tire pressure

gagomes

I got myself this LaPierre Cross 200 bike last year but as I was overweight, I put it aside for the best part since I bought it. I am still overweight, but I have an intention to change that. I am currently 157kg or about 320 pounds or 23 stones. I am now trying to get it back on the road, but the tires are a less inflated than they were back when I bought it - never thought they'd deflate so much over about 8-9 months of no use. I only have a small, manual pump and doesn't even have a pressure indicator, so I am considering pumping it as best as I can and then cycling it to the nearest station to fill it up to a correct (or at least, near enough good) pressure. I am just not sure what pressure to fill it up to and I would appreciate some help from you! I am no expert, but I presume there is no one-size-fits-all pressure measurement and I suppose it will have to account for my size + gear size + bike size. Your help will be greatly appreciated

edit: Forgot to say, mine is the XXL (60cm) as I am 6'8, updated the link to the actual bike specs and I have also removed something where I suggest my bike wheels to be 26".. I was wrong, they are 28".

531

Maximum pressure will be written on the tyre.

Tubes will naturally lose pressure, even overnight, so flat after 8-9 months is to be expected. Most 'serious' cyclists would check the pressures before every ride.

A track pump with a gauge is a good investment.

krissovo

My tyres go flat after a few weeks and I will pump them up at least once a week.

I was over 150kg last year and started on a Kelly's hybrid, I pumped the tyres to 80psi but I did check the side wall for max pressure, it will be printed on the tyre. My experience is that I needed the max inflation for my size or I would get pinch flats and on one ride damaged the rim going over a pot hole.

If you get into cycling then buy a track pump, it's around 40€ well spent just to keep your tyres inflated and puncture free(ish) to reduce frustration.

gagomes

531 wrote: »

Maximum pressure will be written on the tyre.

Thank you for the quick reply, 531. I am confused. Is tire pressure the same as tube pressure?

531

Yes, tyre pressure and tube pressure is the same. It is usually referred to as tyre pressure.

Oryx

gagomes wrote: »

Thank you for the quick reply, 531. I am confused. Is tire pressure the same as tube pressure?

The tube is inside the tyre so yes.

gagomes

krissovo wrote: »

My tyres go flat after a few weeks and I will pump them up at least once a week.

I was over 150kg last year and started on a Kelly's hybrid, I pumped the tyres to 80psi but I did check the side wall for max pressure, it will be printed on the tyre. My experience is that I needed the max inflation for my size or I would get pinch flats and on one ride damaged the rim going over a pot hole.

If you get into cycling then buy a track pump, it's around 40€ well spent just to keep your tyres inflated and puncture free(ish) to reduce frustration.

Thanks a lot. This was a particularly good example as you are (or were, I hope?) a closer example to what I am at the moment. How often did you pump your tires when you were 150kg heavy (in case that improved since)?

531

Yes, Oryx! (Unless it's a tubular or tubeless - no, don't even go there (yet!)!).

sham58107

You could just do it by feel with a hand pump you should not be able to really squeeze the tyre a little is ok.
As suggested a track pump with gauge is very good buy pressure should be about 100 or 8 bar.
I would not recommend garage pump but if using it be very careful as these got to about 40 bar very quickly.
Above all good luck and get out and enjoy your bike.:)

gagomes

sham58107 wrote: »

You could just do it by feel with a hand pump you should not be able to really squeeze the tyre a little is ok.
As suggested a track pump with gauge is very good buy pressure should be about 100 or 8 bar.
I would not recommend garage pump but if using it be very careful as these got to about 40 bar very quickly.
Above all good luck and get out and enjoy your bike.:)

I don't understand the part where you say "should be about 100 or 8 bar" and "careful as these go to about 40 bar very quickly", can you explain it differently, please?

not yet

Can lend you a track pump for 10min if your around d15

gagomes

not yet wrote: »

Can lend you a track pump for 10min if your around d15

Thanks a million, I am Lucan based! I think my next door neighbour might have one and I have just texted him.

not yet

gagomes wrote: »

Thanks a million, I am Lucan based! I think my next door neighbour might have one and I have just texted him.

They are worth their weight in gold...

