For detailed information about the modifications click a section:

- Stock Vehicle Options
- Brush Guards
- Auxiliary Lighting
- Suspension:
     - Suspension Lift
     - Z71 Springs/Shocks
     - Front Shocks
     - Wheel Spacers/Wheels
     - Tires
     - Comparison Pictures
- Rear Cargo Organization
- Underbody Protection
- Custom Switch Panel
- Stream Crossing Preparation
- Spare Tire Carrier
- Roof Cargo Rack
- Rock Sliders
- Custom Steel Bumper


The Vehicle

Above is how I first saw my new vehicle on  The vehicle is a 2005 Chevrolet TrailBlazer with LT trim.  It is essentially loaded, only missing the factory navigation unit.  While those various bells and whistles have little merit on the trails, they are very nice for long trips and everyday commutes.  There were a few options I specifically looked for when purchasing the truck.

The first thing to look for was the 4wd option.  The TrailBlazer is actually very well equipped in this area.  There are four selection choices, described below:

2 HI - Standard rear wheel drive.
A4WD - When the computer senses wheel slippage, the front wheels instantly engage.
4 HI - Locks the front and rear drive shafts.  1:1 drive ratio.
4 LO - Shifts the 4WD into a 2.7:1 crawl ratio.

Click here for a detailed description of the internal operation of the NVG 226 transfer case.

The second major option needed for trail driving is the Eaton G80 factory rear locker.  Look for the G80 code in the glove box to verify that your vehicle has one.  It is an automatic mechanical locker.  Once it senses slippage between the rear wheels (in any drive mode) it locks the rear half shafts together until the input torque is taken from the drive shaft.

The TrailBlazer has a optional V8, however I opted for the I6 due to the slightly increased fuel mileage and room under the hood.  The TrailBlazer also has a long wheel base option (EXT).  If you want to have better luck off road, I recommend the short wheel base (SWB).  There are some members at that wheel the EXTs with some success, however the break- over angle is much better for the SWBs.  The improved angle will help you from getting high-centered.

I also looked for leather seats.  Just between you and me, its a whole lot easier to wipe mud and dirt off leather than cloth.  Plus, the leather option has heated seats, which keeps the Mrs. happy.  The integrated satellite radio and Bose sound system could also be nice for long hauls.  I could go into all the reasons this vehicle is perfect for me, but I will hold off.



Brush Guards - by WAAG

I began my modifications with some minor things.  First to come were brush guards.  These are not essential off road items, but the added front and rear protection off road and in the Baltimore traffic appealed to me.  I chose the best name in brush guards, WAAG.  Yes, they are much more expensive, but they are the only guards for the TrailBlazer that do not mount under the front bumper.  Instead, they share the tow hook mounting holes.  This preserves the approach angle of the vehicle, yet still protects the lowest part of the plastic bumper from a run-in with the ground in a high angle situation.  The WAAG is also the only brush guard for the TB that has a four- point mounting system, thus making it ultra-sturdy when compared to the other guards.  I have no problems pushing other vehicles, and there are no added vibrations in the guard, making it a great mount for auxiliary lights.  I will probably be purchasing the headlamp protectors down the road.

The rear guard is less sturdy than the front, but is still quite useful.  The first being traffic protection.  It also provides extra foot-area when reaching items on the roof.  The guard mounts to the bumper attachment bolts, on either frame rail.  Even though these do sit below the bumper, it does not destroy the approach angle much.  If anything, it will provide some extra ground protection, which is always nice.

I would not advise using either brush guard as a recovery or lifting point, even though they are both frame mounted.



Auxiliary Lighting

For grille lighting, I chose the Hella Rallye 4000s.  Hella offers a few beam options for these 9" monsters.  I opted for the cornering beam pattern.  This does not only throw light to the side, like the name may imply.  Instead, it throws an abnormally wide beam pattern (a cross between a fog and euro beam) that is perfect for tight maneuvering in low visibility situations.  A wide beam is much more useful than a far-reaching focused beam when driving off road.  At 100 Watts per light, the output is formidable.

