Ok, so say that you have a 3% difference in size, and you put your truck in 4x4 and drive on dry pavement in a straight line... something that is normally safe to do, and you drive 100 feet, one axle's tires will only spin for 97 of those feet! Thats 3 feet that the chain had to drag those tires! I don't think I'll be trying that.

That aside, that sounds like a sweet rock crawler you're gonna have!

 

That's what I learned in tech school and GM training, and what I have always went by when building 4x4's and it has never been a problem but if you don't want to risk it that is your choice. I will do a build thread when I get most of my truck done that way it won't be drawn out over six months I am contemplating setting it up more for tough truck than rocks, I already have my Scout to run the rocks with.

 

That's all I'm saying... don't take it personally! I'm not saying you're wrong, I'm just saying thats just a little bit more stress on the transfer case than I'd be comfortable with. But after giving it a bit more thought (I'm a mechanical engineering student, I like to think about things like this) I realized that the tires have some flex in them being rubber, and the fact that the contact pattern actually does stretch the tire, the tires could have enough give to compensate for that 3% without damaging anything.

Gotcha, I figured when you said you wanted to take off the bed and chop the frame that you were building an offroad purpose built machine and the short wheelbase would make a good rockcrawler.

 

Well plans have changed and it is going to be a crawler. My wife has really gotten into offroading so I told her she could have the Scout to wheel and I will wheel the Dakota. So plans for it are D44 front from half ton dodge Ford 9" rear. Keep the stock 318 and trans but put in a twin sticked flipped D300. Here are a couple videos from my last trip.
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Sounds like we have a very similar project going! I'm getting ready to swap a hp dana 44 from a '76 f150 and a full size dodge 9.25" rear on my truck.

Cool videos by the way! Looks like fun!

So what are you planning on running as far as gearing and tire size is concerned?

 

Probably going to run 4:11's because I already have them but may go to 4:88's down the road. I was going to wait till spring to work on this but the city got on me for unlicensed vehicles so now the Dakota is in the garage and the Scout is outside so I may go ahead and get started on it. I will probably start building my exo after christmas, will probably put my nine inch in this week and then start trying to decide how I wan't to do the front for sure. I was planning on running 35's but I have another set of humvee tires on 12 bolt H1 wheels so I may go 37's not real sure yet a lot depends on how high it comes out I am planning on about 4" over stock height with some trimming. I saw your build thread you started on your steering if you get a passenger side knuckle from a chevy or fsj it will be a flat top you just have to drill and tap the holes if you do that you can set up your crossover steering for under $300 and in my opinion is an excellent upgrade. Just modifying the ford steering will work good enough but I really prefer the crossover.

 

Yeah, its got the inverted Y steering on it right now. Thats a good idea about the crossover steering. It would make life really easy to set up. I'll be doing a lot more research on what to run and how to set it up a little later on. Right now I'm still fighting with 30+ year old bolts that won't come out.

 

If you take and heat the bolts up and melt wax into them they will come out no problem. I am a machinist by trade and that is how we have always gotten stubborn bolts out, that is if the PB don't cut it I usually have good luck with it or if you can find there is some stuff called Kroil that is amazing but it is hard to find.

 

Well, PB blaster and heat did the trick for 7 of the 8 radius arm bolts, but before I got the 8th one out, my impact rounded the head off so I had to cut the head off. So now I have the two radius arms off, but one still has a bolt sticking out of it. I'll probably weld a nut to it and try to turn it out cause there is about 3/4 of a inch of it sticking out.

I don't really understand the wax trick you mentioned? How does the wax get into the threads when it takes something as thin as pb blaster to penetrate it? I'm really interested to learn that one.

 

If you heat the bolt up and melt the wax around it, it will soak in just like pb blaster but you don't have to wait for it to start working. It basically just lubes the threads and that along with the heat it works great.