Checking Pressure in Tires with Presta Valves
 

Are there any gauges that work well for tires using Presta valves? Is it practical to try to check pressure levels in high pressure/low volume tires used on most road bikes?

I just finished up a new bike that I took out for it's first real ride today today. I built this up just for use on a couple of "rails to trails" MUP and a couple of rides I do that are a mix of gravel and paved roads. I inflated the 700C x 37 tires to 50 psi front and 60 psi rear to start, the tire's specs call for a max pressure of 70 psi. I wasn't long into the ride before I realized that the tires were way too hard but I didn't want to just let air out because I had no way of determining what pressure I was running. As of right now the only way I can determine tire pressure is by inflating TO a pressure. My mini pump that I carry with me doesn't have a pressure gauge.

The only pressure gauges I've used are for Schrader valves are just push on, they always lose a little air going on and off but considering the volume it's insignificant. I don't think same system would be suitable for use in many of the tires that use Presta valves. I looked at a suspension pump once that screwed on the valve and sealed before opening the valve with a separate level. That system would only allow the volume of air required to fill the gauges chamber. Is there something like that for Presta valves?

They make them similar to this that work for both Presta and Schrader.

https://www.performancebike.com/shop...-gauge-50-7343

Presta Pressure Gauge
 

Here's a suggestion:

Search Amazon for a Godeson Presta Valve BicycleTire Pressure Gauge 0-160psi and 0-11bar, $8.99 (they won't let me post a url, but you will find it)

I have an older one with identical design and features, see attachments. What I like about it is that it "locks" the pressure reading, so you can press it on the presta valve, then remove it to read the dial. You don't release any significant amount of air to take the reading. It has a pressure release valve that releases the pressure and can be also used to release air from the tire while reading the pressure. Seems like it fits your needs perfectly.

Low volume tires will have more air loss with each pressure check. With only a little practice you can figure out about how much pressure level loss is typical for each pressure gage use.


I use Zefal gages, both the twin head and the older single (and either presta or Schrader) valve specific ones. Either one when used well result in a few PSI loss with each use. So if you want 90PSI pump to about 95PSI and check. Recheck until the gage reads about 93PSI. Stop checking and go for a ride.


Tire pressures aren't rocket science and for high pressure/narrow tires a few more or less wont be the cause of any problems. Your riding skills to avoid crap and how to work the bike over/through tricky sections will be the issue. Andy

https://www.amazon.com/Zefal-Twin-Bi...fal+tire+gauge

I've had mine for at least 15 years.

For skinny-tire bikes, I don't bother with a gauge, I just pump them up. (My floor pump has a gauge.)

Bikes with fatter tires (38-42mm in my case), I'll pinch them with my fingers and if they feel a little squishier than usual, I'll hook up the pump.

As posted earlier, this isn't rocket science. :thumb:

you determined that the pressure was to high by 'feel'. what prevents you from determining the right pressure by 'feel' too?

That's my thought. Adjust while riding and check when you get home. Use that as your new number. I carry a $0.50 Schrader adapter with me and can use any run of the mill gauge or gas station pump as needed. Store it on your spare tube if you carry one.

I can't say enough good things about this one. The 90 degree head and the fit are great. Push it on and it stays in place by itself. I over inflate and then use the bleeder button (which works wonderfully) to drop the pressure to my desired number. Being able to bleed down offers easy and great control.

$12.00


https://www.ghmeiser.com/images/stat...s/img_0979.jpg

Pump to the max, squeeze with your fingers. Remember the feel. Inflate to the lower pressure you might run. Squeeze that, remember the feel. Now you have your gauge. I'm not being cute, every gauge I've had has crapped out or got lost. Still have fingers.

I look at how much the tire pooches out under my weight.

https://www.ghmeiser.com/ mine from the 80's are made in USA, but lots of companies like the Chinese overhead costs,

so they shift production to be maximizing profit..


https://www.ghmeiser.com/bicycle-gauges.htm

I carry the Schrader adapter and a digital gauge that weighs nothing. My hand pump mounted on the frame works both style valves and has a gauge that gets me close, but isn't the most accurate. The adapters from China are so cheap I give them away all the time to friends just getting into biking.

