Wie man eine SRAM G8 mit einem Schalthebel für Kettenschaltung rettet
I purchased the whole ‘kit’ for this hub as new old stock on eBay in early 2019, the twist changer dated 2013. As supplied this hub was unusable, but of course I didn’t know that at the time!
I use hub gears for my ‘about town’ cycles, nicknamed here my ‘bank bikes’ as that is the run they normally provide; a round trip of about an hour; a mixture of main roads in traffic, dedicated cycle paths and singletrack through a wood. First gear must be low, the equivalent of a normal ATB’s ‘granny gear’. Until recently I’ve been using the Shimano Nexus 7 with a twist changer; all excellent and thoroughly reliable. So when the chance of the extra gear came up at a bargain price, I thought ‘why not?’.
The rather massive black hub was built into a 26” rim two cross. The twist changer was set up and the cycle tested. Gear selection was all over the place. The cable from the changer had been already set to length at the factory, and the distance between the end of the outer and the little collet that engages with the hub’s ‘ring’ gear selector was wrong, far too long, so 1st gear disappeared. A series of experiments shortening the distance cured that, or so I thought, and enabled me to line up the little yellow marks referred to in the instructions – as mentioned, with the twist grip in third gear.
Then ensued a series of disappointments ending in the reinstalling of the Nexus 7 wheel. If the Sram was adjusted as in the leaflet, gears 1, 2, 3 and 4 were ok but 5 slipped and 6, 7, 8 were unreliable. If five was set not to slip, 1 2 3 disappeared. Such behaviour is of course dangerous in traffic. It struck me that the twist shifter was nothing like as ‘clicky’ as the Shimano Nexus, and rather vague in its indexing. I also noted that with the yellow marks aligned in gear 3, there was actually another first gear missing because the cable was so tight.
Spoke Divider The rescue!
I then recalled reading on the internet (Sheldon’s site I think) [here] that this and the G9 [probably not the G9 though without some alternate cable routing] were the only hub gears that worked with their standard derailleur rear shifter controls, a more normal twin lever shifter (push up, click down) [SRAM 3.0 8-speed shifter]. Finding one on eBay, I recalled how SRAM boasted of their 1:1 actuation system, where shifter movement equalled mech movement (I’ve precis-ed that…). Off the cycle, I tested the fitted shifter, and it behaved very differently from the twist one. It pulled a lot more cable at the upper gear end, and nicely precise. I also set it so that the yellow marks matched in gear 4. It would only just click into gear 8, a judgement I was later to find important.
Installed back in the cycle the change was immediate. 8 gears all working fine. It makes a rather odd ‘purring’ noise in 6, 7 and 8, but the freewheel is excellent, as good if not better than the Nexus. It ‘cogs’ if the cycle is wheeled backwards (the hub drives the pedals slightly), odd but maybe a character of the mechanism.
I’m not surprised SRAM cancelled it. Any sent out the same as mine would have been returned very promptly! But maybe a bargain for those as patient as myself, and good at wheelbuilding.
- Sachs und SRAM Nabenschaltungen
- Alles über Nabenschaltungen
- Montageanleitung für beide Naben (englisch)
- Rahmenweiten-Spezifikation für die SRAM G8- und G9-Nabe (englisch)
- 2015er Ersatzteilkatalog von SRAM listet auf Seite 13 passende Ersatzteile (englisch). Das Innenleben gab es nur als vollständige Einheit.
- Aaron's Bicycle Repair hat eine bebilderte Wiederaufbauanleitung für die SRAM G8- und G9 Nabe (englisch)
- SRAM G8 und G9 Nabenschaltungen
- Radtouren Magazin Artikel über die G8
- Radmarkt Artikel über die G8