As the dust settles on another electric edition of Paris-Roubaix, one thing is clear – road tyres will keep getting wider for the foreseeable future, on and off pro bikes.
The Tour de France may be the sport’s so-called ‘shop window’, but Paris-Roubaix is often where we see the vanguard of road bike tech emerging.
After all, while marginal gains can make a difference in all disciplines of cycling, equipment choices for the cobbled classics can make or break a rider’s chances.
And while aspiring road cyclists might dream of sunny days in the Alps and the heavenly smooth tarmac of the Grand Tours, the reality facing everyday riders often has far more in common with the broken roads of Belgium and northern France.
Given that, when it comes to shopping for new road bike tyres, most of us should stop looking to the Tour for inspiration and turn our attention to the classics instead.
Wider really is faster, most of the time
Old habits die hard, and many cyclists still believe that going for wider tyres will slow you down.
As tyres get wider at Paris-Roubaix, though, it seems the riders go faster. This year’s race, for example, was – at an average speed of 46.921kph over 259.2km – the second fastest edition ever (behind last year’s race).
This year’s winner, Mathieu van der Poel (who shook off a bottle to the face on his way to a third consecutive victory at L’Enfer Du Nord) used 32mm-wide tyres as he did last year. The only change was a move from Vittoria Corsa Pro TLRs to Pirelli P Zero Race TLR RS tyres, because his team swapped sponsors over the winter.
Behind him, the reigning Giro, Tour and road world champion, Tadej Pogačar, was using 32mm tyres on his Colnago V4Rs (and has been using tyres measuring more than 30mm wide for ‘normal’ road races since at least the 2023 Tour de France).
Among the mortals – those who knew they couldn’t simply rely on superlative talent and skill to be in with a chance of glory – riders were pushing the limits of tyre clearance ever more.
Taco van der Hoorn (who finished 20th), for example, squeezed a set of 35mm-wide Hutchinson Blackbird Racing Lab tyres into his Cube Litening Aero C:68X – a bike that nominally has clearance for up to 28mm tyres, according to Cube.
Although it’s unfashionable to admit it, there’s nuance to subjects such as this, of course. Wider tyres aren’t faster in every situation imaginable.
However, on rough roads and where weight isn’t a limiting factor to performance, wider tyres typically deliver better grip and fewer vibrational losses – all of which means you can ride faster and in greater comfort, for less effort.
And if elite athletes at the peak of their powers are racing on 32 to 35mm tyres for these conditions, then it follows that most of us should be using similarly wide, if not wider, tyres for our everyday riding.
Why didn’t Pogačar and van der Poel go even wider?
Given van der Poel finished almost five minutes ahead of van der Hoorn, it could be tempting to conclude his 32mm tyres represent the sweet spot for speed, weight, comfort, grip and so on.
Correlation doesn’t equal causation, though. Just as the strongest rider in the race doesn’t always win, neither does the rider with the best bike setup (despite what brands would have us believe).
Although each of his three victories have come on 32mm tyres, it’s possible van der Poel would still have won on narrower tyres, or perhaps he’d have had even greater margins of victory had he been using wider ones.
Things might also have played out differently if Pogačar had opted for his Colnago Y1Rs aero bike instead of the all-rounder V4Rs.
Likewise, was Mads Pedersen’s unfortunate puncture (on the same Pirelli P Zero Race TLR RS tyres as van der Poel), as Pogačar attacked with 71km to go, bad luck, or was it the result of poor line choice from being on his physical limit?
Ultimately, we can’t know the answers to these counterfactuals – bike racing isn’t a paint-by-numbers affair and there are a huge number of elements at play in any given scenario (which is part of what makes it a unique sport).
What we do know, however, is that 32mm tyres max out the official clearance on both van der Poel’s Canyon Aeroad CFR and Pogačar’s V4Rs, and neither Vittoria nor Continental (who respectively sponsor their teams) offer their all-rounder race tyres in larger sizes.
