Like you, I also want to change the axle on my Compact Jr (CJ) to add brakes
. And like you, I looked at fitting larger wheels and tires.
My wife and I currently have two Camrys, a 1993 with 14" wheels and a 2003 with 15" wheels. I thought it would be great to set up the CJ's new axle to accept these wheels and tires because that would mean I could have two spares (one in the car and another on the trailer) that could be used in either place. I measured carefully and found the Camry tires would fit without rubbing, even with the spring bottomed.
HOWEVER, when I actually tried slipping the Camry wheel and tire into the CJ's wheelwell I discovered a few things!
1. The Camry wheel and tire weighs 50 lbs compared to the 26 lb weight
of the CJ's current 13" steel wheel with tire. That adds to the wrestle factor as well as adds yet another 72 lbs to the overall weight
of the trailer. Yes, the trailer doesn't have to "carry" 48 lbs of that 72, but it does raise the unsprung to sprung weight
ratio, which is not a good thing. And it adds to the load the car has to haul up grades.
2. The Camry wheel and tire fit in the wheelwell, but I have to jack the CJ up higher in order to slip the top of the tire over the hub and under the lip of the outer skirt of the wheelwell. This also adds to the wrestle factor.
Overall, I have decided I would like to go to a 14" wheel, but not as large a tire as used on the Camry -- it is just too much work snaking it in and out between the hub and the outer skirt of the wheelwell.
Here are some pictures showing the differences:
Camry wheel & tire weight
Current CJ wheel & tire weight