Tire Pressure Info

[Romo53]

I am fortunate in that I am able to attend many schools and seminars on high performance and tactical driving. I have heard many people sing the tire wear woes, so I would like to interject some info here.

The tire pressure "recommendations" stamped on your tires is a general bare minimum, (although it says max pressure) guideline. Many tire manufactures test up to a 300 psi burst rating. This rating is usually when the tire seperates the bead from the wheel. It does not "blow" out or explode. At one of the schools I attended, a test was done on an Explorer SUV equiped with the OEM tires, (Firestone). This test was conducted in 2001. First the tires were inflated to the recommended tire pressure of 36psi. The Explorer was then driven through a 100 ft slalom at 55mph. To no real amazement, the Explorer rolled. After picking up the pieces, the tires were inflated to 50psi and driven through the same slalom at 55mph. The Explorer performed well. A top speed of 62mph was managed before "tipping". BTW, the driver executing the manuever is a well known stunt driver. Now, this was primarily done to show the effects of "spring" from various tire pressure.

I run 50 psi in all four tires on my corvette. Makes the ride harsh, but I get better input response and yes....better tread wear. I run 50 psi on the front tires, and 45 psi on the rears of the MM. I had plenty of tread left on the front at 34000 miles, however, I needed to change the rear tires. The center tread of the rear tires was slightly worn more than the sides. I run higher psi in all my vehicles, including a big cumbersome Excursion.

I know 50 psi sounds like too much, but try it. When you put on a set of new rubber, try it. You will be able to see and feel the difference. Scouts honor.

[MM03MOK]

Welcome Back Romo53!!

[hdwrench]

you got 34k out of one set of tires with this method?

[Romo53]

Thanks for the welcome back. And yes...I did get 34000 miles. I would have clocked more on the fronts if it wasn't for the alignment problem I am still battling Ford over.

[Donny Carlson]

Thanks for the welcome back. And yes...I did get 34000 miles. I would have clocked more on the fronts if it wasn't for the alignment problem I am still battling Ford over.
I am not challenging this mileage, just puzzled. I've seen every Marauder on the lift at Team with different suspensions (Eibach's, cut springs, stock) and different ideas about tire pressures, and every last one of them had premature wear on the inner tread in front. According to the techs at Team, this is just the nature of the setup on our cars, and though the Naake coil overs may have a beneficial effect, the prediction I heard was that the coil overs would buy time, but not solve the problem. One theory posted on here about the rears tires was that the tire was too small for the stock wheel width wise, and running higher pressures would hold the side walls and keep the center of the tread from bulging outward, which caused premature center wear. I ran 38 PSI, and my tires still wore out in the centers first.

My question is this - if the inner tire wear is from an alignment issue that can't be adjusted out, how is running 50 PSI gonna help that?

[SergntMac]

Romo53...I've learned a lot over 29 years of LEO prusuit driving, as well as from Kenny Brown's "Doctor Tire" Brad Grissom. I agree with your position on PSI across the board, thank you for posting your 411.

I've had the tire wear you describe, and a serious cupping experience too, which was worked out with alignment and balance. I tried to 50 PSI, it's a bit too harsh for my tastes, so, I compromized on 40, and I won't bit*h about the the wear issues. I'm comfortable with getting 15K on my tires, I've never been comfortable driving on tires with more than 1/2 wear anyway.

[CBT]

Interesting info, another reason I love this place.:P

[MM03MOK]

..... and every last one of them had premature wear on the inner tread in front.... Just had a partial alignment done with new tires (same inside wear on the first set - 31K miles). The Toe on the right, from the factory, was -0.43. The range should be -0.13 to 0.13. We never noticed the inside wear. If caught sooner, the tires would have lasted longer because the tread itself was pretty good.

I say partial alignment since the shop owner wasn't able to loosen the upper control arm to get any movement for the camber. Back this week to try again.

I think we've settled on 32 in the front and 28 in the back (tho we may increase that.)