Of course, both riders may have been able to squeeze larger tyres in if they’d really wanted to, and maybe Continental or Vittoria could have whipped up some chunkier prototype tyres as Hutchinson did for van der Hoorn.
But both would understandably have had lower appetites for risking anything getting jammed in their forks or chainstays given their status as favourites for the win.
It seems likely, though, that if the next generation of road racing bikes has much wider tyre clearances – something WorldTour teams such as Lidl-Trek are known to be asking for – then these options will be explored.
What’s wide enough?
Of course, if wider tyres are indeed faster than narrow ones, it begs the question – what’s the limit?
Are 38 or 40mm-wide road bike tyres even faster than 32-35mm ones? As often with these types of questions, the answer is ‘it depends’. Factors such as rider weight, road conditions, course profiles and so on come into play when determining the best setup for any rider and scenario.
Part of the reason this debate has rumbled on for so long, though, is that it’s often impossible to compare apples to apples.
Wider tyres have been and are, to a large extent, pitched at more endurance-focused riding.
Endurance road bikes have typically featured larger tyre clearances than racing bikes, so tyre manufacturers have tended to only make ‘endurance’ or ‘all-season’ models in bigger sizes to match.
Continental’s GP5000 TT TR time trial tyre is only available in 25 or 28mm-wide options (to match the clearances of typical time trial bikes), with its all-rounder GP5000 S TR extending up to 32mm to suit the current crop of road racing bikes.
To go wider, you need to switch to the tougher GP5000 AS TR, which adds a 35mm option (as run by British rider Fred Wright), and for anything larger, you’re looking at gravel tyres.
Given how much difference tyre casings, compounds and so on make to rolling resistance, and therefore speed, it’s fair to say the wider tyres are often slower than the narrow ones – but it isn’t simply because they’re bigger and heavier.
Even Pirelli’s recently launched 40mm-wide P Zero Race TLR appears to use a heavier, more robust construction than the narrower versions (which makes its slightly slower, according to bicyclerollingresistance.com), perhaps because Pirelli believes riders won’t treat it as carefully as they would a narrow road tyre.
If we could get 40mm-wide racing tyres with an identical construction to the narrower versions, it would make for much fairer comparisons.
It’s understandable tyre brands act in this fashion, of course. After all, it doesn’t make financial sense to make race tyres for bikes that aren’t being raced, or if racers don’t have bikes that will fit them.
It’s also fair to say things are changing – back when Continental launched its legendary GP4000S II in 2013, it was available in sizes from 20 to 28mm.
What comes first?
It’s a classic chicken-and-egg scenario – do race bikes with large tyre clearances come first or do big race tyres? We’ve seen a similar scenario play out in rapid fashion in the world of gravel racing.
Less than a decade ago, many questioned whether ‘gravel bike’ was just a new name for ‘cyclocross bike’ and practically everyone thought 40mm of tyre clearance was plenty. Nowadays, some racers (such as Dylan Johnson) are using 2.2in cross-country mountain bike tyres and pushing bike brands to offer room for more.
Of course, tyres are only one part of the equation. Simply going up a tyre size or two can improve performance in a number of areas for many riders (assuming your bike can accommodate it), but there’s more to an optimal setup, including rim width and bike design.
As Zipp realised when designing its iconic 303 wheelset – the first carbon wheelset to be ridden to a win at Paris-Roubaix – it's important wider tyres are matched to wide rims to maximise their potential.
Taco van der Hoorn was able to just about fit a set of 35mm tyres in his Cube, but we wouldn’t recommend everyday riders do the same – one errant stone or piece of glass picked up by the tyre tread could ruin your frame.
Likewise, Lidl-Trek says it has “tested 35s for Roubaix but didn’t see any huge advantages”, but that’s presumably with its current bikes and wheels. If it had aero wheels and a bike optimised for 35mm-wide tyres, perhaps the balance would tip in their favour. We’ll have to wait and see.
But just as the pros moved from 25 to 28mm tyres at Paris-Roubaix in the early 2010s, and the rest of us followed, today’s trend towards 32 to 35mm and beyond should prompt a similar move from everyday riders.
