Rear tyres running very flat!! Am I too big?

bigjayuk Posts: 7
edited January 2010 in MTB beginners
Hello All, This is my first post so please take it easy on me as I guess to someone a bit more 'in the know' it may seem like a noddy question. Problem is, I'm a big guy 6'6" and close to 19 stone (270lbs) and every time I ride my bike (Scott Aspect by the way) my back tyre is very, shall I say squashed looking. The question is, is this the inner tubes I have or am I too big?......if it is I'm in a catch 22 as I got my bike to lose weight. Hope you can help MTB world, I'm really eager to get started but don't want to push too hard for fear of damaging the tyre/tube/wheel. If it helps my tyres are inflated to the point where they feel really hard (sorry not sure of PSI's).
Any advice is greatly appreciated, even if its lose weight first :D
Thanks, Jay.
Orbea (for my sins)


  • supersonic
    supersonic Posts: 82,708
    You need a pump and a guage, and to experiment.
  • AndyOgy
    AndyOgy Posts: 579
    As usual, the advice from Supersonic is accurate and to the point.

    I'd also like to add that 19st doesn't even put you close to some of the heavyweights that use this forum. You should check out some of the posts by GB155 (mostly in the commuting section). He has lost about as much as you weigh.

    You may well get punctures and damage your wheels. But this is just par for the course and nothing to do with your weight.

    I really do wish you all the very best in your mission to shed some weight. And I recommend that you check out posts by GB155. He is truly inspirational.
  • I have found that my back wheel always look flat when im sat on the bike looking down at it. If you manage to get a picture of it with you sat on it probably isn't nearly as squashed as you think.

    Go big or go home.
  • im glad to see im not the only 1 who has had this type of problem, im 5ft 10 and slightly heavier than you and when i started riding again just over 6months ago i suffered with the same tyre/inner tube issues and also thought "am i just too big to be on a bike" but how do i loose weight doing what i love if i dont :?

    so i had a think i decided to change a few bits n see how i went, after getting several pinch flats because my tyres where pumped up so hard it was over stressing the tubes i popped in my LBS an swopped a few bits....

    swopped my 1.75 - 2.1 tubes for 2.3 - 2.7 dh tubes
    swopped my 2.1 xc tyres for fast rolling 2.35 dh tyres
    swopped my flimsy single wall alloy mtb wheels for a set of double wall xc rims on shimano hubs.... (buckled my cheap alloy back wheel twice)

    6months happy flat free riding later 8)

    in answer to your question NO your never to big to ride u just after to make a few changes to suit!!

    hope this helps a bit
    CUBE ltd 2012,reba sl, XT, saint, DMR, spank, current xc/am ride

    GIANT boulder, marzzochi EXR, LX/alivio, DMR, spank, retro build
  • diy
    diy Posts: 6,473
    There shouldn't be a problem running the tyres too soft, you might get the odd pinch flat and cross up the tyres occasionally under load, but this is par for the course. Just remember, the one thing about cycling is that the heavier you are the more calories you will burn per hour cycling. If you can get 4 hours a of quality riding in per week it will be roughly equive to going without food for a day.
  • Father Faff
    Father Faff Posts: 1,176
    Get a floor standing track pump with built in guage - save you a load of effort. You want to make sure your tyres are at least pumped up to 40psi, and as the previous poster has said consider bigger volume tough tyres and tubes if your bike frame will take them.
    Commencal Meta 5.5.1
    Scott CR1
  • asdfhjkl
    asdfhjkl Posts: 333
    north-sure wrote:
    I have found that my back wheel always look flat when im sat on the bike looking down at it. If you manage to get a picture of it with you sat on it probably isn't nearly as squashed as you think.


    At 20psi my back tyre looks "flat", at 40psi it looks fine. Like supersonic said - just experiment with pressures to find what works best for you.

    Good luck with your goals to lose weight - you can do it! :)
  • Hi

    I have the same issue - 6'5" & 20 stone.

    I have 2.10 tyres and run at 50-55 PSI when XC and using "nobblies" and 65 PSI when on the road with semi-slicks. These amounts suit me fine and and I have only had 1 puncture since I started riding 9 months ago.

    I realise that the PSI may seem high to some people but I always think that the tyre looks too flat at a lower PSI.

    Cheers, BC

    PS - I was 23 stone when I started so keep it's worth it!!
  • Anything over 30psi will feel pretty solid to touch, but when riding, the difference between that and 60psi is massive. I remember pumping my BMX tyres up to 60 years ago because the flatlanders used to do it....the tyre was only rated up to about 35 and soon started bubbling out of the sold sidewalls. It's a lot of of pressure and more than you will get from a cheap small bike pump. In a nutshell, just pump some more air into the sucker.
  • I am 19st and I find 40 to 45psi is the ideal for my hard tail. Anything over 45psi I find the rear skips across the rocky gravel which is part of my local trail.

  • missmarple
    missmarple Posts: 1,980
    Is this not common sense and the laws of physics? You're gonna compress the air inside the tyre when you apply external pressure hence the reason it looks squashed, just add another 15psi to compensate......
  • stevet1992
    stevet1992 Posts: 1,502
    Flicking through i read your username as "biggayuk" :shock: :lol:

    As said above ... Bit more pressure in your tyres if you can !
    On-One 456 Sainsburys Season

    Calling All SouthEastern Riders