Two things fix most of what feels wrong
Ask a shop mechanic what they wish customers did and the answer is not exotic. Inflate the tires, and clean and lubricate the chain. Between them those two jobs account for most of the complaints that arrive as a vague statement that the bike feels bad, and neither one requires knowing anything about how a derailleur works.
Tires lose pressure continuously through the tube or through the casing, and the rate depends on the volume of air inside. A wide mountain or gravel tire holds a lot of air at low pressure and might drop a few psi in a week. A narrow high-pressure road tire, especially a latex tube, can lose a meaningful fraction of its pressure overnight. Riding a road tire twenty psi low does not feel dramatically different at first, which is exactly the problem: it rolls slower, it corners vaguely, and it is far more likely to pinch flat when you hit a pothole.
Chain lubricant is doing two jobs. It keeps the pins and rollers from grinding metal against metal, and it stops rust. A dry chain wears fast, sounds terrible, shifts badly and drags. A chain caked in old lube and road grit wears faster still, because grit is an abrasive and the lube is holding it in place. The correct amount of lube on a bicycle chain is much less than most beginners apply, and the wiping-off step matters more than the applying step.
Tire pressure, without the number on the sidewall
The pressure molded into the tire sidewall is a maximum the casing is rated for, not a recommendation. The right pressure is a function of tire width, your total loaded weight, and the surface. Heavier rider, higher pressure. Wider tire, dramatically lower pressure. Rough or wet surface, lower still.
| Tire type and width | Typical working range | What moves it |
|---|---|---|
| Road, 25-28mm, tubed | Roughly 65-90 psi | Lower end for lighter riders and rough pavement. Modern thinking has come down a lot from the 110 psi people once ran. |
| Gravel, 38-45mm | Roughly 28-45 psi | Loose surfaces reward the low end. Rim strikes mean you went too low. |
| Mountain, 2.1-2.5in, tubeless | Roughly 18-28 psi | Front usually a couple psi lower than rear. Terrain and rider weight dominate. |
| Hybrid or commuter, 32-40mm | Roughly 45-65 psi | Comfort is a legitimate reason to run the low end |
| Kids bikes, 20in and under | Read the sidewall range and stay in it | These are almost always ridden badly underinflated |
A floor pump with a real gauge is the tool that makes this possible, and it is the first thing to buy. Hand pumps and gas station compressors are for emergencies. Set a pressure, ride it, and adjust by a few psi at a time until the bike feels planted rather than harsh or squirmy. Write the number down, because you will forget it.
Chain wear, and why it is the cheapest insurance on the bike
A chain does not stretch in the sense of the metal getting longer. The pins and the inside of the rollers wear, and each worn joint adds a fraction of a millimeter to the pitch. Multiply that across a hundred-odd links and the chain no longer sits correctly in the teeth of the cassette and chainrings. From that point on, the chain is machining the teeth into a shape that matches its own worn spacing.
That is the important part. A worn chain is not just a worn chain, it is a tool that reshapes the cogs. Replace the chain in time and the cassette keeps working for several chains. Ride the chain to the point where it skips under load and you are usually buying a chain, a cassette, and sometimes chainrings, and you have also had months of bad shifting.
| Drivetrain | Replace the chain at | Notes |
|---|---|---|
| Modern 10, 11 or 12-speed | 0.5% wear | Narrow chains and narrow cogs are less tolerant. Waiting to 0.75% here usually means a new cassette too. |
| Older 8 or 9-speed | 0.75% wear | Wider, more forgiving. This is where the old 0.75% rule of thumb came from. |
| Single speed or internally geared hub | Manufacturer figure, often 0.75% | No cross-chaining, so these last a long time |
A chain checker is a small stamped or machined tool that drops into the chain and reads a percentage directly. They typically cost about the price of two coffees and are the single highest-return tool a beginner can own. Check every few hundred miles, or once a month if you ride regularly. Cheap gauges that measure across a roller can read slightly pessimistic because they include roller wear; that error is in your favor and not worth worrying about.
How long a chain lasts varies more than any published figure suggests. Dry summer road riding might get well over two thousand miles. Wet winter commuting through grit can chew one out in a few hundred. Mileage is not the measure. The gauge is.
Cleaning and lubing, done in the right order
Degrease only if the chain is genuinely dirty, using a brush and a bike-specific degreaser or plain dish detergent, then rinse and dry it completely. Applying fresh lube over grit only suspends the abrasive in place, and a wet chain will not take lube properly in any case. On a chain that is merely dusty, skip this entirely.
Then lube one drop per roller, backpedaling slowly through a full revolution so every joint gets some. Wait a few minutes for it to work into the pins, then grip the chain in a clean rag and backpedal several more turns, wiping hard. Everything left on the outer plates is grit-catching surface that does no lubricating at all, which is why a correctly lubed chain looks almost dry. While you are there, pull a rag between the cassette cogs and pick the black paste off the derailleur jockey wheels — those two small pulleys collect a startling amount and hand it straight back to the chain.
