Pumping tires at the petrol station... not enough PSI?

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Pumping tires at the petrol station... not enough PSI?

Postby anonymousmoose » Sun Nov 11, 2012 5:08 pm

I was told my bike is perfectly ok to pump the tires at the petrol station. Its a Hybrid.

One the tyres, it says 'max 75 PSI'. But when I stopped at a petrol station, I noticed their tire pumps only go up to 60 PSI.

Does this mean petrol station pumps are not high enough to pump bike tyres?
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by BNA » Sun Nov 11, 2012 5:18 pm

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Re: Pumping tires at the petrol station... not enough PSI?

Postby il padrone » Sun Nov 11, 2012 5:18 pm

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http://markfunkyhoward.blogspot.com.au/ ... -pump.html

You just don't need the servo's air hose. A good stand pump will easily get air into your tyres. I hardly ever use my frame pump these days.
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Re: Pumping tires at the petrol station... not enough PSI?

Postby jasonc » Sun Nov 11, 2012 5:24 pm

il padrone wrote:You just don't need the servo's air hose. A good stand pump will easily get air into your tyres. I hardly ever use my frame pump these days.


If I took a picture of mine, it would look exactly like that :D
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Re: Pumping tires at the petrol station... not enough PSI?

Postby il padrone » Sun Nov 11, 2012 5:27 pm

Not mine. I use a Silca Pista, but the Lezyne has now surpassed it as the top class stand pump I reckon.
Last edited by il padrone on Sun Nov 11, 2012 7:23 pm, edited 1 time in total.
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Re: Pumping tires at the petrol station... not enough PSI?

Postby ldrcycles » Sun Nov 11, 2012 6:21 pm

If your tyres have a max of 75psi i'm assuming they are 700c (probably 32mm or larger) in which case the next question is what kind of valves you have, if they are presta you will need a little adaptor to use servo air hoses as they are all set up for schrader.

It is POSSIBLE (but not advisable) to use servo air hoses to pump up your tyres, but ONLY if you are careful and patient with the manually operated type, i would never risk the automatic ones you see at a lot of places now, they pump too much air too quickly and you are liable to blow your tyres off. Can be good for seating tubeless tyres though i'm told.

The last couple of days i've been replacing tyres, didn't have my track pump with me so used a mini pump instead and it might have taken me an extra 10 or 20 seconds per tyre.
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Re: Pumping tires at the petrol station... not enough PSI?

Postby boss » Sun Nov 11, 2012 8:45 pm

You can use petrol station pumps to get past 60psi if you use 'flat tyre only'.

Press flat tyre only.

Pump will spit out air, then stops to check the PSI reading. Then spit out air, then stops to check the PSI reading. And so forth.

What you do is put the hose on your valve when its spitting out air, remove before it stops. Then put it back on when it starts spitting air, then pull it off again before it stops.

I've gone up to about 75psi on mountain bike tyres / schraeder valve tubes using servo pumps with this method.

Disclaimer: do not do this with 700c presta valve tubes. Or if you do it, it's at your own risk, because I don't know what'll happen.
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Re: Pumping tires at the petrol station... not enough PSI?

Postby Lukeyboy » Sun Nov 11, 2012 9:02 pm

There are a few servos in Brisbane that will still go up to 100psi. Just got to make sure you know your PSI to kPa conversions :P
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Re: Pumping tires at the petrol station... not enough PSI?

Postby JessicaAlba » Sun Nov 11, 2012 11:42 pm

anonymousmoose wrote:Does this mean petrol station pumps are not high enough to pump bike tyres?


Correct. The pump pressure is capped, so that morons don't over-inflate/burst their car tyres.

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Re: Pumping tires at the petrol station... not enough PSI?

Postby boss » Mon Nov 12, 2012 6:25 am

Lukeyboy wrote:There are a few servos in Brisbane that will still go up to 100psi. Just got to make sure you know your PSI to kPa conversions :P


I forgot about that - petrol stations that have high flow diesel (for big trucks) usually have 100psi pumps.
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Re: Pumping tires at the petrol station... not enough PSI?

Postby Aushiker » Mon Nov 12, 2012 10:59 am

il padrone wrote:You just don't need the servo's air hose. A good stand pump will easily get air into your tyres. I hardly ever use my frame pump these days.


+ 1 for a pump and a Lezyne in particular and oh get one for the bike as well :)

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Re: Pumping tires at the petrol station... not enough PSI?

Postby zero » Mon Nov 12, 2012 11:06 am

Max is a recommendation, not an absolute necessity. If the tires have a max of 75psi, they are probably perfectly safe and comfortable at 60psi, unless you are a very heavy rider / or the bike is loaded. May even be closer to the optimal for an ordinary weight rider.

I wouldn't go about doing the overfill trick, if the pump fails at or about the time you were doing it, you may have some explaining to do.
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Re: Pumping tires at the petrol station... not enough PSI?

Postby boss » Mon Nov 12, 2012 11:12 am

JessicaAlba wrote:
anonymousmoose wrote:Does this mean petrol station pumps are not high enough to pump bike tyres?


Correct. The pump pressure is capped, so that morons don't over-inflate/burst their car tyres.

#cottonwoolsociety


This is pure speculation, but... If 'protecting the masses from themselves' was the reason, they would be capped at 40, not 60psi. I've never tried it, but I don't think your car tyres will enjoy being inflated to 60psi. Willing to be stood corrected, I am not game to inflate a car tyre to 60 in order to test that theory out for myself.

