12" lift questions

[fitz]

  As Greybeard pointed out, if done with care, there is nothing wrong with trimming the fenders.
  Check out this truck (its not mine, found the pic for online).  Someone did a great job of "stretching" the front wheel opening, like the hot rod guys do to the rear 1/4's when they tub a pro street car. Notice how there is no front fender marker light?  Someone did some serious work on this truck to fit big tires with a small lift.
 

[fitz]

Here's the picture.

[5l1p5tr3am]

Don't worry guys; I'm not butthurt. lol. I definitely appreciate all of your knowledge and experience. As I stated in the beginning, safety is my primary concern. 12" lifts are common here where I live, but those are all on newer Ford F250/F350s. Totally different story to be sure. After much consideration I think it would be best for me to sell the 12" lift and go with a 6". I have a set of 37s too, so I should be OK without fender trimming. But if I need too that's fine.
Thank you again for all of your time and insight 

[Engineer]

placeholder

I want to weigh in on this but don't have the time to type a 16 page post.

Check back later.

[Greybeard]

Here's the picture.

I believe those are aftermarket fiberglass fenders, an outfit in Florida (I think that's where they are) makes them, http://www.usbodysource.com/.

[LTZ C20]

Here's the picture.

Yea I was gonna say, that doesn't look like heavily messaged body work on the fenders. I don't think the tires are really as big as one might think.

[fitz]

   I'm thinking fenders like this with a 6" lift might clear the 40" tires.

[fitz]

placeholder

I want to weigh in on this but don't have the time to type a 16 page post.

Check back later.

I'm looking forward to your reply.

[Engineer]

Sorry it took so long to get back to this thread.

This picture is of my '77 with 8" Skyjacker front springs, custom rearched rear springs, and a 3" body lift. 11" of lift total. For steering corrections the truck has the standard Dana60 block, and a Skyjacker drop pitman arm. And that is all.

The 18.5/44-16.5 Gumbo Monster Mudders were purchased, mounted, and balanced by Midwest 4x4 in StLouis, MO.

The truck drove like a dream.



Now, for my thoughts on a 12" lift. Based on previous replies in this thread there may be some disagreement with my opinion, but that is fine, the great thing about this website is that we can discuss our differences and be civil about it.

You can get away with a 12" lift on a street truck. It is doable. But it is not as simple as bolting on the lift and putting the truck in gear. If the Super Duty trucks are getting away with it so can you. However as has been mentioned there are epic compromises to make it work.

A spring that gives 12" of lift will in all likelihood have such a high spring rate that a degradation in stability won't be noticeable.......think of it this way......your suspension will basically be solid. There will be some change in handling as your center of gravity is greatly altered. Ride will be something you cannot consider if you want this to work.

In engunearin skool they preach sprung, (what is held up by the springs) and unsprung (what isn't supported by the springs) weight ratio. If you want a comfortable ride you limit unsprung weight as much as possible. The reason a 1976 Cadillac Eldorado rode like a pontoon boat on a lake is because it has enormous amounts of sprung weight over a moderate amount of unsprung weight.

What relevance does sprung weight have to do with a 12" lift? The more sprung weight you have the more leverage this places on the springs. Without heavy dampening the result is an unstable platform. Now lift that weight up into the air and the result is instability added exponentially.

Now back to my aforementioned theory on spring rate. To gain the lift more leaves will need to be added to maintain the height. This has the unavoidable consequence of adding spring rate. Bad for ride comfort, but, in theory, good for stability. Bear with me on this. By adding spring rate, making the springs less likely to deflect from highway forces, you limit the squishy feeling that makes the truck drive itself. In this case if the truck body could be lighter it would have the effect of lowering the center of gravity. However, since the body is sprung weight, the ride will suffer more.

