I posted this under chevy trucks but haven't had any responses.  I was wondering what is the largest tire  I can fit on my 1980 stock K10 chevy without rubbing?  I have looked around the web and have heard that a 33/10.50/15 may fit.  I'm not sure though as there has been mixed feelings about it rubbing.  BFG KM MT is the tire I am looking at but would be interested to see who else makes this size.  I know Interco does but I am not interesed in something that aggressive.  My current tires are 31/10.50/15s and are almost shot.  Any info would be greatly appreciated.  

WITH THAT SKINNY OF A TIRE IT SHOULDNT RUB UNLESS YOUR WHEEL IS WIDE SAY 15X10 INSTEAD OF 15X7 OR 15X8,WITH BALD 31" YOU PROBABLY HAVE ABOUT 3"-5" CLEARANCE BETWEEN THE TIRE AND FENDER CORNERS WHERE THE RUBBING OCCURS...
YOU MIGHT BE ABLE TO GET A TIRE SSHOP TO MOUNT JUST ONE TIRE TO SEE IF THEY WILL RUB?  MAYBE?  

Thanks for the reply.  Im just running the stock rally wheels.  I was also thinking about putting 3/4ton leaf springs under the truck. Would there be any issues with this?  

yeah i think th stock rallys were 15x8...the 3/4 leafs shouldnt be a prob unless the length is different,then just put new u bolts on it and it should be fine.  

Great! Thanks for the info.  

i was in the same position about a year and a  half ago, before i lifted my suburban. i was planning on a lift in the near future, but i couldn't afford it at the time and i desperately needed new tires. so i went down to discount and had them try a few different sizes on. the biggest i could get under there was a 285/75/16. they actually trimmed a small corner off my front fenders to get them under there, but there was no rubbing after that. i'm still running them, even with a 4" lift, so it all worked out pretty well. mine is a 3/4 ton, so i have 16" rims but if you go to:
http://www.1010tires.com/TireSizeCalculator.asp
you can use my tire size to figure out what will work with 15" rims.
in reguards to the leaf springs, i took my lift off of a 1/2 ton truck and i ran into some problems with spring length. the front leaf springs are exactly the same on 1/2 and 3/4 ton trucks, but the rear springs on a 3/4 ton truck are 4" longer, and a lot heavier. to solve this issue i had alcan custom the rear springs from the 1/2 ton with a longer top leaf, and it all worked out pretty well. if your going from a 1/2 to a 3/4 ton though, you will either have to have them shortened 4", or you can also move the rear shackle mounts fairly easily (i wish i would have know that when i lifted mine). ord makes a sweet rear shackle mount kit that is pretty much bolt on, u just have to grind your old stuff off. u can check it out at:
www.offroaddesign.com.
I have also read quite a few stories of guys just adding a couple of leaves to their rear, this has realatively the same effect.

i hope all that helps.  

Thanks for the great info.  Do you have any pics of the suburban? Where exactly did they have to trim on the fender?  

I have 33/9.50R15 BFGoodrich AT's on my stock hight 1989 Suburban on the factory aluminum 7" rim with no clearance issues at all.  On the steel rally 15x8 wheels with 33/10.50R15 tires will be the limit with out lots of triming on stock hight.  You might have to trim just a minor amount at the bottom of the front fender wheel opening.  

sounds like that man know his stuff... i checked out his tire size and it looks like that is about the max u can put on 15" rims w/o rubbing so i would stick to the 33/10.5/15 if it were me. its better to have your tires a little small than to rub! i'm not sure how to post pics on here but if you give me your e-mail i can send u some if you want.  

I PM'd you my email address. Thanks in advance for the pics!  

To liveoffroad,  my email is nateclark20@hotmail.com so you can send me the pics of your suburban.  I have PM'd you a couple times.  Hopefully you see this.  Thanks.