I believe the pressure is capped because the compressors aren't tough enough to go past 60+ psi regularly. I've run into more than one compressor in my travels that wasn't able to hit 45psi, even though the display would let me select 60psi.

One, in particular, that sticks in my memory was the at the last petrol station before a major highway. I'd bet that more than one trucker had used that pump with the before mentioned 'flat tyre only' trick and over time the compressor got a little bit tired.

zero wrote:I wouldn't go about doing the overfill trick, if the pump fails at or about the time you were doing it, you may have some explaining to do.


As above, compressors get 'tired out' and less efficient rather than catastrophically fail in a shower of fireworks. Either way, I've used the flat tyre trick fairly regularly for the last 10 years or so (however long those pumps have existed) and she's apples.

More risk of blowing tyre off the rim if you are a bit over excited, as when doing the overfill trick you have no idea what the psi is. Obviously it's fairly easy to manage even for a newbie by erring on the side of caution.

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Re: Pumping tires at the petrol station... not enough PSI?

Postby Aushiker » Mon Nov 12, 2012 11:22 am

jimboss wrote:This is pure speculation, but... If 'protecting the masses from themselves' was the reason, they would be capped at 40, not 60psi. I've never tried it, but I don't think your car tyres will enjoy being inflated to 60psi. Willing to be stood corrected, I am not game to inflate a car tyre to 60 in order to test that theory out for myself.


My "space saver" tyre in the Subaru Imprezza needs to be inflated to 60 PSI.

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Re: Pumping tires at the petrol station... not enough PSI?

Postby boss » Mon Nov 12, 2012 11:36 am

Aushiker wrote:
jimboss wrote:This is pure speculation, but... If 'protecting the masses from themselves' was the reason, they would be capped at 40, not 60psi. I've never tried it, but I don't think your car tyres will enjoy being inflated to 60psi. Willing to be stood corrected, I am not game to inflate a car tyre to 60 in order to test that theory out for myself.


My "space saver" tyre in the Subaru Imprezza needs to be inflated to 60 PSI.

Andrew


Corrected I stand. I wonder why that is. Discussion for another day. I still don't buy the protecting ourselves from ourselves as I'd wouldn't like to see what happens when a standard car tyre is inflated to 60psi.
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Re: Pumping tires at the petrol station... not enough PSI?

Postby rkelsen » Mon Nov 12, 2012 12:31 pm

JessicaAlba wrote:Correct. The pump pressure is capped, so that morons don't over-inflate/burst their car tyres.

Back when you could actually get your car serviced at service stations, they'd run air compressors to power their tools. Some even had air-powered hoists. Their "customer air" was simply another line running off the compressor. Nowadays, most "service stations" only sell petrol. They don't need to run any tools, because they don't have any. So why should they run a compressor capable of 100psi if they don't need it and none of their customers require it?
jimboss wrote:I still don't buy the protecting ourselves from ourselves as I'd wouldn't like to see what happens when a standard car tyre is inflated to 60psi.

Not much, unless you drive on it.

Incidentally, those "space saver" spare tyres in cars are a stupid idea. It's simply cost-cutting for no good reason. Imagine having to drive halfway across the Nullarbor on one.
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Re: Pumping tires at the petrol station... not enough PSI?

Postby jasonc » Mon Nov 12, 2012 12:45 pm

rkelsen wrote:Incidentally, those "space saver" spare tyres in cars are a stupid idea. It's simply cost-cutting for no good reason. Imagine having to drive halfway across the Nullarbor on one.


will go a bit off topic to discuss this. so i apologise

the reason for them was to save weight in the car during fuel economy testing. as it weight 5kgs less (every kg helps) it may then be able to run 1 size smaller brakes etc etc saving more weight.
so it makes the car cheaper to make and show a better fuel economy for the official number..

and yes, they are a stupid idea.
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Re: Pumping tires at the petrol station... not enough PSI?

Postby ldrcycles » Mon Nov 12, 2012 2:49 pm

+1 on space savers being stupid, at least in australia.

Re tyre pressures on cars, i remember reading about a stunt bloke in the UK doing some two wheeled driving in a Triumph TR4 or something similar, and he had 90psi in the tyres for the exercise (presumably to stop them tucking under). It did say they were shot afterwards though.
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Re: Pumping tires at the petrol station... not enough PSI?

Postby PB12IN » Mon Nov 12, 2012 2:57 pm

Especially a great idea when the car is loded up, blow a tyre swap the space saver on, then where do you put the blown tyre? car is already loaded and it wont fit in the space saver hole.

60psi wouln't blow the car tyre up but it would be a seriously hard ride.
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Re: Pumping tires at the petrol station... not enough PSI?

Postby ytd » Tue Nov 13, 2012 3:45 pm

when I worked in a petrol station cyclists would often burst their tyres using the manual air hose. Mechanics used a lot of air tools in the workshop and I think they set the pressure pretty high. Worst thing was when little old ladies would ask you to do their tyres for them and you have to refuse with the lame excuse that it might burst their tyre.
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Re: Pumping tires at the petrol station... not enough PSI?

Postby wellington_street » Wed Nov 14, 2012 3:36 pm

Used to always ride up to the local servo to pump the tyres with a manual comrpessor when I was a kid. Now I am stuck with the stand pump. I think my old local still has the manual pump but every 'branded' servo these days has an automatic one. Can still remember dad showing me how to use the old ones!
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