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tyres keep deflating slowly


Lumor_uk
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think I had this problem last year where I have to pump them up every couple of weeks. only in cold weather. losing 5 psi, I had complete front deflation a while ago when I was n't keeping tabs on it. kind of annoying. no dents in rim tyres are under 2 years old. plenty of life left in them.

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go get them filled with nitrogen it doesn't leak as easy as air and may well solve the problem


the molecules are bigger so are harder to get out of gaps :wink:


also it doesn't change pressure with heat not that you will get much at this time of year


I had my car tyres filled with it 15k ago still the same pressure and not lost any 8-)

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80% of air is nitrogen anyway which is why I'm always skeptical about it.


I guess maybe the 20% is the percent that runs away! I'd be interested to see if the air in your tires is more nitrogen rich after it's deflated a little!


But anyway, if it works, it works! How much does it cost? I have the same problem as Lumor.

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Always skeptical about nitrogen in tyres.

The air we breath consists of:

Nitrogen = ~78%

Oxygen = ~21%

Other gasses = ~1%


Size of an Nitrogen atom = 0.075pm

Size of an Oxygen atom = 0.073pm


So yes, Nitrogen atoms are larger than Oxygen molecules, but not by very much!!


Also, Do they suck out the all the old air first or flush the tyre with nitrogen? if they dont, then there is a whole tyre full of normal air mixed in with that nitrogen - why doesn't this leak out??


its a nice gimmick though ;)

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Might not be relevant to your case, Lumor, but I've just had to have a valve replaced. Same problem as you -slow pressure loss. I couldn't understand it until I was putting air in at home with a foot pump and the pressure just wasn't going up. When I pulled the pump adapter off, the top half of the valve came with it!


I'm guessing that the valve shaft(?) was slowly breaking and leaking air. I blame this on the petrol station tyre inflators which are a tight fit due to the angle they fit onto the wheel. I must have been distorting the valve each time I did it. I've bought a 90 degree valve adapter now to prevent this happening again.


As I say, might not be relevant but worth considering.

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  • 2 weeks later...
think I had this problem last year where I have to pump them up every couple of weeks. only in cold weather. losing 5 psi, I had complete front deflation a while ago when I was n't keeping tabs on it. kind of annoying. no dents in rim tyres are under 2 years old. plenty of life left in them.

 

You might have a bit of kack in the valves. try putting a bit of spit over it and see if it bubbles. If it does then that's your problem.

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  • 2 weeks later...

Joeman wrote

'Size of an Nitrogen atom = 0.075pm

Size of an Oxygen atom = 0.073pm


So yes, Nitrogen atoms are larger than Oxygen molecules, but not by very much!!'


No Nitrogen atoms are larger than Oxygen atoms but not larger than Oxygen molecules

but the distance between the two atoms in each molecule (which contributes to most of it's size is)


121pm for Oxygen

110pm for Nitrogen

(Nitrogens triple bond means the atoms have to be closer together)

So oxygen molecules are bigger.


Sorry for being technical and i know this may not have much use, but just wanted to sate people curiosity.

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Though apparently somehow Nitrogen molecules are still larger [1] :?

The main benefit of it is that there is no moisture in purified nitrogen. The same benefit comes with using dry air. Though the differences between how fast the two leak isn't really that dramatic. So if air is leaking fast then i guess there is something else causing it.


references

[1]http://www.theaa.com/motoring_advice/safety/filling-tyres-with-nitrogen.html

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Seems to me someone chose a readily available, cool sounding, cheap to obtain, gas and has managed to convince the world to pay a premium for it!!

Delboy selling "Peckham Spring water" jumps to mine...

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  • 6 years later...

I know this is an old thread, but rather than start a fresh Il ask here.

I check my tyres before each ride, and usually do 50 to 100 miles a time. I notice after a couple of runs tyres drops to 34 psi and dont really go lower. I top up, then they drop again. Think im losing the plot but is it normal?

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Looking at the guides, the stock psi for Suzuki Bandit is 36. I would imagine it is normal if you are riding about 100miles at a time for it to drop a couple of psi' after that distance. Do you top it up every time you fuel up? Or is it more frequent?

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Looking at the guides, the stock psi for Suzuki Bandit is 36. I would imagine it is normal if you are riding about 100miles at a time for it to drop a couple of psi' after that distance. Do you top it up every time you fuel up? Or is it more frequent?

 


7 years ago ….should imagine he's got new tyres by now :lol:

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Looking at the guides, the stock psi for Suzuki Bandit is 36. I would imagine it is normal if you are riding about 100miles at a time for it to drop a couple of psi' after that distance. Do you top it up every time you fuel up? Or is it more frequent?

