What\’s the correct road bike tyre pressure?

Many factors dictate the ideal tyre pressure for you: weight, weather and tyre width – we explain
how to find the right PSI.

It wasn\’t long ago that the
only pressure you were supposed to inflate your tyres to was the maximum
recommended: typically 120 psi or more. You were given this advice by any
experienced cyclist. This was often accompanied by dire warnings of catastrophic
pinch flats if you ran anything lower. Of course, that old \’fact\’ that the
higher the tyre pressure, the faster the bike.

This belief also coincided with a
time when 23mm was as wide as most \’proper\’ cyclists would go, and a 25mm was
seen as a boat anchor more suited to commuting or touring use.

Now, 25mm is seen as \’narrow\’ and
the reserve of race bikes – with 28, 30 and even 32mm tyres now being standard on endurance road bikes. So with this in mind, do we need to update
our thinking regarding tyre pressure? Is maximum still the way to go?

Why is correct tyre pressure
significant?

It\’s probably more appropriate
to talk about \’ideal\’ tyre pressures rather than \’correct\’, as tyre
pressure is a moveable feast – a single tyre pressure is not a fix-all for
every rider.

>>> The
best road bike tyres

Tommaso Cappella, Vittoria\’s
Service and Quality Manager and self-professed tyre pressure enthusiast,
explains why pressure is so significant, \”the ideal pressure allows the tyre to
sag properly, optimising the ground contact area therefore impacting
manoeuvrability and performance.\”

Finding the ideal pressure is
also about balancing, reducing rolling resistance, and increasing
comfort.

Laboratory research using a
smooth surface has proven that higher pressures result in a lower rolling resistance coefficient (car). However, real-world road conditions are as far
removed from the laboratory as to actually result in a cutoff point where
higher pressures impede rolling resistance, due in part to an increase
in energy loss as bike and rider are bounced around and break contact with the
road surface. Lower tyre pressure allows the tyre to deform and roll more
smoothly over broken roads.

What are the factors that impact your
ideal tyre pressure?

According to Cappella, \”the
fundamental factor is the actual width of the tyre, let\’s see at it as an air
chamber – its size depends on the rim width and the tyre itself. As a simple
rule of thumb, the wider the tyre the lower the ideal pressure.\”

Your choice of the tyre is also
significant, namely its specific construction.

A cotton casing deforms and
behaves differently compared to nylon; the TPI (Threads Per Inch) also makes a
difference. A higher TPI implies the more delicate the yarn, making the tyre feel
smoother and roll faster.

Rider weight, normal riding
position, riding style and road/atmospheric conditions must also be considered when calculating tyre pressure. A 100kg cyclist taking their
bike to the smooth roads of Mallorca will want a higher tyre pressure than a
60kg rider covering the rutted, potholed lanes of the UK. 

So, where do I start?

Despite it sounding like an
incredibly complicated formula with too many variables and pitfalls, it can be
pretty easy to achieve a starting point from which to determine your ideal
pressure.

Many tyre and
wheel manufacturers are beginning to introduce pressure guides or easy-to-use online calculators to help you get started.

Zipp (SRAM) has a very detailed calculator that lets you plug in a range of data to get your starting points. Vittoria likewise- although it is working on a new app with additional detail.

Tommaso has some simple advice to
get started on your ideal tyre journey, \”if you used to ride 116-130 psi
(8-9bar) on a 23mm tyre you might want to drop pressure in a 25mm tyre by 1bar
(14 psi), dropping another bar for 28mm and going down to around 72psi (5bar)
for a 30mm tyre.\”

Tubeless?

One of the oft-touted advantages
of going tubeless is the ability to run at lower pressure.

Indeed this can be the case –
just look at the low 72psi limit Zipp has imposed on its latest 303 tubeless
wheels for all tyre sizes. Add to the fact that a tubeless system offers a
lower Crr when run at the same pressure as a tubed tyre, thanks to eliminating the friction between tyre and tube.

However, the pressure differences
might not be as marked as you think. Zipp recommends just 1.5 psi lower
for a tubeless setup over inner tubes with a hooked tubeless rim. This changes when using a hookless tubeless rim when pressures can be reduced by
nearly 6psi.

Tyre pressure calculators, such
as those provided by Zipp and Vittoria, are an excellent place to start. After that,
it\’s all about experimentation and tweaking, \”I would suggest every rider
spends some time experimenting with tyre pressures to find out the ideal,\” said
Capella. 

Recommended tyre pressures

Helpfully, some tyre
manufacturers offer pressure recommendations or pressure calculators for their road bike tyres range; we can take these as general starting points for
dry days on smooth tarmac.

As we come on, you should
pay close attention to the actual size of your tyres when inflated because this
can change optimum pressure for any given rim and tyre combination.

If the inflated tyre width
is larger than the labelled width, the tyre will need slightly less pressure
than recommended by these tables and vice versa.

Likewise, the optimum tyre
pressure will be higher for heavier riders or riders carrying loads on
their bikes and lower for lighter riders.

