Pinch flat cure?

zedhead
zedhead Posts: 109
edited July 2010 in MTB beginners
Just wondered what you think the best solution is to reduce the number of pinch flats...
Is it sky high tyre pressure?
Tyres with thick and inflexible (nad heavy) walls?
Or thick inner tubes (ie 1.3 or 1.5mm thick rubber)?
Or treated tubes with gunk in them?

Or just accept that they happen and always carry a spare tube or two... :roll:
Early Orange 5, Felt Z85, Scott Thicko, modified Giant full suss (both nicked)- beat-up single-speed rigid 1992 Saracen (scrapped), and various 2-wheelers with big engines
«1

Comments

  • tri-sexual
    tri-sexual Posts: 672
    just increase the pressures, but not to sky high levels
  • bennett_346
    bennett_346 Posts: 5,029
    The tyre makes a huge difference, id stay away from relying on changing the pressure, too high and you cant get the traction you need. Go for a high volume tyre. Also, if you dont mind the weight, filled tubes are pretty good IMO. They wont fit in small tyres though.
  • Anonymous
    Anonymous Posts: 79,666
    Or think about either getting wider rims or even better going tubless.
  • antikythera
    antikythera Posts: 326
    tubulars :twisted:
  • robertpb
    robertpb Posts: 1,866
    Most pinch flats are cured by changing the rider input. :)
    Now where's that "Get Out of Crash Free Card"
  • Anonymous
    Anonymous Posts: 79,666
    wider rims sorts it out almost completely.
  • IDave
    IDave Posts: 223
    Can someone please explain to me what a pinch flat is, and what causes it?

    Thanks
  • -liam-
    -liam- Posts: 1,831
    Tube becoming squeezed between the rim and a hard object such as a rock. Normally 2 punctures the width of the rim apart.
    Kona Fire Mountain
    Kona Kula
    Duster
    Mmmbop
  • Anonymous
    Anonymous Posts: 79,666
    -Liam- wrote:
    Tube becoming squeezed between the rim and a hard object such as a rock. Normally 2 punctures the width of the rim apart.

    Yep, basically not like puncture from a thorn or piece of glass puncturing the inner tube, but a puncture caused by the inner tube being squeezed between the edges of the rim and the tyre.

    As said you normally get two holes in the inner tube opposite each other, were each side of the rim has made a hole in the inner tube. Imagine a snake bite, hence why when I was growing up we always used to call them "snakebites".
  • IDave
    IDave Posts: 223
    Thanks for clearing that up for me. I have seen them mentioned in a few posts and wasn't quite sure what they refered to.
  • zedhead
    zedhead Posts: 109
    robertpb wrote:
    Most pinch flats are cured by changing the rider input. :)
    Would you care to elabrate on that? :wink:
    Early Orange 5, Felt Z85, Scott Thicko, modified Giant full suss (both nicked)- beat-up single-speed rigid 1992 Saracen (scrapped), and various 2-wheelers with big engines
  • TowerRider
    TowerRider Posts: 430
    Surely need to know his current pressure, weight e.t.c. increase pressure would be what I would try.
  • zedhead
    zedhead Posts: 109
    TR - I'm 13 1/2 stone, riding my full suss Scott 'Thicko', not an especially hard rider (I don't think), but had pinch flat issues at Lee Quarry last week, having never experienced them before. Tyres are Panaracer Fires, but dunno what pressure, just squeezable! I had actually put a bit more wind in the back tyre shortky after arriving at Lee Quarry, due to the stony nature!
    Early Orange 5, Felt Z85, Scott Thicko, modified Giant full suss (both nicked)- beat-up single-speed rigid 1992 Saracen (scrapped), and various 2-wheelers with big engines
  • piker
    piker Posts: 353
    zedhead wrote:
    TR - I'm 13 1/2 stone, riding my full suss Scott 'Thicko', not an especially hard rider (I don't think), but had pinch flat issues at Lee Quarry last week, having never experienced them before. Tyres are Panaracer Fires, but dunno what pressure, just squeezable! I had actually put a bit more wind in the back tyre shortky after arriving at Lee Quarry, due to the stony nature!
    Had the same problem when i went to lee quarry 3 pinch flats after never having them before,did a ghetto tubeless set up and went back a couple of weeks ago and had no problems.Was it the new set up or me just riding lighter i dont know but so far so good.
  • sailor74
    sailor74 Posts: 48
    different tyres will give different results, i was pinch flatting 2.35 highrollers at 30psi, i have had no problems running 2.4 Rubber Queens on the same trails as 22psi.

    Going tubeless will cure it completely, try a bit more pressure in your current tyres, or try something with a bit more volume.
  • cavegiant
    cavegiant Posts: 1,546
    Is no-one going to mention the cheap 100% cure of this?

    Google and youtube Ghetto tubeless
    Why would I care about 150g of bike weight, I just ate 400g of cookies while reading this?
  • Anonymous
    Anonymous Posts: 79,666
    cavegiant wrote:
    Is no-one going to mention the cheap 100% cure of this?

    Google and youtube Ghetto tubeless
    Not a 100% cure, I've had problems with tubeless conversions - I still have a love/hate thing with it.
  • gazeddy
    gazeddy Posts: 305
    i used to use an old tyre inside the tyre. was a night mare getting on the rim but was absolutely punctureproof problem is it weighed a ton. even better when the tyres i was using at the time were 3quid a pair
    I rode what you dug last summer
  • BigShot
    BigShot Posts: 151
    I had one "snakebite" after another years ago. I popped into a bike shop near my college and they suggested a thicker innertube.

