Lowering Research

[BenKey]

I thought this was worthy of a pinned topic to stay here for all those that look at lowering their trucks. MisterP was gracious enough to go through all of the info and put it in one place. Thanks MisterP

 

MisterP's work:

 

I was up to 3am this morning dredging through all the old lowering threads, and here is the summary over 2-3 years of talk on the subject:

 

FRONT:

* lowering the front suspension will create HUGE changes in suspension toe-in, the truck will "walk like a bull dog" until it is aligned so remember to budget for a good alignment as part of the project;

* Spindles are preferred over keys or nothing at all, nobody has ever posted that they wished they used torsion bar keys instead of spindles, nor has anyone said they regretted using spindles;

* A couple have reported that correctly installed/adjusted spindle kits have actually improved handling by reducing body lean and roll, the torsion key kits have had stock or a touch more body roll (not offensive), and torsion bar jobs have shown significant increases in body roll with several saying they seriously feared driving their freshly lowered truck;

* Early McGaughys spindles caused an increase in turning radius - this design oversight was corrected in later spindles;

* The spindle kits require a moderate-to-professional degree of automotive skill (or talent) to install, these kits are not newbie friendly and take 6-12 hours to completely install; professional shops typically charge $300-400 to install a complete lowering package, not including price of the kit; if you elect to have the kit professionally installed the final expense would be between $750 and $900;

* The torsion key kits can be installed by most automotive amateurs in their driveway with help of jackstands and a couple favorite cold beverages - as these kits cost less plus do not require costs of professional labor these can be a decent bang-for-the-buck option;

* a few enthusiasts who bought the torsion key kits (not all) changed over to, or later added, dropped spindles and reported that doing so finally made their efforts worthwhile;

* almost everyone that cranked down their torsion bars (rather than use keys or spindles) either regreted it later, changed it later, or admited that they were living with a compromise in handling but appreciated its cheap cost (between $100 and $150 excluding shorter shocks);

* Dropping the front of the AWD SS more than 2-inches will cause CV-joint binding and hence front-end vibration at highway speeds - it was discovered that this is corrected by cranking the torsion bars back up a little at a time until the binding is relieved;

* Spindle kits allow you to retain stock-length shocks, torsion key kits and adjusted torsion bar jobs will require correspondingly shorter shocks;

* There have been fit-up problems with the McGaughy's spindles on '05+ trucks, as the OEM ball joint design was changed with introduction of larger OEM rotors; this requires an advanced installation workaround.

 

REAR:

* Installing aftermarket leaf spring hangers (secures front of the leaf to the frame) is an absolute biatch of a task as the OEM hangers are riveted and must be ground/drilled out - this necessitates moving the fuel tank for access, and a few have even pulled the truck bed to make the job easier (8 bolts, a couple extra friends, 20-mins);

* On heavily lowered trucks with the large aluminum driveshafts (SS) it is worth considering cutting-out the mid-bed frame crossmember as it adds no support to the frame and will strike/damage the driveshaft if the truck *totally* bottoms-out;

* When using a combination of front hangers and rear shackles (recommended) it is still important that the installer uses the correct combination of holes to keep pinion angle correct, don't just assume that using the same/matching set of adjustment holes front and rear will keep the pinion angle right (this is a mistake a lot of McGaughys installers make);

* using only rear leaf-spring shackles (without front hangers) will certainly alter pinion angle and introduce vibration, several have reported that this is corrected with installation of either a 2, 3, or 4-degree shim;

* The McGaughy's deluxe kit (comes with both hangers and shackles) maintains stock-length shocks;

* If the truck is fitted with a rear sway bar the links ("dog bones") will need to be shortened/modified so that the bar is level again in its resting/neutral position.

 

I've got all kinds of notes at home, this is what I could remember off the top of my head. I have decided to go with the McGaughy's Deluxe kit on my '03 SS next month. I also know Jonmalibuss is very happy with his Belltech spindles and has a lot of installation experience with both.

 

Mr. P.

[2drTahoe]

Interesting read, thanks for the efforts

[AUTOGUY]

* When using a combination of front hangers and rear shackles (recommended) it is still important that the installer uses the correct combination of holes to keep pinion angle correct, don't just assume that using the same/matching set of adjustment holes front and rear will keep the pinion angle right (this is a mistake a lot of McGaughys installers make);

 

<{POST_SNAPBACK}>

 

So what is actually the correct combination of holes in the shackles and hangers?

[RevolutionRaceWorks]

This is a great read and extremely good timing since this is on the books to be done real soon

 

Thanks!

[misterp]

So what is actually the correct combination of holes in the shackles and hangers?

Ben is going to update the body of the text above soon, and it will include this point -

 

"...according to Mike McGaughy to set the correct pinion angle (assuming a 2"/3.5" drop kit) the leaf spring is to be attached to the front hanger using the lower (2-inch) hole, and to the rear shackle using the upper (1-inch) hole..."

 

Mr. P.

[drako]

mister p....you freaking rock.....i would say more praises but im late for work!

[XGMTech]

Misterp and Ben, this was an excellent idea! We should do something like this for other subjects... maybe when new people join the site, there could be a section where they could go to read these instead of using the search (difficult & frustrating) and posting the same questions over and over again? For instance, there could be the following often-discussed subjects:

 

Suspension Lowering (already done, great job misterp!)

 

Cold Air Intakes

Hand-held PCM programmers vs. mail-order PCM's

Cat-back exhaust systems

Shorty headers vs. long-tube headers

Transmission mods (servos, shift kits, etc.)

Forced induction comparison (I believe TurbochargedBezerker started this one a while back)

 

Just an idea...

[BenKey]

Post replies in the new pinned topic. Wanted it where MisterP could go in and edit since he is the one that worked on it.

[misterp]

Thanks everybody, glad that my reading and notes did not go to waste.

 

This is the link to the complete pinned topic.

 

Mods - would you consider closing this thread to avoid confusion?

 

Mr. P.