what size of tires are too big for a stock fors 9 inch rear end?
i am thinking about putting some 49" tires on my 58 willys wagon but i don’t know if they will constantly be breaking every time i go rock crawling, mudding, or even simply pulling a slightly steep hill.i have seen people put 44s on Chevy 12 bolt rear ends and i am pretty sure that the for 9 is just a hair stronger but i don’t want to invest in these tires if i half to keep replacing my axles. HELP!
The 9-inch rear is indeed every bit as strong as the GM 12 bolt. If you want to be on the safe side, make sure it has 31 spline axles, and of course, the differential side gears would have to match that.
Most of the full size cars had 28 spline ones, and there may have even been a smaller size.
Also, as far as the drop out housing portion, look for one that has a big "N" cast into it. That stands for Nodular cast iron, the strongest they made.
Other than that, about the only thing that beats both of them is the Dana 60.
March 11th, 2010 at 7:50 am
The 9-inch rear is indeed every bit as strong as the GM 12 bolt. If you want to be on the safe side, make sure it has 31 spline axles, and of course, the differential side gears would have to match that.
Most of the full size cars had 28 spline ones, and there may have even been a smaller size.
Also, as far as the drop out housing portion, look for one that has a big "N" cast into it. That stands for Nodular cast iron, the strongest they made.
Other than that, about the only thing that beats both of them is the Dana 60.
References :
ASE Certified Tech
A misspent youth. LOL
March 11th, 2010 at 8:09 am
Those are some huge tires man. You should be fine with a 9" rear, although you will want to upgrade some of the internals like the axle shafts and splines. Personally running a tire that big i would upgrade to a full floating hubs configuration – like a GM 14 bolt.
Make sure you have the front end to match – like a dana 60 reverse with beefier axles.
You need to make sure to have a lower gear ratio too to turn them meats. Consider upgrading the transfer case as well.
References :