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How hard it 30psi?!

concordeconcorde Posts: 1,111
edited January 2013 in MTB beginners
Kind of a stupid question I know. But I've always pumped up my tyres just til they 'felt ok' and rode. For Christmas I had a track pump with built in gauge. I pump up my tyres and they're way way way harder than I've ever had them before and the gauge is showing about 25psi! I'm talking as hard so the back barely changes shape when the bike is sat on (hardtail). Dodgy gauge?
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  • warpcowwarpcow Posts: 1,448
    Dodgy gauge?

    Possibly (probably even). Even with my track pump, I now know where on the gauge is what I used to just think of as 'feeling about right'. From there I can at least know how much up or down I'm messing around with.
  • concordeconcorde Posts: 1,111
    Hmmmm, going to have to find someone with a tidy track pump and compare!

    Cheers
  • Chunkers1980Chunkers1980 Posts: 8,035
    The only reason to use psi is as a reference when you know what you want.

    Otherwise your feel is the best way, pump it to the deformation you require take note of the psi. And as long as your gauge is accurately inaccurate it is fine.
  • I would definitely check the gauge.
    I blew one of my inner tubes when my gauge broke. I was in my garage at the time.
    The f-ing thing sounded like someone had shot a gun next to my ears. They were still ringing 30 minutes later.
    2007 Felt Q720 (the ratbike)
    2012 Cube Ltd SL (the hardtail XC 26er)
    2014 Lapierre Zesty TR 329 (the full-sus 29er)
  • concordeconcorde Posts: 1,111
    The only reason to use psi is as a reference when you know what you want.

    Otherwise your feel is the best way, pump it to the deformation you require take note of the psi. And as long as your gauge is accurately inaccurate it is fine.

    That's the thing, I want a reference point now so I can experiement.
  • PlyphonPlyphon Posts: 433
    It doesn't really matter what your gauge says, it could say Cow, Chicken, Dog, Rabbit, Moose, and if you know that you like your tires halfway between Chicken and Dog, thats where you pump to every time :)

    You'll only get truly accurate gauges on like £100 quid plus pumps, probably.
  • concordeconcorde Posts: 1,111
    Plyphon wrote:
    It doesn't really matter what your gauge says, it could say Cow, Chicken, Dog, Rabbit, Moose, and if you know that you like your tires halfway between Chicken and Dog, thats where you pump to every time :)

    You'll only get truly accurate gauges on like £100 quid plus pumps, probably.

    It does make a difference though as it's hard to tell where I am, the scale on it will be all to censored , so hard to see. THe pump shoulnd't be way off if it's a cheap one, I reckon there's 45/50 psi in my rear tyre and my pump is saying about 20! So if I wanted to drop it to 35 psi the gauge will be difficult to read whether I have or not. Think I'll send the pump back.
  • The RookieThe Rookie Posts: 27,747
    Check the pressure by borrowing a guage.....point is though as long as it reads 15psi every time it's at really at 30 it doesn't matter.
  • LJ.LJ. Posts: 149
    30psi is pretty hard on my tires, as in you can hardly push the tire in at all with both thumbs
  • concordeconcorde Posts: 1,111
    Check the pressure by borrowing a guage.....point is though as long as it reads 15psi every time it's at really at 30 it doesn't matter.

    I will have to find someone, nobody used them who I ride with. I know what you mean yes but the gauge is set in such a way that below 20 the incremements are closer together than past 20, which makes reading the display below 20, difficult.
  • concordeconcorde Posts: 1,111
    Replacement en route! Emailed to say it might be dodgy! Reply within 5 minutes, sending a new one, first class and pre-paid labels to send the old one back. Hope they don't mind the mud on it!
  • raldatraldat Posts: 242
    The only reason to use psi is as a reference when you know what you want.

    Otherwise your feel is the best way, pump it to the deformation you require take note of the psi. And as long as your gauge is accurately inaccurate it is fine.

    So it doesn't need to be accurate, it jut needs to be precise and repeatable.
  • concordeconcorde Posts: 1,111
    raldat wrote:
    The only reason to use psi is as a reference when you know what you want.

    Otherwise your feel is the best way, pump it to the deformation you require take note of the psi. And as long as your gauge is accurately inaccurate it is fine.