With the nice weather coming and a stretch in the evening you should get out as much as you can, best of luck.

macnab

gagomes wrote: »

I don't understand the part where you say "should be about 100 or 8 bar" and "careful as these go to about 40 bar very quickly", can you explain it differently, please?

What he means is 100 psi or 8 bar, which are the same pressure, most gauges read both psi (old imperial) and bar (new metric)
iirc 14.7psi=1 bar.

Wishbone Ash

Rubber is not airtight and will naturally dissipate air over time.

gagomes wrote: »

...then cycling it to the nearest station to fill it up to a correct (or at least, near enough good) pressure..

Most filling station pumps only go up to about 60psi as most motor vehicles don't require anything higher. They are also designed for Schrader valves. If you have a presta, you'll need an adapter.

Oryx

Schraeder are the normal ones on car tyre where you depress a pin inside the valve. Presta are longer, thinner, and the part you depress sticks out of the valve with a tiny nut on it youll need to unscrew. (I wish id been told about that the first time I tried to pump bike tyres )

gagomes

Wishbone Ash wrote: »

Rubber is not airtight and will naturally dissipate air over time.


Most filling station pumps only go up to about 60psi as most motor vehicles don't require anything higher. They are also designed for Schrader valves. If you have a presta, you'll need an adapter.

Mine uses Schrader (?) I think.

It looks like this:



I just checked my bike and it says 50 - 75 PSI. Where can you read the top PSI a station works at? As I understand it, most pumps now charge you money for using the pump, so I don't want to be spending only to find out that, well, it does not even inflate to 75 psi.

krissovo

gagomes wrote: »

Thanks a lot. This was a particularly good example as you are (or were, I hope?) a closer example to what I am at the moment. How often did you pump your tires when you were 150kg heavy (in case that improved since)?

At least once a week they were pumped, I am now 106kg:)

gagomes

krissovo wrote: »

At least once a week they were pumped, I am now 106kg:)

:eek: Fantastic! Very pleased for you! :-)

P.S: I hope you don't mind, but I'm going to ask you a couple of questions privately.

Wishbone Ash

gagomes wrote: »

I just checked my bike and it says 50 - 75 PSI. Where can you read the top PSI a station works at? As I understand it, most pumps now charge you money for using the pump, so I don't want to be spending only to find out that, well, it does not even inflate to 75 psi.

If it's an older type just look at the guage. If it's an electronic type just press the "+" button until it reaches the max or your max.

The charge is usually refundable if the pump is replaced correctly (just like a shopping trolley). Filling stations incur costs when people just throw the pump on the ground and other motorists drive over it damaging it.

gagomes

Wishbone Ash wrote: »

Filling stations incur costs when people just throw the pump on the ground and other motorists drive over it damaging it.

Ah, so does that mean that you don't actually pay for the use, but rather to incentivise you to place the pump back rightly? I thought it was pay-per-use, or perhaps I misunderstood you

Thanks for the tips!

feck sake lads

read this first.

http://interdependentscience.blogspot.ie/2013/06/bicycle-tire-pressure.html

No Pants

Get yourself a track pump. My local bike shop had the BBB variety at €25 just after Christmas, so I picked up one for a friend.

sham58107

gagomes wrote: »

I don't understand the part where you say "should be about 100 or 8 bar" and "careful as these go to about 40 bar very quickly", can you explain it differently, please?

Sorry,100 psi or 8 bar as on gauge in garage a car takes about 28-32 bar,it is just a measure of pressure,75 psi should be on gauge although as stated I would not recommend garage,get track pump, I always find it easier to inflate if I let most of air out,maybe that's just me!!

Wishbone Ash

sham58107 wrote: »

... a car takes about 28-32 bar...

A car would take 28-32 psi (about 1.8 to 2.2 bar).

Cee-Jay-Cee

You will not be able to inflate them at a garage as more than likely your valves are presta and garage pumps are for Dunlop/Schader type valves. I think you can get an adaptor but your better off buying a track pump to have at home.

I bought a Bike Hut pump with gauge from halfords. It's an excellent piece of kit but there are many others available, I would advise though to get one with an aluminium/alloy body as opposed to plastic.

sham58107

Wishbone Ash wrote: »

A car would take 28-32 psi (about 1.8 to 2.2 bar).

Ye mixed that up, what I said about Cycle tyre pressure was right and it is a bike the OP was asking about:)