Does anyone really inflate their tyres to the recommended pressures?.

Discussion in 'The Bike Cafe' started by ACyclingRooster, Aug 24, 2011.

  1. ACyclingRooster

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    Hi to you all out there. Having recently acquired a double sided (Presta & Schraeder) tyre pressure gauge I checked out my tyre pressures. I have a 2000 Bianchi Reparto Corse Gold Race 600 on 700Cx23 Vittoria Rubino tyres and a 2009 Claude Butler Levante Hybrid Road Bike also on 700Cx23 tyres but they are Maxxis. I have inflated both pairs of tyres until they can not be depressed with ones thumbs. I have very strong hands & fingers. This was done with a Beto 10" hand held pump.
    To my absolute astonishment the tyre gauge only showed 80psi in both pairs,I could not get any more into them They both indicate pressures in excess of that. The Vittoria Rubino are to a MINIMUM of 100psi and the Maxxis to a MAXIMUM of 120psi.
    The tyre pressure gauge is accurate (checked against several others that are Schraeder only,the accuracy is +/- 1% +0.5psi.
    Are these pressures only attainable with a Track Pump?.
    The pressures that I normally reach are bone jarring as it is,what is it with this trying to create the equivalent of solid rubber tyres?.
     
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  2. daveryanwyoming

    daveryanwyoming Well-Known Member

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    Yes, many cyclists, myself included, inflate tires to the recommended pressure. BTW, that's the 'recommended' not the 'max' pressure which at my weight and the roads I typically ride around 110-115 psi for 700x23 race tires.

    80psi is a bit low unless you are very light, even my wife inflates her road tires to at least 100-105 psi but 80 is probably enough to avoid most pinch flats and should be a pretty comfortable ride.

    If you're really getting a bone jarring hard ride at 80 psi in narrow 23c tires then something isn't adding up. Roll your bike into your local shop and borrow their floor pump or pressure gauge but 80 is pretty soft. And yeah, it can take some effort to get up to 110 psi with small frame pumps and floor pumps make the job much easier but unless you're using a tiny frame pump you should be able to get well past 80 psi.

    -Dave
     
  3. Froze

    Froze Well-Known Member

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    If you use the PSI calculator I'm going to post you will be very close, if not right on exact PSI you need. PSI is dependent upon weight and tire size, unfortunately the calculator does not do MTB tires or even Cross bike tires but at least with Cross tires you could get close. The calculator was created by Rivendell based on a Michelin formula that has been around for years, even before I started racing in the mid 70's...it's older then me! Use the middle calculator, the first and the third one are not relevant to our needs. So see this: http://www.dorkypantsr.us/bike-tire-pressure-calculator.html
     
  4. nicomachus

    nicomachus New Member

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    I run them low when I'm riding in wetter conditions (mtb) and run them at (or sometimes even above) the recommended pressure for my daily commute (on road and paths).
     
  5. ACyclingRooster

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    Hi Froze. Thank you for your reply. The link that you provided is an interesting one and one that I had never seen before. I am aware that the Gross Weight ( rider+bike) is carried ultimately on the tyres at the point that they create their ' Foot Print'.
    The interesting thing about inflating tyres is just what can be achieved with some of the smallest of pumps. I have a very tiny pump that goes under the name of MAX air gear 100. It is only 98mm long & 21mm in diameter. It will inflate a 700Cx23 to 80psi in circa 90seconds.
    It comes complete with a Schraeder valve head and an adaptor to use on Presta valves. It is held into a dedicated frame bracket that is attached using the bottle cage bolts.[​IMG]
     
  6. Moto700

    Moto700 Member

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    On my Panaracer cyclocross tires, 700x31, recommended PSI is 35-70. I check with a gauge every day and inflate to 70.
     
  7. jhuskey

    jhuskey Moderator

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    I need all the help I can get ...so yes I inflate to 120 psi. The ride is a little rougher but also a little faster.
     
  8. Moto700

    Moto700 Member

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    /img/vbsmilies/smilies/icon14.gif Yup, gotta reduce that rolling resistance. I'm with ya there.
     