[Romo53]

The whole alignment thing is what is killin me. I too had close to -.43 on both the left and the right front. The tech advised me at the dealership that he would have to go alot further than usual alignment "procedures" to get it into spec. I thought it was just my MM.

Yes.....without proper alignment, the wear will be more pronounced in the affected area with higher psi. However, the wear will still occur at 36, or whatever psi you choose. That is why I quander about Ford's decision to toe the front like thay have.

Thank you for your comments......

[David Morton]

My question is this - if the inner tire wear is from an alignment issue that can't be adjusted out....Who says it can't be adjusted out? This is :bs: . I cut my teeth setting alignments and it can be adjusted out and don't you let any dealership tell you it can't.

The day I got mine I had already been on this site a couple of days and was awear of this ware problem. :D I suspected too much negative camber (neg camber means the top of the tire leans in, toward the engine) making the inside of the tire ride harder on the road surface. So I set an appointment for warranty repairs and sure 'nuff spec's were 0.2 to -1.4 (-0.6 "ideal") and it actually had -0.8L and -0.9R! So I had the guy shoot to set it just a skosh on the negative side of 0 and he wound up with -0.1L and -0.2R. Good'nuff, and these are within factory specifications. Toe is spec. (-0.13). Toe doesn't wear the inside of the tire, it wears the tire across the tread creating a "sawtooth" look on the treads.

My guess is the negative settings they use as ideal are to achieve better handling through the turns as body roll tends to make the tires go toward the positive with our unequal length control arms, but this will be minimized when I get some decent stabilizer bars and bushings. I only had the factory settings for three weeks before I made the change but I am very satisfied with the handling.

My front tires are wearing evenly and I am using 40psi (cold) all around.

[Donny Carlson]

My front tires are wearing evenly and I am using 40psi (cold) all around.
What is the mileage on your tires? Are they original tires or have you replaced the first set? and are you running OEM springs, cut springs, or Eibachs?

I replaced OEM tires with new tires at 19,000, and probably should have done it at 15,000. I then installed Eibachs and had my car aligned twice over the next 10,000 miles, but still had inner tire wear, my tech explaining that with the Eibachs I was at the limit for camber adjustment. I'm about to replace tires again at 38,000 miles. It's great that the OEM tires are relatively inexpensive, but it's been less than a year since the last tire replacement. $500 for tires every 8 months I'll have to live with, because I drive the car a lot and put on a lot of miles. I'm hoping these coil overs will allow camber settings to allow better inner wear. We'll see.

I can image those of you who do a lot of burnouts or race cars without a set of special tires for racing see a lot worse wear on the rears, too.

[David Morton]

Donny, I have 9000 miles on the car. At 7000 the fronts were wearing very well and the rears were worn out! I had noticed the middles getting thin at about 5000 miles and let them down to 25 (I had been running 35 all around) but that only acclerated the wear. So I had those replaced.

...and then I had a little fender bender! (actually both got bent) Right front tire and wheel were damaged so I bought a new front tire for the left side, the insurance company bought a new tire and wheel for the right and I went back just a week ago and got the old wheel and tire from the body shop as they were about to trash it. It is now my spare.

The wheel is only cosmetically damaged, so I plan to get it widened as soon as I get a mate for it. And guess where that is? (I can't believe my luck) I went over to the SVT Ford dealership (because the L/M dealerships' service department screwed me over for the second and last time) with a comeback vibration complaint (warranty) to take care of the mounting of the new tire I bought and the tech, apparently a little inexperienced with the roadforce machine, flagged the wheel as bad and ordered me a new one as the machine told him it was bent! (I love talking machines with warranty approval authority :D )

So the other wheel is over there, waiting for the warranty clerk to get the word from Ford. I paid the bodyshop manager $20 for the one the insurance company bought and didn't want. I can only hope they get paid for it so I can get a good deal on that one too!

