Ever since the Lotus élan S1 was released to the public in the early 1960s, it soon became apparent that the drive line would not stand up to vigorous driving habits, many stories abound of the intrepid élan driver stranded miles from the workshop with a broken rubber donut or metalastic joint, and changing a donut by the road side is not the way to spend time with your lady friend in the lotus élan… no sireee.
Several different driveline replacement alternatives to the donut have been produced, some have offered a half & half deal, where a universal joint was used in conjunction with a donut, the thinking behind this idea is that the donut provided a cushioning effect within the driveline, while in theory the idea is sound, the system was still prone to failure.
Another idea put forward was to use two universal joints and a sliding splined yoke to replace the rubber donuts on each half shaft, in the beginning this seemed to be an ideal solution, but unfortunately because of their design, the sliding splines will lock under certain conditions, and universal joints also produce variations in rotational speeds, i.e. they accelerate and decelerate momentarily on every rotation, the phenomena is known as “cyclic variations In speed” it is unique to universal joints when they operate at more than a few degrees off the centre line which, they of course would be subject to when employed in the rear drive line of a lotus élan, the movement in the rear suspension travel will produce several degrees of movement on both bump & rebound. The moments of cyclic variation occur only for milliseconds, but the phenomena can prove to be unsatisfactory in the driveline of a lotus élan.
The Constant Velocity joint is designed so that when the angle of drive varies, the balls are always positioned at the midway point inside the joint. This eliminates the cyclic variations in speed mentioned above that a universal joint produces when operating a few degrees off-centre, if the angle of operation extends to far, the UJs will have a tendency to lock up.
A rubber boot, which keeps the grease in, and contaminants out, protects the constant Velocity (CV) joints. CV joints require only periodic maintenance or greasing, they are engineered to last 100,000 miles (160,000Km) or more.
The initial cost of converting a Lotus élan to a CV driveline system is high, but the initial cost is totally offset by the long-term in servicing and replacement of donuts.
The elantrikbits CV drive shaft system produces 100% reliability, because the system is well designed and is known to give many trouble free years of service.
Another major factor to consider when installing a solid CV drive shaft in a lotus élan is the ease of fitting, a well designed system will only require the removal of the old intermediate drive shafts and donuts, the new system is simply offered up to the inner and outer drive flanges, normal spanners and tools are all that should be required to tension up the high tensile fasteners.
If the drive shaft kit you are considering requires anything other than normal workshop tools to install, and requires dismantling of the rear suspension of your élan, the overall cost of installation will be much higher than just the initial purchase cost, due to having to pay for the services of a professional installation mechanic.