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Puncture Predicament

Discussion in 'Touring and Adventure Cycling' started by HormyAJP, 5 May 2008.

  1. HormyAJP

    HormyAJP Well-Known Member

    Hello all,

    This is probably something that gets discussed all the time, but please forgive me if I display any ignorance as I'm fairly new to cycling.

    I recently bought a touring bike and have been cycling for several months without any problems. Now the weather's improving I've bought some pannier racks and have been attempting to go on day long cycles (previously I was just going out for a few hours with no load on my bike). Both times I've loaded up my pannier racks I have set off and got punctures in my rear tyre. The first time it happened after about 5 mins and the second after about 15. They were both complete blow outs and I heard and felt the pop.

    I was hoping for some suggestions as to why this has been happening. When I've replaced the inner tube each time I've been carful to check the inside of the tyre for debris. I've also checked my rims to make sure there's no problem there. The outside of the tyre has lots of small cuts, but they are only on the surface. None have penetrated the kevlar layer. I've also made sure that the inner tube is completely inside the tyre and not trapped where the tyre meets the rim. The holes in the innertube were in different places each time.

    I'm at a loss. I wondered if it was down to tyre pressure and perhaps the tyres being over inflated. However all the advice I've read says keep tyres pumped up as much as possible. I ride with my tyres at about 40 psi. Is this too high/too low or is there another obvious problem I should be checking for?

    Any help greatly appreciated.

    Thanks,
    Andy
     
  2. wallabyhunter

    wallabyhunter New Member

    Location:
    Perth WA
    Where abouts were the holes in the tube?
    Top (under the tread)
    Bottom (facing the rim)
    Sides?

    What sort of tyre, road tyre or mtb (700C or 26"?)
    Was there just one or two holes, 40 psi seems a bit low to me, if they are road tyres.
     
  3. jags

    jags Über Member

    i ride my marathon plus at 85psi 40 is way to low your on the rims at that pressure.do your self a favour get new tyres marathons plus or panaracer tour guards you wont have a problem try chainreaction for prices or spa cycles.
     
  4. john59

    john59 Guru

    Location:
    Wirral
    What tyres are you using? Have a look on the tyre wall to see the recommended psi, 40 psi does seem a bit low for loaded touring. The tyres I use range form 70 psi to 100 psi.

    John
     
  5. OP
    OP
    HormyAJP

    HormyAJP Well-Known Member

    Thanks for the replies. The tyres are road tyres, Continental Ultra Race (700x25) which came with the bike. The have a kevlar layer apparently.

    The holes in the inner tube were both on the sides.

    Sounds like it could be the tyre pressure causing the problem. Looks like I was way off the mark at 40psi. Do I need special inner tubes for higher pressures or will any inner tube cope with this? I may well look into getting some better tyres as well, but let me know if the ones I have are any good or not.

    Also, John, I couldn't find the tyre wall, where abouts is that?

    Thanks,
    Andy
     
  6. col

    col Veteran

    Hi hormy,it sounds like your getting snake bite punctures because the pressure is too low,and the tube is nipped between the road and wheel rim,just get them pumped right up,till they are hard,check the pressure on the side of the tyre too,thats the tyre wall by the way,the pressure figures should be printed on there.
     
  7. OP
    OP
    HormyAJP

    HormyAJP Well-Known Member

    Ha ha, excellent. I thought the tyre wall was something people could post info on on this site. The tyres can take a max of 120psi, which makes my 40 look a bit puny. If I don't need special inner tubes then I'll give it a go with pressure at more like 80 and see what happens.

    Thanks everyone (although if there are more suggestions then please keep adding),

    Andy
     
  8. Brock

    Brock Senior Member

    Location:
    Kent
    Take them right up to 120, you'll find the bikes rolls along much easier, and it'll help prevent punctures. You don't need special inner tubes, assuming the ones you have are the correct size.
     
  9. Bigtallfatbloke

    Bigtallfatbloke New Member

    I have my marathon pluss pumped up to 95psi..on my old tyres I had them at 100psi...i alos think your problems are caused by low pressure.
     
  10. Fab Foodie

    Fab Foodie hanging-on in quiet desperation ...

    Hi Hormy AJP, welcome.

    Good advice given. Strongly suggest you get a track pump (Joe-Blow Sport approx £20) to get your tyres at the right high pressure. The difference will be enormous. What you describe are "Snake-bite" P*nctures caused by too low pressure, get 'em up to 100psi at least.
     
  11. HJ

    HJ Cycling in Scotland

    Location:
    Auld Reekie
    The pressure is definitely too low Conti recommend that the Ultra Race should be inflated to 95 psi (for the 700 x 25) with 120 psi as the max. Given that you are carrying loads, 100 + psi would make sense for the rear tyre.
     
  12. HJ

    HJ Cycling in Scotland

    Location:
    Auld Reekie
    Thinking about it, if you are planning to carry loads a 700 X 25, might be a wee bit narrow. You might think about 700 x 28 which would give you a more comfortable ride without sacrificing to much speed, something like Conti GatorSkins, but that is more of a personal choice.
     
  13. Dougster

    Dougster New Member

    What do you do if you get a puncture while on tour? Is it possible to get the tyres up to these high pressures using a small hand pump?
     
  14. jags

    jags Über Member

    depends on the pump,zefal is a great pump, as is blackburn frame pumps
     
  15. rich p

    rich p ridiculous old lush

    Location:
    Brighton
    Do the best you can and pop into the next bike shop you see for a borrow of a track pump.

    Back to OP, I did once have a problem with a tiny split on the side wall which was almost impossible to see on close inspection but with the extra weight of rider and pannier caused a blowout after 100 metres or so. I kept assuming I'd trapped or pinched the tube with a lever as they were a bugger to get on and I only found out after I got home.