My Rohloff is 2 years old with 12,000 miles. With an oil change at 4,000 miles yours would just be 'run in' about now if it were Rohloff. 14 gears instead of 8, and you use all of them unlike a derailleur. I'd really take another look at hub gears just from the maintenance point of view. That equates to 45 minutes maitaining them over a two year period for you.
Blade Runner
- Thread starter Archie
- Start date
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My Rohloff is 2 years old with 12,000 miles. With an oil change at 4,000 miles yours would just be 'run in' about now if it were Rohloff. 14 gears instead of 8, and you use all of them unlike a derailleur. I'd really take another look at hub gears just from the maintenance point of view. That equates to 45 minutes maitaining them over a two year period for you.
OP
OP
Archie
Errrr.....
Well I've been back on the bike for a couple of weeks now with a 2nd hand replacement hub from Ebay, which my LBS built a new wheel from. I've finally performed the post-mortem today, so thought I'd relate my findings. For the technically minded you can refer to Sheldon Brown's Nexus 8 service manual to follow the comments.
Step 8 shows the removal of the carrier unit, exposing a large bearing cage which rests on the drive side of the hub. There's a rubber dust cap on the same side which is removed in step 6. This seems to be the weak point as water has entered the hub, rendering the bearing cage into a collection of rusty bearings, twisted bearing retainers and dust. Above the bearing cage you can see two rings around the hub. These have metal loops seated in them. The loop nearest the edge has broken and twisted, allowing a few bearings from the cage to embed themselves in the gap created. I haven't managed to remove these, and the metal between the rings has bent.
The bearings must have been on the way out for a while, as the drive side of the outer casing, the dust cap and the inside of the carrier unit (see the bottom picture at step 8) have a rusty paste coating them. The carrier unit itself and the hub bearings are fine, with plenty of grease protecting them. So is the axle and (thank goodness) the frame. So far I've found no evidence of the ring gear stop ring or ring gear at step 9.
The carrier unit is soaking in degreaser tonight so we'll see if they turn up, but the stop ring may be part of that rusty paste.
I got to see the new hub with the case off at the LBS and I saw the same bearing cage was corroded so without a doubt that's the weak point. I'll be off on holiday soon and I'll get the new hub in for a service and new bearings. What I'm wondering now though is whether the nexus 8 is up to a 26 mile daily commute. There were two days in particular I can think of when the weather would have allowed the water to attack that weak point, and the morning of the failure was also wet. Short trips won't allow much water in, but over 13 miles there's bound to be more water ingress.
Step 8 shows the removal of the carrier unit, exposing a large bearing cage which rests on the drive side of the hub. There's a rubber dust cap on the same side which is removed in step 6. This seems to be the weak point as water has entered the hub, rendering the bearing cage into a collection of rusty bearings, twisted bearing retainers and dust. Above the bearing cage you can see two rings around the hub. These have metal loops seated in them. The loop nearest the edge has broken and twisted, allowing a few bearings from the cage to embed themselves in the gap created. I haven't managed to remove these, and the metal between the rings has bent.
The bearings must have been on the way out for a while, as the drive side of the outer casing, the dust cap and the inside of the carrier unit (see the bottom picture at step 8) have a rusty paste coating them. The carrier unit itself and the hub bearings are fine, with plenty of grease protecting them. So is the axle and (thank goodness) the frame. So far I've found no evidence of the ring gear stop ring or ring gear at step 9.
The carrier unit is soaking in degreaser tonight so we'll see if they turn up, but the stop ring may be part of that rusty paste.
I got to see the new hub with the case off at the LBS and I saw the same bearing cage was corroded so without a doubt that's the weak point. I'll be off on holiday soon and I'll get the new hub in for a service and new bearings. What I'm wondering now though is whether the nexus 8 is up to a 26 mile daily commute. There were two days in particular I can think of when the weather would have allowed the water to attack that weak point, and the morning of the failure was also wet. Short trips won't allow much water in, but over 13 miles there's bound to be more water ingress.
mickle
innit
- Location
- 53.933606, -1.076131
Yeah, but have you checked that the drop-outs are aligned?
OP
OP
Archie
Errrr.....
Well, I've visually checked their side profile alignment which looks OK, and checked the spacing by breaking a stick to the inside length of the drop-outs which shows they're parallel - no deviation in size between various points on the drop-outs.
If there's a more scientific method of checking I'm all ears!
If there's a more scientific method of checking I'm all ears!
mickle
innit
- Location
- 53.933606, -1.076131
Decently equipped cycle workshops use a pair of tools which bolt into the drop-outs and allow you to check the alignment and which are long enough to provide enough leverage to re-align them. Your broken stick technique can't hope to be accurate enough.
Ten out of ten for effort though!
Ten out of ten for effort though!