The Age Old Question, How Many Pounds Of Air Shall I Put In My Tires?

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Well sir, I have never been accused of being terribly smart and politicaly astue, so here I go jumping from the frying pan into the fire on a subject that some have said in the forums is a dead horse and beaten to death. But there is more to the tire pressure story than just when will it fail or blow up. Or how much pressure to ad and when.

We all know that a tire that is under inflated will use more power to make it roll than a properly inflated tire. That is because of these factors:

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Forget Oil! The Future is in Electricity

By Bob Difley
A lot of experts and theoretical think tanks are looking at ways to quickly and drastically reduce our oil requirements, rather than pursuing ways to increase supply to meet demand with unpopular options like increased drilling in places like ANWR and the continental shelf. They are suggesting that we instead put our efforts into producing most if not all of our energy needs from domestic sources.

• No to foreign oil.
• No to war with foreign nations to stabilize their shaky governments and whose oil we want.
• No deals with disruptive, threatening, unfriendly, and unstable governments and rulers just so we can buy their oil.
• No to competing with China and India for oil, whose exploding economies have them gobbling up all the oil they can buy from any source at any price.
• No more oil tanker spills.
• Reduction of CO2 emissions and air pollution.

A pipe dream?

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More Fuel Saving Ideas

Well, we just got back from the Escapee Rally in Gillette, WY., followed by the Life on Wheels Educational Conference at Lewis-Clark State College in Lewiston, Idaho. If you have never been to one of these conferences, you should make time in your schedule to go to one. They are so educational-you can take a class on anything from cooking in your RV and making income on the road to a numerous technical classes.

Traditionally, my classes are about RV chassis, ride and handling-but since I began doing seminars on improving fuel economy by reducing resistance, I have noticed even greater turnout and response. People still want to learn about the handling characteristics, problems and solutions associated with their particular coach, but these topics seem to have taken a back seat to fuel economy, for obvious reasons. Read more

Valid Mileage Comparisons

The mail bag is getting full and it would be the polite thing to do to answer the questions and make room for more. Santa Skip wrote the following after I used the term Tommy Knocker:

“I spent my younger years exploring the ghost towns of CO, to me a tommyknocker was a little elf who lived down in the mine, if he liked you he would show you where the gold, (was) if he didn’t he would cause all kind of problems.”

One of the neat things about traveling is that you get to learn that an expression that you grew up with have different meanings regionally. But this is a new meaning of Tommy Knocker to me.

Chuck wrote the following after my comments on driving at 55 miles per hour:

“I’m posting this as a reality check. I’m getting better MPG at 68-72 mph (2200 rpm) than at 55 mph. I drive a F250 with a V10. With or without the 5th wheel trailer I get better mileage at a higher speed and higher rpm. At my last fill up I got 10.8 mpg. I traveled 107 miles with the 5th wheel trailer and 190 miles without the trailer. In the past if I drove at 55 I would get around 8 to 9 mpg. Has anyone else seen this type of mpg driving faster instead of slower?”

Under real world conditions it is almost impossible to get accurate fuel economy numbers. Back in the dark ages, about 1980 something, the EPA was in the process of certifying fuel savings devices. They invited a group of automotive writers to a test drive to provide the EPA with numbers of fuel economy improvement of the new Volkswagen E Shift light system. It was a computer controlled device that would turn a light on on the dash that would signal the driver when to up shift for best economy. The route was from the tip of Long Island to Newport, Rhode Island. Lots of rolling hills.

VW teamed up the drivers and it happened that Dan Holt, then a writer/editor with the Society of Automotive Engineers publication, and I drew the duty as partners. Now not to say that we were heavy, but between the two of us we exceeded the load carrying capacity of the car, not counting our luggage or our camera gear. Now as every one knows writers have imagination. Dan and I being both engineers decided that we would show some real fuel economy, and here is how we did it.

The first thing that we did was to eliminate rolling resistance. We stopped and pumped the tires up to 80 PSI. The car rode like it had Freddy Flintstone Hard Rock tires. Then we applied some simple junior high school physics. Gravity. We figured with our combined weight, the weight of the car, and gravity, that we could use the engine on down hill runs to get the speed up, and then coast up the next hill. Foot to the floor in high gear going down hill, put the tranny in neutral and shut the engine off for the uphill coast. In several instances on the run we were able to leave the engine off for several hills as well as seeing the tach hit red line in high gear.

VW controlled the record keeping of fuel in each car with a burette attached to the front bumper and at each fuel stop they measured fuel used and filled the burette to the full line and we ventured out again. Well Dan and I placed second in this 50 car run with around 100 miles per gallon. A couple of guys from one of the magazines out did us by a couple of miles per gallon. I think they ran a bit more air in their tires but they used the same techniques. We did show VW that we could get good mileage but it did little for the certification of the Up Shift Light. And we broke speed laws and really had a ball.

The moral of the story, which is a true story all the way, is that determining a difference in fuel economy means measuring apples against apples under like conditions with only one variable at a time. Driving cost over an extended period of time is a valid number.

Hey Ranger! Make your own motor fuel?

