Feeling from wheelset testing: 25mm or 28mm, which tire width should you choose?

Choosing Between 25mm and 28mm Tires: Insights from Wheelset Testing

As carbon road wheelsets have become wider in recent years, both in inner and outer dimensions, tire preferences among professional cyclists have shifted. To maximize aerodynamics and take advantage of lower tire pressures offered by tubeless setups, the trend has moved from 25c (26c) tires toward 28c options. Based on hands-on experience, here’s what you need to know when deciding between 25mm and 28mm tire widths in 2026.

Why Wider Rims and Tires?

• Improved Aerodynamics: Wider rims paired with matching tire widths reduce aerodynamic drag.
• Lower Tire Pressure: Tubeless tires allow for lower pressures, increasing comfort and reducing fatigue.
• ETRTO Standards: For rims with a 23mm inner width, the ETRTO standard recommends using tubeless tires of 28mm or wider.

While some 25mm tubeless tires are available, most manufacturers and standards now favor 28mm for these wider rims. Notably, 28mm tires can be safely run at 60–65psi, offering a smoother ride compared to the bumpier feel of higher pressures above 70psi. Unless you’re riding on perfectly smooth roads, lower pressures can actually result in faster, less fatiguing rides.

Installation and Air Tightness: Practical Experiences

Recent wheelset tests used 28mm tubeless tires on rims with a 23mm inner width. Here’s what stood out:

• Easy Installation: The tires were easy to mount and inflate using a standard floor pump.
• Excellent Air Retention: Air tightness was impressive, even without adding sealant initially.
• Lightweight Setup: Swapping heavy plastic tire pads for tubeless-ready tape added only minimal weight.

It’s important to note that some original tire pads are heavier because they provide tire positioning and anti-detachment features. If you choose to use lightweight tape instead, select tubeless tires with a secure bead fit. For example, the T2/T5 quasi tire, despite being difficult to remove, offers a tight fit that prevents accidental detachment—even when fully deflated.

Performance: 26c vs 28c Tires

Bola experimented with a 26c tire on the front and a 28c on the rear, but ultimately switched to 28c tires on both wheels. The measured tire width reached 30mm. This setup provided:

• Better Aerodynamics: Matching tire and rim widths (our rim has an outer width of 30mm) improved airflow compared to narrower tires.
• Lower Rolling Resistance: Tubeless tires at lower pressures (as low as 55psi) maintained efficiency and comfort without increasing rolling resistance.
• Reduced Risk of Pinch Flats: Wider tires at lower pressures are less prone to “snaking” and bursting compared to narrower, high-pressure setups.

Managing Tubeless Tire Air Retention

While tubeless tires can maintain air pressure for days without sealant, real-world use showed that air retention can differ between front and rear wheels. This is often due to higher spoke tension on the rear wheel, causing minor rim differences. In practice:

• Some wheels may require daily air top-ups.
• Adding sealant improves both air retention and puncture resistance.
• With good initial airtightness, less sealant is needed.

Summary: 28mm Tires Are the Modern Choice

For rims with a 23mm inner width and 30mm outer width, 28mm tubeless tires offer a clear advantage in 2026. They provide better comfort, improved aerodynamics, and maintain efficiency at lower pressures. Installation and maintenance are straightforward, especially with modern tire and rim designs.

Frequently Asked Questions

Should I use 25mm or 28mm tires on a 23mm inner width rim?

For rims with a 23mm inner width, most standards and manufacturers recommend 28mm tubeless tires. This pairing optimizes aerodynamics, comfort, and safety.

What tire pressure is best for 28mm tubeless tires?

Typical pressures range from 55–65psi for 28mm tubeless tires on wide rims. Lower pressures increase comfort and do not increase rolling resistance with tubeless setups.

Do I need to use sealant with tubeless tires?

While some setups can hold air well without sealant, adding a small amount improves air retention and provides puncture protection. The amount needed may be less if the tire and rim fit is excellent.

Is it difficult to install 28mm tubeless tires?

Modern 28mm tubeless tires are generally easy to install, especially on compatible rims. A standard floor pump is often sufficient for inflation.

Can I mix tire widths, such as 26c front and 28c rear?

It is possible, but matching tire widths (28c front and rear) provides better aerodynamics and comfort, especially with wide rims.