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Project Tundra: Leveling it out with a Hellwig Big Wig Air Lift

by Mike Kojima

In the last edition of Project Tundra, we had installed Hellwig's adjustable rear antisway bar in an effort to improve our truck's balance and limit body body roll to help keep our stability control from activating prematurely. 

Now to finish up our chassis tuning we wanted to address a problem all trucks that tow have. With tongue weight in place the back of a trucks sags lower and the front lifts higher.  This makes the handling a little squirrely at times, the steering getting light a lot due to the geometry changes of the front end when under droop. The heavily loaded rear suspension is also prone to bottom out with bigger enclosed trailers which can make things interesting and possibly damage the trailer jack.

To fix this by leveling out our truck without hurting our ride, we decided to go with a set of Hellwig Big Wig air bags.  The air bags can increase the rear suspension's capacity by 2700 lbs and restore the proper ride height improving stability and laden ride.  When finished towing, the bags can be depressurized for a stock ride height. and smooth ride.

The air bags can also be used for chassis tuning by increasing the rear spring rate to reduce understeer.  This is handy if you are autocrossing your 4X4 tow truck or want to make the stability control less active!

To Read More about Project Tundra click here!

The Hellwig Big Wig airbag kit uses these heavy duty air springs and stamped steel brackets to mount them on your truck's axle and chassis.  The brackets are application specific to make installation an easy bolt on operation.
The Hellwig Big Wig air spring is large in diameter with a big air volume.  This makes the air spring more progressive for a smoother ride.  You can also get more lift at a lower air pressure which also means a smoother ride while loaded.  The pleated construction means the bag will not be damaged when running at lower pressure like simple single bag system can.
To keep our system totally self contained and easily adjustable we got Hellwig's high duty cycle compressor system.  This allows us to adjust our air springs easily on the fly without having to stop at a gas station.  This is very convenient for ad hoc suspension tuning and even things like connecting and uncoupling your trailer ball.
Most of Hellwig's compressor systems are plug and play but they did not make a plug and play system for a Tundra so we decided to modify the system from a Chevy Silverado because the brackets for the compressor and air tank looked like they might work.
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Comments
8695Beaters
8695Beaterslink
Monday, April 13, 2015 6:30 AM
>>Project Tundra Rallying. I see a new "Keep Racing Fun" article in the making...

I wanted to autocross my Vehicross, but the local SCCA here in KY wouldn't let me! Even though it has super heavy springs and is relatively low for an SUV. Oh well. Mike, if you do autocross the Tundra, you absolutely have to show it to us. Sounds like a riot.

With all of these upgrades, are you still staying in the factory tow ratings when you tow? Or since you have more headroom with power, brakes, and traction, are you towing more weight than recommended? Curious what an experienced Engineer's take on this is, since all the forum boys shriek bloody murder when you suggest towing over what the OEM or SAE rates.
ED9man
ED9manlink
Monday, April 13, 2015 7:52 AM
What's even worse is trying to tow anything with a car. Identical models in Europe are rated for 2-3x what they are in the US. You can still go by the European ratings, but if anything happens I'm sure that the police and your insurance won't care that the tow rating is higher in Europe.
Shane Laake
Shane Laakelink
Monday, April 13, 2015 10:23 AM
A nice summary of US vs Euro ratings:

http://oppositelock.jalopnik.com/tow-me-down-1609112611

Different roads, driving styles, and priorities, but the physics is the same. Towing with a car is far easier at 35mph vs 70+mph, which is why you'll see a VW Golf with a caravan in Europe.

Enjoying the articles btw!
Mike Kojima
Mike Kojimalink
Monday, April 13, 2015 11:17 AM
I am well under the trucks tow rating. I did tow for many years with my modded DW21 Pathfinder that was only rated for 3000 lbs. That was actually pretty scary. I don't recommend it. The Tundra tows my open trailer and race car like it's not even back there.
Hydrolastic
Hydrolasticlink
Tuesday, April 14, 2015 9:41 AM
The Brits love to go camping. Living in the UK for a few years it was very common to see small cars tow huge trailers/caravans down the freeway at 60mph. Even on the farm roads they'd still drive them at freeway speeds.
Supercharged111
Supercharged111link
Wednesday, April 15, 2015 9:03 AM
Mike are you able to get away without a weight distribution hitch on an enclosed trailer? Regardless of what I do with my back, my front lifts too much so the only safe way for me to drag an 8,000# box is with the bars. On a side note, I totally forgot about a rake's effect on front end caster. I definitely gain a little when I tow and my front is only about 1/4" higher that when empty. I remember the days of an open deck and only mildly impacted fuel economy. . .
Mike Kojima
Mike Kojimalink
Wednesday, April 15, 2015 9:25 AM
I only occasionally tow an enclosed trailer and when I do it's not a big one so it's not a problem at all. Before the bags it was nose high for sure though.
Matt Rothwell
Matt Rothwelllink
Thursday, April 16, 2015 7:22 AM
I'm loving this series of articles on the modification of the Tundra! I've got a Toyota Tacoma that I bought after selling my E90 BMW. I wanted to worry less about driving on dirt and gravel roads, I wanted to be able to tow things and I wanted to be able to haul stuff. Unfortunately, the Tacoma does not handle like a BMW. With that said, people have been making solid rear axle vehicles handle well for decades, and the Tacoma actually has a pretty well setup front end for on-road handling. The rear suspension…not so much.

Now that you've got your airbags installed, have you given any thought to a 3 or 4 bar rear suspension? It would require some fabrication, but you've got access to everything you need to design and install it. You could run the lower links to brackets welded onto the frame, and run the top link between the drive shaft and the exhaust on the passenger side. Panhard bar could go over top of sway bar. Benefits would be better ride, better handling, better hauling, more adjustable roll control by messing with the roll center, and adjustable anti-squat. I don’t think you’d give much up either.
Mike Kojima
Mike Kojimalink
Thursday, April 16, 2015 9:04 AM
It's our work truck so no we won't be doing this! The Tundra actually rides extremely smoothly.
Matt Rothwell
Matt Rothwelllink
Thursday, April 16, 2015 10:09 AM
But it could be an work truck that handles AMAZING!
Mike Kojima
Mike Kojimalink
Thursday, April 16, 2015 11:37 AM
It handles pretty well as is for a jacked up 4x4.
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