Texboy

Is pressure gauge the best way to check tire pressure? How about a large pump with a gauge?

fietsbob

Either Can Have a accurate gage .. whether it does is an open question.

I have both, actually all 4.. a gage and a floor pump for S/V & P/V.

the pump has a gage , the separate gage for double checks ..

I brought a Plastic gage on tour to check my hand pump efforts.

Belt and Braces ..

FBinNY 

Trick question with the answer probably depending on the quality of the gauge and width of the tire. Using a hand gauge after pumping means there'll be a small loss of air when you sample. How big varies on the valve and the gauge, and the amount of hiss you get mounting and removing it. It's not much at all with anything decent, but can be annoying on very narrow HP tires which don't have much to begin with. Plus pumping and sampling, then (maybe) pumping again can be a nuisance.

OTOH - a decent pump mounted gauge gives you real time info as you pump, and with a tiny bit of practice you can get very consistent results without trial and error. So, all things considered I vote for pump gauges, even though they call for a bit more care in how you toss the pump around (for those who toss it in the trunk of their cars for example). Even though I used to import, and later, manufacture bicycle specific tire gauges, I haven't used a hand gauge in decades, and rely on the one in my floor pump.

Texboy

Sometimes, I like to check the tire's pressure to see how much pressure lost after several days or weeks. I think the gauge alone would be handy.

FBinNY 

Then you answered your own question.

For my part I decide when to top off based on a finger squeeze. Low is low, and I don't need a gauge for that. Also when I do top off, I get a decent sense of how low, low was by the gauge reading when line pressure passes tire pressure and air flows.

There's no right answer here, only personal preference.

Retro Grouch 

As long as we're on the subject, how do separate presta tire gauges work? Do they have some kind of gizmo to push in the stem or what?

I'm just curious because I've never owned a presta tire gauge. I too rely on the analogue "squeeze test" to tell me when it's time to top off my tires and I use the gauge on my floor pump to tell me when it's full.

Neddog

My foot pump is about 10psi off. I always check with a regular tire gauge. I trust the gauge on my hand pump which goes in my fanny pack though. That one has proven itself accurate.

Best way to tell is just to test with a number of different gauges, and most should be accurate to each other. If there's any that are off, then it's probably an attached gauge to a pump. But even so, that doesn't mean that gauge isn't useful! It's a hell of a lot better than pumping with no clue. If it gets you within the range, then a quick check with the accurate gauge will let you fine tune it.

FBinNY 

Yes, there has to be a valve depressor built into the gauge. As someone who made these for a number of years, getting the distance from the seal lip to the depressor dialed was a challenge, because the distance varied within a band maker to maker. If the distance isn't right, either there's air loss when the valve depresses early, or you have to really lean on it to get the valve depressor engaged. I solved it with a bushing and support that had some room to accordion, but it was a tough tolerance to hold consistently.

FBinNY 

It doesn't matter what a gauge reads, that's just a number. All that matters is that it's consistent. If a pump gauge is known to read 10psi low, then mentally compensate when you inflate, and pump until it reads 10psi above the desired pressure.

79pmooney

The old finger squeeze. Not always consistent and works better with frequent use. But failure rate is very low, no air is lost and there are real time savings.
I now use a pump with gauge in my garage. A frame pump every where else and haven't seen my separate gauge in years.

Ben

corrado33

My presta gauge is 5 psi different from my pump. I'm not sure which one is accurate. The air volume of the tires is so low that by the time I pump it up, remove the head, test the pressure with the gauge, then replace the head, I could have easily have lost 10 PSI, so making a direct comparison is... hard. Unless I make a tube with two presta valves in it.

fietsbob

+1, Not being on 100psi Tires, I squeeze the tire as my most basic check ..

HillRider

Using the gauge will, in and of itself, cause a pressure loss due to the very small air volume of most bike tires. Sort of the "Heisenberg Uncertainty Principle" applied to bike tires. Taking the measurement changes the results.

corrado33

Unless you do a set of controlled tests in which you know exactly how many PSI using the gauge will release at a certain PSI. But you'd have to practice your technique.

Neddog

Yup, that's exactly what I do! I know what I like to run at.

1 Miyata Biker

I usually rely more on a separate hand air pressure gauge than a tire pump air pressure gauge. I'll use the pump's air gauge to get "in the ballpark", then the hand air gauge for accuracy. I use the "squeeze" test the next couple of days because my tubes don't lose too much air. If the tires/tubes don't pass the squeeze test, out comes the air pump for a top off of the air.

speedy25

Todays tubes dont seem to hold air as well as they used to. If I havent ridden my bike for a week, I'm almost guaranteed that the pressure is low. My most consistent method is a joe blow floor pump. Guage seems to be accurate and I get the same results every time from pumping to a pressure and popping off the chuck.

-SP

79pmooney

Many of today's tubes are lighter, thinner and feel considerably better/more responsive riding than many of the tubes of old. This comes at a cost. Pressure loss is directly related to the tube thickness. Thinner tuber, higher pressure loss. Don't like it? Get a cheaper, heavier tube.

Ben

speedy25

I might believe that for 700 size tubes, but my observation is in ALL sizes and in many cases ages. Older tubes look and feel the same as the newer ones but the new ones leak. My guess is cheaper materials. I will have to try some better name brands to confirm my theory.

-SP

yannisg

Hi,
I find a presta hand gauge convenient when I use my Mtn bike. When I leave my home I have pumped my tires to max since I'll be riding on asphalt for a while. Once I get to the dirt section I'll use the hand gauge to get the right pressure for the ride conditions. I am too lazy to pump the tire back up again with a hand pump on the return. I have found determining the pressure by feel can often be deceptive.
YannisG

79pmooney

SP, another consideration is the tube size. An undersized tube that is stretched a lot will leak a lot more air than the same brand tube a size larger.

Ben

Soil_Sampler