The suspension was comically worn out when I bought my well used 2001 Chevy Tahoe. I first rebuilt it with stock parts. The trails made quick work of those! I then looked into direct bolt on upgrades that have held up since for nearly 50k miles. If you are looking for direct bolt-on trail tested suspension upgrades then read on.
Loosing a shock on the trail
I bought the truck to use on forest service and BLM trails, basically a glorified side by side. On one of my first trail rides I loaded up with friends and headed over a mountain pass. We didn’t get too far when we heard a horrendous clunk. The front driver shock had ripped clean out of the upper mount. Turns out the guy I bought the truck from had put leveling keys (raised front end 2 inches) but never got longer travel shocks! So when I hit a big bump it ripped the shock off the truck!
Compromising with a 1″ rake / front lift
Leveling is a very common modification people do to trucks. They make the front wheel wells the same height as the rear. Mine came with leveling keys and I’m not a terribly big fan. Here’s why, the chassis is tuned; brakes, steering, suspension, everything for that 2″ factory rake.
There’s a specification called the Z-angle. This is the degrees off horizontal your front lower control arm tilts. I lowed the front end back down to point where I was within the factory Z-angle spec. I found I could have 1″ of rake while maintaining the factory suspension geometry. Returning the control arm to factory spec GREATLY improved my brake and steering response.
Chevy Lean: my truck had the notorious Chevy lean where the driver’s side is lower than the passenger. The driver side is heavier than the passenger which leads to this lean over time. I got rid of the lean by adjusting the torsion keys and swapping the rear springs!
Bilstein 5100
I replaced all four shocks with Bilstein 5100 shocks. You can get the Z71 OEM Bilstein shocks but they don’t allow for the longer travel so I opted for the 5100 series so I could keep my 1″ front lift. There’s also Rancho Shocks. I’ve been VERY pleased with my 5100’s though. They work GREAT.
I’d LOVE a shock with a dampening adjustment for factory height but I’ve yet to see anyone who makes one. Until then these 5100’s are the way to go!
Front Control Arm Rebuild
When purchasing my truck the OEM ball joints had ZERO play at 225,000 miles. However, all the dust boots were GONE. I replaced them with Moog ball joints and a couple store brand ones. They all failed. I think the Moog parts lost the dust boots and store brand became loose at around 10k miles of use. I could have warrantied them but what’s the point, they’d just fail on the trail again.
At this point I decided to try…
Mevotech TTX Control Arm Ball Joints: I couldn’t be more pleased. They have held up perfectly and the dust boots are all intact. The TTX line is supposed to be a stronger factory fitment part for heavy duty use and seems to live up to the hype!
When I installed the Mevotech TTX ball joints I pulled the control arms off and did a full rebuild.
Energy Suspension Polyurethane Bushings: I installed poly bushings on the sway bar and front control arms. Wish I’d got them for the motor mounts but that’s long done. I’ve on my list yet to do the rear control arms. I also called Energy Suspension several times and they were SUPER helpful!
The steering and handling feels more responsive. Oh and did I mention it’s MUCH cheaper to rebuild your own control arms with these than buy refurbished control arms. I pulled my control arms off, painted them with enamel paint (rust-oleum) and installed the bushings. Love the upgrade. Now I need to redo the rear control arms!
Word to the Poly Naysayers: People really get all bent out of shape over polyurethane squeak. Yes they do squeak but only when the suspension suspension is highly articulated like going over a big rock. Off road it’s a non issue because it’s so noisy you cannot hear it. Only time I hear it otherwise is if I drive over a steep curb. Otherwise there is ZERO squeak. They insulate from suspension / road noise every bit as well as rubber bushings in my opinion.
Delphi 680 versus 670 Steering Gearbox
I’ve seen some Z71 packages to have the 670 and some have the 680 gearbox. The 680 is MUCH better for off road use. My truck came with a 680 gearbox and I was SHOCKED at how EASY it was to turn the wheel!
Which steering gear do you have? The valve cover where the steering wheel linkage connects is three bolts on the 670 versus four bolts on the 680. The 680 has a larger piston in it for increased turning force.
Given the age of my truck I wanted to have a fresh gearbox. I went to the junkyard and pulled several of them (long story) and rebuild them. Cost me about $40 to rebuild including rebuild kit, paint, and used gearbox. It was SUPER easy although I couldn’t find a rebuild guide so I made a YouTube Tutorial when I did mine.
Tie Rods
The factory tie rods WON’T last long if you go on trails. The ones when I bought the truck quickly went bad. I replaced those and the new ones also went bad. The ball joints develop play. Thankfully I never bent a tie rod. If you bind up your steering against a rock you can bend the factory rods. With all this in mind I tried the following and seems to have worked well since:
- Kryptonite Tie Rod Sleeves
- Moog Problem Solver inner tie rods
- Mevotech TTX outer tie rods
Above is a picture of the setup with about 50,000 miles on it. It has worked VERY well for factory fitment upgrade. When these go bad I may spring for the Kryptonite tie rods.
Larger tires
I virtually NEVER strike off road and when I have it’s only ever been the hitch. That’s with the FACTORY size tire a 265/75/R16 (31.6″ tall). Granted I don’t do much if any rock crawling. It’s your standard forest service roads, some really bad but without boulders blocking them so to speak. Factory tires shown in photo below.
