Puncturing Pneumatic Tires

[flipthedog]

Hello everyone,

Our team has had relatively little experience with pneumatic tires during the competition season. So I wondered how pneumatic tires hold up during competitions. Has anyone experienced flat tires in previous years? I can imagine that the current game will cause even more punctures compared to previous years.

Thank you,

Floris
Team 1389

[Joe Johnson]

Originally Posted by flipthedog

Hello everyone,

Our team has had relatively little experience with pneumatic tires during the competition season. So I wondered how pneumatic tires hold up during competitions. Has anyone experienced flat tires in previous years? I can imagine that the current game will cause even more punctures compared to previous years.

Thank you,

Floris
Team 1389

I've used pneumatic tires many seasons and I don't remember having had a flat tire that wasn't self inflicted. I recall pinching a tube with a screw driver trying getting the tire on/off the hub. I think we popped a tire once when we used too low of pressure and the tire slipped on the hub and over taxed the valve stems that were the only thing keeping the tire from rotating further.

Dr. Joe J.

[Andrew Schreiber]

Years ago I recall getting hit and having the valve stem crack which led to the tire going flat... but that's about it.

[GeeTwo]

We've lost plenty of cheap (e.g. Harbor Freight) pneumatic tires over the past two years. Good luck so far on our AM pneumatics (on our air cannon, not our competition robot this year).

[Mechvet]

Originally Posted by GeeTwo

We've lost plenty of cheap (e.g. Harbor Freight) pneumatic tires over the past two years. Good luck so far on our AM pneumatics (on our air cannon, not our competition robot this year).

We're using those cheap Harbor Freight wheels. Mind detailing how yours have failed, so we can keep an eye out before it happens?

We're having pretty great success with them, too. Kept the split rim, just knocked the bearings out and pressed a hex-broached aluminum plug into place. Nice and cost effective, and so far it's been eating defenses alive.

[MrBasse]

Originally Posted by Mechvet

We're using those cheap Harbor Freight wheels. Mind detailing how yours have failed, so we can keep an eye out before it happens?

We're having pretty great success with them, too. Kept the split rim, just knocked the bearings out and pressed a hex-broached aluminum plug into place. Nice and cost effective, and so far it's been eating defenses alive.

I think it is more of a time issue with those HF tires. The sidewalls will begin to fall apart and the rubber seems to break down after 1-2 years. When they finally let go, it is a fantastically loud noise. Two years ago we were airing up our robot carts tires and one let loose while I was sitting next to it filling it. I am by no means nimble anymore, but without knowing how or why, I was standing up before the room stopped echoing. That was at about 30 psi. We have since decided to run solid wheels and start moving away from HF wheels and tires.

[GeeTwo]

Originally Posted by Mechvet

We're using those cheap Harbor Freight wheels. Mind detailing how yours have failed, so we can keep an eye out before it happens?

We're having pretty great success with them, too. Kept the split rim, just knocked the bearings out and pressed a hex-broached aluminum plug into place. Nice and cost effective, and so far it's been eating defenses alive.

We didn't have any trouble with the metal, tread, or sidewalls, but we were losing inner tubes at a rate of a couple a month. All of the failures I looked at were at the seams, most commonly near the base of the filler tube. While our air cannon is a bit heavier than an FRC-legal robot (closer to 200# on 6 wheels), we never ran it at high speed or over any obstacles bigger than about a 1" transition at the edge of a sidewalk. All the ones I saw were seeping leaks, so we weren't aware of exactly when the damage occurred.

Especially with the brutal defenses of Stronghold you may be better off if you upgrade your inner tubes. At the very least have spares on hand and a procedure to swap them out.

[GeeTwo]

Originally Posted by D_Price

We have had some issues with "self-puncturing" our pneumatic tires not really field or other robots puncturing them. We had a team member this year rivet through the tire but rectified that with a bottle of slime on hand in case something like this happens.

Check out rule R9. Case L in the blue box specifically outlaws tire sealant. (IIRC, this was in a team update.)

[MrBasse]

Originally Posted by GeeTwo

Check out rule R9. Case L in the blue box specifically outlaws tire sealant. (IIRC, this was in a team update.)

Especially because that stuff is a mess, and flammable. When placed in a tire under pressure with air you make a nice little bomb.

[D_Price]

Whoops you are correct. I am completely wrong. Post taken down.

Originally Posted by GeeTwo

Check out rule R9. Case L in the blue box specifically outlaws tire sealant. (IIRC, this was in a team update.)

[frcguy]

Riveted through a tire? Yikes! How did you guys manage that?

[GeeTwo]

Originally Posted by frcguy

Riveted through a tire? Yikes! How did you guys manage that?

Rookie mentor?

Edit: No, I see you've been doing this a while. I haven't seen this particular thing yet, but we just started riveting seriously this year, and we opted not to do pneumatic wheels this year.

[Ryan Dognaux]

We managed to get a rivet mandrel impaled all the way through the tire and intertube. It was funny seeing a small metal dot and then pulling out a long rod. On the plus side, it's made us have spare parts ready to go to easily swap wheels.

[electroken]

Watch your tire pressures. Too low, and when you hit the rock wall the tire (and tube) will fold and compress against the wheel edges. The result will often be 1 to 4 holes in the tube. These pinch flats are well known to offroad bicyclists and motorcyclists.