As a final caveat, it\’s essential
to adhere to the pressure limitations set by the manufacturers of your
rims and tyres, particularly regarding the upper limits. These are
typically printed on the tyre or rim sidewalls.

If you have a set of wheels
with hookless rims, the maximum permitted tyre pressure may also be much
lower than with hooked edges.

Tyre pressure for 23mm and 25mm
tyres

The following recommendations are
from Pirelli for its TLR tubeless road tyres, but are good starting points
regardless of the brand of tyres you’re using, providing you take the various
factors we’ll run through later into account when going on to fine-tune
pressure.

700x23c tyre on a 17mm rim	700x25c tyre on a 19mm rim
Rider weight	Recommended pressure	Rider weight	Recommended pressure
≤ 50kg / ≤ 110lb	84psi / 5.8bar	≤ 50kg / ≤ 110lb	73psi / 5bar
51-57kg / 112-126lb	90psi / 6.2bar	51-57kg / 112-126lb	78psi / 5.4bar
58-65kg / 128-143lb	96psi / 6.6bar	58-65kg / 128-143lb	83psi / 5.7bar
66-73kg / 145-161lb	102psi / 7bar	66-73kg / 145-161lb	88psi / 6.1bar
74-81kg / 163-179lb	106psi / 7.3bar	74-81kg / 163-179lb	93psi / 6.4bar
82-88kg / 181-194lb	110psi / 7.6bar	82-88kg / 181-194lb	98psi / 6.8bar
≥ 89kg / ≤ 196lb	115psi / 7.9bar	≥ 89kg / ≤ 196lb	103psi / 7.1bar
≥ 96kg / ≤ 212lb	Use 700x25c tyre	≥ 96kg / ≤ 212lb	108psi / 7.4bar
On a 19mm rim: lower pressure by 0.4bar / 6psi	On a 21mm rim: lower pressure by 0.3bar / 5psi

Tyre pressure for 28mm and 30mm
tyres

700x28c tyre on a 19mm rim	700x30c tyre on a 19mm rim
Rider weight	Recommended Pressure	Rider weight	Recommended Pressure
≤ 50kg / ≤ 110lb	65 pis / 4.5bar	≤ 50kg / ≤ 110lb	58psi / 4bar
51-57kg / 112-126lb	70psi / 4.8bar	51-57kg / 112-126lb	61psi / 4.2bar
58-65kg / 128-143lb	75psi / 5.2bar	58-65kg / 128-143lb	65psi / 4.5bar
66-73kg / 145-161lb	80psi / 5.5bar	66-73kg / 145-161lb	70psi / 4.8bar
74-81kg / 163-179lb	85psi / 5.9bar	74-81kg / 163-179lb	74psi / 5.1bar
82-88kg / 181-194lb	90psi / 6.2bar	82-88kg / 181-194lb	78psi / 5.4bar
≥ 89kg / ≤ 196lb	95psi / 6.6bar	≥ 89kg / ≤ 196lb	83psi / 5.7bar
≥ 96kg / ≤ 212lb	100psi / 6.9bar	≥ 96kg / ≤ 212lb	87psi / 6bar
On a 21mm rim: lower pressure by 0.3bar / 5psi	On a 21mm rim: lower pressure by 0.3bar / 5psi – On a 23mm rim: lower pressure by 0.4bar / 6psi

Advice from other brands may
vary, but Pirelli recommends riders who weigh over 96kg / 212lb should use
700x25c tyres or more significant because the recommended tyre pressure for a rider of
this mass would exceed the maximum permitted pressure for a 700x23c tyre. 

As always, it\’s vital not to
exceed the maximum pressures indicated on your tyres or rims.

We\’ve got a
separate guide to mountain bike tyre pressure if you ride off-road.

Factors that influence optimal
tyre pressure

As already noted, the above
recommendations are intended as general starting points. They\’ll get you in the
right ballpark, but several factors beyond tyre and rim size and
rider weight affect your personal optimum road bike tyre pressure.

Size matters

Accurately determining your tyre
size is crucial to calculating optimum pressure.

Despite most bicycle tyres being
labelled with a specific size, such as 700x25c, the actual inflated size of any
given tyre will depend on both the tyre\’s design and the wheel\’s internal rim width.

Russell Burton / Immediate Media

Most new road tyres are designed
around a 19mm internal rim width. A wheel with wider inner rim width, as
pictured here, will likely increase the measured width of a tyre when inflated. Russell
Burton / Immediate Media

Most new tyres are now designed
around the latest 2020 ETRTO (European Tyre and Rim Technical Organisation) standards
with a 19mm internal width, so wheels with an inner rim width wider than
this will likely increase the measured width of a tyre when inflated to a given
pressure (and vice versa).

The optimum pressure is,
therefore, likely to be lower than if you were running the exact tyre on a
narrower rim.

System weight and weight
distribution

Russell Burton / Immediate Media

Riding a lightweight, go-fast
road bike? Your tyre pressure will need to be lower than a heavily laden
touring bike, assuming all other variables are the same. Russell Burton /
Immediate Media 

While the rider makes up the vast
majority of the total system weight – and, as we\’ve already covered, a heavier
rider will generally need to run higher pressures than a lighter rider – the
weight of your bike and any kit you\’re carrying also count.

