Why 32 is the new 28: A comprehensive test of 32-millimetre road tyres

Road bike tyres are getting wider and wider. Whilst 23 millimetres was still the norm in racing ten years ago, tyres 25 or 26 millimetres wide are now commonplace, with some professionals even using 28-millimetre tyres on good roads. For races on rough terrain – with the bumpy classic Paris–Roubaix representing the ultimate challenge – riders now fit tyres up to 32 millimetres wide onto their aero rims.

This may seem absurd to long-time road cyclists, many of whom remember a time when road bike tyres could never be narrow enough – as thin as 19 millimetres. But today we simply know better, because we can measure the differences precisely.

Apart from sections of cobblestones that are genuinely rough, today’s professional cyclists are likely to remain largely indifferent to the improved comfort. What matters more is that wider tyres roll more quickly than hard-pumped, narrow road bike tyres, particularly on uneven surfaces – though not exclusively there.

These chunky tyres also offer advantages when it comes to puncture protection: greater volume means better protection against punctures and, consequently, a lower risk of breaking down. With the correct tyre pressure – significantly lower than for narrower road bike tyres – a wider tyre also gives the road bike, which is actually rather stiff, a reasonably comfortable ride. On bumpy roads, the road bike bounces less and is easier to control; on top of that, it offers better grip in bends, especially on wet roads.

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So there are plenty of reasons for amateur cyclists to opt for wider tyres too. For them, the improved comfort is likely to be the biggest ‘aha’ moment. Compared with 28-millimetre tyres, there is, after all, up to four millimetres more suspension travel – on a road bike, that makes a world of difference. Even detours onto country lanes and forest tracks are no longer a problem; touring and travel cyclists benefit from the extended range of their road bike whilst still maintaining a brisk pace. On the downside, there is a slightly higher weight and a (minor) aerodynamic disadvantage due to the larger frontal area: this amounts to just one watt at a racing speed of 45 km/h – as measured by TOUR in the wind tunnel. These are drawbacks that seem marginal in light of the benefits.

A colourful selection of road bike tyres

Our in-depth TOUR comparison test shows how the differences compared to narrower road bike tyres affect performance and which models we recommend. The test line-up offers a diverse cross-section of the current market: Eight clincher and seven tubeless tyres go head-to-head – including both top-of-the-range models and budget tyres, market leaders and own-brand tyres from major bike manufacturers (Cadex by Giant and Bontrager by Trek), as well as some interesting outsiders (René Herse). The test line-up is so varied because not every manufacturer (yet) has such wide road tyres in their range; moreover, many are still struggling with supply issues, meaning we were unable to test all the models that are theoretically available.

An overview of the clincher/folding tyres tested

• Continental Grand Prix 5000
• Continental Ultra Sport
• Pirelli P7 Sport
• René Herse Stampede Pass Extralight
• Schwalbe Pro One
• Schwalbe One
• Vittoria Corsa
• Vittoria Zaffiro

An overview of the tubeless road bike tyres tested

• Bontrager R3 Hard-Case Lite TLR
• Cadex Classics 32
• Challenge Strada Bianca Pro TLR
• Continental Grand Prix 5000 S TR
• Pirelli Cinturato Velo
• Schwalbe Pro One TLE
• Schwalbe One TLE

Our Test track first sends all candidates through the weighbridge. One thing is clear: a wider tyre requires more Rubber, and that means more Weight. Compared to a 28-millimetre tyre – the previous standard for marathon bikes – the difference is negligible. On average, it amounts to around 50 grammes per tyre, and slightly less for the tubeless models. The lightest road bike tyre in the test, from René Herse – the brand owned by the American Jan Heine – weighs in at just 246 grams, making it barely heavier than many 25-millimetre road tyres. The top-of-the-range models from Continental and Vittoria are also quite light. Bringing up the rear in this category are – unsurprisingly – the budget clincher tyres from Continental and Vittoria, weighing more than 400 grams each. Conti supplies the lightest tubeless tyre, though the differences aren’t that great among the more expensive tyres.