    So it doesn't need to be accurate, it jut needs to be precise and repeatable.

    Yes, and prefereably easy to read which it's not below 20psi. Hardly moves. Plus accurate helps for comparing with others on here and out on the trails etc.
  • NewfishNewfish Posts: 121
    Depending on the tyre, 30psi might be quite hard. I pumped my tyres up the other day to 30psi (according to my floor standing pump gauge) and that was too hard when I got up to Cannock and had to let some air out. When I got home I pumped them up to 50psi for a road ride and the gauge said they were at close to 22 psi. Yet they weren't too soft to ride on. Maybe my gauge is fubar too.
    Cheers,
    Simon.
    ____________________
    2012 Spesh Rockhopper
  • The RookieThe Rookie Posts: 27,747
    Or maybe the hose wasn't connected properly...can be a big issue with Schreader valves, less so with Presto!
  • concordeconcorde Posts: 1,111
    edited January 2013
    Don't know why they bother with presta valves, pile of shite! Shrader for the win!
  • cooldadcooldad Posts: 32,904
    Yeah that's why they don't use them on 40gazillion cars etc.
    I don't do smileys.

    There is no secret ingredient - Kung Fu Panda

    London Calling on Facebook

    Parktools
  • Car manufacturers will never ask tyre manufacturers for a different valve option. The costs outweigh the need as its the only part of a car which is a universal fitment. A car tyre doesn't need the psi levels of bike so having a better system like Presta is not a requirement - nor could they sell it to customers as a feature or benefit (though run flat is punted and that is a waste of money and no use to man or beast).
    Family, Friends, Fantastic trails - what else is there

    viewtopic.php?f=10017&t=12898838
    viewtopic.php?f=10017&t=12897374
  • cooldadcooldad Posts: 32,904
    And the problem with them is?
    I don't do smileys.

    There is no secret ingredient - Kung Fu Panda

    London Calling on Facebook

    Parktools
  • ThewaylanderThewaylander Posts: 8,767
    Car manufacturers will never ask tyre manufacturers for a different valve option. The costs outweigh the need as its the only part of a car which is a universal fitment. A car tyre doesn't need the psi levels of bike so having a better system like Presta is not a requirement - nor could they sell it to customers as a feature or benefit (though run flat is punted and that is a waste of money and no use to man or beast).


    But shocks have schrader and are mch higher pressure than my tyres? so whats teh problem with it?
  • concordeconcorde Posts: 1,111
    I find the prestra fiddly. Put it through the rim, put that stupid little nut thing on, unscrew the valve bit, pump it up, lose air doing the stupid valve bit back up, sometimes bend it and it doesn't screw back in properly, tighten the stupid little nut thing again, done! It's like something that's years out of date, lets move on to the easyness of Shrader!
  • OuijaOuija Posts: 1,386
    Presta was primarily designed to reduce structural weakness in narrow bike rims. On cars, shocks and some of the wider mountain bike rims they simply aren't required. Drilling a wide Schraeder hole on a skinny road/hybrid rim isn't the best idea in the world.

    Gotta say i prefer Presta myself, as i can never seem to get a good air tight seal on a Schraeder valve with any of the variety of pumps i own.
  • Don't know if it is just me, but I have always found that the Presta valved inner tubes seem to hold air for a lot longer.
    2007 Felt Q720 (the ratbike)
    2012 Cube Ltd SL (the hardtail XC 26er)
    2014 Lapierre Zesty TR 329 (the full-sus 29er)
  • OuijaOuija Posts: 1,386
    Don't know if it is just me, but I have always found that the Presta valved inner tubes seem to hold air for a lot longer.

    I'd agree with that. Especially on high pressure inner tubes. The screw down inner core stops the possibility of the valve mechanism from moving due to vibration and letting air escape. But both types of tyre will lose air due to osmosis (or what ever it's called), with thicker rubber tending to retain air better than thinner ones.
  • BriggoBriggo Posts: 3,823
    (though run flat is punted and that is a waste of money and no use to man or beast).

    You can factually back that claim up with evidence can you?

    Or you just talking more shite.
  • Briggo wrote:
    (though run flat is punted and that is a waste of money and no use to man or beast).

