Ok My boat weighs 3500 #'s and the trailer weighs 5000 #'s . It's a expandable trailer.
The boat I am not worried about, but like you said the trailer could be tricky.

 

What people are missing here is he asked if 20" wheels will make a differnece and the discussion went to tire clearnace. A 20" wheel with the factory size 265/50/20 tire is the SAME EXACT hight and width 30.5" x 9.5" as a the factory equiped 265/65/17, 265/60/18 or a 245/70/17 tire so there cant be any differnece. Also the reason you needed a 10 ply tire with your 17" are the stock sidewall are so thick and weak. My 20" 265/50/20 are V rated so the side walls are much stiffer and since there is less sidewall the tires feel much firmer. Also the rear axle can only sqwuat about 3.5" then the rear axle is touching th every hard poly bump stops any how. If anyone is towing more than 5500lbs with out a load distributing hitch system with spring bars your askign for trouble. Last a 5500 Bass boat tows like a 3000lb box trailer. There is very little wind load.

If you are talking about the RAM 20" x 9" wheels with 275/60/20" Tires that are 33" tall then yes they will rub.

 

It won't affect it at all as long as you keep the same overall diameter. In other words, a 32" tire (just as an example) with a 17" rim is now different then a 32" tire with a 20" rim. The diameter is still 32", so nothing changes except how much tire sidewall you have.

 

Thanks for info!!!

 

When I talk about 10 ply tires I'm talking about load range (amount of weight the tire itself can withhold) not speed rating. The V rating of your tire is how fast you can safely drive the tires at that continuous speed (in your case around 149mph). I would have to guess that your V speed rated tires are only at best rated for a load range of C (which at best are 4 plys only rated to carry the vehicle weight and passengers) vs my 10 ply 265/70/17's have a speed rating of R (about 106 mph) and a load range of E (about 3500 lbs per tire) and up to 80 psi of air in each tire.

As he has stated he tows. Putting a 20" tire on a vehicle that tows and reducing the width of the tread (the second number in your tire size) of the tire in my opinion is not the safest thing to be doing.

 

Buying a tire depends on the application that your going to be using your vehicle for. If your towing I recommend getting a Light Truck (LTX x/x/R) tire for your vehicle with at least a load range of D. The speed rating isn't as important in this case as you I guess won't be trying to do 100+ mph while towing.

If your travel trailer is a pop up, you won't encounter to much wind resistance with it if it is shorter than the vehicle you are towing it with and no wider than the vehicle that you are towing it with. Depending on your engine and transmission, you likely won't even know your boat is even back there.

 

I agree with everything you just said. It should be noted however that the J-package Aspens with the Hemi, tow package group, and 3.92 gears from the factory is rated for 8900 lbs towing. It comes with 20" rims. I'm not saying that is ideal, but it comes from the factory that way.

That's the Aspen configuration I have, and I have a set of Aspen 18" wheels ready to go on at the next tire change because I don't like towing on the 20's or taking it off the beaten path (no I don't wheel in my Aspen, but we do go take it camping) with so little sidewall.

 

I do agree a E rated tire is one stiff tire. What I was trying to convey with the V rated speed rating is they have stiffer sidewalls than a H or R rated tire of the same size and load range. This stiffer sidewall increases the load carrying capacity.

Example
OEM Goodyear SRA 245/70/17 is rated for 2094 lbs
Goodyear SRA E load 245/70/17 is rated 3000 lbs.
OEM GoodYear SRA 265/50/20 S is rated 2094 lbs
Yokahama 265/50/20 V is rated 2403 lbs

Also anyone who is looking for a great tire the Yokahama Parada Spex -X are great. I have the 2 sets for the Durango and a set on the wifes. They are low priced and the reviews are the highest over at TR.com

Silver Dodge? I can understand off road but what do you see different towing with the 18" over the 20's Also what tires and size do you have on each?

 

The 20's just have less side wall, so they are much less forgiving when you have a trailer back there. The sidewall is a major player in how a tire supports the load that gets put above it. So 18's are naturally a better tires to put a load on then are 20's. The low profile tires have come a long way in the last 10 years or so though, and I beleive the 20's are perfectly capable of handling the load I put on them. I think they look better on my Aspen too, but I still plan to put on the 18's when I am next due for new tires. One other reason I want to go to 18's versus the 20's is the tire selection is a lot better for the 18's.

I can't say for Durangos, but on the Aspens, the two factory tire options where 265/60-18 and 265/50-20 depending on the specific package you got.

 

Silver is correct with that the tire diameter will be the same regardless of the wheel diameter. I traded my wifes Tahoe with 17" wheels in for a Tahoe LTZ XL with 20" wheels and it is the exaxt same size and ride height as the other (I have a low garage entrance),
FF