Tire Preasure

[RJD]

Hello, I'm new to CycleChat.
I have 700x45 Bontrager H5 tires and are using a topeak d2 smartgauge to check my pressure. The tire says to inflate to 60 psi/4.1 bar to 80 psi/5.5 bar. I cant inflate the tire to that much pressure. I'm afraid it will blow. tire gets rock hard and 30 psi seems more like it. My tire pump cant even get near to those pressures. Please help, I'm using 30 psi till i figure it out.

Thank you

 

[iluvmybike]

Have you got a decent floor pump - a portable pump won't get you anywhere near. The tire has the pressure on it - it won't blow as you say (unless you haven't fitted it properly). Running too low a pressure makes you more likely to get pinch flats & Pu*****es and may lead to premature wear on tyre wall

 

[Vantage]

Ignore the tyre markings on the sidewall. They're bollicks and only state what the tyre CAN handle.
Depending on your weight, 45's run quite well at around 35 - 45psi without risk of pinch flats.
Best thing to do is crank them up to about 50psi with a track pump and go for a ride. Each ride thereafter you let a little bit of air out of the tyre till you have a nice balance between comfort and speed. Expect the front tyre to be softer than the rear.
Too soft can lead to the tyre dragging and risk of flats and crap handling and too high can lead to loss of grip, lots of vibration and as as the tyre bounces along through lack of suspension, loss of speed.

 

[Rocky]

What he said ^^

Here's Thorn Cycles recommended pressures

They don't have one for 45c but the 1.75" should give you a guide.

 

[Blue Hills]

Ignore the tyre markings on the sidewall. They're bollicks and only state what the tyre CAN handle.
Depending on your weight, 45's run quite well at around 35 - 45psi without risk of pinch flats.
Best thing to do is crank them up to about 50psi with a track pump and go for a ride. Each ride thereafter you let a little bit of air out of the tyre till you have a nice balance between comfort and speed. Expect the front tyre to be softer than the rear.
Too soft can lead to the tyre dragging and risk of flats and crap handling and too high can lead to loss of grip, lots of vibration and as as the tyre bounces along through lack of suspension, loss of speed.

Yes - very true I think.

I have a weakness for pumping my tyres up to the pressure marked on the tyrewall.

I noticed on a pair of Conti Tyres I bought the other day though that the tag attached to the tyres (haven't checked the tyrewall yet) quoted both a max pressure (very high) and an "optimum" running pressure on something.