barrman : Michelin PSI

Michelin PSI
Post by barrman on Apr 13, 2006, 8:54am

LIke a whole lot of you, I just got my Michelins mounted up and on the truck. What psi are you running?

I put mine on a week ago and drove it at 40. Excellent ride, but the outside and inside of the front tires showed scuffing. I aired up to 60 and things look better. I know the side of the tire says 80 max. I just want to find the sweet spot where the tire will wear evenly and not give me the horse draw carriage ride of the NDT's.

Lee had a laser temp gun and did a bunch of highway speed runs, take the temp, change the air psi and repeat. He reported that on his truck, 56 psi was the best as far as even temperature across the treads. I also have a laser temp gun and just haven't done all of this yet. I was looking for a short cut.

Thanks

Re: Michelin PSI
Post by binfordm715 on Apr 13, 2006, 9:57am

The 70 psi I reported is merely what the tire store put in them. What I plan to do is take some of my kids' sidewalk chalk and put a swath across the tread on the tires and drive it on the pavement a little and check to see at what pressure the chalk wears off most evenly. I'll start at higher pressures and let a little air out as I go. Front and rear I will do independently, since they are loaded differently.

No fancy-schmancy laser thermometers in my repertoire. This is just how the Tool Man is going to deal with it.

Re: Michelin PSI
Post by kwai on Apr 13, 2006, 10:48am

Unloaded, I had to drop mine to around 30 psi to get flat tread-wear. OTW, only the middle was in contact with pavement. XL's will be different than XZL's. Made the ride much more tolerable as well.

Re: Michelin PSI
Post by pistolnut on Apr 13, 2006, 6:21pm

Tim, we've all seen pictures of these trucks with XLs and XZLs, but I want to see a picture of your truck with them. BTW, engine parts went to the machine shop Tuesday.

Re: Michelin PSI
Post by porkchop on Apr 13, 2006, 7:24pm

I am running 45 in mine.

Re: Michelin PSI
Post by binfordm715 on Apr 14, 2006, 12:04am

Well, got my XLs mounted on the M715 today. Man! What a world of difference! It almost makes the yellow look cool! See for yourself:

Old tires:
http://img119.imageshack.us/img119/9...306001a8kl.jpg


Rear new:
http://img109.imageshack.us/img109/6...306002a5gi.jpg


All new:
http://img109.imageshack.us/img109/5...306003a6qw.jpg


The camera was in the exact same position for each shot, though the zoom was set a little different each time.

Here's a front-quarter shot:
http://img212.imageshack.us/img212/2...13060041me.jpg

And a rear-quarter view:
http://img143.imageshack.us/img143/5...306007a6tj.jpg


Sure hope I put them on the right direction! If it's wrong, then it's Porkchop's fault, since I double-checked his pictures to confirm it before I put them on!

Note where I placed the spare. I put it there with the outside of the wheel toward the side of the bed. You can sort of see that the position of the lower-most lug hole is below the top of the bed rail. What I'm thinking of doing is drilling a hole through the bed just under where it breaks over to the horizontal so it would be in line with the lug hole. (From the outside, it would be up underneath the overhang, so it wouldn't be visible.) Then I could run a 4" bolt through the bed and the lug hole to secure the spare in that position. The rear of the tire is up against the wheel well. There is about a 2" gap between the tire and the front of the bed that I could wedge a block of wood in. This would prevent any fore/aft movement of the tire. So the bolt would only have to keep the tire from falling over. It's really quite stable just sitting there on its own, actually. Not "top-heavy" at all. So what do y'all think?

I need to rebuild my carb before I can get it out on the road. (Pssst! Brandon?!) Then I'll give it some test-driving. I drove it about a half mile up and down our dirt road after changing the tires. Ride seems really nice. I can't wait to get it out for a drive and test some pressures to see which works out best.

Re: Michelin PSI
Post by barrman on Apr 14, 2006, 8:05am

I aired mine up to 80 before I hooked up the trailer yesterday. Using a level and a wooden folding carpenters ruler, the shortest tire I have is 38-1/4" from the ground to the top. The tallest I have is 38-1/2". At 80 psi, the outside edges of all the tires even with a 2,000 pound trailer attached don't touch the ground. I know this because I live on a dirt road (almost white calechi actually) and when I got to work after driving 5 miles on paved roads, the outer 1/8" on every tire still had dirt on them.

Even at 80 psi, the ride is a bunch smoother than the NDT's were at 25 psi.

I have pictures, but they are still on the camera and I can't transfer them here at work.

My students who are waiting for the "350" to come back will be glad to know it is moving along. The van is going home today too.

Re: Michelin PSI
Post by barrman on Apr 14, 2006, 4:08pm

Here is a shot of the truck on the new tires.

http://img137.imageshack.us/img137/9688/p41000028xj.jpg

I forgot to get a picture of it towing your van Clint. I had already unhooded before I thought about it. My trailer ball is a little more than 2" higher now too. I am going to have to build a bigger drop hitch I suppose to keep my trailer level.