IGH on a Silvio?
- Thread starter JonB
- Start date
5mm difference isn't that much of a spread considering the fork legs are probably about 380mm long. In fact, my Silvio came with 2 spacers to spread the legs apart to keep the chain from contacting the carbon leaf spring when you shift to the smallest cog. I believe that the spacers were to added to the kit address the problem that some bikes were having. Even though 2 spacers were supplied, the instructions said that the second spacer isn't necessary but can be used if symmetry was an issue for the rider. I think that each spacer is about 5mm thick. So if adding 10-ish mm of spacers is ok, then installing a IGH that's only 5mm larger should be ok...
Gromit
Guru
I searched for the specs of the Alfine 11 but couldn't find the dropout width dimension.
I seem to remember that the Alfine 8 is 132.5 mm wide though. Maybe somebody could confirm this?
So for a road bike dimensioned frame such as the Silvio, you have only to open up the fork legs by 1.25 mm each side.
On a Freerider, Sofrider or Quest you would compress the fork legs by 1.25 mm each side of course.
Gromit
Guru
This page on Harris Cyclery appears to confirm the Alfine 8's dropout width as 132 mm.
"132 mm rear axle spacing may require spreading the frame of older model bikes.."
"132 mm rear axle spacing may require spreading the frame of older model bikes.."
Doug Burton
Zen MBB Master
These are the issues you face with an IGH on a SIlvio:
1. The fork dropout spacing on these forks runs tight, 128mm. They easily spread to 130mm, but it's pretty stiff going any wider. The nominal design OLD distance of the ones I've looked at is 135mm. This will also push the ends of the carbostay out further from the wheel, in the direction the carbostay is designed to resist deflection.
2. The chainstay dropouts fully-encompass the quick release axle (you have to remove the QR to remove the wheel). To accomodate the longer axle length of an internally-geared hub (SRAM is 182mm), you'd need to modify the chainstay dropout unit to accept the through-axle. Dunno how this would work out, and there aren't any spares available.
3. Internally-geared hubs require some method to transfer the torque to the bike frame. SRAM uses a keyed washer or a torque arm. I don't know how either of those parts will get along with the outboard chainstay arrangement, which may occupy the space needed by the torque arm, and the dropout arrangement will need help to manage the keyed washer.
I'm not saying it can't be done, but it's not a bolt-in and there are risks to the fork and frame parts.
Best,
Doug
1. The fork dropout spacing on these forks runs tight, 128mm. They easily spread to 130mm, but it's pretty stiff going any wider. The nominal design OLD distance of the ones I've looked at is 135mm. This will also push the ends of the carbostay out further from the wheel, in the direction the carbostay is designed to resist deflection.
2. The chainstay dropouts fully-encompass the quick release axle (you have to remove the QR to remove the wheel). To accomodate the longer axle length of an internally-geared hub (SRAM is 182mm), you'd need to modify the chainstay dropout unit to accept the through-axle. Dunno how this would work out, and there aren't any spares available.
3. Internally-geared hubs require some method to transfer the torque to the bike frame. SRAM uses a keyed washer or a torque arm. I don't know how either of those parts will get along with the outboard chainstay arrangement, which may occupy the space needed by the torque arm, and the dropout arrangement will need help to manage the keyed washer.
I'm not saying it can't be done, but it's not a bolt-in and there are risks to the fork and frame parts.
Best,
Doug