In addition to the brush guard lights, I built a roof mounted light rack.  This comes in handy when driving in late-day situations or even night driving.  I have also noticed they are quite helpful when driving in snow.  The increased lighting angle allows less light to reflect off the surface of the snow, therefore improving road visibility.  However, it is not to be used in fog because the beam crosses right in front of the windshield.  In that situation, the light reflects right back into the driver's eyes.  Click the link above to for a detailed write up that includes a materials list and detailed build instructions with pictures (just keep reading the thread).



Suspension Lift

After making sure I had the proper recovery equipment, it was time to begin the big modifications.  A proper suspension lift takes a lot of planning on these vehicles.  By proper, I mean upgrading the necessary secondary parts along with the lift.  I also did not want to go through a portion of time with a lift and undersized stock tires, so bigger tires were to accompany the lift 'package.'  For me, the package included the lift, rear springs, front shocks, and wheel spacers.

The TrailBlazer is unfriendly to being lifted due to the front differential's unusual mount to the engine's oil pan.  The half-shaft actually runs through the pan.  I believe this was done by the Chevy engineers in an attempt to make the engine as low as possible.  While this does make a lift greater than about 3" impossible without extreme changes, the resulting low hood does provide the driver with a good view of the trail and the low CG gives us decent lateral stability.

The TrailBlazer aftermarket is very small when it comes to lifts (lowering kids are a different story).  We have four options that I know of: BDS, Suspension Maxx, Rough Country and MarkMC.

A Suspension Maxx kit includes either front or rear spacers.  Their front kit is made of polycarbonate, and the rear is cast aluminum and they offer lifts from 1" to 2.5".  The rear spacer mounts to the axle side of the rear springs.

MarkMC is a member and vendor on that sells quality kits that are similar to Suspension Maxx, except his is metal, as opposed to polycarbonate.  Mark sells kits up to 2.5" high up front and is working to expand his market to new products.

The BDS kit, which I have and personally prefer, (to the right) advertises 2" of lift, front and rear spacers included.  While the BDS kit is the most expensive of the options, I feel it offers the greatest strength and durability, and that matters off the road.  It replaces the front upper strut mounting plate and is made completely of steel.  The rear BDS spacer mounts to the top of the spring and is retained by a couple bolts.  The kit includes new upper strut mounting bushings and new hardware.

I don't know much about the Rough Country lift, I'll update this when I know more.  It appears to be similar to the BDS, but has a smaller rear spacer.  It's sold as a 'leveling kit'... something us off roaders don't care much about.

There have been some questions regarding how strut spacers work, so I made the below diagram to help explain how they add lift, yet retain the stock (and safe) maximum suspension extension.

(roll over with mouse to expand diagram)

BDS also offers a 2" body lift.  A body lift is different from a suspension lift, and is only possible on a frame-based truck.  It essentially replaces the bushings that are located between the frame and the body with taller ones.

For part numbers and in-depth lift information follow the link to the right.




Rear Z71 Springs/Shocks

The last part of the lift equation is the rear springs and shocks.  Stiffer rear springs are desirable here because of the heavy loads I tend to carry with me.  The stiffer springs also produce additional lift and can be coupled with lift spacers.

Here again, the TrailBlazer aftermarket is poor.  Amazingly, a member of TrailVoy Off Road found that Z71 Tahoe springs and shocks (pictured to the right) were direct bolt-ons for our vehicle.  While they have the same resting length as our stock springs, they have a non-linear spring rate, and sit about 1.5" higher than stock when on our vehicles.  This means they will compress less when loaded down or towing.  The Z71 shocks are also beneficial in that they are slightly longer than our stock shocks (to allow slightly greater articulation) and they have a more aggressive dampening effect.  To find these jems, search eBay (and include the description in your search) for the GM part number, 15234633.




Front Shocks

Since the front strut is already all apart when doing a spacer lift, it's a great time to replace the front shocks.  I chose Bilstein HDs (pictured to the right) from  I have read great reviews of these shocks, which are developed to provide better stability and bump rebound control.  With the improved performance combined with the club discount from, they are a no-brainer addition.






