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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Gas Vs Diesel

Should I buy gas or diesel? This question has fueled many a heated debate over the years. A universal response you could expect to hear to this question goes something like this; diesels cost more than gas, don’t buy a diesel unless you plan to put a bunch of miles on it and keep it for a long time. That’s the only way you can justify the extra cost of a diesel.

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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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Minimize Resistance, Maximize Fuel Economy

There’s no question that fuel economy is at the top of every RVer’s list, so in the next few posts, I’m going to talk a little bit about ways to improve fuel economy. I’m not speaking of the typical suggestions, such as driving 55 mph or slower or monitoring tire pressure (although those do help), I’m talking about ways to reduce resistance overall. Reducing resistance improves efficiency, and that means better fuel economy.

Obviously, tire inflation pressure is important, but so is the type of tire that you use on your coach. A tire that is wider than necessary typically produces a better ride, but it can also increase rolling resistance. That’s why a lot of truckers are going to what is called a “super single” on the rear of their trailers; instead of duals, they run one very heavy-rated tire and wheel per side. Our shop hasn’t experimented with this, and the motorhome industry hasn’t introduced super singles yet, but it could come to that. A narrower, heavy-duty tire will ride rougher than its wide, cushy counterpart, so you’ll have to ask yourself if you’re willing to sacrifice a little bit of comfort for improved fuel economy. I should note here that a larger diameter tire won’t hurt fuel economy and may even help it, because a larger diameter tire turns fewer revolutions to cover the same distance and engine rpm is lowered as a result.

Alignment is also extremely important. This is a pretty broad subject, which is why we’re not going to try to cover it all in one post. Incorrect alignment can cause a lot of resistance, requiring more throttle input to maintain a given speed. “Toe in” is the most critical setting of them all. Simply put, “toe in” means the front of the tires are “pigeon toed”. Obviously, too much toe will also cause your tires to wear more quickly. Here’s a little graphic of what toe in/toe out looks like:

It’s a good idea to have the alignment checked even when the coach is new, because the factory runs them through the alignment procedure pretty fast. And, when the coach is loaded for travel, especially an independent front suspension (IFS) coach, the alignment changes as the load changes, except on self-leveling, air suspension coaches, where correct ride height is constantly maintained.

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Bushings on the Sway Bar - Part 2

More Under the Coach Stuff….

By Brad Sears

Ok, when we last left our hero he was under Rover (our old Foretravel DP) and just exclaimed OUCH! Yes, you are right, I would not have exclaimed OUCH had I had on my mechanics gloves. When we started this journey into the ragged edge of the coach (the interior is finished but there are many sharp edges underneath, even the best built units.) For that reason we need to add mechanics gloves to the safety glasses that we mentioned in the first of this series.

I need to add a bit here to the Polygraphite bushings that I removed from the sway bar links on Rover. The bushings that I removed from the sway bar set up on the front of Rover were not totally worn out. But being a hard material, they had enough old age and wear that they would not absorb the sound of them working when the rig hit a bump in the road. Do not get the notion that I am against the Polygraphite or any of the newer material bushings that some consider the second coming of the bushing prince. But each type of bushing has it’s place.

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Diesel Engines Are Getting Quieter And Quieter

Whether in a pickup truck, semi tractor or motor coach, we are all used to hearing the sound of a diesel engine, knocking loudly like a herd of knock kneed cattle on a slow gallop.  But have you noticed that newer diesel equipped vehicles are getting quieter and quieter?   European diesel powered automobiles are extremely quiet and can not, in many cases, be differentiated from the sound of a gasoline car.  So much so, that one could actually mistake a diesel as a gas when filling the tank - not once, but twice.  Please don’t ask me how I know.  Suffice to say, there is an auto rental company in Italy that will only rent me a gas powered ride. 

So, to what technology do we owe this reduction?   Read more

Polygraphite Bushings on the Sway Bar Assembly

Things That Go Bump Under The Floor!

Ok, back to the story. If you remember when we last left our hero, me, he was flat on his back under the coach. I had just finished lubricating the left front king pins and tie rod ends as was about to crawl over to the right side to do the same. But when I am under my coach, or anyone else’s vehicle for that matter, my eyes are constantly roaming and I am pushing and pulling and tugging everything in sight.

But I need to go back a bit for some history here. Last fall leaving Seattle for a trip home to New Hampshire, I developed a heavy thumping under the front end on a pretty good sized bump. A look see underneath did not reveal anything at that time, the shock bushings looked good, I worked the shackles with my pinch bar and they looked tight, the tie rod ends and king pins looked good, so I headed east. I tried applying the brakes a little when it happened to see if I had a brake caliper floating a little but the noise did not change.

It was not too bad on the open road until we got to concrete with the divider strips like in New York, then I thought that the front end was going to fall out. I stopped and got under the rig again, but nothing obvious doing a side of the road check. But this time I found it. It would appear that the previous owner removed the rubber bushings from the sway bar assembly and installed Polygraphite bushings.

Now these bushing are sold as the answer to everything including the heartbreak of psoriasis.

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RV Lubrication ~ Part 2

We Lubricate…

Ok, so now I am flat on my back under the coach, now what coach? Last week we talked a bit about the equipment and such, now this week lets follow the route that I take doing the job. In my case I start at the left front corner of Rover using my 4 foot square piece of plywood as ground cover. I have my drop light or flash light, rag or two, grease gun, clip board and pen, and am wearing safety glasses. Yep, a couple of pieces of sand in your eyes can spoil an otherwise good day under the rig. I also have an old baseball cap that helps keep the yuck out of what little hair that I have left.

Now under the rig there is more to do than locate the grease fittings, wipe them clean, and apply the grease with the grease gun until just a little comes out between the boot and the joint. Some manufacturers claim that you have enough grease in the joint when the rubber boot over the joint balloons out a little. They do not want to break the seal between the boot and the metal around it.

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RV Lubrication - Part 1

To Grease Is To Smear~We Lubricate

Fifty years ago that is what my father hammered into my head at the family owned garage. In his mind the top technician in our shop was the guy that got most of the lube and oil changes that rolled through the shops door. Dad’s reasoning was that the most important job that we did for a customer was to do the periodic lube, oil, and filter jobs. Today, bottom line management with its ideas that jobs in a shop can be broken down into skill levels meaning that a monkey can do a lube, oil, and filter change saving the skilled worker for the computer work is flawed. Read more

Unsprung Weight, Unlocking The Mystery

Lug Nuts latest blog on Aluminum Wheels was, as his usual product is, great. I have aluminum wheels on Rover, our 1990 Foretravel DP, and they are great. But there is one great advantage and that is that they are lighter as Lug Nut said. And as he said that reduces unsprung weight.

With Lug Nuts permission I would like to expand a bit on the mystery of unsprung weight other than the general weight reduction of the rig. Unsprung weight is the weight of the components between the springs and the ground. That includes the tire, wheel, bearings and hub, brake rotor or brake drum, caliper and pads, brake shoes and springs, wheel trim rings, lug nuts, and suspension members between the springs (or air bags), and the ground.

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