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Shimano Nexus und Alfine Acht-Gang-Naben: Unterschied zwischen den Versionen

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Die SG-8R20, SG-8R22 und SG-8R31 haben jeweils einfache Lager. Die SG-8R25, SG-8R27 und SG-8R45 haben jeweils Nadellager. Wie andere Modelle mit Rollengesperre an der linken Seite haben auch die Modelle SG-8R30, SG-8R31, SG-8R35 und SG-C6000 einfache Lager. Die Modelle the SG-8R36, SG-8R55, SG-8R56, SG-C6010 und SG-C6060 haben Nadellager. Alle Alfine Naben haben Getriebe mit [[Wälzlager]]n.
Die SG-8R20, SG-8R22 und SG-8R31 haben jeweils einfache Lager. Die SG-8R25, SG-8R27 und SG-8R45 haben jeweils Nadellager. Wie andere Modelle mit Rollengesperre an der linken Seite haben auch die Modelle SG-8R30, SG-8R31, SG-8R35 und SG-C6000 einfache Lager. Die Modelle the SG-8R36, SG-8R55, SG-8R56, SG-C6010 und SG-C6060 haben Nadellager. Alle Alfine Naben haben Getriebe mit [[Wälzlager]]n.


[[Datei:Drag-spring.png|left|Schleppfeder]]Eine Schleppfeder bringt weitere Aspekte und wird sogar bei manchen Modellen ohne [[Rücktrittbremse]] benutzt, um das Eingreifen des Rollegesperres zu verbessern. Bruce Dance meint dazu:


A drag spring raises additional issues, and is even used in some models without coaster brakes, to improve engagement of roller clutches. Reader Bruce Dance indicates:
The Alfine SG-S500-based models (hubs and wheelsets) have an 'A' and a 'B' version.  The 'A' versions are 'two-roller' internals, i.e. they use a pawl drive on the right-hand side (in 1-4) and the main (body center) roller clutch is preloaded by a drag spring that is set into the hub shell (as also found found in most of the coaster brake versions as well as Nexus hubs with pawl drive e.g., SG-8R25, SG-8R27).<br><br>(The image at the left shows the drag spring as it slips into the hub shell. The part number for the drag spring is the same for the Alfine as for some coaster brake hubs).<br><br>A difference in the SG-S500-A hubs (and some Nexus models) is that the roller retainer is castellated (has points which protrude to the left to engage the drag spring) whereas the Nexus SG-8R25, SG-8R27 (Rollerbrake/brakeless also, later coaster-brake and Alfine) hubs have no castellations on the roller retainer. Instead, there are protrusions on the carrier unit. The castellations, when present, are easily damaged.<br><br>A parts list for the SG-S500 'A' version formerly on the Paul Lange site (now in the Internet Archive) helpfully indicates compatibility with some Nexus 8 hub variants.<br><br>There is considerable compatibility between shells and internals provided the number of roller clutches is the same. However whilst you can usually fit a tension-spring preload clutch internal into one that was originally fitted with a drag spring, you do need to remove the drag spring. If you try to fit a drag-spring preload clutch internal into a hub shell that wasn't originally fitted with one, there usually is no place to fit the drag spring, and the centre clutch won't work reliably, perhaps at all.
 
[[Datei:Drag-spring.png|left|Schleppfeder]]The Alfine SG-S500-based models (hubs and wheelsets) have an 'A' and a 'B' version.  The 'A' versions are 'two-roller' internals, i.e. they use a pawl drive on the right-hand side (in 1-4) and the main (body center) roller clutch is preloaded by a drag spring that is set into the hub shell (as also found found in most of the coaster brake versions as well as Nexus hubs with pawl drive e.g., SG-8R25, SG-8R27).
 
(The image at the left shows the drag spring as it slips into the hub shell. The part number for the drag spring is the same for the Alfine as for some coaster brake hubs).
 
A difference in the SG-S500-A hubs (and some Nexus models) is that the roller retainer is castellated (has points which protrude to the left to engage the drag spring) whereas the Nexus SG-8R25, SG-8R27 (Rollerbrake/brakeless also, later coaster-brake and Alfine) hubs have no castellations on the roller retainer. Instead, there are protrusions on the carrier unit. The castellations, when present, are easily damaged.
 