 


7 years ago ….should imagine he's got new tyres by now :lol:

 

If it was for the original OP, yes, but [mention]jedibiker[/mention] had revived this thread due to sheer laziness! :wink:

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Looking at the guides, the stock psi for Suzuki Bandit is 36. I would imagine it is normal if you are riding about 100miles at a time for it to drop a couple of psi' after that distance. Do you top it up every time you fuel up? Or is it more frequent?

I top it up before bigger rides, if popping out I won't as its usually close. I have a cheap checker which says 32 if it's 34 lol so going to get a better one, but as a guide if it says 32 I know they're around 34 so will use the bike local. But before big rides top it up.

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If it was for the original OP, yes, but @jedibiker had revived this thread due to sheer laziness! :wink:

 

Cheeky sod 8-) most forums have a good moan if you don't try use a thread that exists. Actually was more effort to search for a thread and ask rather than just ask lol

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Last year I got myself a TPMS.

A simple one, you put the sensors over the air valve and you have a reader that will go on when the bike moves.

You will see that the pressure naturally drops if the bike is parked for some time.

The most common pressure loss other than a slow puncture it could be dirt that got in between the tyre and the wheel. This could have been when the tyre was fitted the guy wasn't careful enough and you only need a small grain of grit to make it go wrong.

It could be that the wheel is starting to get corroded, scratched aluminium will oxide and will form a dust that makes the wheel coarse letting air through.


You shouldn't top-up tyres when they are hot because it hot air in the wheel mixing with cold under pressure air will change the pressure around the tyre, in theory you will have spots of low and high pressure within the tyre. This will be balanced when the wheel starts moving but it will be there when you top-up.

Also, the pressure will increase as the tyre warms up. Much more on the rear tyre.

I've noticed since I installed the TPMS that the rear tyre goes from the 40PSI I start with all the way to 50PSI on a warm day. The temperature will go from whatever the outside temperature is, say 8c to high 20's, this because the rear wheel takes the heat from the engine and there is little fresh air ventilation to it.

The front wheel, because is at the front it takes far longer to heat up and the pressure won't increase as much. But both will go up.


This is another reason why if you need to top-up the tyres while riding is because you have an issue being either a puncture or a faulty wheel.

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Pressure in the tyres depends, load, riding stile, length of ride, load etc. Pressure declared on the motorcycle is for oem tyres and that particular tyre. It doesn’t say is it for one rider or rider and pillion or with luggage etc.

If your bike is 10 years old, oem tyres, that model probably doesn’t exists.

Therefore everyone should try to find best pressure that fit him. It will change with the weather, slow or fast tide etc.

Standard pressures 36/42 are industry standard and average.

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Pressure in the tyres depends, load, riding stile, length of ride, load etc. Pressure declared on the motorcycle is for oem tyres and that particular tyre. It doesn’t say is it for one rider or rider and pillion or with luggage etc.

If your bike is 10 years old, oem tyres, that model probably doesn’t exists.

Therefore everyone should try to find best pressure that fit him. It will change with the weather, slow or fast tide etc.

Standard pressures 36/42 are industry standard and average.

 

Very true.

My oem pressure is 36psi but I prefer 42psi. This is when I get a better feel of the tyres :)

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Last year I got myself a TPMS.

A simple one, you put the sensors over the air valve and you have a reader that will go on when the bike moves.

You will see that the pressure naturally drops if the bike is parked for some time.

The most common pressure loss other than a slow puncture it could be dirt that got in between the tyre and the wheel. This could have been when the tyre was fitted the guy wasn't careful enough and you only need a small grain of grit to make it go wrong.

It could be that the wheel is starting to get corroded, scratched aluminium will oxide and will form a dust that makes the wheel coarse letting air through.


You shouldn't top-up tyres when they are hot because it hot air in the wheel mixing with cold under pressure air will change the pressure around the tyre, in theory you will have spots of low and high pressure within the tyre. This will be balanced when the wheel starts moving but it will be there when you top-up.

Also, the pressure will increase as the tyre warms up. Much more on the rear tyre.

I've noticed since I installed the TPMS that the rear tyre goes from the 40PSI I start with all the way to 50PSI on a warm day. The temperature will go from whatever the outside temperature is, say 8c to high 20's, this because the rear wheel takes the heat from the engine and there is little fresh air ventilation to it.

The front wheel, because is at the front it takes far longer to heat up and the pressure won't increase as much. But both will go up.


This is another reason why if you need to top-up the tyres while riding is because you have an issue being either a puncture or a faulty wheel.

 

I only check and top up when cold. But the loss is small over days but is there. I may get them looked at if its a few psi per week.

the book says 36/36 for my bike, at my weight I have started to look at going higher on the rear to see how it feels. Took a while to get the suspension where I like it too. Yesterday went to 38 rear but do think 40 will be the sweet spot.. Im not massive by the way, only17st 4. But i see bikes seem t obe made for an average 10st male.. or so it seems.

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