AndyMark 8 Inch pneumatic hub fail

[Landonh12]

Originally Posted by MrBasse

No ignorance implied, I was simply curious as to what you thought a thread locking substance was going to achieve there.

How much air pressure did you fill your tires to? Did you check the outsides of the hubs as well (take the tire off and really check)? I would be curious if there was any impact directly to the wheel itself that wasn't absorbed by the tire due to a low pressure situation.

We did have the pressure below specifications. We did this because we believed using a lower pressure would help absorb shock from ramping over the defenses.

[Fusion_Clint]

Chuck, thanks for the kind offer!

All, here is situation.

The pressure in the outside wheels was at 15 PSI with the center wheels being at 25 PSI.

We went to add pressure today when we noticed that the frame had a bit of wood from our defenses. Indicating that our tires were compressing enough to allow the wood to contact our frame. Our frame is designed so that the defense can not directly touch the wheel hubs even without a tire on the hub. We have at least a 0.5 inches of aluminum between the hub and any outside contact.

We used the hardware from AndyMark on the Hubs without any locktite.

We drove the heck out of these, thinking we would rather brake it in house that at a competition.

It broke, just not where we thought we were vulnerable.

V/r

[ToddF]

Originally Posted by Fusion_Clint

Chuck, thanks for the kind offer!
The pressure in the outside wheels was at 15 PSI with the center wheels being at 25 PSI.
V/r

If you've done any serious testing, this may be the root cause. Here is some video of our robot going over defenses. Take a look at the slow motion clips near the middle of the video. See the tires compressing nearly all the way to the rims? This was with tire pressure of 35psi. If you were running at 15 psi on your outer wheels, and hitting your defenses as hard as we have been, I have to think your tires have been fully compressing. I don't think the rims would last long if that were the case.