14" or 15" Wheels?

Pat in Speedway wrote:
Last weekend we signed to buy a Shasta Oasis 18BH travel trailer. Specs are 21'9" long, dry weight around 3200 lbs, and tongue weight about 350lbs. GVWR is about 3850lbs. It's a single axle with 205-75-14 tires.

I went to the dealer last night to look over the two they have on the lot, as we bought at the Indy RV Expo, but I wasn't about to buy the one they had at the show due to wear and tear of a 9 day RV show. To my surprise, one of them had substantially more cargo capacity than the other: 546 lbs vs 1403 lbs. After further investigation, I found the one with the larger capacity had 225-75-15 tires on it, compared to the standard 205-75-14. I checked with my dealer about it, who contacted Shasta to see what was up. The answer is that Shasta makes another model called the Flyte, which has the same floorplans as the Oasis, but weighs a little more than the Oasis. With it weighing more, they went with a heavier axle on the single axle Flytes to give it more cargo capacity, and so they wouldn't have to carry two separate axle sizes, they decided to run the same axle on the Oasis. So this is a mid-production change, as the single axle Flyte floorplan has not yet hit the market, whereas the Oasis single axle floorplans have been out for a year.

So now I have a choice as to which to get: the 14" with 546 cargo capacity or the 15" with 1403 lbs cargo capacity. Obviously I'm leaning towards the 15" for the 900 lbs increase in capacity. The specs on a Flyte with the same floorplan as the Oasis I'm getting show a GVWR of 4681 lbs, so I'm assuming an Oasis with the larger axle should be close to that. Other than the 15s raising the overall height of the trailer maybe by 2" and the overall weight increasing due to the heavier axle, what benefits do I gain by going with the larger wheels/axle? One advantage I see when it's time to replace tires is the ability to go with a lot heavier rated tire with the 15". Your comments appreciated!