Gauge Accuracy

We've recently established gauges are commonly inaccurate. Is this by
percentage, or a certain PSI? I'd guess percentage?

There are 3 gauges in my garage @ the race track we use to check & set
pressure. 1 PSI matters. All 3 gauges always agree, within .5PSI (as
close as they get). I realize the difference doesn't matter much @
bike pressures, but am curious. Considering another gauge so I have 1
for my race toolbox and one for around the house, and unsure what to
get. I like my race gauge. Digital, and holds the last measurement
so I can press, then take it off and check.

On Aug 26, 1:12*pm, " wrote:
We've recently established gauges are commonly inaccurate. *Is this by
percentage, or a certain PSI? *I'd guess percentage?


Depends on the design of the gauge and how badly
it was damaged when you ran over it with the riding
mower.

A bourdon tube gauge will (at least in my experience)
be off by a fixed amount. Pencil gauges don't do so
well in the wash.

wrote:
We've recently established gauges are commonly inaccurate. Is this by
percentage, or a certain PSI? I'd guess percentage?

There are 3 gauges in my garage @ the race track we use to check & set
pressure. 1 PSI matters. All 3 gauges always agree, within .5PSI (as
close as they get). I realize the difference doesn't matter much @
bike pressures, but am curious. Considering another gauge so I have 1
for my race toolbox and one for around the house, and unsure what to
get. I like my race gauge. Digital, and holds the last measurement
so I can press, then take it off and check.

Within 1% is pretty good for any pressure gauge. Pressure gauges are
normally calibrated on a Dead Weight tester. Cheap gauges usually can't
be calibrated and are usually thrown away if inaccurate. Digital doesn't
mean accurate. If you're really fussy I'd recommend a calibrated
electronic pressure transmitter as used in industry.

On Aug 26, 1:12*pm, " wrote:
We've recently established gauges are commonly inaccurate. *Is this by
percentage, or a certain PSI? *I'd guess percentage?

If it says zero psi when it's not attached to your tire, then it's
accurate at zero. If it then says (like one of mine) 107 psi when
it's attached to 100 psi, then it's very likely to be off by a fixed
percentage.

- Frank Krygowski

On 26 Aug, 18:12, " wrote:
We've recently established gauges are commonly inaccurate. *Is this by
percentage, or a certain PSI? *I'd guess percentage?

There are 3 gauges in my garage @ the race track we use to check & set
pressure. *1 PSI matters. *All 3 gauges always agree, within .5PSI (as
close as they get). *I realize the difference doesn't matter much @
bike pressures, but am curious. *Considering another gauge so I have 1
for my race toolbox and one for around the house, and unsure what to
get. *I like my race gauge. *Digital, and holds the last measurement
so I can press, then take it off and check.

Dont worry about it, always use the most reliable as your reference
pressure gauge used for final checks and running pressure tests. Keep
it safe, do not loan it out ,ever. Every other gauge is wrong, unless
you know it is as easy to use, is reliable and reads rthe same as your
reference gauge (which may give unusual readings, but is still correct
to you).

On Aug 26, 10:15*pm, Frank Krygowski wrote:
On Aug 26, 1:12*pm, " wrote:

We've recently established gauges are commonly inaccurate. *Is this by
percentage, or a certain PSI? *I'd guess percentage?

If it says zero psi when it's not attached to your tire, then it's
accurate at zero. *If it then says (like one of mine) 107 psi when
it's attached to 100 psi, then it's very likely to be off by a fixed
percentage.

- Frank Krygowski

My digital "zero's out" at turn on, like a digital scale. None of my
team mates trusted it when I showed up to the races with it, and
insisted on using their high-dollar dial/blowoff types. Then we
started checking... mine always matched theirs! Wasn't too expensive
either. I still check it against theirs probably once a weekend to be
sure it's still on, but it's been good so far.

On Aug 26, 10:41*pm, someone wrote:
On 26 Aug, 18:12, " wrote:

We've recently established gauges are commonly inaccurate. *Is this by
percentage, or a certain PSI? *I'd guess percentage?

There are 3 gauges in my garage @ the race track we use to check & set
pressure. *1 PSI matters. *All 3 gauges always agree, within .5PSI (as
close as they get). *I realize the difference doesn't matter much @
bike pressures, but am curious. *Considering another gauge so I have 1
for my race toolbox and one for around the house, and unsure what to
get. *I like my race gauge. *Digital, and holds the last measurement
so I can press, then take it off and check.

Dont worry about it, always use the most reliable as your reference
pressure gauge used for final checks and running pressure tests. *Keep
it safe, do not loan it out ,ever. *Every other gauge is wrong, unless
you know it is as easy to use, is reliable and reads rthe same as your
reference gauge (which may give unusual readings, but is still correct
to you).

Trusting any one tool as an absolute even when it disagrees with
others sounds like a good way to get hurt roadracing to me. I like
checking things, and being double-sure all is right. If nothing else
the mental security lets me focus more on the race, worry less about
the bike, and as such go faster.