Tubeless pressures increasing

mitchgixer6
mitchgixer6 Posts: 729
in Workshop
Hi all

Just wondering if anyone else has had the same experience as I have? Recently converted my road wheels to tubeless (non tubeless rims, schwalbe pro one tyres), and I have noticed that the pressures increase after a ride by 2-3 psi.

Have been setting front to 83, rear to 87 pre ride, but both have gone up after roughly an hours riding. I thought this may have been in relation to heat build up in the tyres/air, but today I checked them about 3 hours after my ride and they were still sitting about 85.5/90 psi. Also temperatures here in Scotland have been pretty low recently, about 3 degrees today. I'm using a digital pressure guage.

Anyone any ideas what's happening?

Comments

  • thecycleclinic
    thecycleclinic Posts: 395
    Faulty gauge? Self inflatjng tyres?
    www.thecycleclinic.co.uk
  • mitchgixer6
    mitchgixer6 Posts: 729
    Pretty sure the gauge is OK. Get the same readings 3 or 4 times in a row, and that's twice I've seen this. Tyre pressures will drop again over the course of a few days as per normal with any tyre/tube combination. The pressures only go up after a ride and will then steadily fall again.

    It's the same as car tyres, warm pressures are higher than cold pressures due to the heat generated from movement. In theory should be the same for bike tubeless, maybe more so as the air volume is much lower/higher pressures. I'm sure this is the cause, but was curious to see if anyone else has had the same.
  • veronese68
    veronese68 Posts: 27,297
    Sounds like a case of too much information, I don’t check pressure after a ride unless there is a problem. I also don’t need to know my pressure that accurately.
    Digital readouts are unnecessarily accurate. I don’t need to know temperature beyond the decimal point or time to the second. Same applies to tyre pressure for me.
    I suspect your reasoning is correct, but I’m happy in blissful ignorance on this one.
    Kinesis Pro6
    Marin Nail Trail
    Cotic Solaris
  • Charlie_Croker
    Charlie_Croker Posts: 1,698
    2 or 3 pounds per square inch is neither here nor there, I’d of thought. Can you feel the difference in the ride? I’d of thought not. But if you really are that bothered about being that precise, you need to get your gauge professionally calibrated before you start.
    Mountains and molehills are springing to mind
  • lesfirth
    lesfirth Posts: 1,382
    veronese68 said:

    Sounds like a case of too much information, I don’t check pressure after a ride unless there is a problem. I also don’t need to know my pressure that accurately.
    Digital readouts are unnecessarily accurate. I don’t need to know temperature beyond the decimal point or time to the second. Same applies to tyre pressure for me.
    I suspect your reasoning is correct, but I’m happy in blissful ignorance on this one.

    A digital readout is very precise but not necessarily accurate.
    Mitch, I think you need something else to worry about. Chill out and go and ride your bike.
  • mitchgixer6
    mitchgixer6 Posts: 729
    Thanks for the very helpful posts there guys, honestly why bother?

    I'd only checked the pressures post ride to make sure I hadn't lost any significant amounts of air as its a new set up. I'm not that bothered about the pressures being that accurate. But I thought with tubeless becoming more popular then someone may have noticed the same. I'll not bother sharing the next time.
  • orraloon
    orraloon Posts: 12,673
    Outside of raised internal temperatures I cannot think of a physical reason why the pressure would be higher post ride. I tend to be more focused on the 'is it lower pressure?' i.e. do I have a leak? angle myself.
  • Charlie_Croker
    Charlie_Croker Posts: 1,698
    mitchgixer6 said:

    Have been setting front to 83, rear to 87 pre ride, but both have gone up after roughly an hours riding...

    I'd only checked the pressures post ride to make sure I hadn't lost any significant amounts of air as its a new set up.

    I'm not that bothered about the pressures being that accurate.

    ? well I'm confused :/
  • mitchgixer6
    mitchgixer6 Posts: 729
    I was wondering if it was a known phenomenon, or if there is maybe something else going on with my set up. If I had written 'I need my pressures to be accurate to 0.5psi in order to satisfy my ocd' then I could understand your confusion.
  • veronese68
    veronese68 Posts: 27,297
    I’ve heard of it in cars and motorbikes, so I guess it’s the same thing. No other explanation I can think of.
    But I only ever thought about not enough pressure on my bicycles.
    Kinesis Pro6
    Marin Nail Trail
    Cotic Solaris
  • david37
    david37 Posts: 1,313
    mitchgixer6 said:

    Thanks for the very helpful posts there guys, honestly why bother?

    I'd only checked the pressures post ride to make sure I hadn't lost any significant amounts of air as its a new set up. I'm not that bothered about the pressures being that accurate. But I thought with tubeless becoming more popular then someone may have noticed the same. I'll not bother sharing the next time.

    looks like his tyres aren't the only thing with rising pressure :D
  • ugo.santalucia
    ugo.santalucia Posts: 28,237
    PV = nRT

    Volume is constant, R is a constant, n (moles of gas) is assumed a constant in this scenario, therefore pressure increases linearly with temperature in your tyre. Now go out on your bike and stop worrying about stupid things
    left the forum March 2023
  • singleton
    singleton Posts: 2,495
    How can there be more air in the tyre after a ride?
    If the pressure is higher then it must only be a temporary change.
    I suggest you check at hourly internals and see the point where the pressure returns to the pre-ride level.

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