Hope this helps.. Here is what I'm planning:
I was going to spend the cash on new bigger fancy tires(Toyo's 315s) and wheels(MT's) but I realized I have to fix the 3.73 gear ratio that I have now with a 285 75 16 tire setup if I want to go with bigger tires..
At 75mph, I'm turing 2000 RPM.. So with bigger tires, it's really going to be even TALLER and hard on the tranny.. especially up hills, running start, etc.. I'm on my second tranny(this time its a bulletproof rebuild compared to stock E40D Tranny) and I believe the first failure of the tranny was due to this tall gearing! Heard it happens alot to users with more torque(Diesel) and the weak stock E4OD Tranny..
I'm at 3.73 gear ratio front and back with 285' 75 16 tire size currently.
So I'm planning to upgrade to 4.10's or 4.56 Gears (front and back).
My other proven Rig, the FJ80 (Landcruiser) is at a gear ratio of 4.10 with 285' 75 16 tire size also and I feel it's the right size and combo for 4x4ing on most terrain with the SMB and I'm not rock crawling. It's a balanced setup.. and I want the same for the Sporto..
Since I'll be upgrading the ring and pinion and they have it opened them up, I'm might as well add a Detroit Locker in the front. I'd go with the Powertrax which the FJ80 has but I don't think they make it for the Dana 60s..
The Powertrax has worked out for me on the FJ. The same automatic manual locking technology will work with the SMB.
The Detroit Lockers in the front only will be in play and engaged when I'm in 4H or 4Low only..
http://www.rearendparts.com/product.php ... 191&page=1
Lock-Right looks promising:
http://www.rearendparts.com/product.php ... 217&page=1
Why not the ARB AirLocker? I'd go with Airlockers but I'm trying to keep the costs down and the EZ-locker/Powertrac setup has been working for me to provide good 4x4 Traction...and it's a lot less expensive..
After all that, I'll be ready to upgrade the tires to bigger sizes beyond 285's.
I'll have to figure out what backspacing and negative offset is all about with the new wheels... gotta make sure it's the right wheel with the right backspacing and offset so it matches the weight spread on the axle ends I hear..
Complicated but crucial to get the balance right.. or I'm asking for it.
I could just be happy with what I have now and do nothing.
Anyone have a opinion on Detroit Lockers and Powertrax? I have yet to confirm if there is a weak point for heavier vehicles..
I would think the torque needed for a heavier application is equivalent to people who use the Detroit Lockers for racing applications..