1989 Suburban

[throttleissues]

You could run the axles you have with 38" tires and not have any problems, especially if you don't want to do the really hard stuff. Keep in mind that there is a huge loss of ground clearance if you go to 1 ton axles. It's not worth it for moderate wheeling unless you are wanting to go big on lift and tires, even if the axles are free (still be worth it to turn them for a profit, though).
When you look at tires, pay less attention to the letter rating and more attention to actual weight capacity. The letters really indicate more about max tire pressure than the weight carrying capacity. A D-rated 285/75 often has a higher weight capacity than an E-rated 245/75. The D will usu have a 60psi max, while the E will have a 75-80psi max. It's screwy, but the lettered rating system doesn't work out to make much sense when you're changing to a different tire size.

[1leg]

Originally Posted by throttleissues

You could run the axles you have with 38" tires and not have any problems, especially if you don't want to do the really hard stuff. Keep in mind that there is a huge loss of ground clearance if you go to 1 ton axles. It's not worth it for moderate wheeling unless you are wanting to go big on lift and tires, even if the axles are free (still be worth it to turn them for a profit, though).
When you look at tires, pay less attention to the letter rating and more attention to actual weight capacity. The letters really indicate more about max tire pressure than the weight carrying capacity. A D-rated 285/75 often has a higher weight capacity than an E-rated 245/75. The D will usu have a 60psi max, while the E will have a 75-80psi max. It's screwy, but the lettered rating system doesn't work out to make much sense when you're changing to a different tire size.

Good info on the tire rating, Thanks
I actually want to run 255/85-16 but the 285's have a 300 more lbs capacity(3300 vs 3000)
I might still go with the 255's tho.

I understand I don't need 1ton axles. It's a want. I plan to build a 383 and keep this truck stock appearing and smog legal as long as i live in California. I hope to move to Nevada in the next 5 years. If i move to NV it will get a Cummins conversion. But this is all a long time off and kind of dreaming.

[rdn2blazer]

Originally Posted by 1leg

The honest reason for me doing the swap will be because. I have access to some free axels and I just think a 1ton Suburban would be cool. (Yes I would upgrade the springs and brakes.)

Not all suburban 2500 came with 14bff, mine didn't. it has the smaller 14bsf. Your right that with what I intend to do a 14bff isn't necessary but it would be more piece of mind knowing I had it when towing. the 60 upfront is not necessary at all so It would be the last mod i do.

Cool, understandable. Well if you do the axle swap a buddy would probably be interested in the set, or atleast the rear 14SF. He's another member here too whos been looking for one. What gears are in it?

[1leg]

I will be sure to post up my old axels when I do it but were talking a year away at least.

I have no idea what gears yet, no tag on the rear or front. They feel like 3.73 on the road(no tach). I still need to put a jack under this thing. Maybe tomorrow, not feel to good today. hope it's not the swine flu

But it has given me sometime to do some research on here...

[1leg]

Been looking up the RPO codes: GOOD NEWS
4:10 gears and locking rearend.

[rdn2blazer]

Originally Posted by 1leg

Been looking up the RPO codes: GOOD NEWS
4:10 gears and locking rearend.

Well that is good news.