Can't pump tyres to required pressure.

declan1
declan1 Posts: 2,470
edited August 2012 in Workshop
Hi!

I have a rather annoying problem. My road bike has 23mm tyres, but I literally cannot pump them up enough. I have a floor pump and a hand pump, and neither can get the tyres solid. There is still a fair amount of 'softness' in them. I don't think the pressure gauges on any of the pumps are working, as one says the tyre's at 8 BAR when I don't think it is, and the other says it's at 3.

How hard are the tyres meant to be? When I'm riding along the rear one almost looks flat at the bottom, which I don't think is right....

Thanks for any help!

Road - Dolan Preffisio
MTB - On-One Inbred

I have no idea what's going on here.
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Comments

  • flasher
    flasher Posts: 1,734
    Buy a decent track pump, 20 quid should do it.
  • declan1
    declan1 Posts: 2,470
    Flasher wrote:
    Buy a decent track pump, 20 quid should do it.

    I can't really afford anything at the moment, but I'll certainly get one ASAP. I have a friend who has a compressor that I can use, but I only go to his house maybe once a week, which isn't enough.

    Road - Dolan Preffisio
    MTB - On-One Inbred

    I have no idea what's going on here.
  • Rodders30
    Rodders30 Posts: 314
    I can squeeze my tyres a bit and my rear flattens also, I weigh 107kg
    Trek 1.5 Road
    Haro MTB
  • declan1
    declan1 Posts: 2,470
    Rodders30 wrote:
    I can squeeze my tyres a bit and my rear flattens also, I weigh 107kg

    I weigh 65KG and it looks almost flat. I suppose I just have to get a new pump :(

    Road - Dolan Preffisio
    MTB - On-One Inbred

    I have no idea what's going on here.
  • amaferanga
    amaferanga Posts: 6,789
    If you really can't afford a new pump at the moment then go to any bike shop and ask if they'll pump your tyres up for you.
    More problems but still living....
  • declan1
    declan1 Posts: 2,470
    amaferanga wrote:
    If you really can't afford a new pump at the moment then go to any bike shop and ask if they'll pump your tyres up for you.

    As I said before I have a friend with a compressor that I can use, but I need something for everyday. I just thought it was maybe something to do with the 23mm tyres.

    Road - Dolan Preffisio
    MTB - On-One Inbred

    I have no idea what's going on here.
  • Giraffoto
    Giraffoto Posts: 2,078
    declan1 wrote:
    I have a friend with a compressor that I can use

    Compressors are for car tyres - the volume of air is much greater. You can easily blow a tyre off the rim with an airline that's meant for a car.
    Specialized Roubaix Elite 2015
    XM-057 rigid 29er
  • Rodders30
    Rodders30 Posts: 314
    declan1 wrote:
    Rodders30 wrote:
    I can squeeze my tyres a bit and my rear flattens also, I weigh 107kg

    I weigh 65KG and it looks almost flat. I suppose I just have to get a new pump :(

    Yea, that doesnt sound good. I think I got my pump from Halfords and it was around £15/20

    Dont go out at the weekend and drink and its covered :D
    Trek 1.5 Road
    Haro MTB
  • declan1
    declan1 Posts: 2,470
    Rodders30 wrote:
    declan1 wrote:
    Rodders30 wrote:
    I can squeeze my tyres a bit and my rear flattens also, I weigh 107kg

    I weigh 65KG and it looks almost flat. I suppose I just have to get a new pump :(

    Yea, that doesnt sound good. I think I got my pump from Halfords and it was around £15/20

    Dont go out at the weekend and drink and its covered :D

    I'm 16 :P

    I got it slightly more pumped up last night with a bit of perseverance, however it's still not right. I'll just have to save up.

    Road - Dolan Preffisio
    MTB - On-One Inbred

    I have no idea what's going on here.
  • Rodders30
    Rodders30 Posts: 314
    I thought you lot started drinking a lot younger than that these days!!
    Trek 1.5 Road
    Haro MTB
  • declan1
    declan1 Posts: 2,470
    Rodders30 wrote:
    I thought you lot started drinking a lot younger than that these days!!

    Haha! Probably true for the majority of teenagers, but not myself :)

    Road - Dolan Preffisio
    MTB - On-One Inbred

    I have no idea what's going on here.
  • desweller
    desweller Posts: 5,175
    Are you undoing the knurled nut on the valve all the way?
    - - - - - - - - - -
    On Strava.{/url}
  • declan1
    declan1 Posts: 2,470
    DesWeller wrote:
    Are you undoing the knurled nut on the valve all the way?

    Yup, until I can't turn it any further.

    Road - Dolan Preffisio
    MTB - On-One Inbred

    I have no idea what's going on here.
  • ricklilley
    ricklilley Posts: 110
    Does you dad have a car footpump? a screw on adaptor will only cost a couple quid. Though not ideal it will at least get up to pressure, until you can buy a proper track pump.
    Specialized Allez sport 2010
    Handsome Dog framed MTB
  • ricklilley wrote:
    Does you dad have a car footpump? a screw on adaptor will only cost a couple quid. Though not ideal it will at least get up to pressure, until you can buy a proper track pump.

