Tyre Pressure

bugler

I can't find my puncture thread from a while back for obvious reasons. It was suspected by many that the issue was related to pressure, which was probably a fair call as I didn't have a track pump.

I have one now. The thing is, when pumping the tube I can get to what the gauge says is around 70/75 psi but by then I'm getting a lot of resistance and feel like I'm about to hear a massive pop as the tube explodes

As I worrying over nothing? Should I keep going hell for leather until I get to 100 psi (what my tyres specify) knowing the tube should be able to take care of itself? The tyre feels quite hard at 70 psi to the touch, it only has slight give to it when pressed, but is it enough?

Thanks.

Thomas_S_Hunterson

Get a proper pump and keep them at 100psi. They should have virtually no give when pressed.

thebouldwhacker

Tubes are made of strong stuff;)

https://www.youtube.com/watch?v=sVla9kyhmRk

DustyBin

Challenge a friend to get the pressure up to 100 psi
Then whilst they're doing this just pop inside / around the corner / behind a wall
If they manage to get it to 100 psi - hooray
If not, well I'm sure you'll remember them fondly

blorg

You need to use a track pump. It is virtually impossible to get pressure up above 70 PSI or so with a hand pump. It is not the tube or tyre that will explode first but rather the pump, I have broken them myself trying to get the last few PSI in. It is however very easy with a track pump.

You also need to specify your tyre size as while 30 PSI may be appropriate for some tyres, others need 110... Basically the smaller the tyre the higher the pressure. And higher on the back than the front.

Chips Lovell

A good track pump should manage 100psi no problem. I've gotten tubs up to 160psi with my bog standard one. You'll feel a bit more resistance as you reach target pressure, but nothing to worry about.

Tyres will feel "hard" at pressures well below the target pressure.

stuf

If the resistance is big then it's probably because your valve isn't opening properly when pumping.

Maybe you're pushing the connector down too hard on the valve which often causes problems for me. If your pump has an air release button make sure you can let air out before you start pumping

Chips Lovell

+1 ^

Good suggestion there. I always bleed a little bit before pumping.

blorg

stuf wrote: »

If the resistance is big then it's probably because your valve isn't opening properly when pumping.

Maybe you're pushing the connector down too hard on the valve which often causes problems for me. If your pump has an air release button make sure you can let air out before you start pumping

Good point, I always let a bit of air out first by pressing down on the valve head before attaching the pump.

Sorry I didn't notice that you already got a track pump.

bugler

Yeah, I have and am using a track pump. I did state that in the OP but might have made that clearer. Stuf's suggestion is probably worth a go. It is quite hard to press the pump down, I'll try to loosen the connector slightly and see how that goes.

In any case the pressure is far far better than what I rode around on for a couple of months. Mustn't have had 30 psi in them previously, don't know how the back tube went so long without puncturing.

trad

There was a pump out years ago, a Zefal HPX. Would blow any tyre off the rim. Have 2 in the garage somewhere. You turned the head of the pump and the damping went out of it and you could just keep pumping until the tyres were pinging. A bit heavy by todays standards but an excellent bit of kit.

gaffmaster

I meet similar resistance inflating my wheels and my friend's wheels with my joe-blow track pump. Sometimes I've to dance on the thing to get the pressure up to 100psi. I use the bleed technique too which helps a little.

PS - Beavis and Butthead are alive and well thankfully...

thebouldwhacker wrote: »

Tubes are made of strong stuff;)

https://www.youtube.com/watch?v=sVla9kyhmRk

LastGasp

bugler wrote: »

Yeah, I have and am using a track pump. I did state that in the OP but might have made that clearer. Stuf's suggestion is probably worth a go. It is quite hard to press the pump down, I'll try to loosen the connector slightly and see how that goes.

In any case the pressure is far far better than what I rode around on for a couple of months. Mustn't have had 30 psi in them previously, don't know how the back tube went so long without puncturing.

Just to be sure, you need to UNSCREW the valve top 2 or 3 turns, then press it in for a split second - justenough to let a puff of air out. Then clamp on the connector and it should pump easily enough. If you're getting a lot of resistance there's something wrong !
Edit- that's assuming you have skinny Presta valves, and not the fatter Schrader Valves (which are the same as a Car valve). There's nothing on a Scrader to loosen.

LastGasp

Have a look at this. Idont have sound on, but it seems to be covering the basics !

http://www.youtube.com/watch?v=Ehf6HL0aLTc

midonogh

Slightly off topic, but is there any merit in lowering the tyre pressure for commuting in town in the wet. I usually do my cycling on the country lanes of North county Dublin. Of late I have been commuting into town as the rail bridge is out. I am quite concious that I can feel my wheels slipping when there has been a bit of rain- greasy oilly surface I suspect. Could this be remedied by reducing the tyre pressure and increasing the surface contact area?

blorg

midonogh wrote: »

Slightly off topic, but is there any merit in lowering the tyre pressure for commuting in town in the wet. I usually do my cycling on the country lanes of North county Dublin. Of late I have been commuting into town as the rail bridge is out. I am quite concious that I can feel my wheels slipping when there has been a bit of rain- greasy oilly surface I suspect. Could this be remedied by reducing the tyre pressure and increasing the surface contact area?

To an extent, yes, but it depends how wide your tyres are to begin with, if they are very thin you may not have much wiggle room before are at risk of pinch flats. But in general, yes, if you run them lower you will have better grip. The wider the tyres the lower you can run them and the better the grip. I don't reduce so much myself in the wet but would use wider tyres and lower pressures in ice/snow certainly.

Raam

el tonto wrote: »

I always bleed a little bit before pumping.

There's a joke there somewhere... right? Anyone?

BostonB

Raam wrote: »

There's a joke there somewhere... right? Anyone?

You looking for someone to throw a bone?

Anyone know what kinda tyres we are talking about. My MTB tyres are only rated to 80.