Anyone care to talk this out with me? ? Z question. . .

Ok. . I'm tryin to see how much of a Z i should do. . . I dont wanna do more than I have to so I dont lose too much lift. . But with the tires i have now, 25" tall, I am about 1/4" from layin frame. . . the tire I am gonna run are 25.3" tall. . .

And I also know the engine crossmember sits lower than the rest of the frame. . Anyone know how much, exactly? ? ?

So, with the larger tire size, and how much I still need to go to lay out anyway, how much of a Z do you thin i need? ? ?


This is what I was thinkin. . I need 1/4" to lay, and the tire is .3" taller. . so, 3/4" Z ? ? ? Which is a lil more than those 2 numbers added up, but jus to be safe. . . OR OR OR. . . I have the frame on 2x4s cuz im bodydroppin it, so should I put 2x4s under the engine crossmember, and put spacers under the tires, and cut the frame, and however much it ends up needin, weld it there? ?

What do you guys think ? ? I need to talk this out! ! !



-Josh

Well Josh - I would like to add my 0.02 to your "talking this out" but I'm afraid my knowledge on the subject is worth considerably less than the 2 pennys.

For what it's worth - your 2x4 rational would be consistant with something I would do.
(not saying thats good or bad, just saying)

Ya I'm thinkin I am gonna put the frame and the tires at the same place. . And cut the frame and weld it back wherever it sits. . .


-Josh

OK...I would start by getting your radius of your end tire...in this case 12.65" (25.3" tall overall) Now you would want to add about 1/8" (.125") to that. So now you have a measurement of 12.775" radius. By adding the extra .125" to the radius you are giving you .25" (1/4") clearance and play. Now with the frame on jackstands and LEVEL (that is the key right there) measure the distance from the ground to the frame. Add that number to your radius. (We will use my numbers for this example) I would add 17" to that and have 29.775". That is a critical number. That is where the center of your rotor will need to be when jacked up to simulate being laid out on your end tire. If you are 2.25" shy of that ....you would need to Z 2.25". Now I now people are gonna say oh what about the effect of the tire cambering and so forth. Yes this is also why you have that extra .25" added in there. You also have the weight of the truck, motor, and compression of the tire on the ground. You also have tread wear too. So essentially this would be a great starting point if you really want to be safe and that .25" to the radius instead of the .125".

As for the cross memeber....measure it. If it sits 16" off of the ground and your frame is 17".... you need to make up 1" somewhere somehow.

The 2X4 method works Awesome too but unfortunately with the tire on you can't see all of you suspension parts to see what they are doing during travel. This could be a key thing to know. You never know when an upper or lower control arm may hit something, ball joints may bind or geometry may just get to out of whack.

Hope that helps.... Maybe some of the pros that have done this before will jump on and add input as well.

if all you need is 1/4 then just let the air out your tires a lil !

Or put the tires on the back, smokem for a few and then put them back on the ffront.

Josh- Did you get those pics I sent you about the Z ?? It was really simple. First is your motor still in the truck and is the cab still on? If so then you need to make some STRONG tacks to support the weight. It will be a whole lot easier with out the two on the frame!!
Lay the truck down as low as it will go right now, making sure everything is level and tack in some 1"X1" tubeing to the 4 corners of the front clip (front frame horns and back where your doing the Z). You can then jack the truck up and remove the wheels. Lower back down to your 1"X1" supports and start grinding the paint off where your going to cut and weld. support the frame section behind the front clip so it doesn't just drop when you cut. After you cut make sure everything is still level, but the two ends back together make sure everything is still square and tack weld it together. Just remember measure, measure, MEASURE!!!!! Now your front frame clip is sitting as low as you want it to go and the rest of the frame is dropped to the ground. If you sit to the side of your frame, look at it and either draw it out on paper or just imagine it, you can see that there really is not anything to it. Good luck and I hope this helps.