The clincher/folding road bike tyres we tested, in detail

Continental

• Model: Grand Prix 5000
• Price: 71 euros >> available here
• Weight/Width x Height: 272 grams / 32 x 28 mm

Driving impressions: A gentle, controllable wobble at maximum lean angle; very stable and confidence-inspiring up to that point

Conclusion: Top marks across the board. The sidewall could be sturdier

Continental

• Model: Ultra Sport
• Price: 23 euros >> available here
• Weight/Width x Height: 408 grams / 33 x 29 mm

Driving impressions: A bit harder and more erratic than the top version, but still fairly predictable

Conclusion: A very heavy tyre, but technically sound, with some weaknesses in puncture resistance. Excellent value for money

Pirelli

• Model: P7 Sport
• Price: 30 euros >> available here
• Weight/Width x Height: 331 grams / 30.1 x 28 mm

Driving impressions: Feels comfortable, but the steering response is a bit twitchy. Stable and very predictable when cornering

Conclusion: An affordable training tyre with good grip in wet conditions; not too heavy, but not fast

René Herse

• Model: Stampede Pass Extralight
• Price: 84 euros
• Weight/Width x Height: 246 grams / 31.5 x 31 mm

Driving impressions: Not much grip, but the limit becomes apparent well in advance. When leaning into a bend, more significant corrections are required

Conclusion: Very light and fast. Little puncture protection, particularly on the sidewall. The most expensive tyre in the test

Swallow

• Model: Pro One
• Price: 63 euros >> available here
• Weight/Width x Height: 312 grammes / 31.6 x 27 mm

Driving impressions: Steers smoothly, is easy-going and stable when leaning into corners. Tends to lift the front end slightly at the limit of grip, but remains easy to control

Conclusion: Excellent wet grip; otherwise, solid performance with no weaknesses. It’s wide and flat.

Swallow

• Model: One
• Price: 60 euros
• Weight/Width x Height: 315 grammes / 32.7 x 28 mm

Driving impressions: When leaned over at a steep angle, it’s only slightly more prone to wobble than the Pro One, yet it’s still one of the most grippy and best

Conclusion: Hardly any differences from the top-of-the-range model, including the price. Only slightly less effective in terms of puncture protection

Vittoria

• Model: Corsa
• Price: 66 euros >> available here
• Weight/Width × Height: 290 grams / 29.3 x 31 mm

Driving impressions: Requires some effort when turning in, but then drives as if on rails. Smooth transition to the grip limit

Conclusion: A light and fast tyre with some weaknesses in puncture protection. It has a relatively narrow and tall profile.

Vittoria

• Model: Zaffiro
• Price: 17 euros
• Weight/Width x Height: 459 grams / 33.3 x 29 mm

Driving impressions: Smooth, neutral handling and hardly any body roll. However, it does skid off quite suddenly

Conclusion: The cheapest tyre in the test rolls smoothly and offers good grip, but provides hardly any puncture protection. Very heavy.

The tubeless road bike tyres we tested, in detail

Bontrager

• Model: R3 Hard-Case Lite TLR
• Price: 68 euros
• Weight/Width x Height: 328 grams / 32.6 x 28 mm

Driving impressions: Unstable when turning in, wobbly when leaning, but skids in a well-controlled manner over both wheels

Conclusion: Relatively light, but with weaknesses in puncture protection and rolling resistance

Cadex

• Model: Classics 32
• Price: 80 euros
• Weight/Width x Height: 329 grams / 34.5 x 30 mm

Driving impressions: Very comfortable, sluggish when turning. Slides easily and feels slippery. Very twitchy when leaning into a bend

Conclusion: Good suspension and comparatively light, but with weaknesses in wet conditions. Has a very wide track

Challenge

• Model: Strada Bianca Pro TLR
• Price: 78 euros
• Weight/Width x Height: 334 grams / 32.5 x 27 mm

Driving impressions: A distinctive, very smooth ride; very comfortable. Low grip limit, but predictable

Conclusion: Design with a bonded tread; rides like a tubular tyre. Difficult to fit

Continental

• Model: Grand Prix 5000 S TR
• Price: 80 euros >> available here
• Weight/Width x Height: 318 grams / 33 x 29 mm

Driving impressions: Stable cornering, slight, controllable body roll. Reaches the grip limit late, and only slips with difficulty once it does.

Conclusion: By far the fastest tyre, and top of the range in the other disciplines too.

Pirelli

• Model: Cinturato Velo
• Price: 65 euros >> available here
• Weight/Width × Height: 369 grams / 33 x 29 mm

Driving impressions: A bit sluggish when turning in. Lots of grip; it sways slightly when leaning, but doesn’t feel twitchy

Conclusion: Excellent wet grip, good puncture protection, but only moderately fast

Swallow

• Model: Pro One TLE
• Price: 73 euros >> available here
• Weight/Width x Height: 349 grammes / 32.2 x 29 mm

Driving impressions: Inspires a lot of confidence; smooth when turning in. Slightly more wobbly when leaning than the clincher version

Conclusion: Smooth handling and excellent grip. Difficult to fit, but often seal on the first attempt