Wheel Spacers / Wheel Backspacing

The TrailBlazer is further unfriendly to people wishing to do a lift or increase the tire size.  The first obstacle is the positioning of the upper ball joint that is located on the steering knuckle, above the tire (see the picture below).  This severely inhibits a larger tire size unless you install wheel hub spacers (pictured to the right) or purchase wheels with a backspacing of less than 4.  I purchased wheel spacers from after the recommendation from fellow TrailVoy members.

If you wish, a wheel spacer can also act as an adapter to change the lug pattern to match a new wheel.  I requested four 1.5" hub and wheel-centric billet aluminum spacers.  Fred (the owner of Wheel Adapter) knew all of the necessary dimensions and shipped them out the next day.  

If you are planning to use the stock bolt pattern, remember, it is NOT 6x5.5", as most Chevy trucks are.  Our stock lug pattern is 6x5", or 6x127mm.




This is one place where we do have a few options, since they are basically universal.  Now remember, without wheel hub spacers, no matter the lift, you are limited to about 30.5" tires due to the upper ball joint (still better than the stock 29.8 inchers).  However, because I am using the hub spacers, I can go quite larger (up to around 34" with a fair amount of hammering, cutting, and more lifting).  I decided to aim a little more reasonably at 32 inch tires.  After a lot of hunting around, I narrowed my decision down to three of the best, yet still reasonably priced, mud-terrain tires.

Each one had its own distinctive advantages.  Based upon my research at the time of this report, I put the following table together.  Keep in mind most tire data for M/Ts is based upon other people's opinions.

Mud-Terrain T/A KM
Destination M/T
Wrangler MT/R
Advantages Rim Protector
Reportedly the toughest
Adapted for Jeep Rubi
Endorsed by Bill Burke
Best wet performance
Aggressive side lugs
Reportedly the quietest
Offers the widest option
Best snow traction
(close to 32" w/ 17" rim)
255 / 75 R 17
(32.1 in)
265 / 70 R 17
(31.6 in)
275 / 70 R 17
(32.2 in)
Cost per $122.00 $181.00 $231.00

The final decision came down to a complex brain-bender based on each tire's price, diameter, and advantages.  A few things weighed heavy on my mind.  First, since I will be purchasing 5 tires, cost was a big deal, you just can't get around that.  The second was the endorsement by Bill Burke, who is essentially an off-road god.  Burke has been teaching off-roading skills for over 20 years and has been using BFGs the whole time with only 2 flats.  The third thing that carried the decision was that Jeep chose these same tires for their off road beast, the Jeep Wrangler Rubicon (knowing this would mean on and off road refinement).  With those facts weighing on my mind, I chose the BFGs knowing I would be in good hands.  I was actually able to purchase the same adapted tread design used on the Jeep Rubicon.  Below is a comparison of the tread patterns.  In addition to the slightly different lug design, the DTs have slightly less tread thickness in an attempt to improve the stock mileage of the Rubicon.  The reduced tire life was offset in my mind by the great price and improved grip.

With an increased tire size, there comes the possibility of needing to trim back some of the fender in order to minimize tire rub.  Follow the link on the left for a detailed write-up by one of the TrailVoy members.  Luckily I did not have to trim, but I came very close.

After installing the tires, I have been quite pleased with the performance of these tires.  They stay fairly true on the highway, they seem to wander less than my previous tires.  They are very quiet; less noisy than driving over a bridge with normal tires.  The grip seems excellent also, as the extra faces on the central lugs seem to really grip well.