I've had this one for over 30 years now:

http://www.os2.dhs.org/~john/kingsbridge-gauge.jpg

Why do people use these things?
Do you not have gauges on your pumps?
Do you not trust the accuracy of the gauges on your pumps?
Do you not pump your tires up before every ride?
Are you checking tire pressures in mid ride?

On my commute bike I'll pump the tires up once a week, but other bikes get pumped up every ride.
I just don't get measuring the pressure to decide whether or not you're going to pump - just pump, and if it only takes one stroke then so be it - you haven't spent much more time than using the gauge-only checker; and you maybe saved time and you don't have to worry about how much air you lose with the measurement.

I determined the tire pressure was high due to the tire's max pressure being rated at 70 PSI and I pumped to 50 front 60 rear, that's 70% and 85% of max rated pressure. The tires were providing little to no suspension and wasn't getting very much traction in the small gravel on the hard packed dirt. I could have stopped and let air out until I got a more subtle ride and/or better traction but from there I'd have no way or accurately correlating that feel to an actual pressure value........but with a pressure gauge I would be able to establish an accurate and repeatable pressure value once I did reach the feel I wanted.

I can't answer why all people use gauges and thought I was pretty clear in my post as to why I would use one, in fact I pretty much provided all the information required to answer all of your questions.

1) I would have progressively let air out until I get to the pressure where I liked the feel of the ride. The I would have measured that pressure with a gauge and had a value that I could inflate to the next time I rode the bike, which might be tomorrow or might be next week or might be 2 months from now.

2) My floor pumps have gauges that I can inflate to, not means to deflate to a pressure. My mini pump that I carry in my saddle bag does not have a pressure gauge.

3) I do accept the displayed pressure on my floor pump to be accurate.

4) Yes, I inflate my tires before each ride TO a pressure that I've determined works well for that bike and it's tire set up but that could be an extended period between rides. Haven't ridden my road bike since last October. I remember I run those tires at 60 and 75 PSI, I don't know how much those pressure mash when I squeeze them.

5) Yes, checking and adjusting mid-ride would be a much quicker way of establishing what I like to run on each bike. In the past I've started near max pressure with a new setup and make adjustments before each ride until I got to where I liked the ride and then it was repeatable before every ride regardless of the interval.

Everyone is different, I work in tool making where normal tolerances are .005" and tight work is done in tenths. I have a 0-20 psi pressure gauge just to check my mower tires (I run 8 psi in the rears and 12 psi in the fronts) and yes, I check them before I use the mower every time. I'd just rather know than guess and once I know what I like and can have it the way I like it every time I use the bike.

I have some of the adapters, bought like a 5 pack of them with one of my China orders for like a dollar. I hadn't thought about trying these with a regular gauge but expect it would work out great for me. I guess you loosen the Presta's screw lock before screwing the Schrader adapter on and then just press the regular gauge down on the adapter losing a minimal amount of air.

Thanks for the information.

"over 30 years"???? I figured you to just be about 30 y.o. :D

My pump works really well. The gauge however has microscopic font and isn't very accurate. Once I determine the perfect pressure for a specific bike/tire combo, I want to be able to duplicate it quickly and accurately. Bleeding them down only takes a few seconds.

https://www.quarq.com/product/quarq-...ystc5xsxsmtqap
Welcome to the future

Wow. Talk about unnecessary overkill. :p

In another thread, there was a comment about squeezing the sidewalls instead of pushing on the tread with your thumb. (and ThermionicScott mentioned something similar in this thread). It does seem to be more accurate for me.

I've let out air in the middle of a ride, too. Sometimes because the roads were a lot rougher than I expected. About 5 or 6 fast blips on the presta valve is good. But I didn't care about the actual pressure -- if I remembered, I'd check with the floor pump at home. I will do the sidewall squeeze to try to remember what this lowered pressure feels like.

Jan Heine (I know, I know...polarizing) says pressure isn't critical. But if I've dropped the pressure during a ride, I'm usually more careful about possible pinch flats on the rest of the ride.

from the link:

+100! Reminds me of the smart phone app to tell you if your indexing is set right... next up is the app that wipes your butt. Andy (who thanks his parents for all those diaper changes with out the help of the interweb)

Just pump your tires up before each ride and use the gage on the pump. It is also the best way to tell if one of your tires have a slow leak.