WHO THIS IS FOR
IS THIS YOU?
The rider choosing tyres for a new bike or replacement set
You want a clear recommendation on what width to buy and why, without wading through contradictory forum debates.
The cyclist on 23mm or 25mm tyres wondering if wider is better
You have heard that wider tyres are faster and want to understand the evidence before making the switch.
THE ROADMAN VIEW
The Roadman view
The tyre-width debate was settled years ago by the data, but the cycling world is slow to let go of old beliefs. For decades, the assumption was thinner equals faster — less rubber, less drag, more speed. The problem is that assumption was tested on perfectly smooth steel drums in a laboratory. On actual roads, with their cracks, patches, chip-seal, and manhole covers, a wider tyre deforms less at the contact patch, absorbs surface imperfections instead of bouncing over them, and rolls measurably faster.
The numbers are clear. Independent rolling resistance tests show that a 28mm tyre at the correct pressure is 2–4 watts faster than a 25mm tyre at the same effort on typical UK or European road surfaces. Go up to 30–32mm on rougher roads and the advantage grows. The comfort improvement is a bonus, not the point — you can hold position and power for longer when your hands and backside are not being jackhammered by road vibration.
Anthony's practical position is straightforward: if your frame clears 28mm, fit 28mm. If it clears 30 or 32mm and you ride mixed surfaces or poor tarmac, go wider still. The only riders who benefit from 25mm are those on glass-smooth roads or racing on closed circuits where the surface is immaculate. For everyone else, wider is actually faster, not just more comfortable.
EXPERT EVIDENCE
WHAT THE EXPERTS SAY
- Roadman CyclingRoadman Cycling tyre and equipment coverage
Most riders are running tyres that are too narrow and too hard. A 28mm tyre at the right pressure — typically 70–85 psi for a 70–80 kg rider — rolls faster on real roads than a 25mm at 100 psi. The physics is straightforward: the wider tyre has a shorter, wider contact patch that deforms less and wastes less energy on surface irregularities.
Hear it: Your Tyres Are Slowing You Down Here’s Why - Roadman CyclingRoadman Cycling tyre pressure coverage
Tyre pressure and width interact. A wider tyre at lower pressure matches the road surface better, reducing energy lost to vibration. This is not a marginal gain — on rough roads it can be 5–10 watts, which is the equivalent of a significant aero improvement at a fraction of the cost.
Hear it: Tyre Pressure — The Free Speed Hack | Roadman Cycling Podcast
PRACTICAL APPLICATION
DO THIS WEEK
Measure your frame clearance
Before buying wider tyres, measure the gap between your current tyre and the fork crown, seat stays, and chainstays. You need at least 4mm of clearance all round for safe running. If your frame barely fits 25mm, you may be limited until your next bike. If you have 3–4mm of daylight with 25mm fitted, 28mm will likely fit.
Set pressure correctly for the new width
Wider tyres need lower pressure. A 75 kg rider on 28mm tyres should run roughly 70–80 psi front and 75–85 psi rear. Use the Roadman Tyre Pressure Calculator for a figure based on your weight, tyre width, and conditions. Dropping from 100 psi on 25mm to 75 psi on 28mm is where the performance and comfort gains come from.
Test on a familiar route
Ride the same route you know well on both the old and new tyres. Pay attention to average speed at the same power or heart rate, comfort over rough sections, and cornering confidence. Most riders report feeling slower because the ride is quieter and smoother — but the data shows equal or better speed at the same effort.
COMMON MISTAKES
WHAT CYCLISTS GET WRONG
MISTAKEFitting wider tyres but keeping the same high pressure as the narrower ones.
FIXWider tyres need lower pressure to perform correctly. Running 28mm at 100 psi negates most of the advantage. Drop to 70–85 psi depending on your weight and let the tyre do its job.
MISTAKEAssuming that 23mm or 25mm tyres are faster because they feel faster.
FIXNarrow tyres at high pressure transmit more road vibration, which the brain interprets as speed. The data shows wider tyres at correct pressure are equal or faster on real roads. Trust the stopwatch, not the sensation.
MISTAKEIgnoring frame clearance and fitting tyres that rub under load.
FIXTyre dimensions vary by brand — a labelled 28mm tyre can measure anywhere from 26 to 30mm on your rim. Check actual clearance with the wheel installed, especially after a few rides when the tyre has stretched to its true width.
FAQ
FREQUENTLY ASKED QUESTIONS
Are 25mm tyres ever the right choice?
Will wider tyres make my bike slower uphill?
Can I fit 28mm tyres on narrow rims?
What width do professional road cyclists use?
Should I go even wider — 30mm or 32mm?
Does tyre width affect puncture resistance?
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