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Old 12-17-07, 08:41 PM   #1
destro713
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How would 40 PSI "feel"? (Filling a tire and don't have a pressure gauge.)

This is sort of a crosspost with the Winter forum but there are more people in here and I'm looking for some quick assistance.

I'm filling some new, just-installed tires (Nokian M&G) and the only pump I have now has no pressure gauge. If I were to press down on the tire with my palms with the weight of my upper body, how would ~40 PSI feel? I realize this is a crappy question but I'd like to get these things in good enough shape to test them out, or maybe to go to the store and actually get a gauge.
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Old 12-17-07, 09:15 PM   #2
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Squeeze a ripe orange, then squeeze your tire. Do they feel similar? They shouldn't.
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Old 12-17-07, 09:15 PM   #3
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2" Mountain bike tires (assuming the size based on desired PSI), will feel sort of firm but deflect a few mm. Many MTB tires have a range of 40-65 PSI, so it's okay to over-estimate a little...at least to get you on the road to get yourself a gauge!
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Old 12-17-07, 09:20 PM   #4
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...at least to get you on the road to get yourself a gauge!
Definitely get a gauge. Improper tire pressure is like school on saturday.
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Old 12-17-07, 11:44 PM   #5
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I filled them up so that they have a couple millimeters of give. It was too late to go get a gauge by the time I was ready to hit the street, but I took them out anyway. They roll, and my tube didn't explode. Success. This was my first time changing tires, and indeed my first time removing the wheels for any reason, so I'm pleased with myself. If I were to take a wild guess I'd say they're probably at around 50 PSI now.

Removing the fair weather tires (1.75" Vittoria Randonneur Cross) was very hard and took a lot of musclem, but installing the Nokians was almost effortless, and so was removing them (which I had to do when I found I'd installed one backwards).
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Old 12-17-07, 11:47 PM   #6
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When I was a kid, we never used a gauge, just the "squeeze" method. Of course, I weighed a 100 lbs, then, too. But I have since discovered that is highly inaccurate. 40 psi feels an awful lot like 30 psi and an awful lot like 50 psi. Spend the $3 and get a gauge.
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Old 12-17-07, 11:47 PM   #7
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Originally Posted by destro713 View Post
This is sort of a crosspost with the Winter forum but there are more people in here and I'm looking for some quick assistance.

I'm filling some new, just-installed tires (Nokian M&G) and the only pump I have now has no pressure gauge. If I were to press down on the tire with my palms with the weight of my upper body, how would ~40 PSI feel? I realize this is a crappy question but I'd like to get these things in good enough shape to test them out, or maybe to go to the store and actually get a gauge.
You are asking how music sounds to a deaf person.
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Old 12-18-07, 06:27 AM   #8
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5.99 will get you a digital gauge at walmart in the auto section.
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Old 12-18-07, 10:04 AM   #9
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Feels a bit like a pumpkin after being boiled for 20 minutes.
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Old 12-18-07, 10:06 AM   #10
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Like a semi hard-on.

Aroused but not yet ready.
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Old 12-18-07, 10:10 AM   #11
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Quote:
Originally Posted by destro713 View Post
This is sort of a crosspost with the Winter forum but there are more people in here and I'm looking for some quick assistance.

I'm filling some new, just-installed tires (Nokian M&G) and the only pump I have now has no pressure gauge. If I were to press down on the tire with my palms with the weight of my upper body, how would ~40 PSI feel? I realize this is a crappy question but I'd like to get these things in good enough shape to test them out, or maybe to go to the store and actually get a gauge.
About as hard as a tennis ball.

See also: http://sheldonbrown.com/pressure

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Old 12-18-07, 02:09 PM   #12
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Destro'. For your future convenience, next time you add air to a known compression, test it "by feel" with your thumb and commit that "feel" to memory. Repeat for all your tire types. . .mountain, road, cyclocross. Not perfect mind, but it'll get you home 'til you can put a gauge on it.
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Old 12-18-07, 10:55 PM   #13
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40 psi should feel just about right. bk
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Old 12-18-07, 11:10 PM   #14
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Quote:
Originally Posted by destro713 View Post
This is sort of a crosspost with the Winter forum but there are more people in here and I'm looking for some quick assistance.

I'm filling some new, just-installed tires (Nokian M&G) and the only pump I have now has no pressure gauge. If I were to press down on the tire with my palms with the weight of my upper body, how would ~40 PSI feel? I realize this is a crappy question but I'd like to get these things in good enough shape to test them out, or maybe to go to the store and actually get a gauge.
ever wake up and take a leak in the middle of the night ?

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