Tires - Extensions and Pressures

ditsjets7 · Dec 1, 2017

This has been split from the Water discussion available Here. -LS

-------------------------

Now that you got me thinking about gas mileage that leads me to these questions.
Class C 31 Foot.. Ford Triton V-10. What speed should I travel at to maximize my gas mileage. is 65mph good? is 10 MPG realistic to achieve?

Tires. My tires are two years old. I was told 55 PSI is idea. Question, what, where do I get an extension for the tires to check the pressure and fill them if need be?

Thanks again for helping out this former Veteran pop-up camper and now Rookie at motor Homing!

kdbgoat · Dec 1, 2017

The correct tire pressure for you motorhome is on the sticker when you open the driver's door. There's very little difference in weight from empty to fully loaded, so need to weigh axles/corners to set tire pressure. That usually is recommended for class A's though, as they can usually carry more weight, and it can be distributed a lot differently throughout the coach. Any decent tire shop can fix you up with whatever is needed to check and fill your tires. I have to use two different chucks to do mine.

Gas mileage- Within reason, 65 is the fastest you should go to get any kind of mileage at all. The problem with motorhomes is the big area pushing wind, causing bad gas mileage. The faster you go, the more wind you push, and the less gas mileage you get. And no, don't expect 10 mpg. 8 mpg will be more like it.

gravesdiesel · Dec 1, 2017

@kdbgoat, I have this for airing my dual wheels on my trucks. It works great and you do not need any special adapters to swap around when you rotate your tires.
https://www.ebay.com/i/201016817820?chn=ps

kdbgoat · Dec 1, 2017

gravesdiesel said:
@kdbgoat, I have this for airing my dual wheels on my trucks. It works great and you do not need any special adapters to swap around when you rotate your tires.
https://www.ebay.com/i/201016817820?chn=ps

Thank you for the help. One of my chucks is like that, but on my two outside rear wheels, I need one that is about 90 degrees from the airline. I could use adapters/extensions, but that's just another place for a leak.

Here's the second type I use. It won't reach the other 4 tires.

https://www.grainger.com/product/AMFLO-Ball-Foot-Chuck-41AA48

CharlesinGA · Dec 6, 2017

For tire service I use these. I do NOT have any wheel covers, just bare steel wheels and a plastic hubcap on the front that doesn't interfere. Its a truck, I don't want fancy wheel covers to make checking tires and lugs more difficult. I tried the long valve stems (Borg) and on mine, they didn't fit, and I realized it was Bit** to remove and install the rear tires without damaging the stems, and made the wheels non-interchangable. They may work for some, but I am a hubcap type of guy.

Foot long Milton chuck p/n S-693-12. Straight on the end, back angle also. Only dislike is that it has grooves inside the ends to "lock on" the threads on the stems. More difficult to push on and off in a restricted place. You can replace them with non groove screw in ends from Milton, p/n P500-2

https://www.amazon.com/Milton-S-693-12-Extended-Reach-Chuck/dp/B004QI1WEA/ref=sr_1_2?s=automotive&ie=UTF8&qid=1512611514&sr=1-2&keywords=milton+s693

https://www.miltonindustries.com/dual-head-chuck-nut.html

To make checking air pressure easier, throw away the caps and buy these [/url]https://www.amazon.com/Alligator-V2B-Inflate-Through-Valve/dp/B014VCY3S2/ref=sr_1_1?s=automotive&ie=UTF8&qid=1512611409&sr=1-1&keywords=alligator+tire+caps[/url] These are inflate thru the cap type, brass, made in Germany. Keeps dirt out, easy to check pressure and air tires up. They have grooves (not threads) on them to allow the locking chucks to bite on, and this is the reason I want the smooth bore end caps on the chucks.

https://www.amazon.com/Alligator-V2B-Inflate-Through-Valve/dp/B014VCY3S2/ref=sr_1_1?s=automotive&ie=UTF8&qid=1512611409&sr=1-1&keywords=alligator+tire+caps

For a gauge, anything long with a chuck like the air chuck, https://www.miltonindustries.com/extended-reach-tire-inflator-423.html

I really do not like the inflator/gauge devices. They have been around for years, but are stupid expensive and if they break, get out of calibration, etc, its a lot of money lost.

