can you tell me why

[madguern]

Hi all


Why is it that my tube after replacement deflates ? pump it up again and its fine ! this is strange and only occurs on my road bike , my commuter and old MTB have never had this problem.

Must be something I am doing but not sure what I am doing to achieve this ....

Cheers


Rob

 

[Aperitif]

Do you replace on the road and use CO2 gas to reinflate? The only other reason is that you are not screwing down the valve tip after pumping to 8 bar and beyond, and air is leaching out from the valve..?

 

[tyred]

Shrader (car) valve or Presta? If it's the car type, there may be a bit of dirt or something sticking the spring which keeps it closed.

 

[byegad]

CO2 leaches out faster than air. Yes I know CO2 is a bigger molecule but it is a fact born out by my own experience. If you are using air then I can't explain it.

 

[madguern]

CO2 leaches out faster than air. Yes I know CO2 is a bigger molecule but it is a fact born out by my own experience. If you are using air then I can't explain it.

Cheers all, valve is presta. I have used co2 last time and had the same issue ie tire flat in morning pump up with air and fine. On Sunday used air which stumped me, unless there is something with the presta I am doing wrong. ie is the valve not sticking on initial pressure .......

Fine this morning so not a big issue more somthing that makes me think why ?

Cheers anyway

 

[e-rider]

does this happen with all tubes?

the screw bit on the presta valve could be loose - I had this once (in 25 years) - it was ok sometimes and then not ok - binned that tube in the end. It was a schwalbe tube - are you using this brand?

 

[Aperitif]

Cheers all, valve is presta. I have used co2 last time and had the same issue ie tire flat in morning pump up with air and fine. On Sunday used air which stumped me, unless there is something with the presta I am doing wrong. ie is the valve not sticking on initial pressure .......

Fine this morning so not a big issue more somthing that makes me think why ?

Cheers anyway

That's what we are trying to say - if you use CO2 it is a quick fix, a 'get you on the road again' etc and needs to be discharged and your bike inner tube re-inflated with "real air"

Your question: 'can you tell me why'

 

[byegad]

If it's going down after pumping up with air then it has a leak. Check the valve by blowing up on the bike and dip the wheel into enough water to submerge the valve, if any bubbles ensue you have the culprit. Otherwise the only quick solution is to dump the tube and use a new one.

 

[madguern]

That's what we are trying to say - if you use CO2 it is a quick fix, a 'get you on the road again' etc and needs to be discharged and your bike inner tube re-inflated with "real air"

Your question: 'can you tell me why'

Hi if you read, on Sunday when I changed the tire I did so using air only no CO2 but tire still went down.

Cheers

 

[madguern]

If it's going down after pumping up with air then it has a leak. Check the valve by blowing up on the bike and dip the wheel into enough water to submerge the valve, if any bubbles ensue you have the culprit. Otherwise the only quick solution is to dump the tube and use a new one.

Hi, pressure after two days since it went flat is fine. Can only think that the presta screw top was not properly sealed.

Cheers