Figuring Tire Pressure & Contact Patch
In the July ’11 In Box, Jay Siller asked about the correct tire pressure. He said, “Would somebody please just admit the answer is ‘Due to all the variables … we don’t know.’” It is true there are many issues that come into play to determine the ideal tire pressure. The weight of the vehicle and the size and rating of the tire make it impossible to give a specific pressure. A set of 38-inch tires for 17-inch rims can hold up a very big truck. Your reply reaffirmed that there is no ideal pressure. But there is a test you can do to find the ideal pressure for your vehicle.
Place some masking tape across the thread from the inside edge of the tread to the outside. Drive a mile or so. If you wear off the tape evenly, the tires are at the correct pressure. If you wear off the outer edge first, you have too little pressure. If you wear off the inner edge first, you have too much pressure. You could do the same test with a chalk line but you wouldn’t drive as far to wear it off.
Dave Norman
Via email
Right you are, Dave. Even wetting the driveway and rolling across it works for a good guide to on-street air pressure. I usually drive in the dirt then on the pavement to get an idea.
Ford Follies
Concerning the June ’11 issue, page 53, caption 3: The owner “wanted to keep the original 400M engine.” This truck started out life as a ’67 Ford F-250, according to the article. Ford did not produce the 400M until 1971. Nice truck, but the engine would not be original for a ’67 Ford.
Richard Grantham
Ocala, FL
Right you are, Richard, but was anything on this truck matching, or really a ’67? Really?
Ultimate Adventure EcoBoost F-150 Idea
Since you’re planning on using the new Ford F-150 with the EcoBoost engine, I have a challenge for the staff when it comes to building. Build it without deviating from the factory design— i.e., if it has an IFS setup, keep it. Use parts to gain the flex and strength you need, but keep it IFS. Keep the EcoBoost engine. That way people can see that you can take a truck, not deviate too much from the manufacturer’s original design, and still conquer a whole lot. Up for the challenge?
Jeff Osterhoudt
Via email
Good ideas, Jeff. Check out the build and see what we are doing. Are you a spy?
Stinky Product or Staff?
In the July ’11 issue on page 100 (New Products) in the description of the JK Freedom Top Headliner, what is this new pee-and-stick adhesive you speak of? You know, I guess I would be OK with that as long as it worked well, but I think I will draw the line at poo-and-stick adhesive.
Love the magazine, guys. Keep up the good work.
Jon Blackwell
Edmond, OK
Wow, that one leaked through!
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