Every tire inflator gets a score from 0 to 100% built from four factors, which maps onto the 5-point rating shown on the site (a 0% score would be 1.5 stars; a perfect score, 5). Each factor is scored against fixed reference points, not against the other products in the list, so adding a new model never moves another model’s rating. Inflators are grouped by how they’re powered, and each group has its own scale.
| Factor | Measures | Weight |
|---|---|---|
| Value | price for its type | 35% |
| Airflow | how fast it fills a tire | 30% |
| Features | auto shutoff, duty cycle, maximum pressure | 20% |
| Warranty | warranty length | 15% |
Where the numbers come from
Airflow, pressure, duty cycle, features and warranty come from the maker’s product page, manual or warranty page. Inflation times, airflow and noise measured by independent testers are shown on product pages where they’ve been published.
The groups
| Group | Power |
|---|---|
| Cordless | A built-in or tool battery, with or without a 12 V cord as backup |
| 12 V plug-in | The car’s 12 V socket, and sometimes a wall outlet |
| Heavy duty | Clamps to the vehicle battery |
The factors
Value is the current price, scored on a scale for each group. Tool-battery inflators are priced as the bare tool when that’s how they’re sold, which the product page says.
| Group | Scores 0 | Full marks |
|---|---|---|
| Cordless | $180 | $30 |
| 12 V plug-in | $80 | $20 |
| Heavy duty | $500 | $80 |
Airflow is the maker’s free-air flow in liters per minute, which decides how fast a tire fills. Makers who publish cubic feet per minute are converted (1 CFM is 28.3 L/min).
| Group | Scores 0 | Full marks |
|---|---|---|
| Cordless | 15 L/min | 45 L/min |
| 12 V plug-in | 20 L/min | 60 L/min |
| Heavy duty | 40 L/min | 120 L/min |
Free-air flow is measured with nothing on the hose, so every inflator moves less once it’s pushing against a tire, and makers don’t all measure it the same way. It’s still the best published guide to speed; independent inflation times, where they exist, are on the product page.
Features adds up the things that make an inflator easy to live with:
| Feature | Share of the factor |
|---|---|
| Stops automatically at a pressure you set | 40% |
| Duty cycle, from 5 minutes of running (none) to 30 minutes or continuous (full) | 30% |
| Maximum pressure, from 60 PSI (none) to 150 PSI (full) | 30% |
Auto shutoff means you can set 35 PSI and walk away instead of watching a gauge. The duty cycle is how long it can run before it needs to cool down, which matters for big or completely flat tires. A higher pressure rating covers RV, trailer and road-bike tires. A feature the maker doesn’t state either way gets half credit.
Warranty: 1 year scores zero and 3 years full marks.
What isn’t scored
Battery capacity, USB charging, lights, noise, hose and cord length, size and weight are listed but not scored. Independent tests are listed where they exist, but there are too few to score.
Missing data
If a figure isn’t published, that factor gets the neutral middle score (50) and the product page marks it as estimated.
Ties and discontinued models
Products are ranked by score within each group. Discontinued models stay listed but rank below every current model and can be hidden with the “Hide discontinued” filter.