Pressure Precision: Why Too High Costs More Than Too Low
Most riders think of tire pressure as a range with even penalties on either side of optimal. It isn't. SILCA's testing on rolling resistance and impedance found the two directions cost noticeably different amounts:
"5psi below optimal pressure for a given surface may cost you 1 watt, 5psi above the optimal pressure may cost you 3-4 watts." SILCA: Asymmetric Effects of Tire Pressure
The mechanism differs in each direction. Underinflation loses power mostly through tire-casing deformation: the tire flexes more than it needs to, and that flex absorbs energy. Overinflation loses power through impedance. An overly stiff tire stops absorbing small surface irregularities and instead transmits that energy into lifting and dropping the bike and rider over every bump, a far less efficient way to cross the same terrain.
If you're unsure which side of optimal to err toward, err low. A rider guessing at pressure and rounding up "to be safe" is choosing the more expensive mistake. Optimal pressure itself depends on total system weight, tire width, and surface. SILCA's Professional Tire Pressure Calculator models all three rather than relying on the number printed on the sidewall, which is a legal maximum, not a recommendation.
Tubeless Sealant: How Often to Refresh It
Sealant is not a set-and-forget consumable inside a tubeless tire. It dries out over time, whether or not the tire has been ridden, and a dried-out tire has no active puncture protection left.
"We'd recommend topping up your tubeless sealant every three to six months." BikeRadar: Tubeless Tyre Maintenance
Heat, low humidity, and high-speed riding all accelerate evaporation, so a bike stored or ridden somewhere hot and dry sits at the shorter end of that range, while a bike kept somewhere cool and humid can stretch toward the longer end. BikeRadar also recommends a full tire removal for inspection once every 12 to 18 months, since a quick sealant check from the valve doesn't show the state of the sealant pooled around the rest of the casing.
A practical way to check without fully removing the tire: dip a cable tie through the valve core like a dipstick. More than a centimetre of sealant on the tie means you can defer topping up. Less than that, and it's due.
Rubber Aging: Why Tires Degrade Even When Not Ridden
Distance isn't the only clock running on a tire. Rubber compound degrades from UV exposure, ozone, and temperature cycling regardless of mileage, which is why a tire on a bike that rarely leaves the garage can still fail.
"Michelin recommends removing tires from service after 10 years from the manufacture date regardless of tread depth."
Michelin also recommends a professional inspection after the first year of use specifically to catch early aging damage: rubber hardening and the fine surface cracking that precedes a puncture, before it becomes visible to an untrained eye. This matters more than it first appears for a multi-bike household where one bike sees most of the mileage. The bike gathering dust in the corner is aging on the same clock as the one you ride every week, just without the tread wear to remind you.
Sidewall cracking is the visible tell. A hairline crack running along the sidewall, especially near the bead, means the compound has already lost enough flexibility that it's no longer a cosmetic issue.
Front-to-Rear Rotation: The One Time It's Worth Doing
Bicycle tires don't wear evenly between front and rear, and the difference is large enough to matter.
"It is common for a front tire to outlast a rear tire by as much as three to one." Sheldon Brown: Tire Rotation
The rear carries more of the rider's weight under pedalling load and does all the driving, so it simply wears faster. Rather than swapping tires back and forth to equalize wear, rotate once, at the moment the rear needs replacing: move the still-good front tire to the rear, and put the new tire on the front. That keeps the newest, most predictable tire on the wheel where a failure is more dangerous. A front-tire blowout risks losing steering control, while a rear-tire failure is generally a more controllable stop.
Reading the Tread Wear Indicator, Briefly
Most modern road and gravel tires include a tread wear indicator (TWI), a small marker molded into the tread that disappears once the tire has worn down to its replacement point.
"The small indentations in the tread indicate how far a tread can be worn down before the tire should be replaced." Schwalbe: Tire Wear
Typical mileage varies enormously by model and compound. Standard road tires commonly cover 2,000 to 5,000 km, while touring-specific tires with harder compounds can run well past 10,000 km. For the full tread-wear picture, including casing failure signs and lifespan by riding discipline, see When to Replace Your Bike Tyres.
How Componentry Tracks Tire Lifecycle
Tread wear is visible if you look. Pressure precision, sealant age, and rubber aging are not. They accumulate silently between the checks most riders remember to do.
Componentry tracks each tire as its own component, synced automatically from Strava, Garmin, or Wahoo. Set a sealant-refresh reminder on a 3-to-6-month cycle instead of trying to remember when you last topped up, and set an age-based service reminder on any tire regardless of how little it's ridden, so a low-mileage bike in a multi-bike stable doesn't quietly age past a safe point unnoticed.
For pressure, the discipline is simpler: check before the ride, using a value calculated for your weight and terrain rather than the number printed on the sidewall. If you're ever unsure which way to round, round down.
Track more than tread wear. Componentry tracks sealant age, service intervals, and every other component on every bike, automatically, from your connected Strava, Garmin, or Wahoo data. Get started free →
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