My wife and I are in the process of buying a 2004 Newmar Mountain Air fiver. The standard GVWR is 16,250 with an empty weight of 13,000 pounds (counting the options we want). They have a dual tire option that increases the GVWR to 20,000 pounds. I have no intention of overloading my truck so I will keep the loaded weight at 16,000 or so. <br><br>The upside of this option as near as I can tell of the dual tires would be better support on soft ground, no need to grease the bearings since they are immersed in oil (the level is easy to check through a sight glass), larger brakes, beefier axles, Mor/Ryde equalizers, load range E tires instead of G, a larger cushion before exceeding the GVRW of the trailer (but again I am careful NOT to overload the truck so this is not really an issue). The downside may be slightly more work to pull the wheels for brake service, increased rolling resistance leading to a slight fuel mileage penalty, 400 pounds of additional weight, a rougher ride for the furniture. I am just guessing here. Interestingly Newmar is the only manufacturer that I am aware of that offers a dual wheel option on an RV. The cost of the option is around $1,600.00.<br><br>Since there is such a vast amount of knowledge and experience on this forum I thought I would ask for informed opinions. I have asked for feedback on other sites but have received few responses, presumably due to lack of peoples' experience with this. So what do you think? This is my retirement trailer and I want to do this right.<br><br>Casey

 

Just a truck driver's opinion, but I would go for the duals. Have seen umpteen zillion vacation travellers waylaid by the damage from blown out single tires on hot summer days. The down sides? You need to check duals REGULARLY cause they don't show it when one of them is going soft (best way is with a tire thumper or a hammer and listen for the &quot;ring&quot. If you have one getting low a lot of times you can slow it down a bit and get to a tire shop to get it fixed. Just my 2 cents...<br>John

 

I dont tow any rv's but i do tow a lot of weight and if single's where so great for weight then all the gooseneck flatbeds that haul a lot of weight would be single instead of dual tandems. big john is right about what he said. the only thing is on my gn it does bounce a lot empty 6.8k but loaded it is smooth. my .02 worth

 

I agree with John and Rich-Cowbow; with more weight the extra tires are a safety factor not to be overlooked. I think that is why some of the larger fivers go to triple axle (because of added weight), but I would rather have tandem axles of higher rating with dual wheel if it were my choice. I suspect that the other manufacturers will begin doing this soon as well. Just my $.02.

 

I agree also...get the tandems....wish I had the option when I got my 5er. <br>Big dawg

 

I think the duals would be better for safety on the road. The last Mountain Aire I saw with duals was in Merritt Island, Florida at WalMart. The tires did not look like they were standard height for load range E tire. To me it looked more like<br>tires one might see on a lowboy boat trailer. I don't known for sure and I might be wrong, but if the tires are smaller than standard height, they will turn many more revs which will mean more friction and heat in the tire(s) which could mean quicker wear etc. <br><br>The larger the tire(s) the less heat, friction, and Revs you have. I have 20&quot; low profile tires on our 53ft trailer and the standard size tires on the Kenworth Tractor. The rears run noticably hotter on the trailer than a trailer equiped with standard size tires.<br><br>I guess if the tires are standard size like you have on your RAM, I'd go for it. If they are less than that size I would look at the option again. <br><br>Dave<br>Currently in Duluth, MN with the 5fer.<br><br>