Real smooth movers
In the quest to perfect sport motorcycles, BMW partnered with Cellasto to craft a unique solution to the BMW K-series cardan shaft, just in time for spring roll-out, leaving customers enthusiastic about the improvements.
In future, Cellasto absorbers in the cardan shafts of BMW motorcycles will eliminate loud impact booms and that annoying bucking during gear changes
Motorcyclists not only enjoy a more emotional driving experience than car drivers, they also have a stronger rapport with their brand. And on the whole, they seem to be more interested in technical details, such as whether a bike is a tourer or a racer, with two or four cylinders and a chain or cardan drive shaft.
The classic image of a BMW motorcycle is a bike that's solid, with a powerful engine mount, high-quality manufacturing, performing well over thousands of miles with a cardan shaft drive instead of a chain. It's not flashy, like Japanese bikes, but you can't mistake that it's a BMW. Over the last few years, the company has brought out new models with chain drives to appeal to a younger target audience. But despite this, BMW has still remained at the top end of the motorcycle market and you expect to pay more in return for greater reliability, technical brilliance, greater driving pleasure and technical features such as the cardan drive draft instead of the conventional chain.
The new wave in cardan shafts
The cardan drive shaft has always had a distinct advantage over the chain drive when it comes to maintenance. But it also had some disadvantages. For instance, the way the gear hammer behaved in the shaft and the impact noises during gear changes had a noticeable influence on drive dynamics and general travelling comfort. And these were in need of improvement to do justice to BMW's reputation as a premier supplier.
The previous cardan shaft drive was manufactured by the company Willi Elbe Gelenkwellen GmbH and had a rubber absorber. And it was this, in particular, that was targeted for detailed improvement. To keep the changeover costs low, any improvements had to use the limited installation space of the old cardan drive shafts. So BMW and ELASTOGRAN hit on the idea of using Cellasto® as a solution and considered whether it would offer advantages over rubber. The goal was to suppress impact noises during gear changes and improve gear hammer behaviour to eliminate the "constant bucking", a better pass-through when accelerating, a highly serviceable life span as well as the conservation of upstream and downstream components. In other words, this would be a whole catalogue of demands, for which there was already a very clear and conclusive answer: Cellasto.
Cellasto gives a more comfortable ride
Firstly, the intermediate shaft between the universal joints was completely redesigned. An internal shaft now rests on an outer one — both have long teeth, which similarly grasp like a cogwheel into one another. Between these, there are striated Cellasto components, which are manufactured directly by ELASTOGRAN. A certain torque twisting angle, characteristic of the cardan drive shaft, is closed down by the flexible and absorbing characteristics of these components. The Cellasto components help to drastically reduce the gear hammer reactions and help suppress the noise during gear changes. In addition, between the inner and outer shaft, absorption is carried out by synthetic panels, which also suppress annoying gear change noises.
No noise, no bucking, just sheer driving pleasure
This change in the cardan drive shaft best suits the new K-series. In particular, models K1300S, K1300R and K1300GT, which are heavy, sporty machines with highperformance Four-cylinder engines and high technical demand. These have been equipped with the new drive shaft since March 2009, just in time for the beginning of the season. And feedback from forums and motorcycle magazines show that customers are extremely satisfied with the reduced gear change noise and the optimised gear hammer behaviour. Switching from rubber to Cellasto has noticeable benefits for motorcyclists: The volumecompressibility and slight lateral strain during compressive load both help the shaft work better in the limited installation space; the very high degree of fatigue limit during compressive load improves the shaft's life span and gives a progressive characteristic line for better co-ordination. Improvements that make BMW motorcycles real smooth movers and give their fans the ultimate driving pleasure.
The new ESA II
|Electronic Suspension Adjustment; upon request, electronically adjustable chassis now available. With this the spring rate, therefore the rigidity, can be changed on the rear suspension strut. This is carried out by means of the Cellasto® component, where the variable expansion clearance varies the spring rate and so prevents the tail sinking even during severe loading.|