I'm a new member and have a question about tire size on a '79 Blazer with 12bolt/Dana44 axle. I heard the max tire size that the axles can handle is 35", maybe only 33". I'd like to run 37"x12.50" . Any thoughts?

I'd say 35's on average, 33's if you beat on it, 37's if you take it easy.

I've got an 80 w/ 33's and a six" lift. They seem to be quit sufficient, been romping it pretty hard with no problems (knock on wood) as of yet. Stock 350?

35's on mine no problems at all and I have a 383 and a heavy foot.

Thanks for the input. I haven't decided wheather I go with 35"x12.50 Mtr's or with 37"x12.50Mtr's. The '79 Blazer is a little project I started. I'm building a tube front and rollcage for it. No doors, tailgate. The engine is a 327 , high compresion, rollers and so on. I wanna use the truck mainly for some medium rockcrawling, but don't wanna spend alot of money.

have you built that motor yet?

Im running 38's on mine, but its mostly dirt and mud here. Is working just fine. another guy in our club is running 40" Boggers on his 12 bolt and it has been working great behind his mild 454. Just my .02. Havent had any real rockcrawling to speak of. Dont know if this helps any. :D oh ya, by the way, we are both running detroits in the 12 bolts.

Yes, the engine is already built, it's actually a used engine , late 60's Corvette. I guess I'm gonna go with 37's then. If I break an axle, so what....:p
I also wanna put a locker in the rear. Any thoughts on that? cheap and good if possible. I don't wanna spend the money on ARB lockers

The cool thing about the 12bolt is that you only have to carry one spare. I bought Superior forged axles for mine, so now I have two spares. Worked out pretty good and they are only like 200 for the set.

As far as the locker, if you are going to replace the gears now then get a detroit. If not then I might get a drop in locker. Be wary of drop-in's though, I hear they break alot. :barf:

what gears are you running?

I run 36" TSL. In 6 months I broke the housing, destroied the spiders, bent a tube, sheared off all the lug studs on one side, and rotated a tube.

If you are going to try it w/ 37's I would pick up a spare axle shaft, and toss in a lock-right. That way you don't sink too much $$$ into it before you go to a 14B

Get a 14 Bolt and shave it.....or get a 60 and shave it......Skip the 12 bolt junk a get THE REAL DEAL......So when you hit the gas you won't be looking for that "snap" and you gotta break your rear apart on a 45 Degree ledge cause if you move it your wheel will come out.......:eek: :beer:

I don't know what gears are in the axles. Haven't checked them yet. What gears do they normally have? Right now I'm busy taking the hole Blazer apart. Since I wanna use it just for offroading( but still be streetlegal) , I took the doors off, the tailgate, the complete front(hood,fenders,inner fenders, radiator support etc.) , the heating/A/C system, all the carpet, seats, moldings. Next step will be installation of the engine, then making the tube front with the lights, radiator brackets. Then I'm gonna make a cage on the outside. Anyone has experience with the new Holley Truck carb? Supposed to be good for 45degree angle and 30degree side angle

The 14 Bolt FF usually come with 3:73, 4:10 & 4:56 ratios......if thats what you are asking......:beer: :beer:

I run 36" swampers on my 12 bolt and have had no problems.I have a Detriot E-Z locker in it.I did blow the pinion bearings in the last 12 bolt I had in.This was just going down the road so it was probally just wear.I had the E-Z locker in that one and it was fine.I rebuilt another 12 bolt and stuck the old locker in.I have had the locker for about 5 years now and is finally starting to go.I think the teeth are wearing and starting to slip.I do wheel pretty hard.In fact I just did 21 Road sat.In one tight spot I lifted the front tires off the ground about 4 feet while powering around a couple of big rocks.Blazin:D