I moved up to a 285/70/R17 (32.7″ tall) to get a bit more peace of mind on the trails. These still let me fit in my 7″ tall garage door and use the spare tire carrier. First, I bought a set of the 17″ snowflake rims from another GMT800 at the junkyard. The spare still had a 16″ rim so I went and bought a metal spare tire rim from a GMT900 so I could keep the tires all the same size.
It’s probably worth mentioning as well the 285/70/R17 tires did virtually nothing to my factory speedometer calibration. I used GPS to compare to dash reading and was so close it wasn’t worth fiddling with.
You can see this combination in the photo below:
The 285/70/R17 tires rub on the rear inner fender liner at full articulation. I don’t think this would be any concern on a GMT800 pickup truck as they don’t have rear inner fender liners.
WORD TO WISE: one of the WORST modifications you can do a truck is a lift kit (or put out of factory spec tires on it). I went 1″ over factory spec with wheel size. This changes up all the angles on the suspension. The easiest to conceptualize is the center of gravity (roll moment). Best to get a FACTORY truck that has more ground clearance. Otherwise companies like Dirt Kings sell engineered widebody suspension (& body) kits that are intended to maintain a stable suspension geometry.
Spare Tire: The 285/70/R17 BARELY fits the spare tire holder on my Tahoe. It ever so SLIGHTLY clears the rear sway bar. Any larger and you’d not be able to carry a spare tire under a Tahoe which is a no go for me.
I’m not one of those macho off road guys who says the spare tire is unnecessary. I don’t buy the argument where you get added ground clearance either. If that’s the case you’ll catch a rock in the spare tire space and rip the bumper clean off.
35″ Tire Fitment: I ran into a guy who fit 35″ tires on his GMT800 Tahoe. The stance was killer awesome. He had to do some mortification of his wheel wells but had a factory geometry suspension otherwise. I was so shocked they fit that I had to take pictures (above). That said, I have no clue what it would do at full articulation off road. Probably be a complete mess. Not to mention couldn’t fit a spare of that size.
Load E versus Load D off road: Another note worth mentioning, I much prefer Load E (10 ply equivalent tires) for trail use. However, I got a set of Load D tires by accident and they worked fine on the trails too.
Locking alignment cam bolts
Below you can see a “locking alignment cam bolt” next to it is a factory cam bolt, and lastly the bent cam bolt off my truck. Truck drove straight as an arrow but burned up a set of BF Goodrich K02 tires. I wanted to cry. Three alignment techs and two shops couldn’t figure it out not due to truck but because they didn’t know how to properly align a vehicle. The last tech got it kind of straight. I digress. I think what happened was I bent a cam bolt and my camber got thrown off which corresponds with what my camber gauge had said as well as the chewed up side of the tire.
Long story short, I put on Dirt Kings locking alignment cam bolts. There’s cheaper knock off brads that do same thing but I was happy to do business with Dirt Kings. I’d had some questions and they were MORE than helpful.
The shops didn’t know how to install them so I put them on myself. You get the sense you maybe able to carefully install these and not need an alignment. My truck needed an alignment afterwards. I did the alignment myself after the mess I went through at the shops.
HP Academy Alignment Course
I’ve done an alignment without an alignment machine before but was 20+ years ago and a royal PITA. Thought it would be good to refresh on how alignments are done so I watched a BUNCH of YouTube but ultimately sprung for the HP Academy Alignment Course. Money well spent and came in SUPER handy when shop couldn’t figure my truck out.
Longacre Caster Camber Gauge
You should have one of these regardless if you decided to do an alignment or not. I’m going to make checking my alignment a part of my routine maintenance at this point. I got a bare caster & camber gauge off eBay w/o the hub adapter (not sure where they sell that otherwise). Was child’s play to check Caster and camber. I was able to get same measurements the shop’s alignment machine got using the gauge and my garage floor.
Additional alignment tools would have made it a bit easier:
Toe plates: They hold tape measures against front and rear of tire. I may make them from plywood but you can buy as well. Shop thankfully got toe correct (but steering wheel angle was wrong).
Alignment Turn Plates: these remove friction out of steering when vehicle is weighted and measurements are taken. I took ghetto approach and poured used motor oil under the tires.
Conclusion
This suspension setup has done me well. It works comfortably on the road yet is strong enough to handle light to moderate trail use. Travel and clearance would be it’s main setback but that’s never had me turn back from a BLM or Forest Service trail.
I imagine I’d need a lift & bigger tires if I wanted to do the next level stuff like rock crawling but that’s not really my thing. Plus I don’t like lifts they destroy a vehicle, can make it unstable on the highway, and ultimately are for off road use only in my opinion. Maybe an exception for a well engineered widebody (pre-runner) kit. Can look at “Dirt Kings” for those.
I originally purchased my GMT800 / 2001 Tahoe to use on the trails. I’d looked at Jeeps, side by sides, and lastly a Tahoe. These are trucks are hidden gems. I’ve put around 60,000 miles on it since I bought it, most of it on trails. I’ve built up a transmission, engine, and updated the suspension making for a capable and comfortable off road rig! Feel free to reach out if you have any questions about your build.
