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scottb
03-12-2010, 09:30 AM
Iím new to 5th wheeling, so would appreciate your knowledgeable opinion on this. I bought a new to me 5th wheel a few months ago, and the tires are date coded 2002. So from everything Iíve read, I definitely need to get new ones.

Being new to 5th wheels, Iím not sure of the best place to get the new tires. Are most tire stores willing to jack up and change the tires on a 5th wheel? Should I trust them if they say they can? Also, is there any advantage to buying from a national chain in case I have problems out of state?

Thanks in advance. Looking forward to getting a lot of my dumb questions answered.

Scott

Motor31
03-12-2010, 12:06 PM
You didn't say what kind or RV you have and how heavy it is much less what weight capacity tires you have. The reason I mentioned that is that trailer tires are not the same as passenger car tires. The sidewalls are different as its the tread pattern. Larger trailers like the Mobile Suites that use the H rated 17.5" tires also generally have to go to a truck supplier to find those kind of tires as the car tire places don't stock them.

You need to know the size, and weight grade tires you have now and what the rig calls for. Do not assume the manufacturer or previous owner has the right grade of tires on it. Look at what weight the tires have to support and make sure the tires you buy are rated for the weight. Heavy weight capacity tires are classed as E, G and H rated. The higher the letter the higher the capacity. H rated being similar to semi tire weight ratings.

What is the Gross or max weight of the trailer? How many axles to you have? What does the manual recommend? Figure that 80% to 90% of the weight of the trailer is supported by the tires. Get weight rated tires for the axle capacity and weight the axles support. The max load of the tires is printed on the sidewalls as is the max cold tire pressure for that load.

scottb
03-12-2010, 09:35 PM
Wow, thanks Motor31 I had no idea there was so much to it. Thanks for taking the time to explain why itís important.

The 5th wheel is a 2003 Montana 3280RL, with a GVW of 14,180 lbs. I havenít actually weighed it on scales yet, but that is on my list of things to do. According to Keystone-Montana I should use 235/85R16E rim size 16x6, and what was on there when I bought it were LT235/85R16ís with a load rating of E.

It has two axels with two wheels per axel (4 wheels). So if I understood your instructions correctly, if 90% of the weight is on the tires than that would be 12,762 lbs out of the 14,180 lbs total. With 4 tires, that would be 3,191 lbs per tire. So if I understand correctly, I need to look for tires that can carry at least that load? I searched the web some but wasnít able to find what load rating this calculates to (maybe I wasnít looking for the right thing).

Am I on the right track? Did I understand your instructions correctly?

Thanks again,
Scott

Motor31
03-13-2010, 01:05 PM
Nope you got it pretty good. The only thing you could do to get more info would be to scale the trailer as it is loaded for a trip. A truck stop has scales but even if you put each axle on a separate weight pad it won't give you the side to side weight balance of your rig. You would need the services of a guy like Stripit, here in the forum, who does RV wheel by wheel weighing.

The load range of E on your tire will also have a printed max load on the side of the tire. Assuming the rig has some miles on it and the tires are wearing evenly (no cupping, flat spotting or uneven wear across the tires) the suspension should be tracking properly and the load should not be excessive for the tires. Weighing it will tell for sure. It will also give you the pin weight or amount of weight transferred to your truck if you run the truck through the scale by itself after weighing the entire rig.

As long as you have a healthy margin of load capacity for the tires over the actual load carried and you fill the tires to the proper inflation for the load you will get the best mileage and reliability out of them.

A last note, make sure the rims are rated for the load as well. Sometimes a lighter capacity wheel ends up on a RV and that can fail from being past it's capacity.

scottb
03-13-2010, 02:44 PM
Thanks motor31,

Iíve only taken two short trips with it so far, so I havenít even had it fully loaded yet. Once I do, Iíll go down to some truck scales near us and get it weighed as you said. Once I get to that point Iíll also contact Stripit about getting it weighed wheel by wheel. Thanks for the tip on the rims too, Iíll look at those.

Also, it sounds from youíre earlier comment like youíd avoid a tire store that sells mostly passenger car tires? As I mentioned, I have a concern about letting them jack up my 5th wheel anyway. Do you see any advantage to buying from a national chain in case I have problems out of state? Assuming so, are there any national chains that are knowledgeable about 5th wheel tires?

