Tyre pressure calculator

Pickled Pig
Pickled Pig Posts: 233
edited May 2016 in Road general
Having read the debate about 23 v 25 tyres I found a tyre pressure calculator which tells you what you should be running based on 15% tyre drop:
http://www.dorkypantsr.us/bike-tire-pressure-calculator.html

Sorry if this has been posted before; couldn't find it in a forum search.

Comments

  • White Line
    White Line Posts: 887
    If I followed this I imagine my front tyre would roll off my rim on the first corner I take ...
    Emiliana the CAAD9
  • slowondefy2
    slowondefy2 Posts: 348
    It's a good calculator. It uses the graph from the "Bike Quarterly" publication: http://www.bikequarterly.com/images/TireDrop.pdf , on the basis that a 15% 'drop' is ideal when the tyre is under load. Whether the whole 15% thing is absolutely right or not is a matter of debate(!), but it's a good starting point.

    The most useful calculator on the page is the second one down.
  • andy46
    andy46 Posts: 1,666
    I tried this one, you can also download it onto your smartphone.

    http://www.vittoria.com/app/
    2019 Ribble CGR SL

    2015 Specialized Roubaix Sport sl4

    2014 Specialized Allez Sport
  • cougie
    cougie Posts: 22,512
    That's bobbins. It has my pressures waaay too high.
  • Tom Dean
    Tom Dean Posts: 1,723
    According to that I should either use 79/122 F/R or just put 187 in both.
  • Graydawg
    Graydawg Posts: 673
    lol - 180psi in the rear tyre. :|
    It's been a while...
  • racingcondor
    racingcondor Posts: 1,434
    61 psi in the front tyre? Hmm...

    96 in the rear is about right though.
  • drlodge
    drlodge Posts: 4,826
    I was out yesterday on a longer ride, pressures were 110lb front and rear (23c), but I suffered vibration and pins and needles in my left hand. I'll try a slightly lower pressure in the front, say 100lbs...worth a try but I am very aware that lower pressures increase the risk of pinch flats.
    WyndyMilla Massive Attack | Rourke 953 | Condor Italia 531 Pro | Boardman CX Pro | DT Swiss RR440 Tubeless Wheels
    Find me on Strava
  • Pickled Pig
    Pickled Pig Posts: 233
    drlodge wrote:
    pressures were 110lb front and rear (23c), but I suffered vibration and pins and needles in my left hand.

    Are pins and needles a symptom of tyres too hard? I get them and ride with with 115psi front and rear.
  • drlodge
    drlodge Posts: 4,826
    Pickled Pig wrote:
    drlodge wrote:
    pressures were 110lb front and rear (23c), but I suffered vibration and pins and needles in my left hand.

    Are pins and needles a symptom of tyres too hard? I get them and ride with with 115psi front and rear.

    Not sure, but I think so...only get pins and needles in my left hand, and there is a fair bit of vibration coming through to the bars. Won't help to make things smoother :)

    Will try my front type at 100 or 90lbs, won't go lower than that though. Which means I won't pump the tyres up for a week or possibly 2, they'll be down to that pressure by then!
    WyndyMilla Massive Attack | Rourke 953 | Condor Italia 531 Pro | Boardman CX Pro | DT Swiss RR440 Tubeless Wheels
    Find me on Strava
  • cookeeemonster
    cookeeemonster Posts: 1,991
    my tyres state 115psi minimum and 160psi maximum...so I run them at 130 front and 140 rear.

    thoughts? Should I ignore this? They are vredestein fortezza tricomp's (23c)
  • drlodge
    drlodge Posts: 4,826
    CookeeeMonster wrote:
    my tyres state 115psi minimum and 160psi maximum...so I run them at 130 front and 140 rear.

    thoughts? Should I ignore this? They are vredestein fortezza tricomp's (23c)

    They're race tyres though and tubulars, totally different use to "Sportive" or leisure riding.
    WyndyMilla Massive Attack | Rourke 953 | Condor Italia 531 Pro | Boardman CX Pro | DT Swiss RR440 Tubeless Wheels
    Find me on Strava
  • andy46
    andy46 Posts: 1,666
    The link I put on for the pressure calculator seems to work for me. 100psi front, 105psi rear.

    Sounds about right. My tyres range are 87psi to 116psi.
    2019 Ribble CGR SL

    2015 Specialized Roubaix Sport sl4

    2014 Specialized Allez Sport
  • rsilvers
    rsilvers Posts: 70
    Says I need 156 psi for my 25mm. Um, I don't think so. I ride around 90psi. I am 65kg.
  • apreading
    apreading Posts: 4,535
    rsilvers wrote:
    Says I need 156 psi for my 25mm. Um, I don't think so. I ride around 90psi. I am 65kg.

    did you put your weight + bike in the top section, headed 'Weight measured at wheel'? That is the weight measured at EACH wheel, so if your weight is distrubuted 50/50 between the wheels, the weight at each wheel will be half of the total.
  • kingstonian
    kingstonian Posts: 2,847
    drlodge wrote:
    Pickled Pig wrote:
    drlodge wrote:
    pressures were 110lb front and rear (23c), but I suffered vibration and pins and needles in my left hand.

    Are pins and needles a symptom of tyres too hard? I get them and ride with with 115psi front and rear.

    Not sure, but I think so...only get pins and needles in my left hand, and there is a fair bit of vibration coming through to the bars. Won't help to make things smoother :)

    Will try my front type at 100 or 90lbs, won't go lower than that though. Which means I won't pump the tyres up for a week or possibly 2, they'll be down to that pressure by then!


    Funny - I only get it in my left hand too, may try lessening the tyre pressure and see if it makes a difference
  • cougie
    cougie Posts: 22,512
    Pal of mine has been riding his vredestein tyres for the last few weeks and getting nasty pains in his neck and back.

    He's followed the advice on that calculator and lowered the pressure a lot. He's loving the difference in the ride comfort.

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