Losing air..

[ninot7]

Am losing 1-2 psi from both tyres every week. 
stock pirellis with stock tubes. 
 

i have so far: snugged valve cores

checked with soapy water for leaks- nothing

 it’s really annoying me and i have several long distance trips planned. 
 

is this normal? 

[Windblown]

I wouldn't call it abnormal.   Sometimes tubes bleed off a bit of air. 1-2psi a week would likely not be enough to ever find air bubbles.  If it bothers you you can always toss in a new set of tubes, perhaps some HD tubes (don't go UHD).  The new tubes might bleed off a bit of air as well though.  Or if you don't want to swap tubes for whatever reason you could throw in some new valves just for kicks to see if it makes a difference. 

 

Bottom line: I wouldn't let that small amount of air loss keep me from taking any trips.

[ninot7]

Cheers. I’ll keep an eye on it. Got a 5 day coming up next month will test it out. Cant put HD as ill be tarmacing it all the way to latvia in summer

[Rider 101]

That is normal. Rubber is porous at the molecular level.

I believe if you use nitrogen the leak-off is less because of the longer chain molecule.

But then who has a nitrogen bottle in their shed?

[mpatch]

Are you checking when the actual tires are at the same temperature?

1-2 psi a week given same gauge, same temperature tells me you have a leak somewhere. 

[ninot7]

1 hour ago, mpatch said:

Are you checking when the actual tires are at the same temperature?

1-2 psi a week given same gauge, same temperature tells me you have a leak somewhere. 

 

same gauge. Same temp, cold tyres

[ninot7]

1 hour ago, Rider 101 said:

That is normal. Rubber is porous at the molecular level.

I believe if you use nitrogen the leak-off is less because of the longer chain molecule.

But then who has a nitrogen bottle in their shed?

 

i read it’s normal for natural rubber, butyl- which is what the stock tubes are made of, normally dont leak

[Rider 101]

I have an old XT600 in the shed which hasn't been used in 6 months. It has stock tubes and both tyres are flat on the bottom.

[mpatch]

12 minutes ago, ninot7 said:

 

same gauge. Same temp, cold tyres

Same temp is why I asked. 
This time of year my garage temperature fluctuates a lot and once everything gets cold inside it takes a few days of warmer weather to warm it up. 
The air temp might be 60° but everything in there is 40°. 

I can tell just by touching the tires they feel cold compared to the air temperature. 

[ninot7]

1 minute ago, mpatch said:

Same temp is why I asked. 
This time of year my garage temperature fluctuates a lot and once everything gets cold inside it takes a few days of warmer weather to warm it up. 
The air temp might be 60° but everything in there is 40°. 

I can tell just by touching the tires they feel cold compared to the air temperature. 

So my bike lives in a wooden garage and yes this time of year temp outside fluctuates. Room temp goes up but all the metal is still cold. 
 

[winddown]

Hell yeah it's normal.  I have 3 cars 3 bikes a trailer, 3 fridge trolleys, a ride-on mower, 6 pushbikes, and that's just off the top of my head.  I spend half my life pumping up tires and one thing I have learnt is that the smaller the tire the faster it loses air.  Thankfully my wheelbarrow has a solid rubber tire.  Oh yeah, I have 5 small air compressors and two are in plastic tool caddies along with little batteries to power them. 

[thepointchris]

I had similar issues after my first tire (and tube) change. I added some MucOff Sealant, which adds a little security,  but then discovered that the aging digital gauge on my floor-pump was off. Purchased a high quality Gauge..problem solved - no more losing air! For 1-2 psi, for sure a gauge and tire temp can make that difference. 

[AZJW]

9 hours ago, thepointchris said:

I had similar issues after my first tire (and tube) change. I added some MucOff Sealant, which adds a little security,  but then discovered that the aging digital gauge on my floor-pump was off. Purchased a high quality Gauge..problem solved - no more losing air! For 1-2 psi, for sure a gauge and tire temp can make that difference. 

Good point by Chris, a cheap tire gauge won't give consistent results. I've got a bunch of them for my vehicle glove boxes, but when it comes to checking my bikes I use a quality gauge. Also as noted, temperature swings will affect tire pressures so fluctuations of a pound or two,  even over the course of a few days isn't something to be overly concerned with. 

[winddown]

I think we all have the idea of a "perfect pressure" in out heads but the safe range is pretty broad.   I rode some fast street twisties the other day with the front @ 27, rear @28, and me a 100kg guy with 20kg of stuff onboard.  In reality I should have been  30/36 or whatever the book says but the bike handled like a dream so there is a lot of leeway in those numbers.  I came home on my rr a couple of months ago and it felt a little sluggish cornering, turns out the front tire had 15psi when it should have had 38psi.  That was a leaky valve, and that's crash pressures, I think I was being watched over that day.   Thankfully I wasn't really pushing it, I never do on that insane little thing.

 

 

 

 

 

 

 

[Lewie]

I need to check mine as I felt that dreaded wobble on the front and hope it’s just low pressure and not a faulty tire (original)

[DanDoesStunts]

On 3/17/2023 at 8:07 AM, ninot7 said:

Cheers. I’ll keep an eye on it. Got a 5 day coming up next month will test it out. Cant put HD as ill be tarmacing it all the way to latvia in summer

Any experience of HD tubes not liking tarmac?

 

I have always run UHD tubes with plenty of tarmac and off-road in 35-45deg C days without issue.

[DT675]

On 3/16/2023 at 4:14 PM, Rider 101 said:

But then who has a nitrogen bottle in their shed?

Well I do! 
 

(Heating/ air conditioning contractor )

[Rider 101]

On 3/18/2023 at 6:25 PM, DanDoesStunts said:

Any experience of HD tubes not liking tarmac?

 

I have always run UHD tubes with plenty of tarmac and off-road in 35-45deg C days without issue.

I always run UHD tubes. Highway speeds usually 100 - 120km/h

No issues and I run full knobbies front and rear.

[Windblown]

On 3/18/2023 at 3:25 AM, DanDoesStunts said:

Any experience of HD tubes not liking tarmac?

 

I have always run UHD tubes with plenty of tarmac and off-road in 35-45deg C days without issue.

 

Yep, I also have not personally experienced anything drastically bad about running UHDs at speed.  My only issue with UHD tubes on extended high speed pavement runs is the additional heat build causes  accelerated tire wear. Even if running higher cold pressures the additional heat build up in the tire is very noticeable. 

 

I swapped to ordinary HD tubes now for the bikes that see much pavement. 

[john_aero]

Not sure why but i find on nay tyre or vehicle I have or do own, when not in use the air drops more than those in use.

 

any bike I leave idle the tyres drop few psi, and those in regular use always stayed hard (has to be a pun in there somewhere)