Accuracy of pumps

[Polar]

Not many talks about how accurate a pumps or gauge is and according to Cycplus their pumps are within +-1 psi which I don't believe is correct since I get 3 psi different readings on a Cycplus AS2 pro pump and Topeak D2 gauge.
Which one is most accurate?

 

[Paulquattro]

Unless you have the gauges tested and calibrated you wont know exactly .

 

[steve_sordy]

I agree with @Paulquattro , but if I had to put money on it, I'd go with the Topeak D2.

However, the important thing is not how accurate the gauge is but how consistent it is. The D2 is very consistent in my 20-years experience. I spend quite a bit of time getting the tyre pressures that work well for me. Once I have them, I record them and use my D2 to check and set before every ride. If I'm going somewhere markedly different or with trail conditions different, then I may alter the tyre pressures by a psi or two. Because I always use the D2, I don't have to worry about its accuracy.

I use the same gauge to measure and set tyre pressures on my car as well. The gauges found at petrol stations and companies that fit your tyres appear to vary enormously, so I always overfill and then correct with the D2.

 

[Polar]

Unless you have the gauges tested and calibrated you wont know exactly .

How can both be tested and calibrated?

 

[irie]

However, the important thing is not how accurate the gauge is but how consistent it is.

Agree. We always use the same pump (Topeak JoeBlow Mountain Floor pump) with the indicated pressures that we know work best for us in the conditions we ride in (UK South Downs) with the tyres we have (Maxxis High Roller 3 DD front, DH rear) on our bikes (blinged 2022 Trek Rail 5's). Indicated front 23psi, rear 25psi but don't know neither do we care what the 'true' pressures might be.

 

[RustyIron]

How can both be tested and calibrated?

It doesn't matter. It's an exercise in futility. The gauges most of us use are imported trash, and there's nothing you can do to change that.

Over the years, I've accumulated a variety of gauges, both analog and digital. Digital gauges can vary with battery charge. Analog gauges are made of parts stamped from junk material. Both are susceptible to accumulated contamination from microscopic droplets of sealant. I've found that most start giving grossly erroneous results after six months or a year.

A while back I decided to "calibrate" my gauges. I found a couple that were in agreement at the pressure that I run my tires. I assumed that those were more likely to be correct. I set the other gauges to show the same reading as the "correct" gauges. On some, the "zero" was off, but that doesn't really matter for what I was doing.

Despite putting in a lot of effort on calibration, consistency didn't improve. Over time, the readings on the gauges changed again. Needless to say, I was disappointed.

My current setup is to set the pressure using the gauge on my Joeblow Mountain pump. The pressures I like are 26/23 on THAT pump. Maybe the actual pressures are different, but it doesn't matter as long as I can fill my tires to the way I like them. This pump is just over two years old, and the pressures still seem consistent. If the gauge starts getting weird, I'll eventually be able to feel it on the trail.

 

[Polar]

Agree. We always use the same pump (Topeak JoeBlow Mountain Floor pump) with the indicated pressures that we know work best for us in the conditions we ride in (UK South Downs) with the tyres we have (Maxxis High Roller 3 DD front, DH rear) on our bikes (blinged 2022 Trek Rail 5's). Indicated front 23psi, rear 25psi but don't know neither do we care what the 'true' pressures might be.

It doesn't matter. It's an exercise in futility. The gauges most of us use are imported trash, and there's nothing you can do to change that.

Over the years, I've accumulated a variety of gauges, both analog and digital. Digital gauges can vary with battery charge. Analog gauges are made of parts stamped from junk material. Both are susceptible to accumulated contamination from microscopic droplets of sealant. I've found that most start giving grossly erroneous results after six months or a year.

A while back I decided to "calibrate" my gauges. I found a couple that were in agreement at the pressure that I run my tires. I assumed that those were more likely to be correct. I set the other gauges to show the same reading as the "correct" gauges. On some, the "zero" was off, but that doesn't really matter for what I was doing.

Despite putting in a lot of effort on calibration, consistency didn't improve. Over time, the readings on the gauges changed again. Needless to say, I was disappointed.

My current setup is to set the pressure using the gauge on my Joeblow Mountain pump. The pressures I like are 26/23 on THAT pump. Maybe the actual pressures are different, but it doesn't matter as long as I can fill my tires to the way I like them. This pump is just over two years old, and the pressures still seem consistent. If the gauge starts getting weird, I'll eventually be able to feel it on the trail.

