This has been a hard Tip of the Day to write for some reason. There is so much that you need to be aware of when purchasing a RV about tires. That I find I am in overload just trying to put it in terms everyone will understand.
Tires are one of the areas that we seem to overlook. Yet many people, both experienced and inexperienced fail to pay attention and suffer the consequences for their oversight.
Tire issues are not a problem with just used units. Many manufacturers are overlooking or worse disregarding the proper tire use on the RVs they are making. So let me start this series of articles with the basics. Please bear with me, I will probably cover things you already know, but I want to make sure we are all on the same page.
Tires for RV are not the same as tires for your car or truck. These are
considered Special Purpose tires. The tires have several things we want to look for. They include the load range, the age, the pressure, the tread and size.
For today, I am covering the size, thread and pressure. The next article will cover the Load Range and the last article will over the age.
The size is easiest to cover as it is mainly determined by the wheel size in inches. They can range from 13 inch to 24.5 inches. The pressure that the tire is pumped up to determines how much weight the tire can safely handle.
Here is an example from Goodyear. It is for a ST175/80R13 tire at 65 MPH Max Speed
15 PSI 670 lbs
20 PSI 795 lbs
25 PSI 905 lbs
30 PSI 1000 lbs
35 PSI 1100 lbs
40 PSI 1190 lbs
45 PSI 1270 lbs
50 PSI 1360 lbs
I think you can see that the change in air pressure greatly affects the weight the tires can safely handle. This is one of the reasons why it is so important to KNOW the weight of the rig and the tire pressure (when cold).
Finally, the tread. Most RV do not have a problem with the amount of thread left on the tire. But just encase you get a hold of a well traveled rig, the depth of the tread should be greater than 3/16 th of an inch and evenly worn across the tire.
You can visit Goodyears website at http://goodyearrvtires.com and follow the links to the rv_inflation.pdf.
Water heaters are beginning to get complicated. It use to be and the majority still are built by two companies, Atwood and Suburban. Atwood used aluminum tanks and Suburban steel. Because of the steel tank, Suburban heaters have an Anode rod that should be replaced at least every other year or when it wears out. Lately two other water heaters have come on the market. One is the tank-less water heater or on demand and the other is the Aqua Hot System. Aqua hot is a combination heater/water heater and will only be found in high end units at this time. Regardless of the water heater type the testing is the same. Make sure water, propane and electric are available. Ensure the water tank is filled with water and turn on the unit. Wait about 30 minutes for the tank to heat up. Turn on the hot water. With the thermometer, check and record the temperature. It should be about 140 degrees.
Some older units may not have an automatic pilot and you will have to manually light them. Make sure you have a butane lighter like the ones use to like charcoal fires with you just in case.
Tip of the Day… Slide Outs. There are basically two types of slide out operations Electrical or Hydraulic. There are however, many different types of configuration.
Hydraulic is the simplest and I only know of one configuration. An electric motor turns a hydraulic pump that through a series of valves pushes or pulls a set of rams to move the slide out or in. As with all fluid based systems, you will want to check the fluid levels before operating the hydraulic slide outs.
Electrical slide outs come in various styles. Some will operate much like the hydraulic units by using an electric motor to turn a set of rams to move the slide out or in. These require less maintenance than their hydraulic cousins.
A newer type of slide out mechanism uses a set of electric motors to directly drive the slide outs in and out. This is the Schwintek Slide Out System and is easily identified by the tracks on each side of the slide out. It basically operates with a set of worm gears that ride in the track and when turning move along the track pulling it in or out as they turn. Two problems have been reported with this system, first is that the motors get out of sync with each other and the slide does not seat or extend properly. The second is that the motor gears are wearing out due to the torque of the motors within their housing.
When inspecting the slide outs, you will want to note the type of slide out installed. You will need to inspect the drive mechanism to determine if it has been maintained. You will be looking for grease or lubrication on the rams (hydraulic or electrical). For the Schwintek systems the motors are normally in the upper corners behind the molding. This molding may just pop of or will be screwed in. If you can access the motor area, you will want to look for metal filings around the motor which will indicate that it is wearing out the bushings.
Operate the slides and check for proper sealing both extended and retracting. Try to slide a credit card between the seal and the wall of the RV. If you can easily slide the card between the seal and wall it may need adjusting.
Examine the rams and the drives for signs of rust or damage.
Tip of the Day… Propane System. The propane system consist of the tanks, lines, propane detector, stove, oven, water heater and furnace. For this article I am going to discuss the tanks only. There are two types of propane tanks. DOT regulated and ASME. On motor homes or Class type RV (Drivable), the ASME tanks are the primary means of storing propane. These tanks do not need to be replaced and are ‘inspected’ by the person that fills them with propane. Normally these will be rated in gallons of propane and not pounds. For your inspection, you want to make sure that the tank appears to be in good condition. Also check the piping coming out of the tank for loose connections. Your nose is the best test equipment. Make sure the tank is on and smell for propane (rotten eggs).
The DOT tanks come in 20 lb, 30 lb and 40 lb for RV. There are larger sizes but you won’t find them in the RV. You may have 1 or 2 tanks. I haven’t seen more than 2 in any RV yet, but that doesn’t mean they can’t have them. DOT tanks are rated for 12 years of life and will have a manufactures date stamped on the top crown of the tank. It then must be inspected and re-certified. It will then be good for another 5 years. After 17 years they must be replaced.
If the system has two tanks, the regulator will probably be an automatic switch over type. You will be able to recognize this type of regulator as it will have an red/green indicator showing that you have propane in the online tank and a switch to change from one tank to the other. When the online tank (the one the switch is set to) is empty, the indicator will be red. You can then switch the tank selector to the other tank and remove the empty bottle for filling.