Richard L. Parish | 2/17/2007 2:30:19 AM
If you have frequent flat tires on tractors, implements, or other off-road equipment you might want to consider using a tire sealant.
Mode of Action: Most of the tire sealants currently available are liquid formulations that are pumped into a deflated or partially deflated tire. The sealant coats the interior of the tire, and the excess puddles in the tire. If the tire is punctured, escaping air carries the viscous sealant out through the hole, where the sealant fibers soon create a plug. Driving with the punctured tire allows the sealant to flow into and plug the hole.
Effectiveness: Some of the tire sealants do work very well. During the cleanup effort after hurricanes Katrina and Rita, numerous flat tires were experienced at one of our experiment stations due to sharp metal debris. After the tractor, trailer and equipment tires were equipped with a sealant, flat tires no longer occurred. In our situation, the sealant was 100% effective.
Installation: The sealants are a viscous liquid that may contain fibers. In most cases, the material is pumped into the tire through the valve stem opening while a jack supports the weight of the vehicle or implement. Special pumps to fit 5-gallon buckets of sealant are common, but the materials are also available in smaller and larger containers with different pumps. It is important to put the correct amount of sealant into each size of tire. The manufacturers offer charts telling you how many ounces are needed per tire. The better manufacturers provide a very detailed table listing most tire sizes (click here for an example); other companies just give a general figure for “automotive” or “ATV” tires and don’t give you a way to adjust the quantity for actual tire size. You may be surprised at how much of the material is needed for a large tire. For example, one brand requires 174 oz. of sealant for a 12.4-28 tractor tire (a common size on compact tractors). Putting in less material than recommended will limit efficacy. Be aware that there are different formulations for tires with and without liquid ballast, and the recommended amounts are different, too. Use the proper formulation and the appropriate quantity for that formulation.
If a Tire Is Punctured: If you find a nail or other object stuck in a tire, you should remove the nail immediately and drive the machine for several minutes to allow the sealant to flow into the puncture and seal it.
Limitations: One caveat is that some of these sealants work only with tubeless tires; they cannot be used with tube-type tires. Other brands claim to work with tube-type tires. Some of the sealants described here should not be used in highway tires; if the sealant puddles in the bottom of the tire, it may cause unbalance in the tire at highway speeds.