Rising gas prices have sparked revived interest in a variety of solutions, including ways to make your own fuel. Advances in technology may eventually allow this process to become a little more practical - and safer.

This is not a new idea, and my local library has a book that claims to explain “how to make your own motor fuel at home.” It’s perhaps not a coincidence that it was assigned a place on the library shelf between two other books entitled “Fireworks.”

I recently read an article about a much higher tech approach that’s about to hit the market, Read more

Blowing All Your Money in Canada

Last week we discussed beating gas prices by camping close to home. So it seems fitting that in this week’s post we consider what happens when you throw caution to the wind, viciously abuse a few credit cards, and camp FAR AWAY from home. For my wife Kristy and I, the time we spent in Canada’s stunning Banff National Park qualifies. Here are a few thoughts about camping in Canada, with some pesky dollar amounts attached.

Airstream RV Blog #26 - Banffff from Sean Michael on TheLongLongHoneymoon.com.

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Tire Check: Me And My Tommy Knocker!

Just Some Thoughts

During the past two weeks, DW and I cruised the coast of Maine on a lobster and lighthouse tour. The RV traffic was light and there was not one “No Vacancy” sign to be seen. We had our choice of campgrounds without reservations. We took all blue roads and kept the speedometer below 55. I was playing as usual, only this time being very intune with fuel economy while being a safe driver. Below are a few thoughts that ran through my addled mind while on the road. Oh, doing a lot of stop and go driving, you know those antique shops keep hollering STOP, we managed 10.79 miles per gallon for a thousand mile run. That is not towing and Rover is a 1990 38′ Foretravel with a Detroit 8.2 and 4 speed Allison.

Meet Tommy Knocker

Growing up around Boston sixty years ago, every kid knew what a Tommy Knocker was. Do you? It was what you used to clobber Tommy over the head. Today my Tommy Knocker is a small ball peen hammer that sits under my recliner right by the door of Rover. It is not used to knock Tommy over the bean with but rather to play the 6 kettle drums on the coach when I stop after a run.

Yep, the tires on your rig are a musical instrument and can be tuned by changing inflation pressure. If you walk around your rig and knock the tires in about the center of the tread, it will let out with a musical note. Now that note will not tell you the inflation pressure of that tire, but if all six tires (if they all have the same pressure) will have the same note. A lower pressure will have a lower note and higher pressure will have a higher tone.

Tire Temperature

The other thing that shares the same place with the Tommy Knocker is a digital infra red thermometer. As I make the circle check of the rig right after pulling in off the road I check the temperature of each tire tread and the center hub of each wheel. Tire temperatures that are uneven can indicate uneven tire pressure. High temperature of the thread indicates possible low pressure. High and uneven temperatures of the hubs can indicate uneven or dragging brakes or problems with a wheel bearing.

Driving Style

BMW several years ago stated that getting up to speed quickly actually saved fuel. What I did was use the turbocharger boost gauge as a driving signal. During acceleration I kept the boost in the lower third of the turbo range. That gave decent acceleration while letting the transmission upshift at lower speed.

When climbing hills, and there are plenty of 9% grades in Maine and New Hampshire, I worked the shifter, the boost gauge and the tachometer when climbing. That is keeping the RPM’s up to 3/4 of red line with the boost gauge somewhere in half gauge range. The RPM’s keep the coolant circulating and the transmission cool preventing overheating. And remember to descend a hill in the same gear that you used to climb the other side using as much engine braking as you can. It also saves a lot of brake.

There are other tricks to fuel economy as well. Try to never accelerate going up hills, accelerate on the down hill side using gravity to help get speed up. Drive ahead, watching cars stop lights 5 or 10 cars ahead allowing you to let off the go pedal well before hitting the brakes. Coast up to stop lights, remembering that using the brakes you are scrubbing off speed that you paid for to get.

A little practice you can get real smooth, not be a slug obstructing traffic, and save some real bucks at the fuel pump. Well with that said it will be back under the coach next week.

Brad

Innovative Future Fuel Savings For Motor Homes

Through the years we have seen motor home manufacturers continue to up the bar with new and innovative ideas. These ideas and new features have attracted buyers, both new to the lifestyle and those trading up. But, unlike the auto industry, no one quoted expected fuel mileage, or in many cases, cared, for that matter. That may be soon to change. You can just imagine the potential buyers now. Even though they are not expecting an economic fuel consumption figure, there will be more people than ever asking “How many miles per gallon”.

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Drilling ANWR: More Questions and Thoughts

I am at the Life On Wheels RV Convention at Lewis-Clark College in Lewiston, Idaho this week, but had a few more thoughts and questions on drilling in the Alaska National Wildlife Refuge (ANWR).

(1) If we need ANWR’s oil so much, why haven’t the oil companies drilled the 65 million acres they already have leases on?

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Is There an Electric Toad in Your Future?

By Bob Difley
How close are we to an electric vehicle? A bit far, I suspect, for motorhomes or trucks powerful enough to pull trailers and fivers, but maybe not as far for a toad. GM has pulled out all the stops for the Volt PHEV (plug-in hybrid electric vehicle) due out in the spring of 2009. Read more

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