    In my experience, schrader adaptors are utterly hopeless and I personally blame my trying to use one for the numerous punctures I endured when I switched to a pukka road bike.
    Honestly, get a proper racer pump like a Joe Blow. I can get a genuine 100psi into my tyres in like 2 seconds and the difference from when I was basically guessing is immense. I bet I've hit a dozen potholes and ruts that would have done the tube if I hadn't had proper pressure in the tyre/tube.
  • ricklilley
    ricklilley Posts: 110
    I agree that Schrader adaptors are a pain to use, i was only offering it up as a temporary solution, until he can afford to buy a proper pump.
    Specialized Allez sport 2010
    Handsome Dog framed MTB
  • declan1
    declan1 Posts: 2,470
    ricklilley wrote:
    I agree that Schrader adaptors are a pain to use, i was only offering it up as a temporary solution, until he can afford to buy a proper pump.

    I got a cheap mini pump in lidl today, and it does the job. It can pump up to 100psi, and is decent for just topping up.

    Still one problem though:

    Using the old pump that I didn't think worked, I have now got my front tyre up to pressure (the pressure gauge on the pump doesn't work, but the tyre feels solid), but I can't, no matter what I do, get my rear tyre to get up to pressure. I don't have a clue why! It just stays 'soft'. Any ideas?

    Road - Dolan Preffisio
    MTB - On-One Inbred

    I have no idea what's going on here.
  • sungod
    sungod Posts: 16,844
    if the pump can deliver 100psi, but the tyre won't go to 100psi, the air must be escaping somewhere...

    loose valve core (if it's a removable one)

    slow puncture
    my bike - faster than god's and twice as shiny
  • declan1
    declan1 Posts: 2,470
    sungod wrote:
    if the pump can deliver 100psi, but the tyre won't go to 100psi, the air must be escaping somewhere...

    loose valve core (if it's a removable one)

    slow puncture

    I hope not. It's the third inner tube and second tyre I've had in about a fortnight. I just don't understand what could be causing it.

    EDIT - After watching a couple of videos, when they attach the pump, air begins to escape from the tyre. This doesn't happen when I'm trying to pump them up. Is that what's causing the issue? How do I fix it if so?

    Road - Dolan Preffisio
    MTB - On-One Inbred

    I have no idea what's going on here.
  • Hoopdriver
    Hoopdriver Posts: 2,023
    A silly thing perhaps, but have you remembered to open the valve before you attach the pump head and start pumping?
  • declan1
    declan1 Posts: 2,470
    Hoopdriver wrote:
    A silly thing perhaps, but have you remembered to open the valve before you attach the pump head and start pumping?

    Yeah; I open the valve and press it down a couple of times to make sure it isn't sticking.

    Road - Dolan Preffisio
    MTB - On-One Inbred

    I have no idea what's going on here.
  • desweller
    desweller Posts: 5,175
    With the Joe Blow aftermarket head I've fitted to my floor pump I've sometimes found that the gripper grommet sometimes grabs the knurled nut as well as the valve stem. When it does this I need to waggle it around gently to free it off.
    - - - - - - - - - -
    On Strava.{/url}
  • Go to your local bike shop. They will talk u thru it and most will have a track pump you can use. Don't bother with a compressor as they rarely go up to the 110-120psi you need and often put the air in too fast.
  • declan1
    declan1 Posts: 2,470
    I know how to pump up a tyre, but I don't know what's wrong with the pump :(

    Road - Dolan Preffisio
    MTB - On-One Inbred

    I have no idea what's going on here.
  • Rodders30
    Rodders30 Posts: 314
    Pump cannot be at fault if it works on the front tyre.

    Maybe you have something on the rear rim thats damaging the inner tube. Take it out and check for a puncture. If you have one, line it up where it would be on the wheel and look for anything sharp.
    Trek 1.5 Road
    Haro MTB
  • declan1
    declan1 Posts: 2,470
    Rodders30 wrote:
    Pump cannot be at fault if it works on the front tyre.

    Maybe you have something on the rear rim thats damaging the inner tube. Take it out and check for a puncture. If you have one, line it up where it would be on the wheel and look for anything sharp.

    I actually forgot what pump I used for the front tyre. I've tried 4 pumps, and interchanged all the heads and tubes and everything so I don't know how I got that front one up to pressure! :?

    Maybe the rear inner tube is too small? Maybe it's pumped up to it's full capacity but there is a big gap between it and the rear tyre?

    Road - Dolan Preffisio
    MTB - On-One Inbred

    I have no idea what's going on here.
  • If you're using 23c tube size should be fine. Have u tried letting all the air out and starting over? Just to see if it takes air thru the valve properly. Think you must have gremlins!
  • declan1
    declan1 Posts: 2,470
    kevprimer wrote:
    If you're using 23c tube size should be fine. Have u tried letting all the air out and starting over? Just to see if it takes air thru the valve properly. Think you must have gremlins!

    Yup, I've taken it right down, and the pump can get it pumped up pretty quick, but it then just stops getting harder and it can't progress from that stage. I think you're right about the gremlins!

    Road - Dolan Preffisio
    MTB - On-One Inbred

    I have no idea what's going on here.
  • Only other thing I can think of is if you've got slime tubes or kevlar puncture protection strips between the tire n tube.
  • Pump the tyre up and stick it in the bath. Bubbles will show leaks. If you are changing tyres as often as that, has the rim got a good band on it? You might be puncturing on a spoke eyelet.
    Everything in moderation