I know of a guy that mounted 14.5 X 20s on wider (11 inch?) rims and put them on a 404.
He used it moose hunting in alaska. He didnt say anything about having trouble with the clearance but it sure looked tight. He did say it gave him plenty of flotation for the muskeg in the area and didnt get stuck.
I never rode in the truck so I cant tell you how it worked off road.
 Wouw. That's one good looking mog! - I'd like mine to look that way. Have already bought 10 liters of Bundeswehr RAL 6014 paint for it. I wood very much like to see some more pictures of your Unimog.  If you want, you can email them directly to me.
Dan at http://www.usa6x6.com has made and sold and mounted 14x20 on a 404 or a 406, i have forgottn now, they fit and rub a tab, most pull the fenders off and mount a read mud flap off a 18 wheel truck in there place, you will never be sorry you mounted the tires, the 404 does not go fast enuff to worry about anyway, the 49 inch tall tires i have give me 19 inchs of clarance at the diff n the lugs go thru just about anything except quick sand, i made my own wheels and had a tractor shop recap a v tread onto a 11x20 dot goodyear tire, they were so freaking cheap, they make these tires up to drive irragation walking systems and are were all there was before the michlins hit the market 3 years ago, good luck with your rig, post some pics up, if u in texas come by for a free hog hunt in ya mog, ya never know
No problems with those 14X20's. I have driven long distances on the highway and hammered it as hard as possible offroad. I have had the truck completely airborne more than once. The Mog is so overbuilt for basic offroading I don't think the large tires could be a factor for mechanical failure, and so far so good. It has 24" of clearence under the diff's and nothing can go through the mud like the Mog. The 406 has a lot heavier axles than the 404 however. I have been following a thread on Pirate 4X4 about locker and portal box failure on 404's with V8's. So maybee a 404 might not handle the tires, but my guess is with a stock motor it will be no problem. All of the failures seem to be lockers breaking and portal boxes breaking a tooth off a gear then the broken piece breaking the portal case, again all this seems to be happening in buggies with big horsepower. An interesting finding by on user of 404 axles was that the locker required a little time to fully engage. The person mounted micro switches on the axles and found they didn't fully engage right away and the lockers breaking may happen by hammering it before they are fully engaged.
BenzWorld.org forum is one of the largest Mercedes-Benz owner websites offering the most comprehensive collection of Mercedes-Benz information anywhere in the world. The site includes MB Forums, News, Galleries, Publications, Classifieds, Events and much more!