Thanks again,
Scott

gypsybill
03-13-2010, 03:46 PM
My previous 5th wheel had the same size/rated tires and when time came to replace them (at the 5 year point) I went to BFGoodrich Commercial TAs and bought them from a Goodyear Tire store. You can get them from Sams (if a member) a few bucks cheaper, but the nearby Sams did not want to mount them. I found a Goodyear dealer right behind a Cracker-Barrel restaurant that had both the parking lot to fit and the experience in dealing with RV'ers and their tire needs. I sold the 5th wheel before I ever needed any repair/replacement work done, but I could have taken it to most any Goodyear store... of course, as in all things, this was my experience and yours may vary...

Good luck with your new 5th wheel..

Motor31
03-14-2010, 01:10 PM
Not all automotive grade tire stores are set for the larger dimensions of an RV either inside or outside. I have also had to let the store use MY bottle jack to change the tire on my trailer on a warranty situation. They didn't have a jack with enough capacity to lift a 8,000 lb axle. If it is a larger store that has a large lot that you can maneuver your trailer in and out of it may be just fine. Remember you have to be able to get out of the lot too.

If you need the larger commercial grade tires, like I do on both the trailer (17.5") and tow vehicle (22.5") then an automotive tire store isn't a good idea. They don't stock them normally and won't have the equipment to mount or balance them either.

A phone and internet connection can save you a bunch of miles to find what you need. Before you commit to a particular store, take the tow vehicle there and look it over to make sure you can get in and out of it with the rig. Also remember to research the torque values of the lugs on the wheels. My trailer has a max torque of 150 ft lbs (aluminum wheels and Dexter axles) so I have to make sure the tire place turns down the speed wrench or sets torque by hand.

scottb
03-16-2010, 05:29 PM
Thanks for the help in deciding the right tires and where to get them. Based on your inputs, I searched for local stores that meet all the criteria you all told me. Iíve called them and that ruled out several. Now Iím going to go hit each remaining location with only my tow vehicle, and make a choice. Thanks to you all, I know what to ask/look for.

Thanks again. Hope to see you around,
Scott

Stripit
03-16-2010, 08:25 PM
HI Scott, you don't say what part of Arizona your in, I'm in Casa Grande. We are going to be weighing 2 different 5th wheels this weekend that both of the owners have had tires fail causing damage to the trailer. They are not sure if weight caused the tire failures or something else. We hope to be able to tell them once they get weighed by wheel position. If your interested in watching the process let me know and I'll let you know the time and the place.

LindaH
03-17-2010, 10:43 AM
Since you are going to get new tires, be sure to tell whatever place you buy them from that you want "new" tires; i.e., tires that have been manufactured within a certain, recent, time period. I would not buy tires that were more than 6 months old, more recent if possible. You may have to wait for them to be ordered if the tire center doesn't have any recent tires in stock. Make sure you personally inspect the manufacture date before they are put on your rig.

And while you're at it, have them put metal tire stems on them instead of the rubber ones most tires come with.

scottb
03-17-2010, 07:30 PM
HI Scott, you don't say what part of Arizona your in, I'm in Casa Grande. We are going to be weighing 2 different 5th wheels this weekend that both of the owners have had tires fail causing damage to the trailer. They are not sure if weight caused the tire failures or something else. We hope to be able to tell them once they get weighed by wheel position. If your interested in watching the process let me know and I'll let you know the time and the place.

Thanks for the offer Stripit. I'm in Tucson, so depending on when you were planning to do the weighing I'd love to see how you do it.

CodyRW
11-18-2011, 01:04 PM
I have a 1988 travel units fifth wheel it has three axles. I know the weight of each tire needed was 4,000 apiece but besides that I was at a loss the date on the tires is 1988 so I assume they are the original tires so they definitively need replaced now I have some idea as to wear to go and what to look for thanks, CodyRW

vvoo222
01-02-2013, 10:52 AM
Hello dude..its totally depend upon you vehical that what type of your vehical..after that i will tell you how much weight of the tires is required yo9u vehcal..but branded tires is i think available in every place you can buy at every place..but scale of tires is essential for your vehical..