adventurebuddies
Adventurer
Update now that I have about 13,000 miles on my 275/80/R20 MPT-81 tires: I had previously stated that I was running them at 55psi in the front. That worked great until we had a really hot drive through the desert. Ambient temps around 115deg plus full sun to heat the road surface. With the tires at 55psi. the inner/outer lugs wore down significantly in only about 400 miles of driving. I was shocked, and dismayed, at how much lug depth I lost - roughly 1/8" on that trip. The center lugs did not wear noticeably. It was like the rubber had just evaporated away. The wear was pretty even on both sides of both front tires with no cupping, though they did start to scallop. The rear tires were at 75psi and did not suffer the same fate, and I should state that this is not a balancing or alignment issue. After that trip, I increased the front to 68psi and have put another 5000 miles on them including more hot desert driving. They are now wearing very evenly.
Based on this experience, it's clear to me that these tires don't like heat and that I needed more pressure up front than I thought. I'm shocked that the EarthRoamers run with such a huge discrepancy between the front and rear pressures. Perhaps the rear is significantly heavier that the front. On my rig (XPCamper), the front axle is about 25% lighter than the rear axle. At 68psi in the front, the steering is a little lighter than I would prefer, but I have noticed a significant improvement in slowing down the rate of tire wear.
Regarding the new tire version - can anyone who has the new version confirm if it has the small Mountain/snowflake icon? This is required for winter driving in some European countries so maybe that's the change. Also, I purchased my tires from ColonyTire on Ebay. Great experience and the tires all had date codes within 1-2 years of my purchase date. I will wear them out way before the rubber goes bad.
On a side note, does anyone have the specs for regrooving these tires? My tires are starting to get close to the point where the "bridge" between lugs will be exposed. I want to use a regroover to take out the bridge to expose the rest of the available lug. I also understand that the base material of the tire is meant to be grooved up to a certain depth. This would decrease the thickness of the rubber (making it more likely that a rock or thorn could penetrate the rubber between the lugs), but it also can increase the life of the tires. But I can't find any specs online for how deep the regroove cut can be. At the rate they are wearing now, it looks like I should be able to get roughly 25,000 miles out of a set by grooving out the lug bridge, plus another 5000 or so by grooving into the base. Any thoughts or experience on this subject? I may make a separate post regarding re-grooving to avoid hijacking this one about pressure.
Based on this experience, it's clear to me that these tires don't like heat and that I needed more pressure up front than I thought. I'm shocked that the EarthRoamers run with such a huge discrepancy between the front and rear pressures. Perhaps the rear is significantly heavier that the front. On my rig (XPCamper), the front axle is about 25% lighter than the rear axle. At 68psi in the front, the steering is a little lighter than I would prefer, but I have noticed a significant improvement in slowing down the rate of tire wear.
Regarding the new tire version - can anyone who has the new version confirm if it has the small Mountain/snowflake icon? This is required for winter driving in some European countries so maybe that's the change. Also, I purchased my tires from ColonyTire on Ebay. Great experience and the tires all had date codes within 1-2 years of my purchase date. I will wear them out way before the rubber goes bad.
On a side note, does anyone have the specs for regrooving these tires? My tires are starting to get close to the point where the "bridge" between lugs will be exposed. I want to use a regroover to take out the bridge to expose the rest of the available lug. I also understand that the base material of the tire is meant to be grooved up to a certain depth. This would decrease the thickness of the rubber (making it more likely that a rock or thorn could penetrate the rubber between the lugs), but it also can increase the life of the tires. But I can't find any specs online for how deep the regroove cut can be. At the rate they are wearing now, it looks like I should be able to get roughly 25,000 miles out of a set by grooving out the lug bridge, plus another 5000 or so by grooving into the base. Any thoughts or experience on this subject? I may make a separate post regarding re-grooving to avoid hijacking this one about pressure.