Charles
2007 Winnebago View 523H on a 2006 Dodge (Daimler-Chrysler aka Mercedes) Sprinter 3500 chassis (T1N). Bought Sept 2015 with 18K miles on it, Prog Ind HW30C, Prog Dymanics PD4645, Coleman Chill Grille, PML/Yourcovers.com deep alum trans pan, AutoMeter 8558 trans temp gauge, Roadmaster sway bar, Koni Red shocks (front & rear), Fantastic Ultra Breeze hood, added OEM parabolic mirrors and RH aspherical mirror, MB grill conversion.

ditsjets7 · Dec 6, 2017

CharlesinGA said:
For tire service I use these. I do NOT have any wheel covers, just bare steel wheels and a plastic hubcap on the front that doesn't interfere. Its a truck, I don't want fancy wheel covers to make checking tires and lugs more difficult. I tried the long valve stems (Borg) and on mine, they didn't fit, and I realized it was Bit** to remove and install the rear tires without damaging the stems, and made the wheels non-interchangable. They may work for some, but I am a hubcap type of guy.

Foot long Milton chuck p/n S-693-12. Straight on the end, back angle also. Only dislike is that it has grooves inside the ends to "lock on" the threads on the stems. More difficult to push on and off in a restricted place. You can replace them with non groove screw in ends from Milton, p/n P500-2

https://www.amazon.com/Milton-S-693-12-Extended-Reach-Chuck/dp/B004QI1WEA/ref=sr_1_2?s=automotive&ie=UTF8&qid=1512611514&sr=1-2&keywords=milton+s693

https://www.miltonindustries.com/dual-head-chuck-nut.html

To make checking air pressure easier, throw away the caps and buy these [/url]https://www.amazon.com/Alligator-V2B-Inflate-Through-Valve/dp/B014VCY3S2/ref=sr_1_1?s=automotive&ie=UTF8&qid=1512611409&sr=1-1&keywords=alligator+tire+caps[/url] These are inflate thru the cap type, brass, made in Germany. Keeps dirt out, easy to check pressure and air tires up. They have grooves (not threads) on them to allow the locking chucks to bite on, and this is the reason I want the smooth bore end caps on the chucks.

https://www.amazon.com/Alligator-V2B-Inflate-Through-Valve/dp/B014VCY3S2/ref=sr_1_1?s=automotive&ie=UTF8&qid=1512611409&sr=1-1&keywords=alligator+tire+caps

For a gauge, anything long with a chuck like the air chuck, https://www.miltonindustries.com/extended-reach-tire-inflator-423.html

I really do not like the inflator/gauge devices. They have been around for years, but are stupid expensive and if they break, get out of calibration, etc, its a lot of money lost.

Charles
2007 Winnebago View 523H on a 2006 Dodge (Daimler-Chrysler aka Mercedes) Sprinter 3500 chassis (T1N). Bought Sept 2015 with 18K miles on it, Prog Ind HW30C, Prog Dymanics PD4645, Coleman Chill Grille, PML/Yourcovers.com deep alum trans pan, AutoMeter 8558 trans temp gauge, Roadmaster sway bar, Koni Red shocks (front & rear), Fantastic Ultra Breeze hood, added OEM parabolic mirrors and RH aspherical mirror, MB grill conversion.

Thank you very very much! I will buy all these products!

KandT · Dec 7, 2017

ditsjets7 said:
And now you have answered my next question so thank you. I figured with approximately 360 additional lbs for a 45 gallon tank that would cause the gas mileage to decline. You say no so that's good enough for me.

Now that you got me thinking about gas mileage that leads me to these questions.
Class C 31 Foot.. Ford Triton V-10. What speed should I travel at to maximize my gas mileage. is 65mph good? is 10 MPG realistic to achieve?

Tires. My tires are two years old. I was told 55 PSI is idea. Question, what, where do I get an extension for the tires to check the pressure and fill them if need be?

Thanks again for helping out this former Veteran pop-up camper and now Rookie at motor Homing!

While the BEST answer for tire pressure may involve weighing the vehicle and checking the tire's website for the pressure, the door jam IS WAY BETTER way than "what you heard", I had the 2006 e450 and if I remember correctly 55PSI is way too low!!

31 feet (what I had) pushes that 2003 e450 to it's limit so I will be the contrarian here and suggest that you may want the cargo carrying capacity for things other than water. Mine had the water tank clear in the back and I imagine that caused quite a cantilever effect for rear axle weight. what I mean is that by putting 1 pound of water in the tank we likely took weight off the front and added more than a pound to the rear axle. We were 1000 pounds over weight on our rear axle on one of our trips - first time I had it checked at a CAT scale.

