Airing Down; Wheel Width vs. Tire Width

I have been trying to find some actual data on the relationship between tire width and wheel width when it comes to airing down.

Specifically I am trying to find out if there is any difference in how low a pressure you can safely achieve and use if your wheel width is the minimum/maximum of the tires rated wheel width.

For example, if my tire has a minimum/maximum width of 7”-8.5” or say 8”-9.5”, will I have issues blowing a bead if I’m airing down to 5/10/15/20 psi and my tire is on the min size rim vs the max size rim?

this is a theoretical question but any real world experience would be appreciated!

cheers,

 

I am genuinely surprised that no one has any input on this.

I’ve seen a few people who are running a 255 tire on an 8.5” rim and say they have no issue airing down to 18-20 psi.

 

From the beginning of time I was told the recommended air pressure was 15 psi. People go below and some above. You may be over thinking this.

 

I have 255 with 8” rims and I run about 8psi on the sand.

 

I have 255/85/16 on the 7” OEM Pro rims and have gone down to 15psi on sand

I’ll bet there is a correlation between minimum tire pressure and rim width but it probably also depends on the terrain and how hard you’re pushing it

 

perhaps. I just see a number of people who have cautioned airing down when at max rim width, and I was hoping to figure out where that was coming from.

 

33x10.5x17 on a 8.5 wide wheel. Normal wheeling I go to 15, in the snow I go down to 5-10psi. I do have a couple wraps of duct tape around the outer bead so it acts like a poor mans beadlock, works great.

 

Do you have any photos of the tape for reference? I’m a visual dude.

 

I'd consider the Side Loads during use:
I have to imagine that running straight down the beach with very low tire pressure wouldn't be any problem at all. Turning might be though. ??
If in the woods with logs, ruts, berms, etc. pushing on the side of the tire at bead height; then, too low of pressure might allow the bead to pop off.
Rock crawling straight up & over may be of no issue. But bouldering with bumps to the side (sliding off one rock into another, or a rut), then I would want enough pressure to hold the bead intact.

I do NOT know if normal sidewall deflection is towards the tire center during low pressure operation. It may be possible that the tire wall will deflect outward (or push the bead area outward) and naturally enhance bead contact. IDK.

I just did some snow ops with 15psi on 255/85R16 on OEM 8.5 steel rims, last weekend and had no problems at all. But 15 psi is quite different than 8 psi.

 

Screenshot off of Pirate4x4, but basically put 2/3 wraps of tape over the safety bead, making the tire have a tighter fit. Method has a new wheel that uses this same idea, but the wheel has a bigger safety bead built in instead of tape