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Bike Tyre Pressure Explained | Road Bike Maintenance

- How hard should your tyres really be

and what is the right pressure?

The first point, if we're starting completely from scratch

is to make sure that you pump up your tyres

to within the minimum and the maximum

recommended pressure that's normally printed

on the side of the tyre there.

Now this one, this Continental,

has a maximum recommended pressure only,

that's 8.5 bar or 120 PSI.

So if you stick close to that,

then you will not go wrong

from a safety perspective, at least.

If you don't have a cycling specific pump

with a pressure gauge on it,

my first suggestion would be to go and buy one

but in the short-term, what 100 PSI feels like,

is actually when you squeeze the side of the tyre,

so not the tread, but the side,

basically you can squeeze as hard as you can

with your thumbs and it will not move very much.

Ambiguous, I know, but you haven't got a pressure gauge,

so what can you do?

Well now we're safe, that is a very good place to start

but it's certainly not the only thing to think about.

We also need to factor in the width of our tyres

and also our body weight as well,

because narrower tyres need higher pressures

than wider ones and heavier riders

need higher pressures than lighter ones

and then just to complicate things further,

we also need to factor in the following points as well.

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Tyres need to grip, that's pretty obvious,

if you want to accelerate or change direction

or indeed slow down, but a tyre that's too hard

won't deform to the road surface

and so less rubber will be in contact

with the road at any one time,

meaning that you have much less grip.

So ideally, you want to run a pressure

that allows the tyre to compress when you sit on the bike.

Now, believe it or not, loads and loads of research

has been done into exactly this topic

and most people, it would seem,

agree with the work of a man called Frank Berto

from back in the 80s and he worked out

that the ideal amount of compression

was 15% of the tire's total height, although admittedly,

that is a remarkably difficult thing to measure.

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Brilliantly, comfortable tyre pressures

can also be faster tyre pressures as well

because for just about all of cycling eternity,

we thought that harder tyres were faster tyres

and with good reason, to be fair,

because in laboratory settings, harder tyres

were measurably much, much faster

so they rolled with much less resistance than softer tyres.

However, out in the real world,

on normal, bumpy roads, a softer tyre

absorbs vibration much better

and that vibration really slows you down, a lot in fact.

So, that is why a softer, more comfortable tyre

can potentially roll faster as well.

(light music)

If it's starting to sound like softer tyres

are the way to go, then hold on,

because a tyre that is too soft will start to roll slower

and then they will also squirm around corners,

which makes it particularly difficult to control

and dare I say, dangerous.

And then also, of course,

a softer tyre will be more susceptible to impact punctures.

(light music)

I'm sure you'll have noticed that

I haven't actually recommended any tyre pressures yet

so perhaps it is time for me

to put my money where my mouth is, okay.

I weigh 73 kilogrammes and when I use a 23C wide tyre,

I put 95 PSI in my front wheel and 100 PSI in the back

because there's a little bit more weight over there.

And for 25's, I use 80 and 85 PSI

and then for 28's, I run 60 and 65 PSI.

As I mentioned earlier, if you are a little bit lighter

you will want to run less, so consider putting in

about one PSI less for every one kilogramme of body weight

and if you're heavier, you want to do the opposite.

And if you're working in bar,

then that's probably about one bar

per 25 kilogrammes of body weight that's different.

Now there are loads of really handy calculators

that are on the internet that will attempt

to do this job for you but if there's one thing

that I think you should take from this video,

it's that you should spend time

thinking about what your own perfect tyre pressure is

because it does vary from rider to rider

and indeed, from place to place.

So think about the things that we've just covered

in this video, does the tyre squirm when it gets too soft?

Or indeed, are you really susceptible to pinch flats?

Or, are you about to go for a ride

on the best, most super smooth tarmac in the entire world?

In which case, you probably want to put a few extra PSI in.

Do not be afraid to play around,

stay within the limits and stay safe.

Oh, and there is also one thing,

it's not just your tyre that will have pressure limits on.

If you've got a really lightweight set of wheels on,

then they too may have a pressure limit

although, if they're anything like these Zipp's here,

we've actually seen them being inflated

to over 200 PSI more than the recommended limit.

(explosion) Whoa.

Well clearly, a little bit

of margin for error built in there.

Now, do make sure you subscribe to GCN,

it's very simple and it's free to do it,

just click on the globe and if you're after

some more content, about tyres in fact,

then why not click up there

and we've got a video about how to reduce the risk

of punctures, or just down there,

we've got a very topical one,

the truth about wide rims and wide tyres.

Check 'em out.