How do I calculate lift kit specs?

[78 GMC Jimmy]

So how do I calculate what lift my rig has?

Can you get the stock specs on what the distance of the center of the hub to the fender should be?

I have no idea how much of a lift I have, but I would like to find out.

 

[Wes Harden]

We compare from the top of the spring to bottom of the frame. No two trucks with the same "lift kit" will be the same.
That is a tuff country 4" HD on K20 burb, all Iron small block front winch and plate bumper.

Look through this thread it may help you narrow down yours https://ck5.com/forums/threads/how-will-my-k5-truck-look-with-xx-tires-on-xx-of-lift.170627/

 

[Bent77]

We compare from the top of the spring to bottom of the frame. No two trucks with the same "lift kit" will be the same. View attachment 472197
That is a tuff country 4" HD on K20 burb, all Iron small block front winch and plate bumper.

Look through this thread it may help you narrow down yours https://ck5.com/forums/threads/how-will-my-k5-truck-look-with-xx-tires-on-xx-of-lift.170627/

The magic number from the top of the rubber snubber to the axle is 12.5 for 4”

So you likely have lost 1” due to weight sag and spring sag

 

[Wes Harden]

yeah actually that picture is the 1983 4" unknown lift springs the Tuff country replaced. Also should mention the 2nd battery and fat ass radiator. Only the 35 pd A6 compressor has been swapped for 18 pd four season aluminum replacement

 

[78 GMC Jimmy]

So basically there is no way to know for sure what the lift is?

 

[cheavyk10]

The proper method is to measure from the top of the axle tube to the bump stop bracket. Stock height is 8 to 8.5". Take your measurement and subtract to get your lift height. Measuring to the top of the spring won't work because of various spring pack thicknesses.

 

[nvrenuf]

The proper method is to measure from the top of the axle tube to the bump stop bracket. Stock height is 8 to 8.5". Take your measurement and subtract to get your lift height. Measuring to the top of the spring won't work because of various spring pack thicknesses.

^^ Winner ^^

 

[MrHappy]

Ya like when I inquired about about my obsolete Rough Country numbers on my leaf springs. Which are supposed to be a 4” lift , but after I measured it’s equivalent to a 6” lift,with some crappy old Gabriel shocks. I would like to go to 4” Tuff Country Lift, but don’t know of any good driveshaft shops to shorten them. The 2 shops that were in Pahrump CLOSED. So probably L. Vegas ..

 

[78 GMC Jimmy]

Ya like when I inquired about about my obsolete Rough Country numbers on my leaf springs. Which are supposed to be a 4” lift , but after I measured it’s equivalent to a 6” lift,with some crappy old Gabriel shocks. I would like to go to 4” Tuff Country Lift, but don’t know of any good driveshaft shops to shorten them. The 2 shops that were in Pahrump CLOSED. So probably L. Vegas ..

There are shops that will custom make you a driveshaft and mail it to you. You just email them the specs. $400 I think.

 

[83ChevyK5Blazer]

Are they for sure legthened shafts? Might not need to be shortened.

 

[MrHappy]

Are they for sure legthened shafts? Might not need to be shortened.

I’m not sure how to measure for spec’s. But here’s a couple pics & I’m sure if I lower to a 4” lift I wouldn’t have the room for it on tail. I’m thinking maybe I’ll just take it down to 4WP in Vegas and have them do lift etc. Least that way I know it’s done correctly.

 

[Wes Harden]

That is close. Possibly your rear spring are sagging, a fresh set might put everything right.
I have a set of slightly use rough country 8001, 2" rear springs in Havasu. Only @ 2 hours from the Air port to here

 

[Blue85]

take it down to 4WP in Vegas and have them do lift etc. Least that way I know it’s done correctly.

I'm not sure that's a sure thing , but maybe others can share their experiences. Shortening a driveshaft should be much cheaper than a new one or lengthening. They cut one yoke off with a lathe, cut the tube to the new length, weld and balance (and the balance shouldn't much). Best to measure after the suspension changes are done. That rear shaft looks too long already.

 

[Wes Harden]

^ I was going to say this about 4wp, but changed my mind. Since @Blue85 brought it up yeah 4wp is not the good 4x4 store they used to be. Techs these days are very hit and miss. If you have the ability you should swap the springs yourself. We will help you get it right.

 

[78 GMC Jimmy]

I’m not sure how to measure for spec’s. But here’s a couple pics & I’m sure if I lower to a 4” lift I wouldn’t have the room for it on tail. I’m thinking maybe I’ll just take it down to 4WP in Vegas and have them do lift etc. Least that way I know it’s done correctly. View attachment 472658View attachment 472660

Cant see pics, I have a free account.

Can you post them in a Craigslist ad and give us the link.

 

[tarussell]

Cant see pics, I have a free account.

Can you post them in a Craigslist ad and give us the link.

We’ve all got budgets to stick to but if you’re getting into the 4WD game then the cost of $2.08 ( $25.00 for a year ) a month for a paid membership is money WELL spent - it’s nothing compared to what you will spend on an old four wheel drive.
Just a thought…

 

[Blue85]

We've already given him more than $25 worth of information, IMO, and we're paying to do it.

 

[MrHappy]

That is close. Possibly your rear spring are sagging, a fresh set might put everything right.
I have a set of slightly use rough country 8001, 2" rear springs in Havasu. Only @ 2 hours from the Air port to here

Darn I was hoping to read you had 4” springs. Even though they are R.C. ! And I could have a good reason to go to Havasu. I haven’t been there since mom passed in 2002. Lived on Cliffrose.

 

[Wes Harden]

I have some unknown used 4" fronts. I did like the RC 8001 springs the ride wasn't horrible in k20 burb. What lift you running now ?
Not far from Cliff Rose, am N of Palo verde North

 

[MrHappy]

I have some unknown used 4" fronts. I did like the RC 8001 springs the ride wasn't horrible in k20 burb. What lift you running now ?
Not far from Cliff Rose, am N of Palo verde North

They’re supposed to be 4” lift of RC but after measuring their more in 6” category. At 14.5” from axle tube to lower metal on bumper stop. The rear leafs are coming apart and twisting..