Wet lube is thicker, lasts longer in rain, and attracts more dirt. Dry lube is thinner, stays cleaner, and needs reapplying more often, particularly after rain. Wax-based systems are cleaner still and involve more up-front work. Any of them beats no lube, and none of them beats a chain replaced on time. Never use a general-purpose penetrating spray as chain lube; it is a solvent that displaces what is already in the joints.
The two-minute check before a ride
Mechanics call some version of this the M-check because you trace an M over the bike: front wheel up to the bars, down to the bottom bracket, up to the saddle, down to the rear wheel.
Squeeze both tires, and if you are in any doubt, pump. Spin each wheel and watch for rub against the brake, a lateral wobble or a broken spoke, then grab the rim and rock it sideways to feel for play in the hub. Check that quick releases and thru-axles are closed and tight, which is the item on this list that actually hurts people. Pull both brake levers hard: they should go firm well before the bar, and a spongy hydraulic lever or one that reaches the grip means you stop and fix it rather than ride. Look at the pads while you are down there, since rim pads worn past their grooves and disc pads down to the thickness of a business card both need replacing.
Then grab the bars and twist against the front wheel held between your knees — loose stem bolts are common after anyone transports a bike on a rack or in a trunk. Finally, lift the bike a few inches and drop it. Rattles tell you something is loose while you are standing still, which is a much better time to find out than at speed.
What to learn, and what to pay for
The repairs worth learning first are the ones that strand you or that you will do dozens of times: fixing a flat, adjusting a derailleur cable with the barrel adjuster, changing brake pads, and tightening a stem or seatpost to a sensible torque. All of them are done with hex keys, a tire lever and patience.
| Job | Reasonable to learn | Usually worth a shop |
|---|---|---|
| Flat repair, tube or tubeless plug | Yes, and practice it at home before you need it in the dark | |
| Chain replacement | Yes, with a chain tool and the right quick link for the speed count | |
| Indexing a rear derailleur | Yes, most of the time it is a quarter turn of a barrel adjuster | A bent hanger needs an alignment tool |
| Bleeding hydraulic brakes | Yes. Wrong fluid or trapped air is a brake that fails when hot | |
| Wheel truing and spoke tension | A light true, maybe | Anything past that. Spoke tension is a system, not a bolt |
| Bottom bracket and headset bearings | Yes. Press-fit standards and specific tools | |
| Suspension service | Yes, on the manufacturer interval |
A basic tune-up at a shop commonly runs somewhere in the range of $75 to $150 depending on the market and what the bike needs, with parts on top, and prices move. That is money well spent on a bike that has been neglected for years, because a mechanic will find the seized seatpost and the cracked rim you were not looking for. It is money wasted on a bike that needs air in the tires.
If you are curious about the gearing itself rather than the maintenance, the bike gear ratio calculator shows what a change in chainring or cassette actually does, and the cycling speed calculator converts a cadence and gear into road speed. Neither will make the bike quieter. The chain gauge will.
Buy the pump, the chain checker and a bottle of lube this week, and check the chain before you ride anything you care about.
Questions people ask
How do I know when to replace my bike chain?
Measure it with a chain wear gauge rather than guessing from mileage. On a modern 10, 11 or 12-speed drivetrain the usual replacement point is 0.5% wear; on older 8 or 9-speed setups, which use wider and more forgiving cogs, 0.75% is the common limit. Check every few hundred miles or roughly monthly if you ride often. Mileage alone is a poor guide because a dry summer road chain might last several times as long as one ridden through winter grit.
Why does a worn chain cost more than a chain?
Because a worn chain reshapes the cassette. As the pins and rollers wear, the spacing between links grows, and the chain stops sitting correctly in the teeth. From then on it is grinding the cogs into a profile that matches its own worn pitch. Replace chains on time and one cassette will outlast several of them. Ride a chain until it skips under load and you generally need a chain, a cassette and sometimes chainrings, which turns a modest part into a much larger bill.
What tire pressure should I run?
Not the number on the sidewall — that is the casing maximum, not a recommendation. Pressure depends on tire width, your total loaded weight and the surface. As rough bands: 25-28mm road tires often live around 65-90 psi, 38-45mm gravel tires around 28-45 psi, mountain tires around 18-28 psi, and 32-40mm commuter tires around 45-65 psi. Start in the middle, ride it, and adjust a few psi at a time. Buy a floor pump with a gauge; it is the highest-value tool on this list.
How often should I lube my chain?
When it starts to sound dry, or after any wet ride, rather than on a fixed schedule. The technique matters more than the frequency: one drop per roller while backpedaling, a few minutes to penetrate, then wipe the outside of the chain hard with a clean rag. A correctly lubed chain looks nearly dry on the outside, because the lube belongs inside the joints. Lube sitting on the outer plates only collects grit, and grit is what wears the chain out.
Is a shop tune-up worth it?
It depends entirely on the bike. On something that has been stored for years, yes — a mechanic will catch the seized seatpost, the cracked rim or the perished tire sidewall that you would not think to look for, and a basic tune commonly runs in the $75 to $150 range plus parts, though prices move by market. On a bike that simply feels slow, air in the tires and a clean lubed chain will very likely solve it for a few dollars, and it is worth trying that first.