H: Hubs, Wheels and Tyres Inner Tubes, Pressures and Argon Gas

Texas John

Well Known and Active Forum User
Non-VOC Member
Any of you had good luck with modern tubes? All the modern (past 5-10 years) tubes I have used leak; typical is 3 PSI per month (or more). I have some on bikes (garage queens) that are close to 40 years old that still hold air better. Even HD tubes made with butyl rubber. Tube suggestions welcome. Thank you.
 

Robert Watson

Well Known and Active Forum User
VOC Member
Like you I have had various success with different tubes. The latest tires went together with Michelin Airstop, so we'll see what happens....
 

Old Bill

Well Known and Active Forum User
Non-VOC Member
Like Robert l have been using Michelin tubes with good results, however trials type tubes are not suitable for road use long term as being of thick wall construction they have a tendency to overheat leading to failure according to several tube manufacturers. One other point is temperature pressure variation, which can vary up to 2-4 lbs, that is from cold to hot so probably the best way to check is immediately prior to a ride with the machine parked outside in its operating atmospheric temperature. A machine parked in my workshop which is cold with tyres set at 28psi will often read 26 when left outside for a short while so that may account for the variation? Mind how you go......
 

vibrac

Well Known and Active Forum User
VOC Member
see my comments on thicker MX tubes post #4 only went on the ride home
 

Texas John

Well Known and Active Forum User
Non-VOC Member
In one case for a tire sitting in my garage for a bike I am working on, I used a new (Maxim?) HD MX tube which lost 3-4 PSI per month which I tracked (date and PSI on a note) over a number of months. I changed the tube to an XHD one with same experience. No miles or weight were put on the tire. Yes, I am aware that temp can affect PSI but going from Jan to July there is not too great a temp spread in my garage (but on a warming trend) to account for the steady loss. I also replaced valve cores with new genuine Schrader cores which made no difference. Either it is the tubes or the metal valve stems are no longer made exactly right for cores to seal against them properly (something I have no way to test for or verify). I will probably replace it with something else when I am ready to use this bike, but not sure what at this point which is why I am looking for feedback from anyone who has had a recent good experience that they actually verified the air-holding ability of their tube(s).
 

danno

Well Known and Active Forum User
Non-VOC Member
I've found that most tubes I fit on my BMW R60/6 seem to slowly leak air. Using Michelin Airstop.
Frequently need to check pressures.
 

vibrac

Well Known and Active Forum User
VOC Member
I've found that most tubes I fit on my BMW R60/6 seem to slowly leak air. Using Michelin Airstop.
Frequently need to check pressures.
Dont think all these problems are the domain of tubed tyres
Be pleased you dont have a GS BMW that back tyre (tubeless) goes down weekly by a pound or so AND the dam electronics blink at you to tell you so, first amber then red!
(I suppose 2024 GS will actually cut the ignition :rolleyes:) . BMW tried to sort it, but of course as it wasn't cured.
My other BMW a 83 K100 had sat for 20 odd years in a dark garage I put new tyres on but did not renew the rim valve so she leaked now its sorted but then thats old technology as its VMCC eligible I took in on a wrinklies run and got two reasons for black looks 1. Its age its too young 2.I had my wife on the back;)
 

timetraveller

Well Known and Active Forum User
VOC Member
Oh dear! This is going to sound pompous but those who know me will tell you that is not my thing. However, when it comes to pressures and temperatures there is a thing called Boyle's Law, which can be written as
P1V1 + P2V2
T1 T2
where P is pressure, V is volume and T is the temperature(in degrees absolute
The volumes can be considered constant as the tyre does not change its size significantly. If we start off with a tyre at 7 deg C, i.e. 280 deg absolute and then increase the temperature to 27 deg C i.e. 300 deg absolute then the pressure will go up by 300/280 = 1.07
So if you start off at 30 lbs/inch squared it will go up to 32.1 lbs/inch squared.
 

Robert Watson

Well Known and Active Forum User
VOC Member
When racing we followed a 10% rule. The tire pressure was just right when an ambient temp pressure went up 10% when thrashed hard for a few laps.
 

Robert Watson

Well Known and Active Forum User
VOC Member
Another interesting tire thing was about using argon. When we ran the Lambky streamliner at Bonneville I had a long chat with a Goodyear engineer as we were running a shaved down Goodyear tire, so I asked about everybody using Argon.

He asked what we were doing with the tire and I told him we ran about 100- 110 psi on the salt, looking to run in the +200 mph range. He chuckled a bit and said plain old air would be fine. They use Argon mostly on NASCAR tires, because a change in tire pressures is often in the order of fractions of a psi. If the air has ANY water in it under these conditions it can boil and change the tire pressures slightly but in just about all cases this is not worth mentioning, however if 1/4 psi means turning a NASCAR (or perhaps and F1) tire or sliding it then argon is the way to go. He said just put in the 100 psi and carry on!
 
Top