This page contains a Flash digital edition of a book.
The Sprung Axle Versus Torsion Axle Tracks The Sprung Axle Versus Torsion Axle By Dexter Axle Company


Do a little research and you’ll find diehard fans for each axle option: torsion or sprung. But there isn’t a right or wrong answer – both have benefits and disadvantages. What’s most important is to make an educated decision on which option is best for your towing application. Let’s decipher the facts…


The Scoop on Sprung


Leaf spring axles are the most common axle type, especially in the industrial utility trailer and RV markets due to its affordability and ability to service the system. Leaf spring axles have curved metal leaves stacked on top of each other acting as the shock absorbers for the trailer. Because of the moving parts, leaf springs lend to a ride that is typically louder and rougher than a torsion axle.


Leaf spring suspension systems are more versatile than torsion, suitable for single, tandem, or triple applications in capacities ranging from 2,000 lb up to 27,500 lb. Springs are either double eye – where both ends of the spring are mounted to the frame with hangers, or slipper spring where one end is mounted and the other is allowed to “slip” or slide back and forth to cushion the ride. Double eye would be used in trailer applications 7K and under where slipper springs work well with higher weight capacities. Double eye generally rides a little more smoothly than slipper; but more moving parts means more maintenance.


Leaf springs can be mounted two ways – underslung, where the spring is mounted under the axle, or overslung, where the spring is mounted over the axle. Overslung is typically used when space


is limited between the bottom of the frame and the top of the trailer.


Spindles are offered in both straight and drop versions. This helps obtain different ride heights which are determined by the manufacturer. Leaf springs are less compact than torsion axles, which affects ride height.


While leaf springs will have more wear and tear because of the moving parts, replacement kits are readily available, (i.e. shackle straps, spring seats and hanging parts). Tandem, double eye applications can be enhanced with an equalizer system. It help absorb road shock and provide a smoother ride and longer fatigue life. Equalizers are typically available for quick install during manufacturing or as a replacement kit. This affordable option does not affect the overall ride height.


The Low Down on Torsion


Torsion axles are made with rubber cords (typically 4) inside an axle tube surrounding a solid inner bar. The rotation of the trailing arm attached to the inner bar compresses the rubber cords between the inner wall of the axle tube causing resistance. Various start angles are available for the trailing arm which helps to control trailer height. Torsion axles are mounted to the trailer frame with metal brackets. The system adds rigidity to the trailer frame reducing flex with cross wind or rough terrain. Torsion axles can also act as a cross member.


Because they are more compact than leaf springs, trailers with torsion axles are often lower to the ground. This lower center of gravity offers improved handling, especially cornering. This also makes torsion axles ideal for boat trailers where a lower trailer makes it easier to launch on shallow ramps. Torsion axles work best in fully loaded conditions and may not perform as well in extreme cold where the rubber is not as elastic.


Due to each torsion axle being independent, the trailer is not equalized, increasing the importance of towing the trailer level. This independent suspension will mitigate side-


Example of a spring axle. 70 March/April 2016 www.NATM.com


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80  |  Page 81  |  Page 82  |  Page 83  |  Page 84  |  Page 85  |  Page 86  |  Page 87  |  Page 88  |  Page 89  |  Page 90  |  Page 91  |  Page 92  |  Page 93  |  Page 94  |  Page 95  |  Page 96  |  Page 97  |  Page 98  |  Page 99  |  Page 100  |  Page 101  |  Page 102  |  Page 103  |  Page 104  |  Page 105  |  Page 106  |  Page 107  |  Page 108
Produced with Yudu - www.yudu.com