Tires 1715 tire swap

[droy]

Will shortly be looking to replace my R-1 tires on my 1715 FWD, & would like to go the R-4 route. Did a search & didn't come up with any help; my concerns are (1) The width of my wheels, if an R-4 is available in the sizes I need. Front = 7-14; rear = 11.2 - 24. I'm afraid that my present wheels won't be wide enough. (2) If R-4s are not available would I encounter any problems going to the closest larger size that would be available? Don't have an FEL, just do about 70% mowing / shredding, & plowing, boxblade, & 3 pth dirt scoop for the rest.
Thanks in advance