Rear gearshift mechanism for coaxial installation
A bicycle gearshift mechanism has a base element, a pivot mechanism, a movable element, and a chain guide arrangement. The pivot mechanism connects the base element to the movable element. The chain guide arrangement is connected, rotatably about a rotary axle, to the movable element. The base element comprises a first attachment end, which is coaxial with respect to the rear-wheel axle or axis, and a second attachment end for coupling to the pivot mechanism.
1. A method of installing a rear gearshift mechanism on a bicycle, comprising:
pre-installing the rear gearshift mechanism on a frame of the bicycle by a base member of the rear gearshift mechanism and an adapter, wherein the adapter and the base member are pre-positioned, but not tightened, relative to the frame in an axial and a radial direction, and the adapter and the base member are rotatable relative to the frame about a rear-wheel axis;
after pre-installation, positioning a rear wheel with a hub arrangement in the frame; and
after inserting the rear-wheel, partially screwing in a plug-in axle, but not fully tightened, such that the rear gearshift mechanism can still rotate about the rear-wheel axis.
2. The method of claim 1 , wherein pre-installing the rear gearshift mechanism includes the base member engaging around a right-hand dropout of the frame, and the adapter being inserted and tightened to a frame opening and at least one centring opening in the base member.
3. The method of claim 2 , wherein the adapter is tightened to such an extent that it is held together with the base member and is still rotatable on the frame.
4. The method of claim 1 , wherein the adapter includes a bolt and nut, the bolt at least partially rotates with the nut in a clockwise direction relative to the base member until at least one stop of the nut strikes at least one counterpart stop of the base member.
5. The method of claim 4 , further comprising:
inserting a chain;
after inserting the chain, tightening the adapter; and
after inserting the chain, tightening the plug-in axle.
6. The method of claim 5 , wherein, the rear gearshift mechanism is driven along until the chain is tensioned, and in the tensioned position both the base member and the nut are fixed such that the bolt is screwed into an internal thread of the nut until the adapter has been tightened against the frame.
7. The method of claim 6 , wherein a setting aid is used to fix a chain guide, which is rotatable about a rotary axle, in a particular angular position and predefines the desired spacing between an upper chain roller and a reference pinion.
8. The method of claim 7 , further comprising:
shifting the rear gearshift mechanism into a reference gear ratio or onto a reference pinion.
9. The method of claim 8 , further comprising:
arresting the chain guide using the setting aid.
10. The method of claim 9 , after the plug-in axle is tightened, the method further comprising:
releasing the chain guide using the setting aid.
11. The method of claim 4 , wherein tightening the plug-in axle causes an inner arm to be clamped between a hub end cap and the adapter, causing the inner arm and the base member to be oriented orthogonally with respect to at least one of the hub end cap or the rear-wheel axle.
12. The method of claim 11 , wherein when the plug-in axle has been tightened, the base member is rotationally fixed relative to the frame.