Accurately Measuring Pressure of Pneumatic Tires

How do measure the pressure of your tires? Normal car tire gauges don’t seem to work and the in-line one we have seems inaccurate also.

1 Like

We use a regulator like the one used on the robot to fill them. It seems difficult to test them with regular pressure testers because that little puff of air you let out when you put the tester on and take it off seems to let a significant amount of the pressure out.
So we just use the regulator to fill them and check them by how hard they feel.

We used a regulator as well last year. We built a jig that had:

  • A connection for the tire
  • A manual relief valve
  • A regulator
  • A pressure gauge

We’d stick the hose end into the relief valve of the robot (Thus having a relief valve on the tool, so we’d always have one available!) and have the regulator pre-set to the pressure we wanted (viewable via the gauge!), then stick the end onto the tire - you could hear the air flowing until the pressure equalized, and then you were done.

1 Like

Something like a latching schrader valve filler would make this operation easier than using a filler you have to hold on.

I would think a bicycle pump with a gauge would be the best way to pump up small pneumatic tires.

This is what gets us close enough with them. We had the same issue with separate gauges, the volume of air is so small that checking pressure would drop 3 - 5 psi from the tire.

Oooh, perfectly timed necro*. I just picked up the Milwaukees M12 inflator for some misc. projects and because I have a nice 1-2 PSI per month leak on my tyres now. Yes, it is a lil pricey**, but several teams are already in the M12 ecosystem thanks to the cordless riveter. The main selling point is the auto shut off, which can go down to 1 PSI increments. Tyre pressure differences can have massive effects on auto odometry and in-match handling, especially if you put pneumatic tyres as center wheels for a variable drop (EricH likely has a story of a student in 2005ish accidentally filling up a “flat” tyre and ruining a match). Messing with a 12v pump with alligator clips to a robot battery and an analogue gauge is a nightmare if you’re going for consistency. $80 is a no-brainer for auto insurance.
It looks like Ryobi and Dewalt also make similar products with PSI-based auto shutoff for $50 and $100 respectively.

*it would seem that I am now the necromancer :confused:
**(ofc I was cheap and picked it up used for like $40, and they regularly go on sale for around $65 new)

3 Likes

+2 for the M12 inflator from Milwaukee.

Surprisingly, I don’t. I must have been busy scouting at the time.

But I do have a few from 2006 when we had 6WD all pneumatic tires… that lasted one bounce-filled regional at best.

Oh, and Troy? Didn’t know you were British. :wink:

We use the old analog gauge version of this thing. For the $20 we paid for it, it works very well. It’s a light trigger though. As others have mentioned, you do need to pull the chuck off the stem quickly though, or you’ll lose some air.