There are stupid fads in off-roading that come and go. Like kicker shocks. Crossover steering is not in this category. There is a reason crossover steering has been around for 30 years, it works. Spend the coin for crossover steering. It is the only sane way of making this work. Modifying the factory steering requires too many changes that are only patches at best. The crossover steering keeps the steering forces in a more workable plane. Still not perfect but better than the short linkages that result from modifying the factory stuff. Dropping one pivot point 12" away from the travel plane of the other pivot point will result in less angular stress across the front of the truck which is about 48" away versus using the factory drag link which is only about 15" between pivots on the factory drag link.

Now there is an advantage to retaining the factory front-back traveling steering linkage. If modified properly bump steer can be avoided with the factory setup since it can be made to cycle in an arc that will change in a similar amount as the natural rearward travel of the front axle as the suspension cycles. Crossover steering cannot be built in a way that prevents bump steer entirely. With crossover steering as the suspension cycles the front axle travels laterally to the centerline of the truck whereas the crossover link arcs perpendicular to the centerline of the truck. The best bet there is to keep the crossover link as level as possible to minimize the arc it travels in.

To run 40"+ rubber you need a Dana60/14-bolt. 'Nuff said.

If I were to build a street rig with the 44" tire route again I believe I would opt for 2 1/2 ton Rox. Stronger knuckles, housings, axle shafts, and the raised location of the pinion with the double reduction helps keep the u-joints from slinging themselves apart every 6 months. Which brings up another point. With stock axles a 12" lift will force you into radical u-joint angles, especially on the front. The Saginaw CV-joint, after the tabs are ground off, still won't accommodate much more than 8" of lift.

As far as legality, CA regulates even how you knot your shoe laces. I can't imagine the noobs in Sacramento have managed to ignore even the slightest modified pickup.

I love lifted trucks, the bigger the better. I encourage you to build the truck of your dreams, but there are reasons why most tall lifted trucks are trailered to the car shows and mud pits.

[LTZ C20]

As far as legality, CA regulates even how you knot your shoe laces. I can't imagine the noobs in Sacramento have managed to ignore even the slightest modified pickup.

Everything Engineer said is great. This part tho, couldn't be a more accurate statement of the truth. Hahaha.

[Irish_Alley]

im going to add one thing.
everyone talks about the dana 44 or 12 bolt needing to be upgraded
but this is me and my dana 44 with a posi unit up front turning 40s (first time for the posi unit which could be why it held up idk)

now dont think this means it will hold up, cause i know its only a mater of time before one breaks again. ive broken i think 3 with just 38s and granaded the dif with 44s. the dana 60 is 3" longer than the dana 44 so you will need a shorter driveshaft. so if you start with a dana 44 and decide to switch you will need to have the driveshafts shortened.

[5l1p5tr3am]

Engineer, can't thank you enough for your insight. It's great to hear some practical examples of theory as it helps understanding. Your projects are awesome! I appreciate your input and experience as well, Irish. At this point, as much as I'd loooooooove to have that 12" on, I just can't throw another 2k at the truck for the, D60, x-over steering, upgraded steering components, changing the pinion angle, etc. I know I could get by with the D44 for a while but still. I think I'll be just fine with the 6" suspension lift and maybe a 3" body down the line if I feel the need. Assuming I can get this 12" kit sold, I will recoup enough to pay for the 6" plus some small additional stuff.

Thank you again, gents!

[Irish_Alley]

you might want to wait till tax money comes along and you can sell it to someone with a big pay check from the irs

[Greybeard]

Sorry it took so long to get back to this thread.

This picture is of my '77 with 8" Skyjacker front springs, custom rearched rear springs, and a 3" body lift. 11" of lift total. For steering corrections the truck has the standard Dana60 block, and a Skyjacker drop pitman arm. And that is all.

The 18.5/44-16.5 Gumbo Monster Mudders were purchased, mounted, and balanced by Midwest 4x4 in St. Louis, MO.

The truck drove like a dream.

