GKN has launched the new ballspline sideshaft, which pairs excellent off-road characteristics with safe handling on the road.

GKN say that most sport utility vehicles (SUVs) are almost never used off-road. What SUV drivers expect is the same level of dynamic on-road handling and comfort as a saloon car. Because these weighty vehicles have an inherently large ground clearance and thus a higher centre of gravity, they present major challenges when it comes to designing their running gear and are dependent upon long suspension travel.

SUV development engineers were previously often forced to accept compromises in order to combine good off-road characteristics with car-like handling as the sideshafts available permitted only limited wheel movement, often at the cost of ride comfort. The GKN ballspline driveshaft now delivers outstanding plunge length of up to 70 mm. This substantial movement is facilitated by linear ball bearings with the balls running in multiple deeply cut profiles thus enabling axial displacement of the sideshaft.

The new ballspline has major benefits, especially for use in SUVs: The high ground clearance often requires installation angles of ten degrees and more, a configuration factor that restricts the scope for long suspension travel even further. The new ballspline sideshafts solve this problem for SUV suspension engineers as they can now combine wide installation angles with long suspension travel.

Ballspline sideshafts are easy to recognise from their characteristic shape as the displacement mechanism requires different diameters along the shaft. A prerequisite for continued reliable function of this complex design is an exceptionally high level of manufacturing precision as it is vital for safe driving that there is absolutely no play in the axial displacement, otherwise suspension response will not be good enough, which will, in turn, compromise road holding. For this reason, only top-quality materials are considered for the manufacturing ballsplines. They facilitate quiet running and high torque transfer.

GKN developed its ballspline sideshafts for OE SUV applications and is now also offering them to exactly the same quality in its aftermarket programme.