  9. ACyclingRooster

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    Hi Froze. I replied to you post and thanked you for the link,I also put some info on about a Mini Pump and I have posted an image but as yet neither the post nor the image have been displayed.
     
  10. 64Paramount

    64Paramount Active Member

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    The max psi for my tires is 120, but I inflate them to 95 in the front and 105 in the rear and that seems to work very well. That may actually be a bit more pressure than I need, I weigh around 155lbs, but if I go much lower than that I think I can see the rear sidewalls deflect when I'm standing up mashing. The sidewall deflection may not be hurting anything ( if it's really happening and it's not just my imagination ), but I put in an extra 5 pounds of air just in case.

    One of the folks at my lbs told me I should run at max pressure to reduce rolling resistance, and I ran them that way for awhile. But, that gives a harsh feeling ride and the tires tend to break loose in fast turns.
     
  11. Froze

    Froze Well-Known Member

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    Your IBS don't know what their talking about. You discovered, by accident the best inflation for your weight. If you use the calculator site I gave earlier you'll see your pressure is real close for a 700c x 23 tire. I imputed 175 pounds into the second calculator (155 for you and 20 for the bike and gear) and it came up with 110 for the rear, and your close at 105; then 70 for the front which your a tad high, you could try 75 to see how you like that, and by doing the 110 rear and 75 front you maintain the 40/60 percent ratio recommended for road racing setup.
     
  12. maydog

    maydog Well-Known Member

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    Sheesh, that calculator says I should be riding at 160 psi in the rear on a 700x23. Time to get some larger or higher pressure tires.
     
  13. davereo

    davereo Well-Known Member

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    Using the calculator my 40/60 was 79/110. I already ride 110/110. I may give the lower front pressure a shot.
     
  14. jpr95

    jpr95 Active Member

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    I found that I could ride harder and longer with lower pressures in my tires. The bone-jarring ride really adds to the fatigue factor, plus if your rear tire goes airborne on a bump, you are no longer getting power to the ground.
     
  15. OldGoat

    OldGoat New Member

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    When setting tire pressure at high levels, it's a good idea to check your wheel manufacturer's website (yes, wheel manufacturer, not tire manufacturer) to be sure you are not exceeding the maximum pressure the wheel itself is designed to handle. Just because the tire says something like 150lbs/11bar max pressure doesn't mean the wheel can take it.
     
  16. 64Paramount

    64Paramount Active Member

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    Actually it wasn't quite by accident that I came up with the tire pressure I currently use, I had an old Michelin air pressure chart and used that since I couldn't find one for my tires ( Bontrager RaceLite Hardcases 700c x 25 ), and then just fiddled with the pressure till I thought it felt right.

    If I use the 40/60 calculator you listed for 700c x 25 it shows me 58 in the front and 93 in the rear. That sounds like a really low pressure in the front, but I think I'll try your suggestion and drop it down to 75 just to see how it feels. If it seems okay I'll try dropping it a bit more in small increments.

    I really need to weigh my bike again with wedge bag and water bottles in place so I know what it actually weighs, since it's been so many years since I last did that. It's probably heavy by today's standards.
     
  17. Froze

    Froze Well-Known Member

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    Maydog what is your weight plus bike and attached equipment? You may need a 700x25 tire, but I just want to check your figures.
     
  18. Froze

    Froze Well-Known Member

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    Is this pump a CO2 pump? I've never heard of this brand nor ever seen one. I had a mini pump made by SKS called the Puro and it was rated for 144 psi but that damn thing wouldn't go above 65 and that was after over 500 strokes! Then on the second flat the thing broke and wouldn't go above 45 so I rode the bike with 45psi till I got to a gas station and used my adapter to squirt some air into the tire. SKS though does have fantastic customer service, I called them about the issues with the Puro and they sent me a CarbonRace Day for free which is a vastly superior pump over the Puro.

    I did a web search for that MAX brand and I could not find it, do you have a link? Thanks
     
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