How accurate are pump pressure gauges?

[Dromen]

I see folks huffing and puffing there tires to the max all the time using using only the pump gauge as their guide. Just wondered how accurate and if any tolerance info is out there.

[FlashUNC]

Tires have to ride great at max pressure...

[DfCas]

I have 3 pumps and a seperate guage. From the lowest to the highest they vary by 40 PSI, so my experience says they are not accurate at all.

[CNY rider]

I have a Topeak and I can assure you that the pressure displayed on the gauge has absolutely no relation to what the pressure is inside the tire.

[d.vader123]

Wow...then how does anyone know if they are pumping their tires to the correct pressure?

[Ralph]

I think my Topeak floor pump is fairly accurate.

[Ken Robb]

if you use the same pump and/or gauge you start low, increase 5psi at a time until you like the ride and that's the pressure you use with that pump. Bike tire volume is so small that I haven't had consistent readings with separate gauges due to the air lost when I put the gauge on and then remove it from the stem. It's easier to use a "lock-on" type of pump head and integral gauge although I know the reading may not be accurate in absolute terms. As long as it's consistent I can always get my preferred pressure.

Because of the above facts I wonder how useful our frequent discussions about inflation pressures can be. I guess it's useful for everyone to know that the optimal pressure is probably NOT the maximum listed on the tire. :beer:

[Louis]

I would guess that around 100 psi most gauges are accurate to about +/-10%, or +/-10 psi.

There is no one "right" pressure. Before riding I check the tires (with my thumb on the tire, fingers on the inside of the rim, force applied radially) and if it barely gives that's good enough for me. If it gives more than that I pump them back up to "nominal" and go.

YMMV

[beercan]

yeah i give it a thumb test and ready to go

[dekindy]

I purchased an SKS digital guage and the SKS guage readingsare almost identical to my Blackburn AirTower 2 guage. I had a Blackburn TPS-2 prior to that and the guage compared almost exactly to the LBS pump. I keep my tires in the 90-100 psi range. When checking pressure with the SKS guage there is almost no loss of air which I was concerned about because as we all know it does not take much loss to lower the tire pressure significantly in a tire, especially a road bicycle tire.

[godfrey1112000]

yeah i give it a thumb test and ready to go

2 Thumbs up

[Sandy]

Tires have to ride great at max pressure...

I think in most instances max pressure is far from ideal. Perhaps for a very large rider, but in most instances, I think max pressure causes the tire to lose max traction with the imperfect roads we ride on....It also deteriorates the ride quality. I used 95-97 f and 105-107 rear on 700x25 tires with a max of around 120, I think, and my average riding weight was about 215.

Most riders would be much better served at psi well below max, especially lighter cyclists..... my opinion.



Sandy

[Peter P.]

The accuracy of your pump's gauge is practically irrelevant. Most of us use the same pump whenever we pump up our tires so all we need to know is how our tires feel when they're pumped up to the number we see on that particular gauge.

[thwart]

Was reading something on Velonews the other day that most pros are (surprisingly) not picky about exact tire pressure.

And if they're not...

[dcpdpayne]

I stopped looking at pressure gauges a long time ago and simply look at the amount of "give" the tire has on the road. Not scientific, not worried.

[bigreen505]

I have a Topeak and it is very accurate at 100 psi and pretty worthless below about 75 psi. I know on my mountain bike, 20 on the gauge equals about 40 in the tire, but it is consistent.

[Ken Robb]

I totally ruined the accuracy of a Blackburn pump gauge by using it to pump 150psi into my mtn. bike shock absorber. I really had to put a LOT of force on the handle to achieve 150 psi. My error=your warning. :)

[Chance]

I see folks huffing and puffing there tires to the max all the time using using only the pump gauge as their guide. Just wondered how accurate and if any tolerance info is out there.
Don't know for bike pumps but data is available for other pressure gauges.

If you want (or need) accuracy and have a floor pump with a threaded gauge, you can replace it with a quality gauge. Grainger for instance has 100 and 160 PSI Ashcroft gauges rated at +/- 1 percent (that’s +/- 1 or 1.6 PSI) for about $100.

Even higher quality gauges used in industry can run plus or minus ½ percent (of full range) accuracy. Less expensive gauges are normally rated at 2 to 3 percent or even lower for the very cheapest.

Gauges that come on a sub $50 pump are probably not very accurate to begin with and will likely become less accurate with time.