As an added tip, when purchasing 5 tires (one as a dedicated spare) it is important to incorporate the spare wheel into the tire rotation.  This will result in equally distributed use and maintain similar tread depths through the life of the tires.  I've seen numerous spare tires that never get rotated into the mix.  The result, when it's finally called into action, is overworking of the differential at highway speeds due to the extreme difference in tread depths.  This is especially possible with the deep tread of mud-terrains.  For your reference, the proper 5 wheel rotation pattern is displayed at the right (courtesy of



Suspension Package and Tire Installation

When you have your lift completed, it is critical to obtain a proper front end alignment.  When changing the geometry of an IFS, the camber and toe of the wheel can be affected.  This can lead to poor wear on your tires due to them slightly scrubbing along the road during normal travel.  I had the entire install done by my trusted mechanic at the Towsontowne Garage.  Total charge for the install was about $500 (including tire mount & balance, suspension install, and alignment).

I have included some various comparison photos and photos after the install:

Keep in mind, the measurements are somewhat inaccurate and will not all agree,
but they are a pretty good approximation.



Front clearance:

Rear differential clearance:

Front suspension droop: 

Tire clearance to fenders:
1/8" in front, 1/2" in rear

Suspension Details:


I experimented some with the affects the modifications had on my gas mileage.  I drove a 300 mile trip before and after the install and the following are my results.  Keep in mind, the car's computer estimated the gas mileage based upon the 29.5" tires, and must be adjusted to give comparable results (they must be multiplied by 1.085).

  Before Install After Install - by computer After Install - adjusted
Going to 21.8 mpg 16.5 mpg 17.9 mpg
Coming from 22.3 mpg 18.5 mpg 20.07 mpg
Average 22.05 mpg   19 mpg



Rear Cargo Organization

After driving around with tons of recovery, repair, camping, and survival cargo rolling around in the back, I took a note from other expedition vehicles I had seen.  The only word to properly describe these vehicles was organized.  I realized I needed to start taking steps in the proper direction.

I loosely followed the designs I had seen, including a fellow TrailVoy member's own design.  Wanting to retain use of the storage tub in the bottom of the rear deck, I made the drawer half-size.  This allowed the drawer to be big enough to fit my gear cases, yet allow me to fit taller pieces of cargo when necessary by removing the drawer entirely.  To remove the drawer itself only takes minutes.

I used retaining pins that can hold the drawer in during transport, or out when accessing the contents.  The top is equipped with tie-down locations for securing cargo, and there is a cavity between the rear seat and the drawer where future electrical components will be mounted.



Underbody Protection - by Skidplate Mafia

When you rely on your vehicle to get you out of the forest, protecting the moving parts of the vehicle is of utmost importance.  The TrailBlazer is severely lacking in this manner of protection.  The stock vehicle can come with a few options for skid plates which are discussed at length on

With these plates being plastic, they provide little protection in real off road situations.  The radiator skid, which is metal, does not protect the radiator from moving backwards once hitting a rock.  This can bind up the fan and has proven detrimental in some circumstances.

There are four main possible areas for protection: the radiator, the oil pan, the gas tank/transfer case area, and the differential.

Oil Pan
Thanks to Mike Barton (bartonmd), the stock plastic oilpan skidplate has been replaced.  Mike manufactured a replacement, bolt-on aluminum plate.  Shown below (note the carnage to my old skidplate):

After installing the custom bumper (details below) I realized the radiator became very susceptible to damage by road or trail debris.  The lowest lip of the bumper left about 2" of the radiator end cap open to the road.  Being that the end cap is plastic, a rock in the right place would easily leave me stranded on the trail.  So after speaking with Mike Barton again, I designed an aluminum skid plate to span the distance between the IFS lower frame and the front bumper.

The differential is something that is rarely considered something that needs more protection.  While the axle housing is quite stout, the differential cover is somewhat susceptible to damage.  The cover could be dented or bent at an edge by a rock (or other foreign object), which may allow fluid to leak out.  A good cover reinforces the lower mounting flange of the diff cover (where it may get bent by a rock sliding by), and also protects the center of the cover (where it's more likely to get dented).  The cover I purchased was made by Purple Cranium, called the Spider.



Custom Switch Panel

After having mounted multiple lights on the vehicle, I needed a solid way to mount the associated switches.  I found one area that was unused, out of the way, and discreet.  The problem is that it did not have a mountable surface.  So to fix that I modeled my own switch panel.  Follow the link to Trailvoy for more pictures of the construction.