    You can factually back that claim up with evidence can you?

    Or you just talking more shite.
    Err no need for that language thanks.

    And yes I could factually back it up, I work in the industry and with the vehicle manufactuter who pushes it the most - this thread though is not a debate on the pro's and cons of run flat tech!

    TTFN
    Family, Friends, Fantastic trails - what else is there

    viewtopic.php?f=10017&t=12898838
    viewtopic.php?f=10017&t=12897374
  • BriggoBriggo Posts: 3,823
    Briggo wrote:
    (though run flat is punted and that is a waste of money and no use to man or beast).

    You can factually back that claim up with evidence can you?

    Or you just talking more shite.
    Err no need for that language thanks.

    And yes I could factually back it up, I work in the industry and with the vehicle manufactuter who pushes it the most - this thread though is not a debate on the pro's and cons of run flat tech!

    TTFN

    Of course you do. From first hand experience at speed I can tell the run flat did exactly what it was ment to very well and got me to a garage easily without the hassle of being stuck on the side of the road spending an eternity changing it on a dangerous road (dual carriageway, no shoulder).
  • NewfishNewfish Posts: 121
    Briggo wrote:
    Briggo wrote:
    (though run flat is punted and that is a waste of money and no use to man or beast).

    You can factually back that claim up with evidence can you?

    Or you just talking more shite.
    Err no need for that language thanks.

    And yes I could factually back it up, I work in the industry and with the vehicle manufactuter who pushes it the most - this thread though is not a debate on the pro's and cons of run flat tech!

    TTFN

    Of course you do. From first hand experience at speed I can tell the run flat did exactly what it was ment to very well and got me to a garage easily without the hassle of being stuck on the side of the road spending an eternity changing it on a dangerous road (dual carriageway, no shoulder).


    An eternity?! How long does it take you to change a wheel? I'm not a mechanic but can undo a few bolts, ford fiesta 10-15 minutes, my medium wheelbase merc van, 20. And that's because the jack won't quite lift the suspension high enough so needs to be put on planks.
    Cheers,
    Simon.
    ____________________
    2012 Spesh Rockhopper
  • cooldadcooldad Posts: 32,904
    Newfish wrote:
    Briggo wrote:
    Briggo wrote:
    (though run flat is punted and that is a waste of money and no use to man or beast).

    You can factually back that claim up with evidence can you?

    Or you just talking more shite.
    Err no need for that language thanks.

    And yes I could factually back it up, I work in the industry and with the vehicle manufactuter who pushes it the most - this thread though is not a debate on the pro's and cons of run flat tech!

    TTFN

    Of course you do. From first hand experience at speed I can tell the run flat did exactly what it was ment to very well and got me to a garage easily without the hassle of being stuck on the side of the road spending an eternity changing it on a dangerous road (dual carriageway, no shoulder).


    An eternity?! How long does it take you to change a wheel? I'm not a mechanic but can undo a few bolts, ford fiesta 10-15 minutes, my medium wheelbase merc van, 20. And that's because the jack won't quite lift the suspension high enough so needs to be put on planks.
    Try that in the rain on the hard shoulder of the M25. Especially if some idiot tyre fitter has had his hydraulic wrench set on Schwarzenegger mode.
    I don't do smileys.

    There is no secret ingredient - Kung Fu Panda

    London Calling on Facebook

    Parktools
  • NewfishNewfish Posts: 121
    cooldad wrote:
    Newfish wrote:
    Briggo wrote:
    Briggo wrote:
    stuff
    More stuff
    Sarcastic stuff
    Moaning stuff
    An eternity?! How long does it take you to change a wheel? I'm not a mechanic but can undo a few bolts, ford fiesta 10-15 minutes, my medium wheelbase merc van, 20. And that's because the jack won't quite lift the suspension high enough so needs to be put on planks.

    Try that in the rain on the hard shoulder of the M25. Especially if some idiot tyre fitter has had his hydraulic wrench set on Schwarzenegger mode.
    Schwarzenegger mode made me chuckle. I would recommend that everyone buy's and Long arm brace for this very reason.
    £15 or a good hour sat on the hard shoulder? Although fair point.
    Cheers,
    Simon.
    ____________________
    2012 Spesh Rockhopper
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