Hi,

I made an observation over the past 2 days I have spent driving freshly graded gravel roads in the bush. On both of these days I have had a flat tire caused by rock punctures between the tread of nearly new, quality on/off-road light-truck tires.

Does road grading break the larger stones into sharp points which increase the possibility of flats caused by stones?

Has anyone else noticed this problem or am I just having a bad string of luck?

Mike

Freshly quarried gravel is sharp and grading the road may have exposed rock that wasn't dulled by traffic. That's sort of a guess because I spent part of a year living in a camper at a quarry when I was a kid and the fresh rock wasn't good to play in, but after being loaded,hauled,dumped and leveled it seems like the edges would be worn down.

Depends on the rocks. Some areas have stone that fractures with sharp edges, other rock is softer, and the edges are not as sharp.

Last winter we were in a "sharp rock area" (The American Girl Mine in So.Cal. We are now in a softer rock area (Eastern Rim of Arizona). I still find cuts in my tires, but they are not the razor clean cuts we experienced near the American Girl Mine.

The general feeling of the forest service folks I have talked to on the "East rim" here in AZ is that there are a lot of slow leaks in their tires, but seldom a large failure.

No matter how you cut it (<<pun), tires take a beating on gravel roads.

We spent the first part of last year prowling around the Mojave Desert in southern CA, dirt and gravel roads, and had a lot of flats. These were not fresh type roads, but roads that have been there for a long time. About half of the punctures were in the tread area (these were new AT tires on a Ford Ranger 4wd), the others were in the sidewall, caused when we brushed up against something sharp. Later in the year we were in Alaska, and got two flats on the same tire, couple of days apart, thanks to the graveled streets of Valdez and the surrounding area. I heard of people driving into the Kennicott copper mine area, about 60 miles one way, gravel, who got three flats on the trip. So it seems that gravel and tires don't mix well...

I wonder if airing down for those roads would help? Don't the rock crawelrs air down or is it just the ones that go on sand, I can't recall now.

Hi,

Airing Down (within reason) is what I am going to try next. My work truck is a 3/4 ton Ford usually with a a heavy ATV/ramp/tools in the back so we run 10 ply, on/off-road, high pressure tires. I am going to reduce the pressure by 25% and see if that helps prevent the stone damage. The trouble is that I also drive a lot of highway to get to the gravel access roads so airing down may effect my gas mileage and highway handling, well see?

Mike

Well you could at least stop and air down when you get to the gravel road so your still running full pressure on the trip there.
Now you'll have an excuse for on board air.

Freshly graded roads are notorious for ruining tires. If your going to be running at normal road speeds 25-50 mph reduced pressure would be a bad thing, it wont help much to reduce damage at those speed and will reduce your control. They air down for rock crawling but speeds rarely exceed 5mph. the best way to reduce the damage is slow down, it will get better in a week or so.

Well, jeez louise! I thought it was just my bad luck! I've had that happen three times, and the repair guys said all were caused by sharp broken rocks. At least the horseshoe nail I could understand.

Kevlar slippers for tires... its always something.

Sue

Airing down might work, but also be careful when driving on wet gravel roads. The tires get cut easier when they're wet.

I was thinking the same thing only with rubber. Kevlar is 1000 times better though.

You either air down for flotation (sand) or conformability (rock crawling). In either case you need to air back up on the highway because a tire with low air pressure heats up more and is more prone to a failure at highway speed. Airing down will also put the sidewall closer to the ground and in a better place to get punctured. You can plug tread holes (within reason) but sidewalls are a completely different animal.

Bill

I know not how to answer your specific question, concerning smaller but sharp stones.

But on a somewhat related topic, -I've read in books concerning Desert Vehicular travel, (Sahara Overland by Chris Scott / Trailblazer has got to be one of the Very Best!), -that a Washboard Effect develops on typical unpaved Desert Trails. This from the repeated driving which takes place on them, over time. Its something that you've got to be Aware of, -and Watch Out for / Adjust to.