Road Bike Tyre pressure.

[DarrenH]

Should I have to pump both my tires up every time I want to use my bike, say once a week. Well I seem I have to as they go from hard to slightly spongy after a week or so, or when I want to go out on it. - I hope that make sense.

Also the pump that i have, Giant Control Mini Road+ http://www.giant-bicycles.com/en-gb/gear/product/giant.control.mini.road/587/50082/ I seem to only be able to get a few pump, before it is really hard to pump, then the end of the valve comes away from the rubber hose. When I unscrew the presta valve, all the air I have put in seems to come out, this cannot be right.

Any suggestions?

 

[Roadrider48]

The pump you have goes up to 160psi, Which is plenty for any road tyre.
But, a hand pump like yours can be hard to apply enough pressure to inflate the tyres enough. It can be done, but with some effort.
A floor standing pump with a pressure gauge would do you nicely and are available at the price you paid for the one you have already. With the gauge you can check your tyre pressure before you ride.

 

[DarrenH]

I find it very hard, workout hard.... to use and pump, not to mention pinching my hand as the pump is backwards. I though about getting a Lezyne guage drive hp. as it is small, has a gauge and the pump is the 'wright way around'.

 

[Mile195]

+1 for a new pump. Get a track-pump (floor standing, hand operated - DON'T get a footpump designed for cars). I do my tyres once a week up to 100psi (700/23c tyres). After a week they've usually dropped about 15-20psi. I'm sure someone with better understanding of gasses and molecules could tell me where it goes, but I'd rather just re-inflate once a week!

 

[Profpointy]

Whilst the above posters are absolutely right that a track pump is a Good Thing, almost essential really, given your description, I do think there's something amiss.

Having to pump up weekly is reasonable, especially if you are trying to keep them pumped hard (100+ psi) as indeed you should.

However, the "not being able to get air in" issue sounds like there's something wrong. Maybe you are not undoing the thingy properly. Are you perhaps unscrewing the whole inner valve not just the little bit on the outside - which screws along the threaded rod. If "all the air's coming out" then this could be the case. Alternatively the valve is buggered - but this would be odd if it's both of them. Sorry if this is teaching you to suck eggs as it were, but just going by what you've said.

I think the only real option is to get a local cyclist pal to have a look as it's hard to diagnose / describe on the internet. Perhaps there's something on youtube?

 

[DarrenH]

+1 for a new pump. Get a track-pump (floor standing, hand operated - DON'T get a footpump designed for cars). I do my tyres once a week up to 100psi (700/23c tyres). After a week they've usually dropped about 15-20psi. I'm sure someone with better understanding of gasses and molecules could tell me where it goes, but I'd rather just re-inflate once a week!

I have the same tyres size, mine are min pressure 102psi to mac 131psi. I think I will get another pump for the bike and maybe also a workshop floor pump.

As for the air in the tyre disappearing is because the air molecules are small and escape through the valve, rubber, like in a car tyre, also the weather plays a part in it too. Car tyres you can fill them with nitrogen as the molecules are bigger than oxygen which makes up 21% of compressed air also it has no moisture. thus the nitrogen won't escape through the valve rubber as easily. I don't think it is worth the £fee in a road/mountain bike.

 

[winjim]

Your tyres shouldn't need inflating every ride, but I suspect you are not getting enough air into them in the first place. Your existing pump is good enough for a quick repair job on the road, but for home you could do with a good track pump. Lots of people like the Joe Blow Sport for £25, but if you can stretch to £50, the SKS Rennkompressor is the best there is.

 

[winjim]

Further to @Profpointy post, you need to unscrew the locknut but not the valve core. If the locknut is on too tight they may start unscrewing together so be careful.

 

[DarrenH]

Whilst the above posters are absolutely right that a track pump is a Good Thing, almost essential really, given your description, I do think there's something amiss.

Having to pump up weekly is reasonable, especially if you are trying to keep them pumped hard (100+ psi) as indeed you should.