Time for a prayer thread.! :D

[Smokie]

I waited too long to get my aligment corrected by Carfixer (with adapters to protect wheels) but my fronts except for the worn inner edge have at least 10,000 more miles on them (current 23k) my camber was -1.3L / -1.7R, now -.4L / -.5R

The rears are worn in the center badly, the outside is good for about 5k, the middle is toast. I keep the pressure at about 40 psi all around.

[Kramer]

So is the consensus here that the alignment should be checked and adjusted right away?

I do notice that the car does drift a bit while driving. Do I have to specify certain settings or will the LM dealer do the right job?

I bought my MM about 45 days ago. It was on the lot since Feb.

[michburt]

I haven't own the MM long enough yet to offer any opinion on the wear of the tires. I do know what I have learn through years of running motorcycles. The first thing I did after purchasing the MM was increase the tire pressure. Motorcycle tires have a problem of cupping. High pressure means longer life and no cupping. Figured it would work for the MM as well. 12K and no abnormal tire wear.

Mike:)

[David Morton]

So is the consensus here that the alignment should be checked and adjusted right away?

I do notice that the car does drift a bit while driving. Do I have to specify certain settings or will the LM dealer do the right job?

I bought my MM about 45 days ago. It was on the lot since Feb.Can't hurt. Take it in on the drift complaint and tell them you want camber as close to zero as they can get it. Tell them the truth, that you hear from us that front inner tire wear is a problem, that some of us are experienced ASE techs and that we're getting good results with camber closer to zero. Specs. allow for as much as +0.2, so they should't balk at giving you what you want.

Watch out for one thing though. Camber adjustment could be constrained by the limits imposed by the caster specification. Best thing is not to let the caster go lower than the ideal setting as this minimizes the tendency to wander the higher it is.

[Romo53]

I took my MM to a friend of mine who is a service manager at a dodge dealership. That is where they aligned the car, and that is who told me to take it back to Mercury because they needed to look at it. I took it back to the dealership where I purchased the car and gave them the alignment sheet and told them what the tech had said. I was told that the alignment "issue" would not be covered under warranty. I am still within the factory warranty, and I purchased the extended as well. What gives?! I am currently looking for another dealer that is willing to help. :help:

[David Morton]

I took my MM to a friend of mine who is a service manager at a dodge dealership. That is where they aligned the car, and that is who told me to take it back to Mercury because they needed to look at it. I took it back to the dealership where I purchased the car and gave them the alignment sheet and told them what the tech had said. I was told that the alignment "issue" would not be covered under warranty. I am still within the factory warranty, and I purchased the extended as well. What gives?! I am currently looking for another dealer that is willing to help. :help:This is not suprizing. Many dealerships don't appreciate working under warranty as it is not as profitable as "customer-pay". The one I bought my car from isn't quite that bad, but I think if you stand your ground and complain that the car pulls and you're gonna call the factory if they refuse to fix it, maybe they might start to see things your way. If they have to go in to fix the pull, it's no hair off their a$$ to adjust the camber while there they're.

Still, this is a bad sign. I'd get 'em to fix the pull and if they didn't do the camber too, I'd go to another SVT dealership and generate another pull complaint just to give those guys a "comeback" to hurt their CSI numbers. See if the new dealership wants a customer that'll appreciate your business, promise to get your oil changes and services done there, and keep that promise, then, the chances are greater that they will watch out for you when you, say, break the crankshaft after you've put a supercharger on it. :o

[Donny Carlson]

I took my MM to a friend of mine who is a service manager at a dodge dealership. That is where they aligned the car, and that is who told me to take it back to Mercury because they needed to look at it. I took it back to the dealership where I purchased the car and gave them the alignment sheet and told them what the tech had said. I was told that the alignment "issue" would not be covered under warranty. I am still within the factory warranty, and I purchased the extended as well. What gives?! I am currently looking for another dealer that is willing to help. :help: I don't know if your extended would cover it (is it ESP?), but after 10K most dealers won't do an alignment under warranty, unless you had an alignment issue prior to then that they hadn't fixed.

