes. And that turns a minor annoyance into a destroyed wheel and possibly a crash.
Tyre boot for sidewall cuts: the repair that looks sketchy but works
A sidewall cut is one of the most dramatic mechanicals you'll encounter. A sharp rock, a piece of debris, a pothole edge — and suddenly there's a gash in the side of your tyre with the tube or casing bulging through. It looks terminal. It usually isn't.
What a tyre boot does
A boot is a reinforcing patch that goes on the inside of the tyre, bridging the cut and preventing the tube from herniating through the gap. It doesn't make the tyre as good as new. It makes the tyre rideable. Good enough to get you home. Good enough to finish a sportive if the cut isn't too severe.
What to use
Purpose-made tyre boots: Park Tool and others sell adhesive-backed tyre boots that are designed exactly for this. They're thin, lightweight, and stick to the inside of the tyre casing. Carry one in your saddle bag — they weigh next to nothing.
A section of old tyre: Cut a piece roughly 50mm by 30mm from a dead tyre and keep it in your saddle bag. This is the classic solution, and it works brilliantly because an old tyre is literally designed to withstand the pressures involved. Geater carries one — if it's good enough for a WorldTour mechanic's personal rides, it's good enough for yours.
A folded energy gel wrapper: Not ideal, but in a pinch, a thick gel wrapper folded over twice and placed inside the tyre over the cut will hold long enough to limp home. It's a bodge. It works.
A folded bank note: The same principle. Paper currency is surprisingly durable under compression. Fold it twice, place it over the cut inside the tyre, inflate to slightly lower pressure than normal.
The process
- Remove the wheel and unseat the tyre on the damaged side
- If there's a tube, remove it (or if tubeless, let the remaining air out)
- Clean the inside of the tyre around the cut — remove any debris, sealant, or grit
- Place the boot centrally over the cut, extending at least 15mm beyond the cut in each direction
- If using an adhesive boot, press firmly. If using a section of tyre or wrapper, it will be held in place by the tube and tyre pressure — just make sure it's positioned correctly before you reseat everything
- Install the tube (even on tubeless, use a tube behind a boot — sealant will push through a booted sidewall cut)
- Inflate to 70-80% of your normal pressure. Lower pressure means less force pushing against the boot
- Ride home. Avoid potholes, avoid aggressive cornering on the booted side, and keep the speed sensible
A well-done tyre boot on a minor sidewall cut can last hundreds of kilometres. I've seen riders finish sportives on them. But get the tyre replaced as soon as you're home — a boot is a temporary repair, not a permanent one.
What should be in your saddle bag
There's a specific set of items that covers the three most common roadside mechanicals — puncture, chain break, and shifting issues — without turning your saddle bag into a toolbox. Here's the list.
The essentials
- Spare inner tube (one, correct size for your wheels, even if you run tubeless)
- Tyre levers (two, quality plastic ones — cheap ones snap)
- Patch kit (a small self-adhesive patch kit for a second puncture — because two flats in one ride happens more often than you'd think)
- Mini pump or CO2 inflator (CO2 is faster, but carry two cartridges because one might not be enough for a road tyre. A mini pump is heavier but unlimited)
- Quick link (the correct speed for your chain — 11-speed, 12-speed, whatever you're running)
- Tubeless plug kit (if you run tubeless — Dynaplug or similar)
- Tyre boot (a purpose-made one or a piece of old tyre)
- Cash or bank card (for the cafe, the train station, or the emergency taxi)
The multi-tool
A decent cycling multi-tool is the single most important item in your saddle bag after a spare tube. But not all multi-tools are the same, and the critical feature most people overlook is the chain breaker.
What your multi-tool must have:
- 4mm, 5mm, and 6mm Allen keys (these cover 90% of the bolts on a modern bike)
- T25 Torx (increasingly common on disc brake rotors and newer components)
- A chain breaker
- A Phillips head screwdriver
- A spoke key (if your wheels use external nipples)
What's nice to have but not essential:
- 2.5mm and 8mm Allen keys
- A tyre lever built into the body
- A valve core removal tool
Keep the total weight under 300g for the entire saddle bag including contents. If it's heavier than that, you're carrying things you don't need. And check it before every ride. Not every week. Every ride. Because the time you assume the tube is there and it isn't is the time you'll need it most.
