Yes it is a stock 12' Triton trailer with a Triton cap. As far as flats, one of the first things that we did was upgrade to 20.5x8x10 load range E's. The axle is a 2500# axle so we are fine there, and nothing hangs out. We do this all the time. Probably have 8000 miles wroth of hauling our sled like this. It takes some doing but everything fits under the hood just the way you see in the picture. I just posted the picture so that people can see it can be done but it's not easy. Not the way i want to do things but its just a matter of making the best of the cards your dealt(or can afford). If anyone want i can explain how to make this work. It took us about 2 hours to figure it out the first time.