Tyre pressure

[Mattk50]

Hi,

The side of my hybrid bike tyres state 55-100 PSI. What should I pump them up to for road cycling? I'm 77 kg. Why is there such a range? The tyres are narrow, is that something to do with it?


Thanks

Matt

 

[vickster]

Go somewhere in the middle and see how it feels. If too soft, a bit more, too hard and jarring a little less (too low you risk pinch punctures esp on rubbish rough roads)

 

[Mattk50]

Thanks

 

[bpsmith]

I am about 73kg and used to use 100psi.

Very recently dropped to about 80-85psi and it’s both more comfortable and a touch quicker too.

I would try about 90psi as a starter point

 

[mjr]

The best guess is BQTireDrop.pdf if you can find it. It varies by tyre width, your weight and riding position.

 

[SkipdiverJohn]

Google "Frank Berto tyre pressure chart" and you'll get pressures for most common sizes, and if yours is in-between you can guesstimate by going between the next smaller and larger widths.
There is a big difference between front & rear tyre loads, especially on bikes with flat bars where the rider sits upright, and more weight is carried on the back wheel.
My rule of thumb (my bikes are all flat bar) is I find the correct pressure for my back tyre, then run the front one at about 75-80% of the rear pressure.

 

[mikeymustard]

Depends also on the width of your tyres - the wider they are the lower the pressure you can run. You don't want them so low that they '"squirm", OTOH you don't want them so hard that you feel like they're made of wood!
As @vickster said, somewhere in the middle's a good start

 

[Mattk50]

Rather strangely I couldn't get them above 65 with my car pump. I wondered if the adapter 'widget' I used on the tyre valve to allow me to use the car pump 'leaked' a bit? But even still, they are a lot harder than I can get with the pump

 

[vickster]

Rather strangely I couldn't get them above 65 with my car pump. I wondered if the adapter 'widget' I used on the tyre valve to allow me to use the car pump 'leaked' a bit? But even still, they are a lot harder than I can get with the pump

Get a proper bicycle track pump. You’ll certainly need one when you buy a roadbike. Good ones cost about £25 online

 

[Elysian_Roads]

Rather strangely I couldn't get them above 65 with my car pump. I wondered if the adapter 'widget' I used on the tyre valve to allow me to use the car pump 'leaked' a bit? But even still, they are a lot harder than I can get with the pump

+1 for the bicycle track pump. Really pleased I got one, as quick and easy to use.

 

[DCBassman]

Get a proper bicycle track pump. You’ll certainly need one when you buy a roadbike. Good ones cost about £25 online

Indeed, even the cheapo tenner from Tescos one that I got exceeded my expectations!

 

[Randy Butternubs]

Why is there such a range?

The markings on the side of the tyre give what the manufacturer (conservatively) considers the safe range of pressures. I don't think it's meant to be a recommendation for comfort, speed, or whatever.

If the tyre pressure is too low you risk pinch flats. If it is really low the tyre could roll off the rim during cornering. If it is too high the tension in the tyre carcass could cause failure and a blowout.

Also, the tyre pressure you want depends largely on weight and people's weight varies massively.