Jersey pocket carry
Some riders prefer to carry their repair kit in a jersey pocket rather than a saddle bag, especially for racing or short rides where aero matters. That's fine, but the same essentials apply. A tube, a CO2 inflator with one cartridge, tyre levers, and a quick link will fit in a single jersey pocket. Add a multi-tool in a second pocket and you're covered for the most common mechanicals.
The one thing I'd say about jersey pocket carry: make sure nothing can fall out. Wrap the tube in a small zip-lock bag, secure the CO2 with tape, and check after you stand up on climbs. Losing a tube out of your pocket mid-ride is annoying. Losing it and then getting a puncture is a disaster.
When a roadside fix is not possible
Let me be really clear about this: not everything is fixable on the side of the road. And knowing when you're beaten is just as important as knowing how to fix things. Attempting a repair that's beyond your skill or beyond the damage threshold wastes time, can make things worse, and occasionally puts you in danger.
Mechanicals you cannot fix roadside
A cracked or broken frame. If you see a crack in the frame — especially around the head tube, bottom bracket, or seat tube — stop riding immediately. A cracked frame can fail catastrophically and without warning. No amount of roadside ingenuity fixes structural damage.
A destroyed wheel. A buckled wheel that won't spin past the brake pads might be straightened enough to limp home if you can open the brake caliper. A wheel with broken spokes on both sides, a cracked rim, or a hub that has seized is beyond roadside repair.
A sheared derailleur hanger. If the derailleur hanger — the small sacrificial tab that connects the rear derailleur to the frame — has snapped, the rear derailleur is hanging loose and the chain won't engage the cassette properly. The bodge fix here is to remove the derailleur entirely, shorten the chain, and convert to a single-speed by sitting it on a middle cog. This works but requires confidence and a chain tool. If you're not sure, don't attempt it.
Hydraulic brake failure. If a hydraulic brake line has been cut or a caliper is leaking fluid, that brake is done. You cannot fix hydraulic brakes roadside. Ride home very carefully on one brake if the other is functional. If both brakes have failed — and this is vanishingly rare — do not ride. Walk.
Electronic shifting battery death. If you're running Di2, eTap, or AXS and the battery dies, your shifting dies with it. Some systems lock in the current gear. Some give you a few emergency shifts. Carry a spare battery or a charging cable if the system supports it, but a dead battery mid-ride is mostly a "ride home in whatever gear you're in" scenario.
Have a plan B
Before every ride — especially long ones, solo ones, or rides in remote areas — have a plan B for getting home. This isn't pessimism. This is what experienced riders do.
Phone and a charged battery. Obvious, but carry it. A phone with 5% battery is nearly as useless as no phone at all. Consider a small power bank for long rides.
Emergency contact who knows your route. Tell someone where you're going and roughly when you expect to be back. Share your live location if your phone supports it.
Knowledge of the train network. Many UK and Irish train services allow bikes on board outside peak hours. Know which stations are near your route. A broken bike on a train is still better than a broken bike 50km from home.
A small amount of cash. A twenty-pound note can get you a taxi, a bus ticket, or at minimum a cup of tea while you figure out the next move. Card machines need signal. Cash always works.
Roadside assistance. Cycling-specific breakdown cover exists — British Cycling membership includes some, and third-party options are available. For the cost of a couple of inner tubes per year, it's worth considering if you ride alone regularly.
The mindset shift
Here's what separates a mechanical that ruins your day from a mechanical that costs you ten minutes: preparation and practice. Every skill in this article is learnable in your garage in an afternoon. Change a tube five times and you'll do it without thinking. Use a chain tool twice and you'll trust it. Turn a barrel adjuster a few times and you'll understand which direction does what.
The time to learn is not when you're standing on the side of the A44 with rain coming down and a group ride disappearing up the road. The time to learn is a quiet Sunday afternoon with a cup of tea, a YouTube video, and your bike on the floor.
Craig Geater put it better than I can: the best tool in your saddle bag is the knowledge in your head. Tools are useless if you don't know how to use them. And knowledge weighs nothing.
These are the conversations we have inside the Roadman Cycling community every week — sharing what works, what doesn't, and the stuff that actually makes you a better, more self-sufficient rider. If you want in, join us on Skool.