Rohloff Splined Sprocket wear

[Joe C]

Howdy,

Just been doing and annual oil change on mine and a freinds Rohloffs, we are both running the splined setups, and on my freinds one we noticed quite a but of play as per the attached, has anyone else seen this?

I popped the clip off and pulled the sprocket for investigation, the splined carrier looks ok (it looks like this is hardened steel so should be fine) the internal faces of the sprocket showed a little wear but not lots, obviously enough to cause movement though. the front and back faces of the sprocket aso showed wear (sorry for got to get a picture!) where there had been movment against the carrier and clip, with most wear on the rear face.
I cleaned everything up and put it back reversedand it seems to have no movement now, which i presume is due to che clip holding the sprocket more tightly due to the fresh metal against the carrier.

As the splines are "triangular" Im thinking that once there is a rotational load it might self centralize, so this movment may not actually be to much of an issue, as long as the chain is not too tight.

Thoughts anybody??

[buffet]

Did you ever bring up this issue to Rohloff? We have a similar story here at the local cycling forum, splined sprocket is having about 1mm of lateral play (see attached photo) although the teeth of the sprocket are only showing 30% of wear or so. The circlip was intalled correctly.

Any other reported issues for new splined sprockets getting themselves loose after certain period?

[Joe C]

I didnt, I was going to see if the problem came back first.

Interestingly there has been some talk of this on the roloff facebook page today, and there is mention of the Gates splined carrier with the lock ring fitting the chain type sprockets, whic i didnt realize.

https://www.cyclemonkey.com/blog/tech-talk-installing-rohloffs-locking-splined-sprocket-carrier

that could be a decent solution as ive been using the miche splined setup on a fixed gear tt bike and its been great.

[buffet]

Thanks for the heads up on the Rohloff page on FB, I didn't know there was one. The lockring-style carrier does look more failproof (since it's a common way to lock the cassette and/or centerlock disk rotors), however it makes you purchase an additional tool (8518)/ So Rohloff

[martinf]

The splined carrier with lockring will fit the sprockets for chain drive, with the exception of the two smallest 13 and 14 tooth sizes.

A downside is that it isn't compatible with a Chainglider, unless Hebie develop a new version that is.

I wonder why Rohloff went for triangular splines. In my experience, rectangular splines as used by Shimano cassette sprockets don't seem to develop play. There again, Sturmey-Archer have been using just 3 rounded splines for many decades, these can sometimes develop play with very hard use but cost very little to replace. 

[GamblerGORD649]

Gawd, What a stupid design. Perfect slope to create movement of the cog up and away.
The wear looks like all on the cog. The lockrings are too weak on those too, I hear.
So, I'm just glad I didn't buy this crap. But I use 1/8" anyway. I had already made 3 cogs by having SA 1/8" 16T cogs carved out and Tig welded to the original 13T Rohloff cogs. It nicely ended up the same chainline.

And I have not noticed the slightest wear on my 3 nub SA parts. But I guess none have more than 4,000 miles. They could not be more solidly attached to the driver.

[buffet]

Can this splined sprocket play lead to more serious consequences other than more frequent sprocket replacement? There were some reports about hub seals getting damaged more easily with the splined sprocket/carrier as opposed to the older threaded mechanism.

(I'm waiting for my hub to arrive from online store, so I'm trying to rule out any weird recent Rohloff decisions, maybe go for the older threaded sprockets, thanks to Jtek those can still be purchased)

[Andre Jute]

Oops! This just demonstrates the wisdom of the wise old heads who bought some spares of the threaded sprockets and were thus prepared to wait and see if the splined sprockets turned out to be worthy of the Rohloff HGB's renowned foolproof ruggedness.