A parts list for the SG-S500 'A' version formerly on the Paul Lange site (now in the Internet Archive) helpfully indicates compatibility with some Nexus 8 hub variants.
 
There is considerable compatibility between shells and internals provided the number of roller clutches is the same. However whilst you can usually fit a tension-spring preload clutch internal into one that was originally fitted with a drag spring, you do need to remove the drag spring. If you try to fit a drag-spring preload clutch internal into a hub shell that wasn't originally fitted with one, there usually is no place to fit the drag spring, and the centre clutch won't work reliably, perhaps at all.


Nexus and Alfine axlesWhile the axle assemblies are mostly identical, a section of the left end of the Alfine axle shown, as well as others, is fatter to withstand the bending moment from the optional disc brake, as shown in the image at the right (courtesy Aaron's Bike Repair). The Alfine left bearing cone threads onto the wider part of the axle. The Alfine requires a wider overlocknut distance than the Nexus without Rollerbrake. There are several different left-bearing-cone part numbers. Mix and match at your own risk.
Nexus and Alfine axlesWhile the axle assemblies are mostly identical, a section of the left end of the Alfine axle shown, as well as others, is fatter to withstand the bending moment from the optional disc brake, as shown in the image at the right (courtesy Aaron's Bike Repair). The Alfine left bearing cone threads onto the wider part of the axle. The Alfine requires a wider overlocknut distance than the Nexus without Rollerbrake. There are several different left-bearing-cone part numbers. Mix and match at your own risk.
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Bruce Dance sends the following warning:
Bruce Dance sends the following warning:


It is very easy for parts (pawls or balls) to come adrift during assembly. For example commonly a ball (or balls) can come adrift from the ring bearing, either during assembly, or even in service (if the bearing adjustment slackens). This very often results in destruction of the hub internal, especially in the single or dual-roller hubs with a pawl-drive in the RHS, because the balls can easily get into where the pawls sit and then break them.
It is very easy for parts (pawls or balls) to come adrift during assembly. For example commonly a ball (or balls) can come adrift from the ring bearing, either during assembly, or even in service (if the bearing adjustment slackens). This very often results in destruction of the hub internal, especially in the single or dual-roller hubs with a pawl-drive in the RHS, because the balls can easily get into where the pawls sit and then break them.<br><br>I therefore advise anyone working on these hubs to assemble the internal into the hub shell without the sprocket and the dust cover, and to be sure that all the balls are still present, and that the cone adjustment is pretty much done before the covers are refitted. Similarly if the hub has a pawl drive on the LHS (for gear 1 and 5), the internal ought to be rotated backwards as it is installed, else pawls may be dislodged.<br><br>I have seen one hub in which a roller came adrift (presumably during the factory assembly, since they cannot easily come out in service) and this smashed the hub shell to pieces. Kind of ugly.
 
I therefore advise anyone working on these hubs to assemble the internal into the hub shell without the sprocket and the dust cover, and to be sure that all the balls are still present, and that the cone adjustment is pretty much done before the covers are refitted. Similarly if the hub has a pawl drive on the LHS (for gear 1 and 5), the internal ought to be rotated backwards as it is installed, else pawls may be dislodged.
 
I have seen one hub in which a roller came adrift (presumably during the factory assembly, since they cannot easily come out in service) and this smashed the hub shell to pieces. Kind of ugly.


Shimano has information on most but not all 8-speed models. These hubs have gone through several minor design changes, resulting in new model numbers and parts incompatibilities. Hubs parts numbers start with SG but there are also other parts listed, including brakes and shift levers. globeThese pages are available in multiple languages, with a language list box at the upper right corner of the screen.
Shimano has information on most but not all 8-speed models. These hubs have gone through several minor design changes, resulting in new model numbers and parts incompatibilities. Hubs parts numbers start with SG but there are also other parts listed, including brakes and shift levers. globeThese pages are available in multiple languages, with a language list box at the upper right corner of the screen.
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