Hello all. I'm new here and new to diesels. This is my first diesel truck. I own a 2000 F-240 c/c s/b 4x4. I am currently running 315/75/16 tires on it. i have 4 inches of lift on it and was wondering if i could run 38's on it with out any problems. If anyone knows if i can or not please let me know. thanks  

The answer to that querry is NO!  With 4 inches of lift max tire size should be roughly 35" or the 315's you are running (roughly 34.6")anything bigger will more than likly contact the fenders.  If you want to run 38's and don't want to do any fender trimming I'd recommend 8-10 inches of lift.  

Thanks i was just wonderin. The guy i talked to at the tire shop said that i would be able to fit 38's with no problem and i was unsure of it. It looks like they might fit but i think they would hit in a hard turn.  

Yeah, the guys at tire shops, or "tire jockeys" as I like to call them, are just salesmen.  Most of them will try to tell you any tire will fit, just get get that commision check.  The best thing to do to find out is make friends with your local 4X4 shop, and they'll shoot you strait.  The guys at Discount, or where ever don't give 2 squirts about you once you drive off the lot.  But with a 4 inch lift, the biggest tire size I'd go with is 35", 6" lift 37's and 8" lift and above then 38's.  One good thing to check too is to check the true height of the tire, some are a bit larger than advertised, some smaller.  I can tell you from experience,if you put 38's on a 4" lift, the first time you did and mild offroading, you'd here tire to fender contact.  Hope that helps.