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August 2007 4x4 Tech Questions - Tech Line

Willie Worthy | Writer
Posted August 1, 2007

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Question: In Techline (Jan. '07) there was a question about the use of nitrogen in tires. I am a heavy equipment mechanic, and mining companies use nitrogen in tires of the equipment to starve fires of oxygen during equipment fires. This could be the case why race cars are running nitrogen.
Tim Blossom
via fourwheeler.com

Answer: A Interesting thought, and thanks for your input. However, race cars use nitrogen in the tires not because of fires. If you think for a minute, there is a lot more O2 in the air surrounding the tire than in it, especially if the tire should go flat. The reason they use nitrogen is that it is a pure gas that has no other natural "additives" in it like air has.

The biggest problem with air is moisture. As you well know, air compressors pick up great quantities of moisture during the compression cycle and easily transfer this moisture into the tire where it can, and will, cause an out-of-balance problem. Yes they have filters for the water, but why even mess with it when a pressurized container of nitrogen fills a tire so much faster? Overall, nitrogen I believe has larger molecules than O2 has, so it doesn't escape through the tire as easily and doesn't react with pressure changes as readily as air does.

Question: I have a '93 Ford Bronco 4x4. I was hoping to put a small suspension lift on it and it needs to be cheap. I was thinking 2 inches. I don't want a body lift. Would it be possible to just put a 2-inch spacer in the front coils and a 2-inch lift block in the rear leaves? Would I need to replace the shocks also? Would I need to purchase adjustable alignment bushings?

The suspension kits I've looked at are more expensive than buying just spacers and lift blocks, but they also come with shocks and whole new springs and drop brackets. Do I really need new springs and the other stuff that drives the cost up?

What would be the cheapest way for a 2-inch lift besides a body lift?
Donald Kiner
via fourwheeler.com

Answer: For your answer I went to Jim Cole, VP of Cage Off Road (866/587-CAGE, www.cageoffroad.com). Jim's specialty is Ford products, so I knew he would have a complete and very useful answer to your question. Here is what Jim had to say on the subject:

"This is a prime example of 'You get what you pay for'. Do it right and you'll love it; do it wrong and you'll be ready to sell the truck in short order because it won't steer correctly and the ride will be horrible, let alone the odd wear on the tires that will appear from it being out of alignment.

"In order to properly lift your TTB (Twin Traction Beam) suspension 2 inches, the bare minimum is going to be to use alignment cams on the ball joints and replace the shocks with longer versions (which most likely need to be replaced anyway if they have more than 35,000 miles on them). Keep in mind that most TTB suspensions need these cams with stock-height coils so there is a chance that after the spacers are installed that you won't be able to get it aligned without buying drop brackets anyway.

"Yes, it is possible to put a 2-inch spacer under the coil to achieve the lift, but make sure it is bolted in place as a TTB moves in multiple intersecting arcs during suspension travel, and you don't want it popping out with that lower location (I highly recommend a replacement coil for over 1 inch of TTB lift).

"Out back, the leaf springs can be lifted either via an add-a-leaf or a block. Since the vehicle is nearly 15 years old and Broncos tended to be a bit soft in back anyway, you may find the add-a-leaf a better way to go as it will give more arch to the springs and possibly won't lead to axlewrap issues like a block might. Again, new longer shocks should be installed. Better yet would be some brand-new spring packs, as add-a-leaves tend to ride stiffer.

"On some vehicles, a spacer lift works out great and is perfectly safe, and on a TTB, up to a 1-inch spacer works OK, but a 2-inch spacer is too high on a TTB suspension, in my opinion. In this case, and on this vehicle, I think you should ask yourself why you need the extra 2 inches of lift or if trimming sheetmetal (basically a free modification) would provide the clearance necessary. If you're after a taller suspension, then I highly recommend saving up a bit longer to come up with that extra few dollars to buy a complete kit to do it right. A complete kit will have new coil springs, the alignment cams or, more likely, drop brackets for the I-beams and radius arms, four new shocks and a rear add-a-leaf. This is true for kits up to roughly 4 inches of lift, as past that there are more things needed.

"As a side note, double-check the I-beam pivot bushings and the radius-arm bushings as these are almost always shot after 60,000 miles. Replacing them makes a big difference in maintaining alignment (something the TTB has issues with, especially if used off-pavement). Save for this extra bit and do it right and your Bronco will provide a much better ride, better performance and-most important of all-be safe for you and those driving around you."

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