Michelin XDA Energy or Bridgestone M713 drives?

[Chamberpains]

You might be surprised how much different fuel mileage is when your tire pressure is lower. I know the tire manufacturers and the guys that take everything they say as word from the all mighty OZ himself say that lower air pressure doesn't change rolling resistance and blah blah blah. But for those of us that dare try it for ourselves and take that pressure up, we have found that extra .3-.5 + mpg much easier to achieve.

I take mine right up to the sidewall max rated pressure. I know some guys take all tires up to 120 psi. I can vouch that I see no odd or different tread wear. Even when I'm 50/50 loaded/empty running for months on end for 10's of thousands of miles.

[JimT]

It's pretty well known that stiffer tires have lower rolling resistance than soft tires, but it's also a balance between rolling resistance, grip/traction, ride comfort and durability. The lower the tire pressure the more the tire flexes as it rolls around. That extra flex takes away some of the rotational energy and converts it to heat. Lowering the pressure will help smooth out the ride a little and may improve traction slightly, but it will result in lower fuel mileage and more heat buildup in the tires - maybe not enough to cause a failure, but enough to notice a difference in fuel. You see the effects of differing pressures very clearly in racing applications where slight changes of even 1 psi can have drastic effects. Personally I try to keep my tires within +/- 5 psi of the max inflation as long as they are all equally pressurized.

[SquareOne]

I ran the Sumo's at max psi since the day they were put on the truck. Although there was a slight variation in wear at the middle couple tread bars, it was negligible. Nothing to prevent me from doing it again with the new tires. The M713's have a more rounded profile, whereas my previous Sumos were much flatter and very little siping when new....maybe the M713's will be a little more prone to odd wear at full PSI do to that characteristic?

Although the Sumo's had there share of issues, I will say this about them...they never left me on side the road, rarely had a loss of pressure (even with all of the hardware in them lol), and netted high 8's to 9.0's for miles per gallon, right off the bat.

I'm going to go up to full psi once I get off vacation to see what gains (if any) I'll see. I'll report back within a few weeks or so.

[Chamberpains]

These new low rolling resistance tires do arch more when not loaded. But with the m710's I had zero noticed odd wear by running them at max tire pressure.

You could see the tire crown when driving through dusty roads. The middle treads would be dirty and the outer would be clean. Again, I had zero noticeable odd wear.

[SquareOne]

Since installing the M713's I've put right about 50k miles on them. Still running true and much smoother than my previous Sumos (see earlier post in this thread). The deeper lugs certainly have helped with puncture resistance as I've already noticed a few nails that have gone sideways through the lug rather than through the case itself.

Unfortunately, like mentioned and expected, the Fuel mpg def suffered. I've yet to see a 9mpg tank yet. Gotten close, but no dice. I'm averaging 8.47mpg for the last 49k miles and obviously with the cold coming in, it won't get any better for a few months. So, lost a solid .5-.6mpg with these tires to this point.

Tread depth currently is at 20-21/32nds with all tires wearing similar. I didn't measure the depth when new, but according to the B/S website these tires start with 24/32nds. I'm assuming these will wear like my previous drives with the first 8-10/32nds wearing faster, then slowing up once the tires settle in (at least that's what the Sumos did).

Something odd to me is the way these are wearing. Although all look very similar to one another and also measure just about the same up to this point, when I get down eye level with the tread I can see a very light 'stepping' from the rear to the front of each section of lug. Could this be cause be all the siping? Would the siping cause the flex and maybe abnormal scrub? When I see other trucks with the same tires I notice a similar pattern as long as the tires are wore to about the same depth. When I see these tires with significant wear, they appear much flatter. Normal tire wear or alignment issue? Again, my previous tires had no where near the level of siping or tread depth these M713's do. In fact the tread depth on the Sumos started 7/32nds LESS than the M713's.

