Determining what lift size I have.

[Nastardly]

Thanks for reading my thread. I have a 1975 K10 short bed that was lifted by a previous owner, supposedly it's lifted 3 inches in the front 2 inches in the rear. I want to swap the rear springs to 56" inch springs and level it out. How do I go about determining what lift size I currently have?

 

[Honky Kong jr]

Thanks for reading my thread. I have a 1975 K10 short bed that was lifted by a previous owner, supposedly it's lifted 3 inches in the front 2 inches in the rear. I want to swap the rear springs to 56" inch springs and level it out. How do I go about determining what lift size I currently have?

If there is blocks, measure them.

 

[Nastardly]

No blocks, just suspension lift on both axles.

 

[Honky Kong jr]

No blocks, just suspension lift on both axles.

That makes it kinda tough

 

[Craig 85]

This is a link from the GM Heritage Center for your 1975 truck. It's a 145 page PDF. Great document to save.

Page 19 has the info. With the tailgate down the bed floor should be 28.75" to the ground. The top of the cab should be 69.75" to the ground. These are based on a L78-15 tire or 235/75R15 = 28.9".


https://www.gmheritagecenter.com/do...its/Chevrolet-Trucks/1975-Chevrolet-Truck.pdf

 

[Nastardly]

Thank you, I will look over this tonight.

 

[77 K20]

Another way to compare lift height is:

-Ground to wheel well (this also depends on what size tire you are running)

-Mid hub to wheel well

Keep in mind the front and rear wheel wells are cut different (FYI).

To compare this is some measurements that I took two weeks ago.

My old measurements (2" Tuff Country HD front springs, 3" rear block):
-ground to wheel well Front 40", Rear 40" (tires are 285/75R16)
-mid hub to wheel well Front 25", Rear 24.5"

After ORD 4" front springs, rear 2.5" shackle flip on new 56" springs (3" block removed):
-ground to wheel well Front 42", Rear 42.5" (tires are 285/75R16)
-mid hub to wheel well Front 25", Rear 27"


There is another and probably better way to measure. Go from the axle tube to the bump stop bracket. But I don't have those measurements with me. They are somewhere at home (I'm at work).

 

[Nastardly]

Thank you, 77 K20. This should be very helpful.

 

[DanMcG]

85 K10 with 4" Rough Country all spring.
Ground to wheel well 41.5" but tires look a little soft. the bedsides are off it so no rear measurement. tires are 235x75x15


The better method is; (all my trucks are K10 short beds)

Top of axle tube to front bump stop mounting plate, 14"
Top of rear axle tube to stop mounting plate 14.5"
These haven't seen the road yet. so that might end up being less

Just measures my 78 k10 with what I assume are original springs.
front 2 leaf spring 7.25"
rear 5 leaf with a helper 7.5"

Now I got to wonder if they sold me a 6" lift instead of a 4

The 77 is close to the 78 but it's on the side of a small incline so they measure different side to side ..

Lets see what it looks like, the little avatar looks like my 77

 

[77 K20]

I just noticed it looks like you have a stepside? I have no idea if the rear wheel well on a stepside is the same as far as cutout/height as a standard bed. It might be different.

I took axle tube measurements today on my truck:

Front: 12" (again, 4" ORD front springs)
Rear: 11" (2.5" shackle flip, new 56" stock leaf springs, and an 0.25" axle relocation plate)

EDIT: Not sure either if the rear measurement would be the same from a 1/2 ton to a 3/4 ton (different axle...). Mine is a 3/4 ton.

 

[Nastardly]

Mine isn't a step aside anymore and it is a half ton shortbed.

 

[Nastardly]

So your truck is lifted and leveled?

 

[77 K20]

It isn't level unfortunately. The rear of the truck is 1.75" higher than the front in that pic.

This pic shows it the day I got the 315/75R16 tires on it. I wasn't happy the rear tire was not centered after the 2.5" shackle flip.

So about a week after that pic was taken I used an axle relocation plate to move it 1" back. This also raised the back 0.25" Tire is nice and centered now, but the back is 2" high.

Maybe it will settle once I haul a few loads with it.

You must be registered for see images attach

 

[Nastardly]

I went to the shop to get my measurements today and the results were confusing.

8.75 front axle to lowest point on bumpstop
3.5 rear axle to lowest point on bumpstop
30.75 Bed floor to ground
74.5 Cab roof to ground

They must have either moved the bumpstops or I measured to the wrong point.

 

[colonel mustard]

85 K10 with 4" Rough Country all spring.
Ground to wheel well 41.5" but tires look a little soft. the bedsides are off it so no rear measurement. tires are 235x75x15


The better method is; (all my trucks are K10 short beds)

Top of axle tube to front bump stop mounting plate, 14"
Top of rear axle tube to stop mounting plate 14.5"
These haven't seen the road yet. so that might end up being less

Just measures my 78 k10 with what I assume are original springs.
front 2 leaf spring 7.25"
rear 5 leaf with a helper 7.5"

Now I got to wonder if they sold me a 6" lift instead of a 4

The 77 is close to the 78 but it's on the side of a small incline so they measure different side to side ..

Lets see what it looks like, the little avatar looks like my 77

I have the 6" kit...I measure 16 3/4 inches. you have the 4". also if you had the 6" you would know it...cause you would be buying driveshafts..