Short answer
For many riders, 28mm is a sensible choice if the frame and rims allow it, because it tends to feel more comfortable at lower pressure without a large penalty on smooth roads. 25mm remains a reasonable option for lighter bikes, tight clearances, or riders who prefer a firmer feel. The best width depends on your frame, rims, road surface, and weight.
What changes with tire width
A wider tire has a larger air volume. That lets you run lower pressure for the same support, which generally improves comfort and grip on rough surfaces. A wider tire also weighs more and can be slightly less aerodynamic, depending on how it matches the rim. These effects are usually modest, which is why the choice is less dramatic than it once seemed.
Comfort and pressure
Because wider tires hold more air, they are typically run at lower pressures than narrower ones. Pressure still depends on rider weight, tubeless or tube setup, and the tire maker’s recommendation, so use a manufacturer’s pressure calculator or guidance as a starting point and adjust. Never exceed the maximum pressure on the tire or the rim. For typical starting numbers, see the bike tire pressure chart.
Speed and rolling resistance
Tests commonly show that on rough road surfaces, a wider tire at suitable pressure can roll as fast as or faster than a narrow one, partly because less energy is lost to vibration. On very smooth surfaces the difference tends to be small. Treat any specific speed claim carefully, since results vary with tire model, casing, and test conditions.
Clearance and rim limits
Before moving from 25mm to 28mm, check:
- Frame, fork, and brake clearance, with a few millimeters to spare once the tire is inflated.
- Whether your rim’s internal width suits the new tire. See matching tire width to rim width.
- Whether the tire label matches actual width, since tires can measure wider or narrower than stated.
Who suits 25mm, 28mm, and 30mm or more
- 25mm: tight clearances, older rim-brake frames, smooth roads, riders preferring a firmer feel.
- 28mm: a flexible all-round choice for mixed road surfaces if the frame allows it.
- 30mm and above: rough or patched roads, mixed pavement, heavier riders, or light gravel. You may then want to read about gravel tire width.
How to test a change
Change one thing at a time. Fit the new tires, set the pressure from the maker’s guide, ride a familiar route, and adjust in small steps. Note comfort and grip rather than relying only on speed numbers.
Is a 28 inch tire the same as 700c?
The two labels refer to the same bead seat diameter of 622 mm, so they can fit the same rim (more in what 700c really means). “28 inch” more often appears on city bikes and in older labels, and the width labeling can differ, so confirm with the ISO number. The road bike tire sizing guide explains how to read these labels.