sidlaroo

Hi all -

Wondering if anyone out there has had any issues with a Shimano Nexus 8 Speed Internal hub slipping in certain gears - 5th to be precise. Its a Masi Soulville and I've had it for a month or so and its super smooth in 6 and 7, but when I get in the 4s and 5s its hard to get in gear and then slips every 10 seconds or so until i monkey with the shifter - ( I usually end up going up a gear). I'm usually on an incline and I'm pedaling through the shifts.

I took it into my LBS and they checked it on their "stand" (sorry don't know the correct term) and it worked fine, and he said the yellow markers were aligned.

Is this normal? Am I doing something wrong? My old external hub never had any issues. I've read such good reviews on it the Nexus internal hubs, I'm kinda confused.

thanks much!!
Sid

K6-III

Make sure the cable nut is fully tightened. Also make sure that you have the correct anti-rotation washers.

unkchunk

I'm not sure what you meant by that. Are you shifting under load, that is putting high torque on the pedals while you shift? I back off on the pedals pressure for just a second while I shift.

Sometimes problems can be traced to chain tension (sometimes a panic stroke can pull the wheel in the dropouts if I didn't tighten the nuts enough) or if the wheel is a little askew to the left or the right.

One other thing is maybe is your pedal stroke. It's been over two years that I have been riding with my Nexus and I vaguely remember a few problems I had when I first rode it. What I think may have happened is that I adapted my pedal stroke over time to suit the Nexus hub. Actually I think I developed a better smoother pedal stroke. Before, I think my pedal stroke was just a series of high powered jerks which cause the hub to make some noise, if not slip. After a while, I pedaled with a smoother more consistent torque applied evenly throughout the pedal stroke. I think that's when some problems I had just disappeared. This is my hunch as to what might be happening with your hub. Anyway, I think improving my pedal stroke is important and that's why I ride a fixie an hour a week to improve it more.

dbg

If it is similar to the 7 speed there is a red line on hub and gear mechanism that should line up perfectly when in 4th gear. I have found that I get some awkward slips if they are not perfectly aligned. Check yours out and adjust them to be perfectly lined up.

sidlaroo

Thanks all. Yes, I guess I am downshifting under load. I'll try shifting before I get to the hill and check the cable nut to see if that helps. I do know the red line (yellow on mine) is aligned.

Hey K6-III - I'm in saint paul too - small world.

thanks again!

day_tripper

Yes, it can slip. I am bruised all the way down my right side at the moment after my Alfine slipped whilst I was standing on the pedals going uphill. The terrain was rolling hills. I was pedaling down in a high gear, then dropping to 5th and standing to crest the next hill. The nexus slipped and I did a stroke at full power, biting air. I smashed onto the road. Luckily I wasn't hit by the car behind.

The hub is less than two years old and has done about 10,000 km, a mixture of light touring and commuting.

I haven't checked the adjustment yet (it hurts too much to bend down), but it was ok a month ago. I have changed a flat tube since then, so that may have upset something. It probably is an adjustment issue, but the hub should be fail-safe - it should be guaranteed to always be in some gear. I believe the Rohloff is better in this respect, since the indexing is in the hub, not the shifter.

I'm dumping the Alfine and would not use one again, unless the design is changed so that the hub cannot slip into "neutral".

Dan Burkhart 

Is it worse downshifting than upshifting? If so, you may have some hangup in the cable preventing it from dropping smoothly down into 5th from 6th.
I sold one bike model in my shop that had terrible cable routing to the Nexus 8 hub and they suffered from this. I was able to cure it by changing the routing of the housing and putting in slick cables. (And 5th was always the problem gear.)

Ex Pres 

Another thread resurrection.

Dan Burkhart 

Ha! I didn't notice.

day_tripper

Yes, I've only noticed it downshifting. I've since spoken with a couple of other people with Nexus & Alfine hubs who have experienced the same problem. Some near misses, but no accidents.

Thanks for the advice, but I think I'll switch out the Alfine 8 for a derailleur. I may end up with something worse than painful bruising next time!

Dan Burkhart 

Shame you feel that way. I'm pretty sure it's a cable issue. Should be easy to resolve.

jamesss

Is it a production bike you are riding? Also maybe you should alter your riding style. Dont stand up, pedal, and shift at the same time. I ride an alfine hub and I take care on my shifts to make sure it is in gear before I stand on the pedals.

tcs

Jobst Brandt, call your office.

tcs

noglider 

Thanks for the pointer to that article by Jobst. Interesting reader. As Sheldon pointed out, this problem is typically shown with very strong riders. Jobst is very tall and very strong, and he finds all sorts of defects that I would never have heard about.

tcs

Legend relates that Mr. Brandt was injured some 50 years ago when his Sturmey-Archer AW hub unexpectedly popped out of gear, and over the last 15 years he has made several 'net postings on the subject, mostly advancing his belief that it is not an adjustment or operator issue but a fundamental flaw of the design. As the late Mr. Brown points out, millions of AW users have gotten good service out of the AW without experiencing this problem.

