Author Topic: Mike's Threaded Sprocket/Chainline/Chain Cover Clearance Question  (Read 2363 times)

Andre Jute

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Mike's Threaded Sprocket/Chainline/Chain Cover Clearance Question
« on: September 03, 2016, 05:02:41 pm »
Admin Note:
In another, off-topic portion of a post now addressed here, Forum member Mike Ayling asked...
Quote
Now going slightly off topic will there be a big issue with chain line if I go to the splined sprocket system.?
I have read that it does not work well some of the encloses chain cases.
The topic will now be picked up with a reply by Andre below.

Dan.
Danneaux, Thorn Cycling Forum Administrator
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Mike asked...[quote ...will there be a big issue with chain line if I go to the splined sprocket system.?
I have read that it does not work well some of the encloses chain cases.[/quote]

CHAIN LINE

1. A Rohloff chain is supposed to run straight (i.e. parallel to the centreline of the frame) to within 1mm, so there are now three Rohloff chainlines, one for 13mm threaded sprockets (58mm), one for all other original threaded sprockets (54mm), one for splined sprockets (57mm). The two important ones for tourers are old-style threaded sprockets at 54mm and new style splined sprockets at 57mm.

2. Most derailleur chains work all their lives on skewed chainlines, simply from the nature of the number of chainrings and sprockets in the cluster requiring width. Single speed chains are intended to run straight and are thus made stiffer.

3. However, many Rohloff owners use derailleur chains like KMC X8 for reasons of quality, cost and availability rather than the equivalent singlespeed Z8 chain, so for them a straight chainline is less important, though it may be more expensive in sprocket and chainring wear.

4. Fast and relatively inexpensive ways of adjusting the chainline to suit the sprocket fitment include a longer axle on the bottom bracket, spacers on the spider (a set actually comes in the Rolloff box, and extra sets are sold by Rohloff agents like SJS), and moving the chainring from the middle to the outside position on a road crank.

CHAIN COVERS

5. Chain covers like the Hebie Chainglider which is popular with Rohloff tourers must be checked for compatibility with number of teeth on the sprocket, and its type, so that it clears the hub and the sprocket carrier: this means each type sprocket probably requires a different type of "Rohloff Chainglider rear end". Currently a Chainglider rear end is available to suit the threaded sprockets.

6. Furthermore, the chain cover must clear the seat stay, and in this regard some Thorn owners have had a problem even with the threaded sprockets installed, which some solved by carving out a piece of Chainglider; it is likely that the problem will become more acute with the 57mm chainline, especially with higher tooth-count sprockets on short wheelbase bikes. Herbie will no doubt in time provide a rear end that works with Rohloff's splined sprockets.
« Last Edit: September 03, 2016, 07:29:20 pm by Danneaux »