Tire Ballast 

   
 
 

Adding ballast to the front tires is a cheap and easy way to make a buggy climb better as long as you are willing to put up with a few tradeoffs. Typical ballast material is either water or metal shot,  I have always used water, the metal shot was first done on competition rigs to avoid spilling fluids on the courses (which would result in a penalty).  Metal shot is much harder to get in and out of the tires so I won't be covering how that is done.

What are the benefits?

Adding water to the tires results in adding weight below the axle centerline which is the best possible place to add weight to a buggy. The added weight will noticeably lower the center of gravity of the rig which makes the rig more stable.  Traction is also effected thanks to the extra weight on the tire contact patch. Lastly the weight in the tire will help pull it down when you are climbing steep obstacles. A great place to demonstrate the benefits to climbing is the large waterfall on Collateral Damage.  Without water in the front tires I cannot crawl the fall as my front tires lift if I stay far to the left.  With approximately 150lbs of water per front tire the rig easily crawled the fall as the front tires never lost contact with the top of the fall.  For reference each gallon of water adds approximately  8.3lbs of ballast

How do you get the water in the tires?

It's much easier than you think.  While there are fancy valves you can buy at tractor supply stores I learned that a typical rubber washing machine makes for a great low buck alternative. Here's how I fill my tires:

1.  Pull the valve core and empty all the air from the tire.

2.  While the tire is deflating, jack up the axle so the tire can be rotated.

3.  Take the rubber washing machine hose and attach one end to a garden hose.  Cut the other end off and slide it over the deflated tires valve stem and secure it using a hose clamp.

4.  Use a pair of vice grips to pinch off the washing machine hose (this will be your on/off switch).

5.  Rotate the tire so the valve stem is at the level you want the tire to be filled to.  So if you want the tire filled halfway, rotate the valve stem so it is at the 9 o'clock position.

6.  Turn on the water supply and remove the vice grips.  You should hear the water rushing into the tire. When the water level reaches the valve stem the water rushing sound will go quiet, that is your signal to clamp the hose off with the vice grips.

7.  Rotate the tire so the valve stem is higher than the water level.  With your valve core & core installation tool ready in one hand, remove the washing machine hose from the valve stem and quickly install the valve core.

8.  Adjust the air pressure (always do this with the valve stem above the water level).  

9.  Go back to step one and do the other tire.

How much water should I put in the tires?

I'd go at least halfway.  On a 40" tire this equates to about 150lbs of water.  If you fill it any less than that the water will slosh around and cause a lot of vibrations. With my tires filled halfway I can go about 50mph before I experience vibrations.

How do I empty the tires?

You have to pull one of the beads off and dump the water out so if you don't have beadlocks I wouldn't recommend adding water to the tires.  If you have beadlocks you can just pop off the ring and turn the tire over which will drain most of the water.  Then a shop vac or towel can be used to suck/soak up the remaining water. 

Note - If you want to adjust the water downwards you can rotate the tire so the valve stem is at the new desired water level and pull the valve core.  Obviously the lowest you can get the water is to the bottom of the rim with this method.

Should I put water in the rear tires?

Filling the rear tires will make the rig much more stable but I don't believe it buys you much as far as climbing performance. I wouldn't recommend it.

What are the downsides?

1. The extra weight takes more power to move.  In my experience an extra 300lbs really puts the hurt on a 4 cylinders performance. 

2.  You will experience vibrations when driving at speed.  How much vibration is determined by how high the tires are filled, a higher fill level usually experiences less vibrations.

3.  The added vibrations will loosen stuff up.  Be prepared to go over the rig regularly looking for loose bolts.

4. The added weight puts a lot of strain on the drive train.  I'd recommend only doing this if you run upgraded alloy axles or if you have ample stock spares.

5. You may loose the inner bead more often.  The water tends to lubricate the bead seat so if you have problems maintaining  the inner bead without water, it's going to become even more of a problem.

6. Tire changes are now a 2 man job.

7. Beware if you live in a cold climate.  You will need to get some anti-freeze in the tire along with the water to keep it from turning into a large chunck of ice.

Conclusion

So there you have it. This is an easy modification to do and provides a noticeable improvement in your rigs capabilities as long as you are willing to put up with the downsides.