Car compressed air?

[bobcat]

Please forgive my ignorance, but if I put an adapter of some sort on a presta valve could I fill up with compressed air at the garage?

 

[fossyant]

Don't do it. Not very safe really.

 

[bobcat]

Don't do it. Not very safe really.

Why not?

 

[martint235]

I tried it once and got away with it but I don't think I'd do it again.

I think the problem is to do with the flow rate and the pump I used had a dial that only went up to 80psi. I imagine inner tubes will go bang quite quickly

 

[bobcat]

I tried it once and got away with it but I don't think I'd do it again.

I think the problem is to do with the flow rate and the pump I used had a dial that only went up to 80psi. I imagine inner tubes will go bang quite quickly

That will do me for a reason, thank-you!

 

[subaqua]

oh FFS people.



most car tyres are pumped to 35psi or about 2.2 Bar. even my MTB tyres take a pressure of 65psi- nearly twicw the pressure . there is no risk its a myth perpetuated by garages and lazy insurance companies. ask to see the risk assesment why its dangerous and i bet you can't have one produced .

I have diving cylinders that are filled to 300bar. I have an attachment which goes on the low pressure (10 Bar) hose for pumping tyres up. works a treat.

 

[Little yellow Brompton]

oh FFS people.



most car tyres are pumped to 35psi or about 2.2 Bar. even my MTB tyres take a pressure of 65psi- nearly twicw the pressure . there is no risk its a myth perpetuated by garages and lazy insurance companies. ask to see the risk assesment why its dangerous and i bet you can't have one produced .

The risk is as you said, nothing to do with the pump, and everthing to do with being outside of a motor vehicle in an area where drivers are manouvering.

 

[peelywally]

Please forgive my ignorance, but if I put an adapter of some sort on a presta valve could I fill up with compressed air at the garage?

i carry a brass adapter for just this purpose works fine just be cautious and check connections .

 

[the snail]

The risk is as you said, nothing to do with the pump, and everthing to do with being outside of a motor vehicle in an area where drivers are manouvering.

but even car-drivers have to outside their cars to pump their tyres up?

 

[classic33]

The pressure may be higher in a bike tyre, but the volume is smaller when compared to a car tyre.

Some pumps on garage forecourts will have a maximum pressure, whilst inflating the tyre, that may be well into triple figures. To get an idea of the problem, use a track pump with a pressure gauge fitted. Watch the needle as you're inflating the tyre. The pressure can spike at over five times the pressure that is actually in the tyre. Watch at the bottom of the stroke as the needle settles.

The pumps/airlines in garages use a short stroke, wide bore cylinder. About 10 inches wide with a stroke of upto 12 inches. Most do not have a resevoir so will be pumping air directly into the tyre. Those with a resevoir are a lot safer.

That said, I've used them and had no problems. Used in short bursts & checking the pressure as you're inflating the tyre will help minimise the risk of the it exploding. The ears will be left ringing if it does go. I've also used airlines at work where the pressure was 115lbs a square inch constant.

 

[Little yellow Brompton]

but even car-drivers have to outside their cars to pump their tyres up?

And have a tonne of metal to traverse the forcourt in and hide behind. Plus drivers expect to see cars on the forecourt.

 

[ColinJ]

Anyway - why would you need to?

If you get a puncture when you are out on your bike, needing to go to a garage to pump your tyre up isn't exactly convenient, unless you happen to be outside a garage at the time.

If you are not out on your bike, use a track pump at home. It takes less than 15 seconds to pump a tyre up and hardly any effort since you can use your weight on the pump rather than strength.

 

[slowmotion]

I think that the problem with garage pumps could be that the pressure sensor reacts fairly slowly. It doesnt have to be very fast if the pump has to inject a very large volume of air into a car tyre....the inflation process is pretty slow. With a bike tyre, the required air volume is comparatively tiny, and the pump might keep going for too long before the sensor cuts off the flow.

This could be utter garbage, of course. Anyway, garage pumps are always "out of order", so the issue is a non one...

 

[classic33]

oh FFS people.



most car tyres are pumped to 35psi or about 2.2 Bar. even my MTB tyres take a pressure of 65psi- nearly twicw the pressure . there is no risk its a myth perpetuated by garages and lazy insurance companies. ask to see the risk assesment why its dangerous and i bet you can't have one produced .

I have diving cylinders that are filled to 300bar. I have an attachment which goes on the low pressure (10 Bar) hose for pumping tyres up. works a treat.

Diving cylinders are made normally of steel & pressure tested every five years. Fail that & you have to replace it.

Your system includes two pressure reduction systems. Most air hoses/pumps have no pressure reduction system in place.

 

[gaz]

Some pumps on garage forecourts will have a maximum pressure, whilst inflating the tyre, that may be well into triple figures. To get an idea of the problem, use a track pump with a pressure gauge fitted. Watch the needle as you're inflating the tyre. The pressure can spike at over five times the pressure that is actually in the tyre. Watch at the bottom of the stroke as the needle settles.

5 times? I've used many a track pump and not once have a seen the needle get anywhere near 150psi let alone 500psi