Stream Crossing Preparation

The trailblazer is a decent vehicle for stream crossings.  Most vents are located at a decent level when stock.  The lowest vent that I am aware of is the rear differential vent, which is located at about 20" when stock.  It is located above your spare tire.  With a few minor changes (as discussed in the link to the right) I was able to increase the height to 33".  The mechanical fan in the front of the vehicle can also be stopped with a quick de-snap of an electrical connector.  This will keep the fan from throwing water all over the engine bay.

I feel safe in anything up to the middle of the bumper, however I am still wary about water ingestion in the engine.  For this, a member of the forum is working on modifying an Xterra snorkel for our use.  Check the off-road section of for updates.



Rear Spare Tire Carrier - by CBI Offroad Fab

The trailblazer's under trunk spare tire system cannot fit tires that are bigger than the stock size.  So, that leaves us with two options.  The roof, or a custom rear carrier.  I found a great product made by CBI Offroad Fab to take care of that issue.  Click the link above for detailed pictures and discussion.

I had a few particular things I was looking for. First was a pass-through receiver, so that I can use a receiver shackle mount for the rear. Second was a hi-lift mount. In addition, I didn't want wobble, I wanted to be able to see out my rear view mirror, and I wanted to be able to open the glass without having to swing down the carrier. Lots of stipulations, I know.  Steve was able to produce a great product.



Roof Cargo Rack - by BajaRack

I decided to get a roof rack for the TrailBlazer due to a few key factors.  First of all, I wanted to carry spare fuel.  I also wanted to be able to strap my mountain bike to the roof (now that my rear was being used by the spare tire).  Lastly, so I could use the rear seats to transport people if necessary.  (I've always wanted to be able to bring a group of 4 camping.  Before the rack, I had to carry cargo in the rear seats.)

I was looking for something that was solid, lightweight, and aerodynamic.  BajaRack fit the bill with the Mule.  It is a welded carbon steel construction with a powdercoat finish and aluminum wind faring.  I designed aluminum support bars for the rack that bolt into my roof rails.  This makes for an incredibly strong platform.  However, due to the simplistic mounts and the light weight of the rack, I am able to remove it or install it in under three minutes.  This makes for a strong and versatile setup.

To fit my bike, I worked up my own mount using a DeltaCycle Bike Hitch and some U bolts.  So far it's worked perfectly.



Rock Sliders - by FTF (Freaky Tree Fab)

I sprung for rock sliders due to the increasingly difficult trails that I find myself on.  Rock sliders act both as protection and as a tool for traversing obstacles that are taller than your underbody clearance.

I contacted Freaky Tree Fab ( about making some sliders.  He jumped at the opportunity and came up with a great design.  Take the link back to TrailVoy for in depth photos.  The sliders are made from 1 - 3/4" DOM tube.  Instead of bolts, we decided to weld directly to the frame.  Gussets were added to increase the rigidity.

I contemplated different coatings, including line-x, powdercoating, and rattle canning.  I had seen some other people have good luck with powdercoats lasting a few good rock bashes, and decided to follow suit.  I'm glad I did, as the powdercoat has been extremely tough.

Eric at FTF is currently selling these for anyone interested.  Contact him or follow the link to TrailVoy for cost details.



Custom Steel Bumper - by FTF (Freaky Tree Fab) and KMA (Kennesaw Mountain Accessories)

I decided I needed a full metal bumper for a few reasons:

- To provide better recovery points for heavy recoveries
- Obtain a better approach angle and frontal clearance
- Mount new fog lights that would provide better light in poor visibility conditions
- Provide a method of mounting a removable winch
- Protect the front-end of the vehicle from collisions

The bumper originated as a Kennesaw Mountain bumper.  I liked their overall design, but I didn't like some of the details, such as the fender hangover, and their brush guard design.  So I had my fabricator with FTF fix it exactly to my liking (notice the resemblance to both the WAAG brush guard and my sketch on the future modifications page?).  Follow the jump to Trailvoy for more detailed pictures and a glimpse into the making of the bumper.