[Marauderjack]

What I don't get is the fronts on my car will go at least 50,000 and maybe even 60,000 miles!!! The rears.....OEM's went about 10,000 and now the second set that I got under warranty may make 20,000 or so?? :confused:

I have never had a car that the fronts outlasted the rears....I STILL THINK THE BFG REARS ARE OF LOWER QUALITY!!! Heck....Tire Rack has them for $79.00 each now while the fronts are still over $100.00?? Go figure!!?? :o

Marauderjack :coolman:

BTW.....The car still won't spin them from a stand still and no perceptible "chirp" at 1-2 shift!! :mad: I guess the S/C will change that!! :banana2:

[David Morton]

Jack, sounds to me you could use some better brakes! ;)

My KVRs will stop on a dime and give you 5c change. :banana2:

[Bradley G]

Ford covers adjustments for a period of twelve months or twelve towsand miles.Unless you have complained of the same symptom before,then it's a judgement call by the S/M

Bradley G


I don't know if your extended would cover it (is it ESP?), but after 10K most dealers won't do an alignment under warranty, unless you had an alignment issue prior to then that they hadn't fixed.

[RF Overlord]

Ford covers adjustments for a period of twelve months or twelve towsand miles.

That's mighty convenient...for THEM... :rolleyes: My front tires showed no abnormal wear at that point; it was only in the last 8,000 miles or so (car has 32,000 on it now) that the inner shoulders started showing significant wear...the rest of the tread was still very good and probably would have made it to 40,000...but as 'jack said, the rears were almost toast (and not from burnouts...my name's not Barry... :P :D )

[Bradley G]

I looked at the tires for wear (uneven) and after closely looking them over, I still exibit similar front inner wear,and rears wearing in the middle :burnout: I've since boosted pressure to the maximum stamped PSI @44.That was about a month ago.I don't think these tires on the MM were ever intended to be a mileage tire, due to it's characteristics: traction rating and such.If I can get 20-25 K thats about all she wrote (maybe not the rears:burnout:but that's OK!)I have never seen rear tires outlast front tires on any vehicle especially on a Marauder:burnout:

Bradley G

[Marauderjack]

Hey Bradley....

I have had several FWD cars where the rears went over 75,000 miles while fronts went about 40,000.....Depends on available power and RWD....I guess?? :confused:

Marauderjack :rolleyes:

[Romo53]

I am definately looking for another dealership. I was without my MM for 3 weeks while the dealership waited for a fuel gauge they thought was out. Turned out to be the fuel sending unit. Then they wanted to rotate the tires. :argue:

[Daily 03]

I looked at the tires for wear (uneven) and after closely looking them over, I still exibit similar front inner wear,and rears wearing in the middle :burnout: I've since boosted pressure to the maximum stamped PSI @44.That was about a month ago.I don't think these tires on the MM were ever intended to be a mileage tire, due to it's characteristics: traction rating and such.If I can get 20-25 K thats about all she wrote (maybe not the rears:burnout:but that's OK!)I have never seen rear tires outlast front tires on any vehicle especially on a Marauder:burnout:

Bradley G

Bradley, If your rears are wearing in the middle you have to much air pressure in them.

Dale

[Fourth Horseman]

Bradley, If your rears are wearing in the middle you have to much air pressure in them.
Dale

Seems many people here are of the opinion that, however counter-intuitive it might seem, the center wear problems on the rears are due to not enough pressure rather than too much.

I'd like to increase tire pressure to try it, but it makes my ride rather harsh.

[Bradley G]

Yeah Marauderjack,

You're right.,I've been driving trucks for so many years I forgot about all the wrong wheel drive(s)I sould have Qualified my statement:o
Bradley G

Hey Bradley....

I have had several FWD cars where the rears went over 75,000 miles while fronts went about 40,000.....Depends on available power and RWD....I guess?? :confused:

Marauderjack :rolleyes: