1987 K5 (GMC Jimmy) Lift and Tire Options
 

Hey gang. I'm new to the full size blazer scene. Truck is actually a 1987 GMC Jimmy, 4wd. Purchased it already lifted; it has lift springs up front and 2" blocks in the rear, and 33x12.5x15 tires.

I'm looking to remove the blocks in the rear to 'fix' the lift. It is also in desperate need of new tires. My uses for the truck are mainly going to be on-road / bad weather driving (my S10 sucks in snow), occasional towing (possibly towing another vehicle at some point?). I'll be honest, I want to truck to look a little bit 'meaner', but be functional and I don't want to neuter the off-road capabilities either. I'm looking at 35x12.5x15 BF Goodrich All-Terrain T/A KO tires to replace the worn out tires on there now.

The front springs have a sticker on them; I believe it says "Superlift Suspension Systems". Fender height straight up from the axle is approximately 38-1/2" at all four corners. With the 33" tires on it now, I believe that means I have 2.5" springs in the front. The blocks in the rear measure 2" and are flat.

My questions:
1. Are 35" tires going to work for me for daily (or weekend) use?

2. Is the lift in the front sufficient for 35" tires? (keeping in mind I don't plan on serious off roading)

3. Is the DIY shackle flip (the cutting the stock bracket, put the shackle through it, and weld a reinforcement in one, not the DIY brand one) going to give me the correct height so I can remove the 2" block?

4. Pinion angle. I'm sure I'll have to measure it, but does anyone have any info up front about what I'll need to do to correct it, if anything?

5. Sort of related to lift height are the body bushings, which I intend to replace since they seem to also be pretty piss poor. I've read that there are 1" pucks I can add, but I don't know if they make any sense for me. If I need the additional inch, is the easy-inch / zero rate the best way to go about it?

Thanks in advance for any help. I'm just trying to make sure I'm on the right track and I have the right plan before I start buying things like $1000 worth of tires for a $700 truck. :)

1. Are 35" tires going to work for me for daily (or weekend) use?

the bigger tires you go the slower your truck is going to go, if you have stock gearing and a tired motor it might be a issue. but i daily drove a truck with 38s for a while. if you dont mind the jumping in and out of that thing it will work ok.

2. Is the lift in the front sufficient for 35" tires? (keeping in mind I don't plan on serious off roading)

if it only has a 2 inch lift 35s wont fit. 33s barely fit with a 2 inch lift. you may be able to get away with putting a 2 inch body lift on it as you said you were replacing the bushings. be careful when you go to do this, last blazer i tried i broke every bolt off in the floor


4. Pinion angle. I'm sure I'll have to measure it, but does anyone have any info up front about what I'll need to do to correct it, if anything?

you really cant mess with it much as you will screw up your steering. ever front lift springs i ever seen when you start to go taller have a shim at the bottom to correct it. if you only have a 2-4 inch lift on that truck it should be fine, same thing with the back. after about a 6inch lift is when you start to have problems

I'm fine with this, I'm not a speed demon (at least not in the truck I won't be). I posted on another forum and regearing/swapping axles came up. If it's an issue with 35s, the next step can be searching for new axles. They suggested 33s being a better choice, so I think I'm going to shop on craigslist till I find a decent set of either.

For the rear, the shackle flip should take care of the lift for 33s or 35s and is the cheapest option; for the front it should fit 33s (which it has now) and I can use the body lift or easy-inch/zero rate to get it up for 35s if I go that route, right? I'll have to check to see if there are any shims on it currently, I didn't notice any when I checked it out previously.

Thanks for the info!

it all depends on your gear ratio now. my first k5 blazer had 273 gears and 38s. needless to say it was insanely slow but i got around and had fun with it. when i eventually put 373s on it was like i put a turbo on it. i ran 33s on a 2inch lift for a while and it occasionally rubbed if i cut it too hard or hit a bump. even my current truck has a old 4 inch lift so its more like a 3 inch and it hits occasionally