Now, for my thoughts on a 12" lift. Based on previous replies in this thread there may be some disagreement with my opinion, but that is fine, the great thing about this website is that we can discuss our differences and be civil about it.

You can get away with a 12" lift on a street truck. It is doable. But it is not as simple as bolting on the lift and putting the truck in gear. If the Super Duty trucks are getting away with it so can you. However as has been mentioned there are epic compromises to make it work.

A spring that gives 12" of lift will in all likelihood have such a high spring rate that a degradation in stability won't be noticeable.......think of it this way......your suspension will basically be solid. There will be some change in handling as your center of gravity is greatly altered. Ride will be something you cannot consider if you want this to work.

There are stupid fads in off-roading that come and go. Like kicker shocks.

Now there is an advantage to retaining the factory front-back traveling steering linkage. If modified properly bump steer can be avoided with the factory setup since it can be made to cycle in an arc that will change in a similar amount as the natural rearward travel of the front axle as the suspension cycles. Crossover steering cannot be built in a way that prevents bump steer entirely. With crossover steering as the suspension cycles the front axle travels laterally to the centerline of the truck whereas the crossover link arcs perpendicular to the centerline of the truck. The best bet there is to keep the crossover link as level as possible to minimize the arc it travels in.

To run 40"+ rubber you need a Dana60/14-bolt. 'Nuff said.

If I were to build a street rig with the 44" tire route again I believe I would opt for 2 1/2 ton Rox. Stronger knuckles, housings, axle shafts, and the raised location of the pinion with the double reduction helps keep the u-joints from slinging themselves apart every 6 months. Which brings up another point. With stock axles a 12" lift will force you into radical u-joint angles, especially on the front. The Saginaw CV-joint, after the tabs are ground off, still won't accommodate much more than 8" of lift.

As far as legality, CA regulates even how you knot your shoe laces. I can't imagine the noobs in Sacramento have managed to ignore even the slightest modified pickup.

I love lifted trucks, the bigger the better. I encourage you to build the truck of your dreams, but there are reasons why most tall lifted trucks are trailered to the car shows and mud pits.

Hi Engineer,
   You live in or near the St. Louis area? I am originally from Florissant, MO. I knew Bob Chandler through my brother-in-law first before he ever opened Midwest and was simply selling some items out of his garage. Back in the mid-seventies to early eighties I used to wheel with some of his early frame fabricators and mechanics down on the Black River in Lesterville
My '78 truck is on the left, still in it's 4" lift and 36's. This was in about 1984 I guess. Not a beauty by any stretch but more than capable of running in 5' of water all afternoon.

before I moved permanently out of the state in 1985. They closed the Black River to public wheeling about 1987 I believe. My last year on the river was in 1986 when I traveled back there from Colorado to visit with the gang. I haven't been back to Missouri since.

Me and my future niece in 1986 at Midwest 4x4 visiting. This is BF2.




I'd like more of your thoughts on the stock steering setup. You mentioned that you had an 8" lift on your truck and used a block under the steering arm and a dropped pitman arm. With a D60 this is all that is necessary with a 8" lift to get the steering as close as it can be. A D44 will still come up rather short of the desired alignment IIRC. However, beyond 8" I shudder to think of those that use the bent drag links. They do work (if reduced lock-to-lock steering is acceptable) but like every piece of steel that has a bend in it the overall strength of the rod has been severely compromised under compression not to mention that the angle between pivots, like you said, should remain as level as possible no matter the style of steering used. Even though the axle housing does move in a rearward plane (arc?) during spring compression, the actual movement does not cause as much feedback through the steering as does the misaligned pivot points. Am I correct?

As an aside, back in the days when I spent three weeks a year on the Black river I talked to a few folks that mentioned they dislocated or outright broke a thumb because of bump steer with a bent drag link. It happens I guess.

[enaberif]

I will say this.. my truck with a 4" lift rides pretty rough. I would hate to be in a truck with 12" of lift on the road. UGH.