Welcome guest, is this your first visit? Click the "Create Account" button now to join.

To disable ads, please log-in.

Shop at TeamEstrogen.com for women's cycling apparel.

Results 1 to 6 of 6
  1. #1
    Join Date
    Aug 2009
    Location
    venice, california
    Posts
    83

    Question uh... inflating tires and pressure gauge...

    To disable ads, please log-in.

    really embarrassing question.
    But I'd rather be embarrassed than... deflated?



    Usually with my mountain bike, I pumped til the tire felt firm, and off I went!

    Now with my new road bike, I want to get precise. I got a new standing pump (my old one only had schraeder valve option) which also has a built-in pressure gauge.

    My tires felt firm-ish, but after a 25 mile ride I figured I'd add some air. My tires say min 100 psi max 125 psi.

    So I took off the cap, unscrewed the nut, attached the pump as the instructions specified... and the pressure gauge read at 0.

    So I started pumping... went to 20... 40... 60... 70... and then it got too hard to pump anymore. Plus I was too scared I was doing something wrong and the tires would explode.

    Am I doing this right? Is this pressure gauge only reading what I've added? After I stopped, I felt the tires and they felt super firm... so why is the gauge only saying 70? Is it defective? Do I just not know how to get correct tire pressure?


  2. #2
    Join Date
    Dec 2005
    Location
    WA State
    Posts
    4,364
    Here's a possibility. You may not have broken the seal that the valve sometimes forms. You can push the valve down and let a tiny bit of air out before you put the pump on or just listen for the "click" that lets you know the air is actually going into the tire and its not just pressure building up between the pump and valve. You won't always hear it click because it doesn't always seal up so tight that you need very high pressure to get it going.
    "Sharing the road means getting along, not getting ahead" - 1994 Washington State Driver's Guide

    visit my flickr stream http://flic.kr/ps/MMu5N

  3. #3
    Join Date
    Aug 2009
    Location
    venice, california
    Posts
    83
    Thanks Eden.

    I felt for sure I broke the seal on both tires but maybe I'll try again. I think I didn't hear the click, but I'll give it another go tomorrow.

    Maybe I didn't put the pump on the valve properly/fully ... was too afraid of breaking the delicate looking presta valves!

  4. #4
    Join Date
    May 2006
    Location
    Md suburbs of Wash. DC
    Posts
    2,131
    Speaking of pressure gauges, I hope no one minds if I add a question to this thread...

    I've got a 10 or so year old Joe Blow pump with gauge, and a hand-held tire gauge that I picked up just a couple of years ago. The hand-held gauge consistently measures 10psi below the pump gauge. Which is more likely to be accurate?
    "How about if we all just try to follow these very simple rules of the road? Drive like the person ahead on the bike is your son/daughter. Ride like the cars are ambulances carrying your loved ones to the emergency room. This should cover everything, unless you are a complete sociopath."
    David Desautels, in a letter to velonews.com

    Random babblings and some stuff to look at.

  5. #5
    Join Date
    Sep 2007
    Location
    Uncanny Valley
    Posts
    14,501
    I don't think it's possible to say which is more accurate. You just have to find a known accurate gauge to compare them against (or at least compare one of them against a known accurate gauge, then compare that one against your other one).

    If your handheld gauge is Schraeder valve, you should be able to find an ISO-certified auto or truck facility with an accurate tire gauge to calibrate yours against. Be sure it's ISO-certified though. Lots of auto dealers and tire shops don't bother to calibrate their gauges at all.

    Tire service people at motorcycle races (international events excepted) are usually happy to calibrate a tire gauge, when they're not busy with the race tires. Probably would be the same with auto club races. I'm not sure how tire service works at major bici events, anyone?
    Speed comes from what you put behind you. - Judi Ketteler

  6. #6
    Join Date
    May 2006
    Location
    Md suburbs of Wash. DC
    Posts
    2,131
    I think they're both Schrader compatible, though I use them for Presta. I wonder if my auto repair place would be able to calibrate one or both for me... Might have to ask about that the next time I get an oil change. Thanks for the idea!
    "How about if we all just try to follow these very simple rules of the road? Drive like the person ahead on the bike is your son/daughter. Ride like the cars are ambulances carrying your loved ones to the emergency room. This should cover everything, unless you are a complete sociopath."
    David Desautels, in a letter to velonews.com

    Random babblings and some stuff to look at.

 

 

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •