I see a lot of people asking about front leaf spring codes and what their actual capacity is so I went through my spring books and matched up the codes with capacities so here you go. I'll list the spring code and then the capacity in pounds next to it and the capacity is per side.

R = 1430
S = 1630
T = 1830
U = 2030
V = 2230
W = 2430
X = 2630

Now in the middle of 00 Ford switched from a berlin eye design to a standard design so some of the springs such as the R code was only used from 99-00 and when you switch out springs you want to be sure to switch out to the 01-04 version because of the standard eye receiving full support from the spring underneath it. Easiest way to tell on the berlin eye is if there's a gap between your 2 leafs and you should always replace this design with the standard eye.

FYI - There is also a 3950 lb capacity spring but this is the X code with an extra tapered leaf installed on it so the 2630 is the heaviest Ford made.