Can you over inflate??

Discussion in 'Bicycle Mechanics and Repairs' started by pda, 9 Apr 2010.

  1. pda

    pda Active Member

    Can you over inflate tyres? I borrowed my mates floor pump and put 120psi into both my wheels. On the ride home my bones were shaking, on smooth bits of road all was fine but on the cycle path or any uneven terrain I thought something was going to break.

    Did I put too much air in?

    Cheers
     
  2. gaz

    gaz Cycle Camera TV

    Location:
    South Croydon
    Whats the recommended pressures on your tyres? i pump mine up to 135PSI every time i go out.
     
  3. aJohnson

    aJohnson Senior Member

    Location:
    Bury, Manchester
    When the pressure is higher you'll feel the bumps more.

    I have no idea what I inflate mine to as I'm puzzled by my gauge, but I pump them so I can just squeeze them in a little.
     
  4. Bayerd

    Bayerd Über Member

    Won't they pop once there's too much pressure in them?
     
  5. Gerry Attrick

    Gerry Attrick Lincolnshire Mountain Rescue Consultant

    The pressure you use is dependent on your weight, the tyre size and the road surfaces you expect to experience. The maximum pressure recommended by the manufacturer is, IMHO, to be used on a perfectly smooth surface such as a track. Using too high a pressure not only causes a harsh ride, but can result in poorer grip due to tyre hop on rough bends. On the other hand, too low a pressure can result in a distinctly unsafe ride due to lack of grip and a tendency to p***tures.

    As in many things, the ideal is somewhere between. You can only experiment to find your ideal. If it helps, I am 11 stone in weight and use 23mm tyres on my road bike. I use 90psi in the rear and 80psi in the front. I find this an excellent compromise between comfort and grip and p***ture resistance. (No p***ture in three years).
     
  6. OP
    OP
    pda

    pda Active Member

    min - 100 max -130psi
     
  7. youngoldbloke

    youngoldbloke The older I get, the faster I used to be ...

  8. PpPete

    PpPete Guru

    Location:
    Chandler's Ford

    Very interesting indeed.
    Looks like I should, at the very least, be lowering the pressure in my front tyre. I shall try it, especially as been getting some numbness in the hands on longer rides, this might help.
     
  9. Berto's 15% drop theory is interesting but his graph becomes less and less believable at the extremes: 155+PSI for my back tyre?

    I know bike shops whose equipment cannot achieve such pressures, and I suspect neither can the the majority of road bike owners.
     
  10. youngoldbloke

    youngoldbloke The older I get, the faster I used to be ...

    - or tyres/worn rims withstand such pressures?
     
  11. Hilldodger

    Hilldodger Über Member

    Location:
    sunny Leicester
    You'll struggle to put enough pressure into a tube with a bike pump.
     
  12. GrasB

    GrasB Veteran

    Location:
    Nr Cambridge
    +1... the numbers don't make good sense to me. My partner should be running around 50/60psi front/rear on her 700x23c tyres, I'm sorry but that's just wrong! For me it comes out at a semi-resonabe 80/100psi for 700x23s but even at those pressures the front will wander around & there's a highish risk of pinch punctures. For 700x28c comes out at 60/70psi which is well into treacle territory for rolling resistance & will cause handling problems.
     
  13. GrasB

    GrasB Veteran

    Location:
    Nr Cambridge
    but on long hill descents you're far more likely to pop the tyre/tube.
     
  14. PpPete

    PpPete Guru

    Location:
    Chandler's Ford
    Well under the graphs it does point out that:

    (I have corrected his "colonial" spelling)

    But as you say Mickle - less believable at the extremes.

    I don't know that I'd want to go above the tyre manufacturer's recommended pressure anyway, whatever Berto's theory says. And I'm sure LBS won't either in this litigous age.

    OTH it makes think that whilst inflating my rear tyre (25mm) to its rated max 115psi is probably correct for my bike and weight, 115 psi maybe too much at the front.
     
  15. PpPete

    PpPete Guru

    Location:
    Chandler's Ford
    You're a lightweight !:smile:

    Well if you will go running round with these "size zero" models :blush:

    Yup less believable at that extreme too.
     
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