Newbie-Tyre Pressure Query

funkidunc

New Member
Hi guys

I have some Specialised all condition road tyres, size 700 x 25c. On their side walls it states a pressure of 120psi.

After a puncture I replaced the inner tubes and used a track pump to inflate. The gauge stated that the pressure was 80psi when I could not pump no more. The tyres feel hard now but there was no way I could get the pressure close to 120psi, have i done anything wrong/?
 

MJN

New Member
Location
Bristol
No, it's just your pump. Don't fall into the trap of assuming that a pump's maximum gauge scale reading is necessarilly achievable by it.

Do the tyres have a pressure range rather than a single figure?

Mathew
 

Oldlegs

Frogs are people too.
Location
Norwich
That's going to be the maximum pressure. I use 25's over winter generally about 90psi (for comfort) no problems.

Having said that it does sound like there is a problem with the track pump or valve somewhere. Getting up to 120psi should be no problem. Try the pump on the other tyre and see what happens?
 
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funkidunc

New Member
No, it's just your pump. Don't fall into the trap of assuming that a pump's maximum gauge scale reading is necessarilly achievable by it.

Do the tyres have a pressure range rather than a single figure?

Mathew

Hi the pressure range of the tyre is 115-125psi.

I bought a brand new track pump today, like this http://www.bikechase.co.uk/index.php?p=124416. The gauge seems to be working fine pumping the inner tube from flat.

Just tried deflating and inflating several times, and I cant get the pressure of the inner tube greater than 80psi, the resistance is too much.

Bought some inner tubers like this http://www.chainreactioncycles.com/Models.aspx?ModelID=18908 but S42mm rather than 60mm. Just wondering if the 80psi is the max pressure of the inner tube rather than the tyre?
 
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funkidunc

New Member
That's going to be the maximum pressure. I use 25's over winter generally about 90psi (for comfort) no problems.

Having said that it does sound like there is a problem with the track pump or valve somewhere. Getting up to 120psi should be no problem. Try the pump on the other tyre and see what happens?

I have tried the pump on both tyres and 80psi is about the max pressure I can get to. The tyres feel absolutely solid (pretty much like I when I received my bike from the lbs), dont think much more air in there.
 

potsy

Rambler
Location
My Armchair
Maybe the guage is faulty,I pump mine up to about 120 it is tough though after 100psi I have both feet off the floor and all my weight pushing down
ohmy.gif
that is with a Topeak Joe Blow.
 
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funkidunc

New Member
Maybe the guage is faulty,I pump mine up to about 120 it is tough though after 100psi I have both feet off the floor and all my weight pushing down
ohmy.gif
that is with a Topeak Joe Blow.


Hope not its brand new. When I approach 80psi the resistance does get so much that i, a big lad, cant pump no more. The tyres feel rock solid with hardly any give in then.

Theres no leaks from the valve or the pump head. Perhaps it is the gauge. Will take it back to the shop and ask them to have a go pump up a tyre with it.
 
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funkidunc

New Member
Hope not its brand new. When I approach 80psi the resistance does get so much that i, a big lad, cant pump no more. The tyres feel rock solid with hardly any give in then.

Theres no leaks from the valve or the pump head. Perhaps it is the gauge. Will take it back to the shop and ask them to have a go pump up a tyre with it.


Just tried to put the pump end on to the valve a bit more and managed to get up to 100psi.
:whistle:

However put it on to much on the back tyre and when I yanked it off I ripped the valve from the inner tube.:sad:

Good job I bought two inner tubes today.

Apologies all, i am a numoty of the nth degree :wacko:
 

MacB

Lover of things that come in 3's
I'd still get the pump checked, I use a Joe Blow II and can get to 100 psi quite easily, gets tougher after that but I only go as far as 110 anyway so not to bad.
 
Oh dear. Oh deary deary me. The image of Potsy putting all of his body weight on a track pump with both feet in the air to do it is quite funny.
I just ordered a road bike...I better get a better track pump!

tongue.gif
 
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