| In was in the early 1900's that the hirth | | | | |
| joint or hirth coupling was born, from the | | | | No need for external flanges or bushings thus |
| tinkering of Hellmuth Hirth, the young son of | | | | less rotational mass, greater pedal |
| a German engineer. He was fascinated with | | | | efficiency and smoother riding. |
| developing new and emerging technologies for | | | | |
| the maiden aircraft industry. Hellmuth | | | | External bearings can now be mounted on the |
| developed the hirth coupling as a high | | | | half spindles leaving the entire |
| strength locking joint used initially to | | | | circumference of the bottom bracket shell |
| connect two ends of a shaft, in gasoline | | | | available for a larger hollow spindle. This |
| engine crankshafts. | | | | larger spindle makes the drivetrain more |
| | | | rigid. |
| It looks like a set of teeth milled on the | | | | |
| end profile of each half shaft. They mesh | | | | The Campagnolo crank arms can be fused to |
| together in a self centering and self | | | | each half axle, so no pinch bolts are |
| aligning locking joint. The amazing | | | | necessary for crank attachment. This reduces |
| engineering of the Hirth coupling is that it | | | | the weight making the ultra-torque the |
| offers such a high strength connection on | | | | lightest crankset in the industry. |
| such relatively small diameter shafts. It has | | | | |
| since been used for reversing gears in marine | | | | The final benefit of using a hirth joint in |
| applications and cooling water pumps in | | | | the ultra torque crankset is that Campagnolo |
| almost every sector including automotive, | | | | can promote themselves as having THE most |
| rail and nuclear. | | | | easily installed crankset in the industry. |
| | | | With traditional tools the cups can be |
| Thus it is not surprising that Campagnolo was | | | | inserted followed by the half axles and a |
| interested in using such a proven piece of | | | | 10mm bolt to hold it all in place. |
| technology in their newest cranksets designs. | | | | |
| It has a long history of testing for strength | | | | Certainly this particular Campagnolo |
| and reliability in the most extreme | | | | component has taken technological |
| environments from marine to nuclear energy. | | | | sophistication to the limit offering cycling |
| | | | enthusiast something to talk about. At these |
| Advantages of Using the Hirth Coupling in the | | | | is further information about Campagnolo's |
| Campagnolo Crankset Design: | | | | bicycle parts innovations including the scoop |
| | | | about their newest carbon fiber forming |
| The axle of the new Campagnolo Crankset can | | | | capabilities and new ceramic bearing bottom |
| be spliced in the middle of the bottom | | | | brackets. |
| bracket shell | | | | |