I thought the old discussion/debate was appropriate here because it is claimed the Shimano 8-speed IGH can also unexpectedly go into a neutral. Well, with no wish for anyone to get hurt, reasoned, inquiring minds have to ask: Adjustment? Operator error/abuse? Or a dangerous flaw of the design?

tcs

PS - SunRace Sturmey-Archer, the manufacturer of Sturmey hubs for the last 10 years, have always and only built an improved three speed design, the AW-NIG, without the netural position between 2nd & 3rd gears.

noglider 

Jobst has also broken many Campagnolo Record cranks! Read stuff by him, and you get an idea of how much force he can generate. I trust he's not exaggerating. His experience is different from others' because of his abilities.

day_tripper

Yes, the Alfine comes standard with the Giant CRX City-Pro 2009 model. It's not a retro-fit. The frame geometry is set up for the hub, so I don't think it's feasible to hang a derailleur. I'll continue to use it for shopping and other leisurely trips, checking the shifts as you say. I'll not use it again for day rides or touring.

I just ordered an expedition tourer with a Rohloff (Thorn Nomad Mk2). This uses two cables rather than a return spring and the index mechanism is in the hub, so I'm expecting that it doesn't suffer the same problem.

semilofi

it is completely unacceptable for an internal hub to 'slip'.

imagine if automobiles were designed with the same flippant attitude that bikes are.

car tires would go flat every thousand miles or so

stepping on the gas too hard could break a vital component in the drivetrain leading to serious injury.

wheels break. WHEELS. when was the last time you heard about a car's wheels breaking? but bicycle spokes break all the time, and the new 'carbon fiber' spoke wheels broke on a racer.

--

the saddest part of all? the kool aid drinking intellectual cowards of the 'bike community' who somehow believe its the 'riders fault'.

if a hub slips and causes injury, shimano should be sued for building a **** product and failing to disclose the dangers of using it.

i.e. shimano should build hubs that DONT SLIP. fascinating concept. like building a computer that doesnt catch on fire or a car that doesnt explode.

noglider 

semilofi, I don't compare the reliability of cars with that of bikes. If bikes were as reliable as cars, they'd be too heavy to ride. We make big compromises between rideability and reliability. I don't care for the latest trends which heavily favor a good ride for poor durability, but even my really old bikes, which are more reliable and durable, can't approach the repair record of cars.

vredstein

You'll have to forgive "BICYCLE MECHANICS" forum members for offering common adjustments or easily executed solutions rather than posting Johnny Cochran's phone number.

mriley

Don't stand up and pedal with a hub gear. Sturmey Archer made this point 75 years ago and it is still true. There are small parts in your hub.
M Riley

RunningBulldog

Sorry for the thread resurrection... but: my Nexus 8 has exactly this problem -- 5th gear, any kind of load, you'll find yourself pedalling air about every mile or so. Half a rotation or so, and then it catches. No warning. And the dots on the cassette are PERFECTLY aligned.

Of course, I have partially disassembled the bloody thing now and am having the devil of a time getting it back together. There appears to be no return spring engagement to the cable cassette, and if I rotate it (simulating shifts) by hand there is no changing of gears...

RunningBulldog

So I've been scoping the web and can find no intel that is useful. For whatever reason, it is as if I have no return spring. Can someone who is experienced with these hubs tell me the likely place to check? Why would the notched ring that the shift cassette engage with not be spring loaded at all? What did I miss when I put the hub back together after cleaning it? All I did was pull the innards out of the hub, clean them up, lubricate them, and put them back.

Dan Burkhart 

I'm assuming the spring was active before disassembly? This spring can become disengaged if you try to remove the drive side cone without using the special Shimano tool.
Here's a source for instructions on how to rectify it. Note that Aaron says this is beyond the abilities of many/most mechanics, and even if it's not, paying shop time to do these jobs is one reason why assembly replacement is usually the first resort.
Follow down to about step 6
https://www.rideyourbike.com/shimano8...ructions.shtml
Good luck.

RunningBulldog

That's a great resource, Dan! Thanks.

I have a suspicion there may be a derailleur rear wheel in that bike's future....

Thaddeus