How to measure Trailer Leaf Springs

Measuring Trailer Springs Are you thinking about replacing your boat, caravan  or trailer springs and want to make sure you order the correct ones? Following are some tips on how to properly measure trailer springs, to help make sure you get it correct the first time.

 

Step 1:

DETERMINE THE TYPE OF TRAILER SPRING 

Double Eye Spring Double Eye Spring
Slipper Spring - Open Eye Slipper Spring - Open Eye
Slipper Spring - Radius End Slipper Spring - Radius End
Slipper Spring - Flat End Slipper Spring - Flat End
Slipper Spring - Hook End Slipper Spring - Hook End

 

Accurately measuring your trailer springs and choosing the correct replacements is important for the function of your trailer and will make the job of replacing them much easier. Using replacement trailer springs with the correct length will keep the axle in the same position, eliminating the need to move guards or suspension components like spring hangers. Matching your weight capacity, arch, and leaf count will keep the ride height of the trailer the same and keep the ride characteristics the same. 

 

Step 2:

MEASURE THE WIDTH OF THE TRAILER SPRING

Measure the width of the spring. The majority of trailer springs for boat, motorcycle, horse, camping, flatbed, and utility trailers are 45mm wide.  To determine the width, simply measure along the center of the top leaf. Measure the Width

 

Step 3:

MEASURE THE LENGTH OF THE TRAILER LEAF SPRING

Measure the length Measure the length of the trailer leaf spring. If you are replacing a spring, getting the same length is important. To measure the free length, refer to letter “C” above. It is important that your trailer is unloaded when measuring the length. When determining length (C), measure from the center of one spring eye to the center of the other spring eye for double eye trailer springs. Measurements will vary depending on the age and fatigue of your spring. We offer a large selection of trailer springs. Determining the length first will narrow your selection down considerably and make finding the correct spring quicker.

 

Step 4:

DETERMINE THE CAPACITY OF THE SPRINGS

Determine the rating of your trailer axle and then select the capacity of your springs. If you have a 1500 Kg. rated trailer axle with two springs, you will use two 750 Kg. rated trailer springs or higher. Please note, the capacity ratings are for each individual trailer spring.

Once you have determined the capacity, and number of springs, count the number of steel leafs your current springs have. If you are replacing all of your springs, the number of leafs will not be as important. You can switch from a 4 leaf to a 3 leaf trailer spring with thicker steel if you prefer.		 Spring Count

 

Step 5:

MEASURE FREE OPEN AND ARC OF THE TRAILER SPRING

Measuring Trailer Spring Arc Measure the free open (H) and the arc (A) and (B) of the trailer spring. These measurements are more for reference and will change with the age and fatigue of your spring. These measurements can show you the importance of replacing all of your springs rather than one at a time. If you have an older spring that has lost its arc over time and you add one new spring with a taller arc to the other side of your trailer, your trailer will lean to one side causing for an uneven load and unsafe conditions.

 

NOTE:

CHANGE SPRINGS IN PAIRS

All trailer springs are sold individually, but it is highly recommended to change them in pairs. Changing only one spring may cause your trailer to lean to one side due to the spring fatigue of the unchanged spring(s).