wirides

The gauge below has a bleed off function that allows you to over inflate slightly and bleed off to the EXACT pressure you desire. The display adjusts in real time. I can tell you it works as advertised. I found my floor pump was reading over 10psi higher than the gauge.

​​https://www.topeak.com/global/en/pro...-smartgauge-d2

noimagination

Agree. The thumb test is good enough for bicycle tires.

(May be different if you're a racer - I wouldn't know, never raced.)

Koyote

Your pressure gauge is telling you that you are running way too much psi.

livedarklions

It's the Michelin Uncertainty Principle.

livedarklions

Purveyor of the Trek Ho?

kenshireen

I weigh 180 and average 15 mph when riding. I will drop my pressure to 110/100. I have never had a road flat... only had a flat when my bike was sitting in my garage on the rack.. could not figure... heat was not bad

Reynolds 

There could be a gauge that measured the deflection of the tire, like a thumb test but with a calibrated spring and a dial gauge?

GlennR

BTW.. who says the gauge is accurate?

I'm not concerned about my pump/gauge since I mine is set by "feel". Meaning once I found what feels right I jsut pump them to the same setting which is 90/100. Doesn't matter if it's actually 87/102 as long as the gauge is consistent.

Kapusta

Have you considered that perhaps the gauges on your pump and hand gauge may not calibrated the same?

Phil_gretz

Try lower. You could get away with less pretty readily. Why not 90 front and 100 rear?

livedarklions

[QUOTE=Phil_gretz;21501951]I weigh about the same as OP and ride a bit faster, and that's what I run at. Anything higher and I hate the ride, I feel every tiny bump.

Rides4Beer

I don't trust the gauges on either of my floor pumps (one of them is more than 5psi off), so I pump my tires above where I want it, and the check/bleed it down to where I want it with this:

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Works great, and minimal pressure loss when removing the gauge, with a swift movement just a slight hiss of air. I've double checked the pressure and saw no loss. I run latex tubes on the road bike and tubeless on the gravel bike, so I'm pumping and setting pressure on every ride no matter which bike I'm on.

Sy Reene

Couldn't you just 'calibrate' your floor pumps to your digital gauge every so often if you don't trust them to hold consistency?

Cyclist0108

I was going to say ΔP was the uncertainty in tire pressure, and ΔX was the uncertainty in tire width.

But this one is better:

MadKaw

There are many variables... rim width, tire, and personal preference. But one possible explanation for the experience you mention is imbalance. On a road bike I typically have 5-10psi (.3-.6 bar) higher pressure in the rear tire. I would expect having higher pressure in the front would feel weird. BTW: I don't have a power meter, my search for efficiency, such as it is, is based on time and heart rate.

Wileyrat

Amazing how this went from a complaint about problems with a specific tire gauge, to a thread on tire pressure.

​​​​​​The gauge the op is using is a major pain to get off a presta stem without losing pressure, if you all have any suggestions on how to remove it without dropping 5 lbs or so, I'd also like to know

GlennR

Maybe it's a poor design. I would suggest getting a different gauge.

Personally i use a floor pump with a built in gauge. Is use the same one everything and whatever the number is, it's consistent. If it drops a few psi when I take it off, it's always the same. And the number doesn't matter as long as it rides the way I like.

Kapusta

That's pretty on-topic by BF standards.

mprince

I used to use a gauge long ago, I think it was an Accu-Rite or something like that, it was digital and measured to the 1/2 psi. It didn't lose any pressure either. In any case, I stopped using it when I realized that level of resolution really wasn't necessary, and the gauge broke when using it on car tires . I also realized that the gauge on my Silca floor pump is "good enough" and a quick squeeze of the tire is adequate to get a good feel for how much pressure was adequate.

To keep the spirit of this thread morphing into something else, in my younger days I ran 700x23 and 25 tires (usually Vredesteins) pumped to ~120psi, I weighed between 200 and 220 lbs back then. Now I'm an old man in the mid-250's, run Continental Grand Prix 25 mm tires (measure 26mm wide on my rims) at between 90-100 psi on my Silca pump's gauge. Great ride and no pinch flats (I ride on pretty decent roads). I've gone higher than this and don't like the handling of the bike.

kenshireen

I have a BB Air Tower 3. I attach to the bike and lock lifting the thumb screw into a vertical (upright position). to unlock I move the thumb screw back down to a 90 degree angle and pop-off.
What I noticed was if I leave the thumbscrew in the unlock position that the tire pressure slowly fizzles out.. you don't hear a hiss but you can watch the dial on the pump and see pressure dropping.
This leads me to believe that even if the pump reads 110 while in the LOCKED position that as soon as I switch to the UNLOCKED that I will lose pressure between the time it is in the UNLOCKED and removal from the open valve

SethAZ 

Or it's different if you're very heavy, and need to be up at the max pressure because you ride on roads of unpredictable and often terrible surface quality and want to avoid pinch flats.

That being said, I just get up to my target pressure, give it one more stroke, then disconnect and don't worry about it. I also don't particularly care if the pressure reading is lab-grade accurate. I know that if my pump shows 90 psi with my 32mm tires then I'm safe from pinch flats on some bad roads around me, and if I let it go 10-15 lbs down from that I'm at non-trivial risk of a pinch flat, verified through experience. It doesn't bother me that what my pump shows as 90 may actually be 87 or 95 and I'd just never know.

greatscott

I've owned two gauges in my life, one was an Accu Gage, which I lost when we moved, and the one I have now is a Zefal gauge and neither of them lost air either connecting or disconnecting.

I use a tire pressure calculator on the internet to get the supposedly correct pressure based on the rule of 15% tire deflection, see: Bicycle tire pressure calculator Use the middle one and enter your clothed body weight and your total bike weight ready to ride, enter your tire size, if you have a typical road bike set up leave the F/R weight dist alone unless you have a more upright riding bike then change it. Now there is room to adjust those pressure depending on the the kind of ride you like, firm or comfort, or the roughness or smoothness of the surfaces you ride on, or if it's raining.

veganbikes

Terrible title. I use a Topeak digital gauge and maybe lose a couple PSI if I am less careful.

livedarklions

Might want to check the gauge for over-thinking stuff.

Rigsson

Back about 90-100 years ago car tires had cotton belts instead of steel belts. There was a gauge that could be pushed into the sidewall to read the pressure. I tried mine on my 29er and it read about half what I normally run. Can't post links yet, but Google 'JIF air tire gauge' if you're interested.