Shimano SG-8R30 hub problems

[Andy Grayland]

I have recently purchased a Gazelle Easy Glider. It is a fantastic bike with very comfortable riding position. However after 300 miles the gears have stopped working properly. The hub is a Shimano 8 speed. The problem is that when changing below 4th gear the "cassette joint unit" gets stuck so the bike will not change down. The cable is completely free and bunches up close to the cassette joint. The joint can be moved to 1st with a small amount of pressure. It is as if the spring inside the hub is to weak. Has anyone else had this problem and does anyone know how to fix it?
Thank you in advance
Andy

 

[flecc]

I don't know this new design hub Andy, but it sounds possible that lubrication might be the problem. Have you tried some thin lubricant to get things running freely?
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[Andy Grayland]

I have lubricated around the cassette joint but it did not make any difference. I cannot find many internet references to the SG-8R30. I think it is similar to the SG-8R20 from what I can find.

 

[flecc]

It is very similar but apparently strengthened in some ways, though those don't seem to have been publicly specified. The SG-8R30 is the same thing as the Alfine hub gear, that differing in the controls.
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[JamesC]

I have recently purchased a Gazelle Easy Glider. It is a fantastic bike with very comfortable riding position. However after 300 miles the gears have stopped working properly. The hub is a Shimano 8 speed. The problem is that when changing below 4th gear the "cassette joint unit" gets stuck so the bike will not change down. The cable is completely free and bunches up close to the cassette joint. The joint can be moved to 1st with a small amount of pressure. It is as if the spring inside the hub is to weak. Has anyone else had this problem and does anyone know how to fix it?
Thank you in advance
Andy

Andy
Have you already come across this site ? hubstripping.com
It has some additional technical docs on the Nexus hubs.

James

 

[fishingpaul]

A frayed cable could also affect gear changes,after removing the wheel on a hub gear bike, my gear cable had one piece of wire untwist on reassembly and prevent free movement.