If you\’re riding a sub-4kg
weight weenie optimised road bike and don\’t have it loaded with heavy
gear, you might need to lower your tyre pressure by a few psi.

The opposite is also true. If
you\’re riding a heavy touring bike or a road bike loaded with bike-packing
bags, you may need to add more air to your tyres.

With road bikes, the rider\’s
weight is generally not evenly distributed across both wheels. The exact split
will be different for every rider, depending on riding position and
bike, but it\’s usually the case that the rear wheel takes slightly more of the
load than the front.

As a rule of thumb, it\’s worth
putting a few psi less in the front tyre than in the rear.

Road conditions

The condition of the roads you
ride will impact the ideal pressure of your tyres. Russell
Burton / Immediate Media

Higher pressures are faster if you\’re riding on a perfectly
smooth velodrome. However, on imperfect
surfaces, like roads, very high pressures simply increase vibrations and can
slow you down.

As roads get rougher, with bigger
holes and bumps, the optimum tyre pressure decreases further.

When roads get very rough,
smaller tyres (anything 25mm or smaller) running at relatively low pressure
may not be able to provide enough protection for the rim or inner tube –
especially for heavier riders – which can lead to pinch flats or even rim
damage.

If you ride on rough roads or
roads with a generous coating of gravel, dropping your tyre pressure can help
improve comfort and reduce the likelihood of pinch flats. Russell Burton /
Immediate Media

Switching to larger tyres will
give you more tyre volume to play with, so you can fine-tune the
pressure to account for both rolling resistance and comfort on rough roads.

The pros switch to
28mm+ tyres for cobbled races such as the Tour of Flanders and Paris-Roubaix. 

Weather and temperature

Russell Burton / Immediate Media

Dropping your tyre pressure a
little in wet conditions might give you more grip. Russell Burton /
Immediate Media

When road surfaces are wet, or if
it looks like it might rain during your ride, it\’s worth dropping tyre pressure
by around 5psi on both tyres. This helps increase the amount of rubber in
contact with the road, improving grip.

Higher temperatures, whether
ambient or induced by rim braking, can also increase tyre pressure.

If you\’re riding long descents on
hot summer days on a bike with rim brakes (particularly one with carbon
clincher wheels or latex inner tubes), be careful to not over-inflate your
bike\’s tyres. Doing so could lead to dangerously high pressures building up
inside the inner tubes or tubeless tyres if too much excess heat is introduced
to the system.

Tyre construction

Russell Burton / Immediate Media

The materials and construction of
a tyre can also affect the optimum pressure. Russell Burton / Immediate
Media

The materials and construction
methods a road bike tyre manufacturer uses can also affect the optimum
pressure to a small degree.

Road bike tyres designed for
racing or summer use tend to have casings that use a higher number of thinner
nylon or cotton threads (this is what the Threads Per Inch or TPI number of a
tyre refer to), and only a thin layer of rubber tread on top. This makes them
easier to deform under pressure, making for a smoother and faster ride.

Conversely, winter road bike
tyres typically have stiffer, more durable casings with fewer, thicker
nylon threads. The rubber tread on top also tends to be wider for improved
mileage and puncture protection.

Given this, you may need to drop
your road bike tyre pressure slightly when moving across to winter tyres
because the optimum pressure for comfort and grip will likely be a few psi
lower.

Tubeless

Russell Burton / Immediate Media

Running tubeless tyres removes
the risk of pinch flats. Russell Burton / Immediate Media

If you\’re using tubeless
tyres, it\’s worth remembering that the absence of an inner tube means you can
safely run lower pressures without the risk of pinch flatting the line.

Because lower tyre pressures can
improve off-road grip, running tubeless tyres can be particularly useful if
you\’re riding a road bike with relatively large tyres and looking to take in
some light off-road or gravel riding.

Fine-tuning road bike tyre
pressure

No one likes to be stuck at the
side of the road fixing a puncture. Russell Burton / Immediate Media

So, you have all the information
at your fingertips, but how do you actually go about fine-tuning tyre pressure?
The simple answer is experimentation.

Start with the recommendations
above and then consider the road conditions where you ride. Do
you have miles and miles of freshly laid tarmac? If so, the above
suggestions are probably close to optimal.

If you don\’t – perhaps because
you live somewhere like the UK – start with the above recommendations and
experiment with taking a little pressure out of the tyres each time you ride.

Start with small steps in
pressure of around 5psi, and if you pay attention, you should eventually be
able to determine a sweet spot for speed and comfort.

You\’re looking for smooth pressure without feeling like the tyre is collapsing underneath you
when cornering. And, as already mentioned, erring on the side of too low rather
than too high is a good thing to keep in mind.

Field testing

Simon Bromley / Immediate Media

If you\’re serious, you
could conduct basic field testing with a power meter to try and find your
optimal pressure. Simon Bromley / Immediate Media

Alternatively, if you have an
accurate and reliable power meter, you could do some preliminary field tests.