As far as alignment goes, my truck does have a slight pull right in the right lane with a hard cambered road, will stay straight (or drift a hair to the left )in the middle lane, and will lightly drift left in the hammer lane. My last drives had good even wear and, according to the shop that sold them, claimed I got more miles than any others who ran those same drives. I put about 128k-ish miles on my last set of steer tires when they were pulled with 5-6/32nd left. Steer tires were even, with very little difference in the outside vs inside tread wear. Those were Toyo M177s...now I have Bridgestone R284's and centramatics which are doing even better (both wear and ride quality).

So, if you've made it this far, anyone have any info who run these drives or others with heavy siping. Did you see a similar pattern at first or even at all?

[Rawze]

(12-23-2021 )SquareOne Wrote:  ...
when I get down eye level with the tread I can see a very light 'stepping' from the rear to the front of each section of lug. Could this be cause be all the siping? Would the siping cause the flex and maybe abnormal scrub? When I see other trucks with the same tires I notice a similar pattern as long as the tires are wore to about the same depth. ...

That is caused by how hard you push the pedal up a hill and have it under high engine loads. The harder you push it up hills, etc.. the more prominent that type of wear is. It will also be the most prominent on the passenger forward rear axle, more than anywhere else, due to flex. That is the point where there there is the most twist in the frame, and that set of tires will slip the most in a hard pull.

[SquareOne]

(12-23-2021 )Rawze Wrote:  ....That is caused by how hard you push the pedal up a hill and have it under high engine loads. The harder you push it up hills, etc.. the more prominent that type of wear is. It will also be the most prominent on the passenger forward rear axle, more than anywhere else, due to flex. That is the point where there there is the most twist in the frame, and that set of tires will slip the most in a hard pull.

I was expecting you to say this exact response lol and I almost added the next info to the previous post, just knew it was getting long winded...... While I agree that action causes the exact wear you're describing I'm not sure how it would apply here. The pedal on this truck is babied....and I mean 'babied.' If it sees anything over 10lbs on any pull it's a very rare occasion. My running is flat ground with the occasional overpass. Speed stays low (62-64) and acceleration is very long and drawn out. I'm very mindful of how it's driven, as I want very red cent I can keep.

The wear on these are all nearly identical. If I pulled them off, IMO you wouldn't know which went where due to how similar they are.

What I have considered if the fact I run 110psi, but have plenty deadhead on what I haul. When loaded, I'm always at or near gross (especially the wet year we've had...), but I do have fair amount of empty time as well. Maybe the light weight and high psi may have something to do with it.

Thoughts?

[Nostalgic]

According to manufacturers, the 2 biggest causes are high torque application (jack rabbit starts and mashing pedal up grades) and overinflation.

I ran my cheap Roadmasters for about 110k miles at 100 psi, and rotated 2 or 3 times to keep heel-toe wear at bay. Averaged about 25% deadhead miles.

Running a horribly high rolling resistance Firestone 690+ I decided to try at 80 psi and had virtually zero detectable heel-toe wear for the first 50k when they're most susceptible, but my mileage took a hit, light or empty wasn't as bad, but loaded heavy really pulled the averages down. I increased pressure first to 85, then to 95 psi and while mileage improved ever so slightly, I've noticed some heel-toe wear develop in just the last 20k. Deadhead is about 14% and mpg average is down .4 for the year.

Personally, high dollar fuel saving drives just doesn't seem to be worth it. Mine will probably either dry rot or take some type of damage before I wear them out, and even with high fuel prices, it would take a long time to make up for a .4 mpg improvement, especially considering that the driver (me) could probably make more improvement by a little less use of the right foot.

[SquareOne]

Over-inflation is more of a fit to this particular issue. I'm the only one that runs the truck so I know exactly how it is being treated. High torque wouldn't apply here.

The other drives these replaced did not have an issue like this, but again, no where near as much siping or tread depth. I ran those at max psi as well from the very beginning. The tread pattern was very different as well, full longhaul steer tread design (actually they were steer tires). The profile was much flatter as opposed to the rounded profile of the M713's.