The "calculator" linked to this page was developed to estimate the total load on a slip-on fire truck prior to fabrication. It requires the input of accurate information that you, the designer, must obtain. Your reward for doing this "homework" will be the reduction of costly design errors and the likelihood of a well balanced truck. You will need to enter good numbers into the calculator. This discussion will help you determine the numbers.

If you have not read the REC booklet, Guidelines for Designing Wildland Fire Engines, please do so before calculating. An on-line version is available by clicking here. Guidelines provides background information and definitions that will aid the user.

The vehicle manufacturer or dealer can provide you with the pick-up truck's Gross Vehicle Weight Rating (GVWR) and each Gross Axle Weight Rating (GAWR). This  information is often found a data plate on a door or door jam.   Military vehicles will have this data on a dash plate.

In this section, you will enter weights of major objects that you place in the vehicle. Estimate the horizontal distance between the object’s CG and the center line of the front axle. Click here to see a diagram that helps describe this.

Important: This is a simplified version of our "Wildland Engine Weight Calculator" It only considers adding items that will be behind the front axle.   If your slip-on unit will have components added in front of the front axle, please use the other calculator.

After checking that your entries are correct, click the "Calculate" button. The estimated weight of the completed truck and the weight on each axle will appear. The results will also display the estimated percentage of the weight on each axle and the percentage of the payload on each axle. A dialog box will give a general statement of what the results mean. It might recommend that you make some changes. Use "Reset" to start over.

Considerable effort has been made to make this "calculator" accurate and easy to use. The better the information you enter, the better your estimate. However, it is your responsibility to determine the accuracy of the results. Your final check for accuracy should be to weigh the completed vehicle with water, all equipment and occupants to see that it does not exceed the manufacturer’s GVWR or GAWRs.

User's Pledge: I have read the instructions and understand that the "calculator’s" accuracy depends on my understanding of vehicle design principles and accurate input of the data asked. The interpretation of the results and decisions about their accuracy are my responsibility. I am willing to take this responsibility and use the "Slip-on Engine Weight Calculator".