It's like other products not all can be trash, some better than worst but as far as I have understood it's best to use the same gauge every time to get the most precise measurements.

Anyway I'm satisfied with the D2 and now just jumped on the Cycplus hype but kept my $10 pump in reserve so I got a open return.

 

[irie]

It's like other products not all can be trash, some better than worst but as far as I have understood it's best to use the same gauge every time to get the most precise measurements.

Are you sure about that?

 

[Jackware]

It's like other products not all can be trash, some better than worst but as far as I have understood it's best to use the same gauge every time to get the most CONSISTENT measurements.

FIFY

 

[Polar]

Are you sure about that?

I'm never sure about anything

 

[Paulquattro]

How can both be tested and calibrated?

There are company's around that will do this in the UK but not sure about your home turf where they are
Google would be a good start

PS . It probably wont be cheap .

Search Results: Gauge Page 1 | Calibration House

Whatever you are looking for, you should be able to find it on our site using our search feature. If not, contact us, we are always happy to help.

www.calibrationhouse.com

Pressure Calibration | Vacuum Equipment Calibration | Gauge Calibration

We offer Pressure and Vacuum Equipment Calibration. Accredited calibration of all types of pressure devices including pressure gauges, vacuum gauges, manometers, barometers and more.

www.calibrate.co.uk

 

[Type1]

The actual number isn't necessarily that important, its more the consistency of the figure. It gives you a datum point to start from and tune from there.

 

[Stihldog]

My bike cave shop compressor is hardwired to a barometric weather sensor and a vacuum container for automatic and accurate calibration with nanometer sensitivity ..…Whoa! Sry bout that, just woke up. No coffee yet.

My regular method of psi testing on my tires is the pinch test using the index finger and thumb. I do this before each ride, or sometimes during a ride if I feel something weird. If I’m switching between road and trail I will use a gage.…but mostly for trail. 22-26 psi. I’ll drop the psi lower (12-16 psi) for snow conditions.

CushCore helps, and the fact that I hate loosing psi. A soap and water spray formula helps me find the source and I do everything in my power to solve that.

I’ve only had two punctures and two burps on the eMTB. I now carry a C02 cartridge and adapter only because I’m close enough to home.

 

[Overkillit]

My bike cave shop compressor is hardwired to a barometric weather sensor and a vacuum container for automatic and accurate calibration with nanometer sensitivity ..…Whoa! Sry bout that, just woke up. No coffee yet.

My regular method of psi testing on my tires is the pinch test using the index finger and thumb. I do this before each ride, or sometimes during a ride if I feel something weird. If I’m switching between road and trail I will use a gage.…but mostly for trail. 22-26 psi. I’ll drop the psi lower (12-16 psi) for snow conditions.

CushCore helps, and the fact that I hate loosing psi. A soap and water spray formula helps me find the source and I do everything in my power to solve that.

I’ve only had two punctures and two burps on the eMTB. I now carry a C02 cartridge and adapter only because I’m close enough to home.

I've been waiting for someone to say something along the lines of the feel test. I typically push down on the tire from the top with my palm as a feel test. Not recommending this to the OP since accuracy sounds like a priority but it gets me close enough.

 

[Polar]

My bike cave shop compressor is hardwired to a barometric weather sensor and a vacuum container for automatic and accurate calibration with nanometer sensitivity ..…Whoa! Sry bout that, just woke up. No coffee yet.

My regular method of psi testing on my tires is the pinch test using the index finger and thumb. I do this before each ride, or sometimes during a ride if I feel something weird. If I’m switching between road and trail I will use a gage.…but mostly for trail. 22-26 psi. I’ll drop the psi lower (12-16 psi) for snow conditions.

CushCore helps, and the fact that I hate loosing psi. A soap and water spray formula helps me find the source and I do everything in my power to solve that.

I’ve only had two punctures and two burps on the eMTB. I now carry a C02 cartridge and adapter only because I’m close enough to home.

CO2 cartridge is outdated and bad for the environment.
Anyway what l have learned today is to always use the same gauge therefore I will from today only carry AS2 pro and leave D2 at home.

Coffee won't do it you need a Napoli style ristretto.

 

[Stihldog]

CO2 cartridge is outdated and bad for the environment.

True…but it’s lighter than my hand pump.

I've been waiting for someone to say something along the lines of the feel test.

I must be in a rush to get outta the cave. We must be sensitive souls to have metacarpal accuracy (+\- 4 psi).