Note that one millimetre of movement perpendicular to the frame would move any chainline which is not absolutely spot on (zero offset from the Rohloff recommendation for any particular type or tooth count of sprocket) out of spec* because the permitted latitude is only 1mm. Though there are engineers on this forum who're not at all worried about Rohloff chainlines off by a few millimetres, I'm a sometime motor racer who is generally finicky about the fit and finish of mechanical contrivances, and in any case it seems obvious to me that a straight chainline contributes to the longevity of the Rohloff geartrain by putting less grinding angle and stress on it.

*Don't count on being so lucky that the wandering sprocket moves the chainline back into spec. Murphy will get you every time!

[JohnR]

The splined sprocket on my Mercury seems to be tight but it's only done 2200 miles. If the chainline isn't close to perfect then would the load from the chain try to pull the sprocket slightly skew resulting in the observed wear?

[Andre Jute]

If the chainline isn't close to perfect then would the load from the chain try to pull the sprocket slightly skew resulting in the observed wear?

There will be someone along soon now who knows answer in general terms to that question.

However, in the particular case of the Rohloff hub gearbox, there is an additional complication: In a correctly tuned Rohloff system, the chain is quite a bit slacker than the drop bar crowd would expect, and thus any stress at the sprocket/chain interface, even apart from the bottom to top differential load, is likely to be less than in, for example, a tip-top derailleur setup.

[JohnR]

Overall chain tension might be a factor but the real load on the sprocket results from the tension in the top half of the chain due to the downforce on the pedals. If the chainline is off, part of that force is trying to pull the sprocket off when the whole force should be trying to turn the sprocket. When I recently changed my chainring, not only did I try to measure the offset of both chainring and sprocket from the bike centreline but I also did an optical check (ie use human eyeball) to look along the chain and make sure that chainring, chain and sprocket were all in line.

[marshall2389]

I just inspected my Speedhub and found that my splined sprocket had developed a lot of play on the carrier. I flipped the sprocket and this reduced but did not elimnate the play. I just bought a new carrier and splined sprocket. I figured there will have been wear on the old carrier that would then wear out a new sprocket. So I've mounted a new carrier and sprocket and the hub is emitted a worrying click sound. I'm worried it's the new sprocket shifting and causing the click. We'll see.

[mickeg]

My reading of this situation is that the carrier used for belt drive with a threaded on ring instead of circlip spring might be better. 

I am still using the old thread on sprocket (pre-splined), thus have not yet experienced this.

[PH]

So I've mounted a new carrier and sprocket and the hub is emitted a worrying click sound. I'm worried it's the new sprocket shifting and causing the click. We'll see.

Sorry if it's asking the obvious, but have you put a new chain on at the same time?
I haven't experienced a lose sprocket though I've heard of enough examples to consider it a manufacturer's failure. It's sometimes advised to use a lockring carrier instead, that's a £100 experiment (Carrier + tool).  I'd be interested to hear of anyone who went that route, the interface between sprocket and carrier looks identical, so I'm not sure it is the solution. 

[mickeg]

...
 It's sometimes advised to use a lockring carrier instead, that's a £100 experiment (Carrier + tool).  I'd be interested to hear of anyone who went that route, the interface between sprocket and carrier looks identical, so I'm not sure it is the solution.

Would the tool be necessary?  It is my understanding that the tool is absolutely necessary if used on a belt drive sprocket because that sprocket is wider.  But the chain type sprocket is flat.

So I am wondering if an old style tool like were used decades ago on the lock ring on cup and cone bottom brackets would work on a chain type sprocket.  Or in the case of my S&S coupled Nomad, the S&S wrench.
https://www.sjscycles.co.uk/tools/thorn-s-and-s-5-in-1-spanner-wrench-special-coupling-eccentric-tool/

I wonder if anyone has tried this type of tool on a chain drive bike that uses the lock ring carrier?

More detail on the carrier:
https://www.rohloff.de/en/service/handbook/speedhub/workshop/splined-carrier-lockring-conversion

On a long tour, I can clearly see the advantage of a circlip type carrier where it is easy to remove the circlip.