However, the "not being able to get air in" issue sounds like there's something wrong. Maybe you are not undoing the thingy properly. Are you perhaps unscrewing the whole inner valve not just the little bit on the outside - which screws along the threaded rod. If "all the air's coming out" then this could be the case. Alternatively the valve is buggered - but this would be odd if it's both of them. Sorry if this is teaching you to suck eggs as it were, but just going by what you've said.

I think the only real option is to get a local cyclist pal to have a look as it's hard to diagnose / describe on the internet. Perhaps there's something on youtube?

This is what I do, bare with me on explaining this:

undo the dust cap > unscrew the presta valve fully > press the 'thingy' down fully to let some air out > screw on the giant pump fully > pump > 12 pumps or so maybe more, the pressure gets harder and I cannot fully compress the pump without exerting a lot more force > keep pumping then the metal bit of the pump that connect to the valve comes off/away. See picture > but the tyre is still spongy > re connect > pump a bit more > undo the presta pump and the air comes out whilst unscrewing as it is difficult to get the valve off quickly being a screw on > screw the presta valve back down > screw the dust cap back on lightly.

pump1 by djmhughesuk, on Flickr

pump2 by djmhughesuk, on Flickr

Darren

 

[Profpointy]

This is what I do, bare with me on explaining this:

undo the dust cap > unscrew the presta valve fully > press the 'thingy' down fully to let some air out > screw on the giant pump fully > pump > 12 pumps or so maybe more, the pressure gets harder and I cannot fully compress the pump without exerting a lot more force > keep pumping then the metal bit of the pump that connect to the valve comes off/away. See picture > but the tyre is still spongy > re connect > pump a bit more > undo the presta pump and the air comes out whilst unscrewing as it is difficult to get the valve off quickly being a screw on > screw the presta valve back down > screw the dust cap back on lightly.

pump1 by djmhughesuk, on Flickr

pump2 by djmhughesuk, on Flickr

Darren

That's sounds absolutely right to me, which leaves me stumped. Maybe the pump is buggered - and you really do want a track pump anyway, get that first, and if it all works OK, you'll know to replace the carrying-around pump.

 

[Turbo Rider]

You're probably just knocking the valve when you take the pump off. Also, the pin may be slightly bent if you're using a hand pump, so when you take the pump off, it probably wedges into a very slightly open position. If you go super fast, you should be able to screw the nut down to close it up, if that is the issue.

About the actual pressure though, as everyone says, it's hard to get up to the sort of pressure you want with a hand pump and if you have no gauge on it, then you don't even know when to stop. To me, it sounds as if you stop too soon and when I had a hand pump, I used to get to around 50 PSI, but I only found that out when I took the bike in for it's 1st service and the technician pointed it out to me. Defo get a track pump with a gauge if you can, I'd say, and that way, you stand less of a chance of breaking a valve when you take the end off as well. Still recommend a weekly pump up though, for the 20PSI loss reason.

This one is cheap and it works, though you do need some welly to get past 80PSI, so be strong and don't stop when you feel the bounce!!

http://www.halfords.com/cycling/too...air/halfords-metal-track-bike-pump-with-gauge

 

[ColinJ]

Should I have to pump both my tires up every time I want to use my bike, say once a week. Well I seem I have to as they go from hard to slightly spongy after a week or so, or when I want to go out on it. - I hope that make sense.

If you have latex (very lightweight, flexible, brightly coloured) tubes in your tyres - yes. If you have the normal butyl (black) tubes - no!

 

[jack smith]

I used to run latex and that was a pump every day affair, i run the same brand butyl now and have to pump those weekly or so they tend to drop to about 50-60 psi from 100

 

[ColinJ]

I used to run latex and that was a pump every day affair, i run the same brand butyl now and have to pump those weekly or so they tend to drop to about 50-60 psi from 100

The butyl tubes on my other bike hold the air much longer than that, but they are not lightweight butyl, just an average kind of weight.

 

[guitarpete247]

Another here for getting a track pump. I got a Revolution from EBC a few years ago for £20 but I can't see it on their site now. Don't go for the Aldi or Lidl pumps. I got one and it's OK but only as a last resort. Might be alright to be the one to leave at work. The pump you have is a really good pump but best for on the road repairs.