Swallow

• Model: One TLE
• Price: 60 euros
• Weight/Width x Height: 385 grams / 34 x 30 mm

Driving impressions: Slightly softer suspension as it is slightly wider; otherwise, it is almost indistinguishable from its more expensive counterpart

Conclusion: Slightly heavier and a touch slower than the Pro One TLE, but with significantly better puncture protection

Here The full test, all individual assessments and tyre ratings are available to download for 2.99 euros

Download “Road bike tyre test: 32 millimetres”

How TOUR tests road bike tyres

TOUR has been setting the standard for road bike tyre testing for many years. The test set-ups are constantly being improved; new to this issue is our own wet grip test on a watered circular track. An overview of the test procedures and evaluation criteria.

Test rides with the road bike tyres

Even before the Bench tests we’ll put all the road bike tyres through a head-to-head test on a standardised test track, with poorly tarmacked sections, cobbled and gravel surfaces, as well as fast, winding descents. Along the way, we document our subjective impressions in terms of comfort, straight-line stability and handling when cornering.

Weight of road bike tyres

The following are listed: the weight we calculatede. Four tyres of each model are weighed, and the average weight is recorded. Tubeless tyres are given a slight advantage of 70 grams in the assessment, which compensates for the difference in the system weight of the two designs (excluding the 120-gram inner tube, but including 70 millilitres of sealant). The 1.0 score for a clincher with an inner tube therefore corresponds to the 1.0 score for a Tubeless tyres with sealant. The weighting accounts for 10 per cent of the overall mark.

Rolling resistance of road bike tyres

The rolling resistance test is a Developed in-house by TOUR. In this test, an oscillator (a mechanical system capable of oscillation) is fitted with two wheels and the test tyres that have already been run in, and weighted down. Part of the weight is mounted eccentrically to the axle, causing the apparatus to roll back and forth like a pendulum after being set in motion. The lower the rolling resistance of the road bike tyres, the longer the machine oscillates. We measure the rolling distance until the machine comes to a standstill and use this to determine the rolling resistance in watts, converted for a system weight of 85 kilograms and a speed of 35 km/h. The measurement is – apart from the fact that the system rolls much more slowly than a road bike whilst riding – very close to reality. Resistance measurements on a roller typically yield values that are too high because the tyre deforms too much. The biggest advantage of the TOUR method is that we can take measurements on a flat surface and on a variety of realistic substrates - In this test, we carry out measurements on smooth concrete and a rough surface modelled on coarse asphalt. Both values are weighted equally and each accounts for 15 per cent of the overall mark.

Puncture protection for road bike tyres

This assessment is based on three laboratory tests: In the so-called Puncture test The inflated tyre is subjected to a vibrating blade that cuts its way into the tread – in the same way as stones or shards of glass picked up by a road bike tyre. The time taken for the blade to penetrate the tyre is measured. We terminate the test after 180 seconds as a ‘pass’; shorter times result in a fail. The second attempt determines the puncture force, which is required to penetrate the tread, including the puncture-protection layer. To do this, the tyre – which is firmly clamped in place and not inflated – is pierced using the sharpened blade of a screwdriver. A third test checks, in a similar manner, the Shear strength of the side wall. This type of puncture was not taken into account in previous tyre tests. However, as wider tyres are also used on rougher surfaces, where such punctures occur more frequently, we have included this criterion in our assessment for the first time. All three tests contribute equally to the score, which accounts for 30 per cent of the overall mark.

Wet grip of road bike tyres

For the Wet grip test In this year’s tyre comparison, we have further developed our original test method. The test set-up was modelled on that used by tyre manufacturer Pirelli, where we were able to trial the method for the first time in 2019 for a road bike tyre test. The Tyre grip in bends We carried out the comparison on a watered concrete circular track; it is located at the airfield in Jesenwang near Munich and forms part of the test site of the former tyre manufacturer Metzeler. The TOUR test rider accelerates round the circuit on an electric bike until the tyres reach their grip limit. The speed is measured and recorded throughout the ride.

The advantage of this method is…that the rider can carefully approach the limit and keep the road bike tyres operating at the limit of grip for an extended period. The differentiation is even more precise than in our previous test setup; furthermore, it enables more accurate conclusions to be drawn about behaviour at the limit. Last but not least, the risk of injury to the test rider is lower. The maximum cornering speed achievable is our measure of wet grip; the handling rating indicates whether a tyre handles predictably and safely when pushed to its limits, or whether it requires a lot of correction when leaning. Both assessments are weighted equally in the wet grip test, which accounts for 30 per cent of the overall mark.