Sure if you have a diesel pusher with a tag and 6000 pounds of ccc you may want to start with tanks full but that isn't what you have.

good luck!

ditsjets7 · Dec 7, 2017

KandT said:
While the BEST answer for tire pressure may involve weighing the vehicle and checking the tire's website for the pressure, the door jam IS WAY BETTER way than "what you heard", I had the 2006 e450 and if I remember correctly 55PSI is way too low!!

31 feet (what I had) pushes that 2003 e450 to it's limit so I will be the contrarian here and suggest that you may want the cargo carrying capacity for things other than water. Mine had the water tank clear in the back and I imagine that caused quite a cantilever effect for rear axle weight. what I mean is that by putting 1 pound of water in the tank we likely took weight off the front and added more than a pound to the rear axle. We were 1000 pounds over weight on our rear axle on one of our trips - first time I had it checked at a CAT scale.

Sure if you have a diesel pusher with a tag and 6000 pounds of ccc you may want to start with tanks full but that isn't what you have.

good luck!

So how much PSI would you recommend?

KandT · Dec 7, 2017

Whatever is on the door and check the tire sidewall to make sure all is good. I think mine was 80psi on all 6 but yours may be different so don?t go by my memory.

Larry N. · Dec 7, 2017

ditsjets7 said:
So how much PSI would you recommend?

To add to the above, weigh the coach, at least each axle separately, and preferably each wheel. Then use that information on the manufacturer's load inflation table (generally found online). This site has links to a lot of information about care of and proper inflation of tires, including inflation tables that show weight vs. pressure for different sizes, and even different models of tire, for many brands.

KandT · Dec 7, 2017

I agree with Larry N 100% but until you have a chance to do that go by the placard on the door jam - not what someone said. My guess is you are going to be close to your max weight with the vehicle alone and in this instance the placard won?t be too far off.

kdbgoat · Dec 7, 2017

Guys, this is a Class C, not a coach with 22" tires. It's got 16" tires, and the inflation on the placard will be fine from unloaded to max weight. The only reason to weigh corners or axles on a C is to ensure that neither is overloaded. It's a waste of time, energy, and money to weigh a C just for tire pressures, just be sure the tires on the C match what it says on the placard, then just inflate to what the placard says to inflate them to. No need to make it any harder than what it needs to be.

Gary RV_Wizard · Dec 8, 2017

Ditto. Use the psi shown on the tire & loading sticker on the driver door post. It should be right on for a fully loaded rig, but maybe a tad high for light or no load. That's fine - a bit of over-inflation helps fuel economy and tire life.

Agree with kdbgoat that a weight-in is a good thing, but hardly a necessity for this type of rig. The difference between "typical" and "optimal" will be small.

To answer the question about speed, 65 is probably high for best fuel economy. Slower is better because it cuts wind resistance dramatically, but on the highway you want to stay at a high enough speed that the tranny stays on its top overdrive gear. That's usually around 60 mph, but it varies a bit with the individual rig and driving conditions, e.g. hills, headwinds, etc. Watching the tachometer will tell you whether the tranny has downshifted or not.

decaturbob · Dec 9, 2017

In 5000 miles of driving my E450 V10, my optimal speed for gas mileage is in the 55mph and I can hit 9.5 mpg under optimal conditions. Driving in high winds will push that down to 5mpg.

I usually expect 7.5-8mpg when I plan trips and expenses on gas.

kdbgoat · Dec 9, 2017

decaturbob said:
I usually expect 7.5-8mpg when I plan trips and expenses on gas.

^X2^

billwild · Dec 9, 2017

You mentioned extensions for checking tire pressure. Do you mean the long inflater as the guys have shown above, or do you mean the short braided line that reaches from the inner dual wheel valve stem and clips onto the outer dual wheel? The braided lines sell for about $15.00 on EBay. I had them on my coach and they really save a lot of effort in airing up the inner dual tires. They are called tire valve extensions.

jatrax · Dec 9, 2017

I disagree about just going with the placard tire pressure. My e-450 placard says 80psi but the weighed number from the tire chart is 74psi. And depending on your loadout it might be different front and back. Regardless getting your rig weighed preferably all 4 corners is important. Otherwise you really have no idea what is going on.

Gary RV_Wizard · Dec 9, 2017

My e-450 placard says 80psi but the weighed number from the tire chart is 74psi.

I think that example just proves the point about the placard psi being fine for most cases. The psi in the inflation tables is the minimum for that weight, so I would want to use at least 5 psi more. The actual pressure should be above the minimum. Further, exceeding the minimum by 10-20% is very acceptable and much preferred versus being even 1% low.

Tires - Extensions and Pressures

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