Tyre pressure

Karol

Hi Guys,

I have bought recently a new road bike with already inflated tires.

I've just wanted to check whether I have a correct pressure. I am using stationary Beto pump with pressure gauge.

When I start inflating around 5 bars (70 psi) there is a big resistance on the pump. Should I continue to pump it further into 7 bars (100 psi)? I don't want to damage tube or tire.

Both the pump and tires are new.

scottishgeek

Someone sent me this (below) some time ago as a guide for tyre pressures.

Rear
Tyre Width=20: = (0.33 * Rider Weight in lbs) + 63.33
Tyre Width=23: = (0.33 * Rider Weight in lbs) + 53.33
Tyre Width=25: = (0.33 * Rider Weight in lbs) + 43.33
Tyre Width=28: = (0.33 * Rider Weight in lbs) + 33.33
Tyre Width=32: = (0.17 * Rider Weight in lbs) + 41.67

Front pressure 0.9 x rear pressure.

All in PSI. Divide the figure by 14.5 to get the pressure in bar.

rjkflyer

This tends to be a favoured article:

http://www.bikequarterly.com/images/TireDrop.pdf

kajjal

Check side of tyre for recommended pressure range. Wider tyres need more air in them but at a lower pressure. My MTB tyres are over 50psi less than my road bike tyres. As a rough guide too low pressure means poor control and more punctures as the tyres move on the rim. Too high means a boneshaker ride and again more punctures.

imposter2.0

Seeing as I appear to be the first one to actually read the thread properly before answering...

You will always get resistance at the pump handle when inflating a road tyre, the higher the pressure the more resistance. It's not unusual, so just keep pumping until you hit your desired PSI.

scottishgeek

Imposter wrote:

Seeing as I appear to be the first one to actually read the thread properly before answering...

You will always get resistance at the pump handle when inflating a road tyre, the higher the pressure the more resistance. It's not unusual, so just keep pumping until you hit your desired PSI.

The OP was querying whether to go to 7 bar. I, and others, were pointing out that 7 bar may of may not be required and, as another poster stated, would depend on what was on the tyre sideway. All relevant as we do not know the OP's strength and how much resistance they are feeling.

fenix

I'm with oxoman - you've probably not got the pump on properly.

Have you unscrewed the knurled bit properly ? I usually unscrew, let a tad of air out and then pump to the desired PSI.

Without knowing your weight or tyre its impossible to advise of the specific pressure to put in.

itboffin

As stated already expect more resistance as the pressure increases, check the tyre sidewall for min max inflation pressure or the manufacturers website, as a general rule of thumb I go max psi if heavy rider plus load and work down from there.

Only today I checked my London commuter to find 60 from at back, should be 90 and felt a hell of a lot better once back up to full pressure.

MishCliff

ScottishGeek wrote:

Someone sent me this (below) some time ago as a guide for tyre pressures.

Rear
Tyre Width=20: = (0.33 * Rider Weight in lbs) + 63.33
Tyre Width=23: = (0.33 * Rider Weight in lbs) + 53.33
Tyre Width=25: = (0.33 * Rider Weight in lbs) + 43.33
Tyre Width=28: = (0.33 * Rider Weight in lbs) + 33.33
Tyre Width=32: = (0.17 * Rider Weight in lbs) + 41.67

Front pressure 0.9 x rear pressure.

All in PSI. Divide the figure by 14.5 to get the pressure in bar.

Like it.. never knew about this but correlates bang on with what i run

drlodge

MishCliff wrote:

ScottishGeek wrote:

Someone sent me this (below) some time ago as a guide for tyre pressures.

Rear
Tyre Width=20: = (0.33 * Rider Weight in lbs) + 63.33
Tyre Width=23: = (0.33 * Rider Weight in lbs) + 53.33
Tyre Width=25: = (0.33 * Rider Weight in lbs) + 43.33
Tyre Width=28: = (0.33 * Rider Weight in lbs) + 33.33
Tyre Width=32: = (0.17 * Rider Weight in lbs) + 41.67

Front pressure 0.9 x rear pressure.

All in PSI. Divide the figure by 14.5 to get the pressure in bar.

Like it.. never knew about this but correlates bang on with what i run

This gives me 110/100 for 23c tyres which is what I run with clinchers. For tubeless I run a bit lower 105/95.

simon_e

ScottishGeek wrote:

Someone sent me this (below) some time ago as a guide for tyre pressures.

Rear
Tyre Width=20: = (0.33 * Rider Weight in lbs) + 63.33
Tyre Width=23: = (0.33 * Rider Weight in lbs) + 53.33
Tyre Width=25: = (0.33 * Rider Weight in lbs) + 43.33
Tyre Width=28: = (0.33 * Rider Weight in lbs) + 33.33
Tyre Width=32: = (0.17 * Rider Weight in lbs) + 41.67

Front pressure 0.9 x rear pressure.

All in PSI. Divide the figure by 14.5 to get the pressure in bar.

A touch high for me for normal road riding (not racing) on 25c tyres.

This Michelin pressure chart is a simple visual guide. Try 10 psi steps either side of the recommended starting point.

Mantas

good tire pressure gives you +100 respect points to your bike.

imposter2.0

Mantas wrote:

good tire pressure gives you +100 respect points to your bike.

I'm not even sure what that means?

sungod

Imposter wrote:

I'm not even sure what that means?

yoda says driving up their post count they are

sheffsimon

Simon E wrote:

ScottishGeek wrote:

Someone sent me this (below) some time ago as a guide for tyre pressures.

Rear
Tyre Width=20: = (0.33 * Rider Weight in lbs) + 63.33
Tyre Width=23: = (0.33 * Rider Weight in lbs) + 53.33
Tyre Width=25: = (0.33 * Rider Weight in lbs) + 43.33
Tyre Width=28: = (0.33 * Rider Weight in lbs) + 33.33
Tyre Width=32: = (0.17 * Rider Weight in lbs) + 41.67

Front pressure 0.9 x rear pressure.

All in PSI. Divide the figure by 14.5 to get the pressure in bar.

A touch high for me for normal road riding (not racing) on 25c tyres.

This Michelin pressure chart is a simple visual guide. Try 10 psi steps either side of the recommended starting point.

What's the accuracy and repeatability of your track pump gauge?

Taeo1

Guess I've been running under inflated tyres for the past few years!