What do you guys feel is the best tire pressure for highway driving, with a load in the back? I'm in an '04 E350. Looking for best mpg. And will be driving around 9,000 miles over the next month, 95% highway.

And what are y'all's thoughts on Rain-X on the windshield? Any drawback to using it? Seems to do what it says when I've been a passenger in others' cars with it. Just wondering if there's any negatives to it.

 

I run 75 psi and love rain-x

 

best thing I have found for the windshield is to:
1. clean with dawn dishsoap and water. wipe clean with a microfibre towel
2. Use a silicon polish after 1 above, let dry and then burnish with a clean microfibre towel.

Rain x seems to be put on dirty and then stay the same way (dirty) some water does flow away but the inital cleaning is the most important aspect I have found out. Large windows on school bus, only have to use damp cloth to reclean after above.

 

Interesting. I've never heard of that method.

 

sure try this. With the hand turned place your finger nails on the windshield/windows and slide across. You will feel the drag from the glass. Do the above and then do the fingernail test and you will be surprised at the difference. We have .99 cent stores here and they used to sell the silicone liquid polish but sadly they dont have it any longer. You can try some other stuff that is a silicone polish and probably have the same results. The dawn I use is because its also used to cut grease on water fowl and it does work well to cut mech grease on your hands. Road grime is hard stuff to get rid of and even will look clean till it start accumulating grime dirt etc.

 

Whatever is just enough to produce a full contact patch. Use the chalk test to figure that out, it will likely be different front to back.

 

I use max pressure on mine.
I just bought new Coopers and they are max 80psi and I had the tire place do 80 instead of the recommended 55front 80rear.
I assumed it would be harsh but I have no complaints.

I prefer Aquapel over Rain X. But I’m not sure it’s available any more.

 

I run 55 in the front and 70 in the rear unless I have a heavy load.

 

i used to run exactly that also. But then I thought maybe the fronts would wear the outside edges less if inflated to the maximum.

So when I got new Coopers this month I set them all at 80 and I haven’t looked back.

 

That is an unfortunate characteristic of this front suspension system.

 

ive heard and believed that for a long time. But during that whole long time I always ran lower pressures in the fronts.
So what I’m doing now is an experiment.

Im surprised and pleased that 80psi fronts doesn’t make a noticeable difference in ride comfort.

 

I use Rain-x on my vehicles which helps alot in Florida's thunder storms. Only thing I hate with Rain-x is in the morning times. The windshield will have the morning dew and it doesn't wipe off clean till the dew beads get larger and are wiped off. And that's with new wiper blades too. I tried many ways to clean the windshield off before using Rain-x and get them same thing. I guess it's the high humidity that causes it.

Also Rain-x does help in keeping those %$&# lovebugs from really sticking to the windshield too!

 

Yes, there are drawbacks.

1. When you have a light mist, or just road spray, sometimes your wipers will chatter. There is a point where this stops, but that in-between condition really is not fun with Rain-X.
2. It works so well you have to pay more attention to your speed. You may find yourself blazing down the highway and wondering why everyone is driving so slowly, and then it hits you: "Oh, yeah. I can see where I'm going, and they can't."

Seriously, it's that good.

Put it on a CLEAN windshield, let it dry thoroughly and then put on a second coat. Also use the Rain-X windshield washer fluid, and you'll be very happy with it.

Use it on your side windows and rear-view mirrors, too. The difference in visibility is amazing. I don't think you'll ever want to be without it.

 

Driving style has a big impact on this, I find I have much less of a problem with uneven tire wear now that I'm not as much of a lead foot.

New tires ride better than worn out tires for sure, I was surprised how nice my van rode with a brand new set on inflated to max pressure.. compared to the baldies it had just before. And I was surprised again when it didn't change appreciably when I backed the pressures down to 50psi.

 

You should have a decal inside the driver's door with the recommended pressures for your build.