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Shimano Alfine Elf-Gang-Naben: Unterschied zwischen den Versionen

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==Kommentare==
==Kommentare==
In der Alfine Elf-Gang-Nabe sind alle Planetengetriebe rollengelagert (wie bei Alfine 8, höherwertigen Nexus 8 und [[Rohloff]]-Naben), um Reibungsverluste zu minimieren.


In the Alfine 11 hub, all the planet pinions run on roller bearings (as per Alfine 8, premium Nexus 8 and Rohloff hubs), so as to decrease losses.
Wie auch schon bei den [[Shimano Nexus Siebengang-Naben]] hat [[Shimano]] es vermieden, einen netten direkt übersetzten Gang Fünf (oder Sechs) zu schaffen. Wie wir weiter oben ermittelt haben, wird eine einzelne Antreibssufe für die Gänge 1,7, 8 und 9 genutzt. Daher sollten diese die effizientesten Gänge sein. Zwei Antriebsstufen werden in den Gängen 2, 3, 4, 10 und 11 genutzt, so dass diese mitteleffizient sein dürften. Drei Antriebsstufen werden in den Gängen 5 und 6 mit vermutlich der geringsten Effizienz genutzt. Unter sehr geringer Last können die Blindverluste von übersprungenen Rollengesperren aufälliger sein als die Antriebsstrangverluste aus dem Ineneinandergreifen und den Lagern. Widerstanände aus dem Rollengesperre sollten vermutlich im achten und neunten Gang am geringsten sein, weil dort nur eine der drei Antreibsstufen zum Einsatz kommt und die Rollengesperre der beiden anderen Stufen eingreifen.


Once again (as in the Nexus 7), Shimano has avoided having a nice efficient direct drive gear 5 (or 6). As it is, the hub uses a single gear train in gears 1, 7, 8, 9, thus these are likely the most efficient gears. Two gear trains are used in gears 2 ,3, 4, 10, 11 (medium efficiency), and three are used in gears 5 and 6 (probable lowest efficiency). Under very low loads, the parasitic losses from the overrun roller clutches may be more apparent than the gear train (meshing + bearing) losses. Roller-clutch drag should probably be least in 8th and 9th gears, which use only one of the three gear trains, so the roller clutches for the other two are engaged..


If the gear ratios are set in a vaguely sensible fashion (i.e. so that the 'flat road, no wind' gear is about 70-80% of top gear, (see advice here) then gears 7, 8, 9 (which are relatively efficient) are likely to be the most used gears. On a heavily loaded touring bike, gear 1 is likely to be heavily used too. This being the case, the weighted average efficiency of the gear may not be as bad as the numerical average efficiency might suggest. Because the Alfine 11-speed first-stage gear teeth are cut helical instead of straight, there is a question about the efficiency of gears 1-6, as axial thrust loads must be supported by non-rolling-element bearings. Some folk have suggested that there ought to be more gears yet with different clutching (because there are sixteen possible permutations of four clutches) but the two sun gears of the second stage cannot be usefully locked at the same time. Unity ratio in all three stages is the only allowable and unused combination.
If the gear ratios are set in a vaguely sensible fashion (i.e. so that the 'flat road, no wind' gear is about 70-80% of top gear, (see advice here) then gears 7, 8, 9 (which are relatively efficient) are likely to be the most used gears. On a heavily loaded touring bike, gear 1 is likely to be heavily used too. This being the case, the weighted average efficiency of the gear may not be as bad as the numerical average efficiency might suggest. Because the Alfine 11-speed first-stage gear teeth are cut helical instead of straight, there is a question about the efficiency of gears 1-6, as axial thrust loads must be supported by non-rolling-element bearings. Some folk have suggested that there ought to be more gears yet with different clutching (because there are sixteen possible permutations of four clutches) but the two sun gears of the second stage cannot be usefully locked at the same time. Unity ratio in all three stages is the only allowable and unused combination.
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On subsequent pages there are several other useful photos and posts.
On subsequent pages there are several other useful photos and posts.
==Zuverlässigkeit und bekannte Probleme==
==Zuverlässigkeit und bekannte Probleme==


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