35's on stock rims
 

Can I put 35x12.5-20 on my stock 2004 f250 Harley Davidson rims? Or am I going to have to aftermarket rims?

You can put them on no problem. Now whether or not they'll rub... But yes they can be mounted on those rims with ease.

35's on stock rims
 

Good I heard that you couldn't put a 12.5 tire on a 8 in rim.

I put 33x12.5x17's on my stock 17x7 rims before. It sucks it in pretty good, but you can. I'm sure it's probably not "recommended" but it gets done.

35s on stockers
 

the only issue will you have is the "floating feeling" If your wheel is 7 or 8 inches wide and your tire is 12 1/2 wide, there is a lot of room for side to side movement or "sway" Its kinda like this; Have u ever towed a trailer that was loaded to heavy in the back? and the whole time it felt like your a$$ end was floating around, yea thats pretty much it just not as bad.
That being said.. yes it can be done and it also has alot to do with the tire you choose to put on... I did it with a set of 16" stock wheels and with bfg's it wasnt bad at all, put on the same size yokohama's and i can wait to get them off the truck!!! Either way good luck

I put 35 12.5 17, 17x8.. I got alot of "Sway"... good luck

i run a 38.5x15x15 on my jeep on a 8"rim but it floats everywhere:scare2::tttt:

Do you have aftermarket wheels? The stock 17's are only 7" wide.

yeah.. they were 17x8

As far as I know they only offered 17x7's and 18x8's as well as 20x8's. My stock 17's are definitely 7" wide.