These Milestar Patagonia MTs having been driving me nuts. The degree to which they bounce on the highway seems to get worse with every day. I made the decision to put in an order for some Mickey Thompson Baja Boss MTs, but those won't be here for a month. So, in the meantime, I decided to try to make these Patagonias round again.
Tools, Tire Cupping Measurements, and Shaving Difficulties
I tried a few tools to cut these tires. Certainly isn't easy with the tread blocks of a mud terrain, especially with respect to keeping the cut consistent.
With my angle grinder, I tried a 40 grit flap disc, and that seemed to do little more than polish or remove some rubber dust. I also tried a grinding wheel, which melted the rubber, ruined some clothes, and was a disaster to wipe clean (days later, still finding things I touched that have melted rubber on them).
I didn't have a method for keeping the circular saw still, so it was a matter of putting the truck on 4 jack stands, putting it in drive, and trying to hold the saw in a consistent place. This cut material much more easily, but was super sketchy (again, the truck is also RUNNING on jack stands) and was difficult to keep consistent.
One thing that became really clear here is that each tire had 1-2 flatter (cupped) spots, usually around a foot or so long. Though I didn't measure, I would say it was more than 1/4in, which was clearest when holding a straight edge near the tire.
The Planer (sort of) Won
I also tried using my planer, attached to some hastily-cut blocks of wood I typically use with jack stands. That seemed to have the most consistent cut, but it didn't seem quite fast enough. It was better to have the engine off and just slowly rotate the tire by hand. After using this, the tires really needed to be hit with the flap disc to smooth out.
Perhaps the most challenging aspect is that anything I was using was much smaller than the tire, so I mostly tried to stick with the center contact patch, which was probably fine given that the Patagonia has a crowned design.
Outcome
Here's a rough look at what it was like before. There was typically a noticeable flat spot and then maybe another smaller one. Driving on the highway, they bounced a lot. As in, other drivers could visibly see the truck bouncing.
Today, the tire is still not round, but it's a little better. Now, instead of one really noticeably flat spot, it drives like there are a greater number of smaller ones. In the same areas where the truck used to bounce, it now feels like more of a mild rumble in the seat. I'd say it took away 80% of the bouncing. Here's the best way to describe it:
Before: "holy crap are we going to be OK?"
After: "...is the truck bouncing a little bit or am I crazy?"
The drawback is that I'm feeling more vibration in the seat and steering wheel, which makes me just as anxious to shed these tires. They seem mildly louder right now as well.
Conclusion
Was it worth it? Yes, I would say so. I can manage to live with them for another month, but with the poor ride quality (especially considering they're aired up to 38-40 psi to keep the heavily-cupped lugs off the ground), I expect I'll intentionally keep my travels to short distances, and I'll most certainly be dying to swap them out when the Mickeys show up.
I wouldn't consider this a long-term solution by any means, and I wouldn't recommend it to someone who plans to use their tires long-term.
UPDATE: Another rotation + rear weight
Rotation
I decided yet again to rotate the tires, this time moving front to back, but keeping passenger on passenger, driver on driver. The idea was to go back to the ride I had before my last rotation (which is when the ride went from bad to terrible).
This seems to have reduced a fair amount of the vibration. Still far from perfect and I still can't wait for the Mickeys to show up, but this setup will work for now.
Rear Weight
With some leftover 1/4" rectangular tubing, I made a set of weights that I welded together and filled with sand. The intent was to put it under the bed where the spare would normally be suspended.
Previously, I had tried a patio furniture weight that was right at 150lbs (seriously). It really made the bumpiness "quieter" but the plastic just wasn't going to hold up long-term. This new weight is right at 70lbs. The idea was to match the stock wheel/tire, which should've been around 80lbs. If I need to add more to it later, that shouldn't be a problem.
Though I haven't had much time with the new weights, the truck really does seem to bounce a little less. I could see myself keeping it on long-term, but perhaps removing it when the RTT goes back on the rack in the spring.