Can't pump tyres to required pressure.

declan1

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!

flasher

Buy a decent track pump, 20 quid should do it.

declan1

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.

Rodders30

I can squeeze my tyres a bit and my rear flattens also, I weigh 107kg

declan1

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

amaferanga

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.

declan1

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.

Giraffoto

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.

Rodders30

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

declan1

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

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.

Rodders30

I thought you lot started drinking a lot younger than that these days!!

declan1

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

desweller

Are you undoing the knurled nut on the valve all the way?

declan1

DesWeller wrote:

Are you undoing the knurled nut on the valve all the way?

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

ricklilley

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.

Sesquepidilian

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

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.

declan1

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?

sungod

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

declan1

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?

Hoopdriver

A silly thing perhaps, but have you remembered to open the valve before you attach the pump head and start pumping?

declan1

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.

desweller

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.

kevprimer

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

I know how to pump up a tyre, but I don't know what's wrong with the pump

Rodders30

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.

declan1

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?

kevprimer

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

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!

kevprimer

Only other thing I can think of is if you've got slime tubes or kevlar puncture protection strips between the tire n tube.

roadietoo

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.