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Thread: extra 40psi?

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    extra 40psi?

    Will going from 120psi to 160psi lessen my "contact patch" and the extra friction that is the obvious reason I'm slow? Serious about the 40 extra psi. Not on the rim, but close.

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    Senior Member socalrider's Avatar
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    most clincher tires are not rated to 160psi.. Only a few I use are rated up to 145psi.. I usually run 130psi with no issues.. what make-model tire are you using and what does it recommend as max psi?

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    Senior Member teamontherun's Avatar
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    you might want to see if your rim will handle a slightly bigger tire as a wider tire will support the same weight with less pressure. That way you can support the weight and not risk a tire explosion.

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    Thanks for the points. Here is some more information...

    I am riding on Mavik Ksyrium Equip rims with Continiental Ultra Sport 700x23 tires. The max psi is 120 and I inflate to about 125. I saw the Vredestien Fortezza SE has a max psi of 160. It's a kevlar and folding, which I've never used before.

    Questions:
    1) Will a 700x25 tire fit?
    2) Any pros or cons with a folding tire?

    Thanks for the input/help.

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    The Fat Guy In The Back Tundra_Man's Avatar
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    My dentist discourages the use of pumping tires to 160 psi as he doesn't want every little road imperfection to jar my fillings loose.

    No offense, but if you're slow I highly doubt it's because your tires are only filled to 120 psi.
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    @Tundra_Man..............The part about being slow was an attempt at humor. No offense taken. I am asking if more psi will make a smoother ride as there will be more space between rim and the road. I know there's a point where it will become too hard and jarring though.

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    Senior Member Mr. Fly's Avatar
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    Quote Originally Posted by jmeade73 View Post
    I am asking if more psi will make a smoother ride as there will be more space between rim and the road.
    Conventional wisdom says that the higher the pressure, the harsher the ride. Thus, if you want a smooth ride, you'll need to go lower pressure but on a wider tire so you don't pinch flat.

    Wider tires may not necessarily be slower anyhow. In fact, for otherwise identical tires, the wider one typically roll better. There are many factors involved but generally speaking, if you're 200 lbs and up, 700x23c probably isn't the best choice. Go at least 700x25c or 700x28c. Now, whether these will fit your frame/fork (should fit your wheels) is an entirely different question that we cannot answer because it's not clear what bike you have.

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    Quote Originally Posted by jmeade73 View Post
    @Tundra_Man..............The part about being slow was an attempt at humor. No offense taken. I am asking if more psi will make a smoother ride as there will be more space between rim and the road. I know there's a point where it will become too hard and jarring though.
    It's not clear the motivation for increasing the pressure if not to increase speed. Increasing pressure makes the tire harder it doesn't make the road smoother. Increased speed is primarily a function of the motor and aerodynamics. If you can't ride in an aero position the tire pressure is irrelevant.

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    To answer your question, YES, it will. Pounds per square inch is exactly that.

    If you weigh 160#(including bike), and put 160 in your tires, exactly 1/2 sq inch of each tire will contact the pavement. If you deflate to 80, exactly 1 square inch of rubber, from each tire, will contact the pavement.

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    Unless this is on a track bike you're taking to the local velodrome, I'd suggest staying away from ultra high pressures like 130 and up. Every little speck of fly poop you run over will feel like hitting a speed bump.

    As others have suggested, check out a wider tire like a 28mm, if it can fit your frame. Even a 32mm if you can clear it. The ride quality will be so much more comfortable, without a tremendous impact to your speed (unless you're a mid-Cat classified racer.) The rest of us average riders won't see significant differences. There was a big write up a while back in Bicycle Quarterly which discussed tire width vs. rolling resistance etc.

    At 225 pounds, I ride Conti Gatorskin 28mm tires on my rando bike, at 115psi. That's hard enough that smooth roads are fast (even with what many randos complain is a harsh and non-compliant tire), but soft enough that 20 miles of chip-seal doesn't feel like my brain is in a paint shaker.
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    Banned. Mr. Beanz's Avatar
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    Something to think about.

    Continental GP400 in a 23 is known as a smooth but fast comfortable ride ($62)

    Continental Utra Race in a 23 is not as smooth and half the price($30)

    But yet the GP 400 measures about .100 wider than the other tire.

    The wider tire is known as a smoother and faster "racing tire". Hmmm!

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    Senior Member socalrider's Avatar
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    One of the nicest clyde friendly tires I used is the Vittoria Open Pave CG tire.. I have found them for 99.00 pair on sale but normally around 65.00 each.. Slightly wider at 24c.. Very Fast with good puncture protection..

    review: http://reviews.roadbikereview.com/bl...es-pro-review/

    http://www.excelsports.com/new.asp?p...jor=1&minor=27

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    I've found the Serfas Seca 25 is the same width as the GP4000in the 23, but wears much better than any of the Conti's I've ridden. Got a Serfas on my tandem too, wearing nicely and rolls much better than the Gatorkin and Armadillo. Far better protection than the Gatorskin.

    Sefas is $22 at REI (wire bead). What do I care about weight?

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    Take at look at Schwalbe's website some interesting info.

    They seem to recommend larger tires as being more efficient. http://www.schwalbetires.com/tech_in...ing_resistance .
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    Senior Member Sir-Loin's Avatar
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    Wow, Mr Beanz, Great advice. I will try a pair of these Serfas.
    Sir-Loin
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    Senior Member socalrider's Avatar
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    the serfas are very nice tires.. Jenson has the folding 700x23's on sale for 20.00 right now.

    http://jensonusa.com/store/product/T...Tire+2009.aspx

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    Senior Member Sir-Loin's Avatar
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    I just got a set of Mondo Sport tires on the Allez Elite take-offs I bought. The Serfas are next!
    Sir-Loin
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