    I can't remember the brand or model name, but it's bright green and has a bright green dustcap... which probably means absolutely nothing worth knowing. It's not a slime tube though.

    In the hand it's noticeably heavier than a regular tube, on the bike, I dunno. I can't say I felt much difference when it went on and that was a LONG time ago so wouldn't know the difference now.

    All I know is without any changes in riding style, pressures, tyres or anything else I've not had another flat since. *touch wood*
  • Anonymous
    Anonymous Posts: 79,666
    BigShot wrote:
    I can't remember the brand or model name, but it's bright green and has a bright green dustcap... which probably means absolutely nothing worth knowing. It's not a slime tube though.
    I know the exact one you mean, but I'll be damned if I can remember what they were called.
    They were VERY popular among DH and trials riders.
  • BigShot
    BigShot Posts: 151
    The fella in the shop did say something along those lines too. I might be mistaken but they may have come in a couple of different weights, one for DH and another for a slightly more or slightly less heavy use (can't remember which way it went now).

    It's no wonder they were popular though - I thought they were a bit pricey at the time but in no time at all I was delighted with them. Probably the best value for money part of all considering the price and service life! :P
  • Dirtynap
    Dirtynap Posts: 28
    yeehaamcgee wrote:
    cavegiant wrote:
    Is no-one going to mention the cheap 100% cure of this?

    Google and youtube Ghetto tubeless
    Not a 100% cure, I've had problems with tubeless conversions - I still have a love/hate thing with it.

    Please expain how you pinch flat an inner tube if you don't have one?

    You can break the seal or roll the tyre off the rim when running tubeless.
  • Anonymous
    Anonymous Posts: 79,666
    well, instead of pinch flatting, the tyre burped, then on the next hit (I guess) the tyre's sidewall was destroyed.
  • Anonymous
    Anonymous Posts: 79,666
    BigShot wrote:
    I can't remember the brand or model name, but it's bright green and has a bright green dustcap... which probably means absolutely nothing worth knowing. It's not a slime tube though.
    Hutchinson Green tubes! I remembered! :D
  • cavegiant
    cavegiant Posts: 1,546
    yeehaamcgee wrote:
    well, instead of pinch flatting, the tyre burped, then on the next hit (I guess) the tyre's sidewall was destroyed.

    So how many flats have you had tubeless compared to non tubeless?

    It is not a 100% prevention of flats, just a 99%, but is almost impossible to pinch flat.

    I have had a few flats on tubeless, probably less than 5, I would not be surprised if I was nearing 3 figures of tube flats.

    Tubless also lets me run 10/20 psi, so have a mile of grip and a reduced rolling resistance.

    It is not perfect, but it is a mile better than tubes.
    Why would I care about 150g of bike weight, I just ate 400g of cookies while reading this?
  • paulbox
    paulbox Posts: 1,203
    cavegiant wrote:
    Tubless also lets me run 10/20 psi, so have a mile of grip and a reduced rolling resistance.
    I thought that higher pressures reduced rolling resistance... :?
    XC: Giant Anthem X
    Fun: Yeti SB66
    Road: Litespeed C1, Cannondale Supersix Evo, Cervelo R5
    Trainer: Bianchi via Nirone
    Hack: GT hardtail with Schwalbe City Jets
  • Anonymous
    Anonymous Posts: 79,666
    cavegiant wrote:
    Is no-one going to mention the cheap 100% cure of this?

    Google and youtube Ghetto tubeless
    cavegiant wrote:
    It is not a 100% prevention of flats, just a 99%, but is almost impossible to pinch flat.

    Precisely my point, although it does massively reduce the chances, it isn't a 100% cure.
  • bennett_346
    bennett_346 Posts: 5,029
    PaulBox wrote:
    cavegiant wrote:
    Tubless also lets me run 10/20 psi, so have a mile of grip and a reduced rolling resistance.
    I thought that higher pressures reduced rolling resistance... :?
    +1
  • Anonymous
    Anonymous Posts: 79,666
    higher pressure will reduce rolling resistance on smooth surfaces, but, up to a certain point, obviously, lower pressures can give lower rolling resistance over bumpy surfaces.
    this is because the tyre will deform over small rocks and suchlike instead of having to roll up on top of them.
  • tjwood
    tjwood Posts: 328
    yeehaamcgee wrote:
    higher pressure will reduce rolling resistance on smooth surfaces, but, up to a certain point, obviously, lower pressures can give lower rolling resistance over bumpy surfaces.
    this is because the tyre will deform over small rocks and suchlike instead of having to roll up on top of them.

    Rolling resistance in tyres mainly caused by the tyre wall deforming. Such flexing of the tyres heats them up, which causes energy to be lost. (Like if you play with a ball of blu-tack, strecthing it repeatedly, it gets hot). Riding over bumpy (but firm) surfaces, the tyre won't deform any less, so the rolling resistance isn't lower.

    Riding over loose surfaces (e.g. dry sand) the surface itself may deform, and this energy lost to the surface may form part of the rolling resistance. I suppose if you had soft tyres then there would be a larger contact area on sand therefore less pressure on the surface so less deformation of the surface, but probably not as significant as the fact that with lower tyre pressures your tyre walls flex more. And on sand most of the rolling resistance is due to the deformation/displacement of the sand no matter what pressure your tyres.

    http://en.wikipedia.org/wiki/Rolling_resistance

Categories