Intro, oil leaks, and sprocket chainlines

[TheShipwright]

If anybody needs anything else measured or snapped pls just ask.

[David Simpson]

Thanks for the photos. A picture makes all the difference.

I have a question: What holds the sprocket in place? That is, what stops it from sliding off towards the right side of the bike? Is it just the friction of the splines? Or is there a retaining clip?

Thanks,
DaveS

[TheShipwright]

David, I've not taken my new sprocket off yet but my understanding is that there's a large'ish circlip holding the sprocket it place. The Alfine/Nexus and also some SA hubs I think use the same system if you've used any of theses hubs.

The Alfine/Nexus circlips I always found quite tricky, I always managed to get them off and back on again without losing the circlip or an eye!

I guess the idea is idea is that the sprocket is more easily user replaceable.  I mentioned to Dave at SJS that as the carriers could potentially be on longer than the threaded sprockets, I.e. they could see  many new style sprockets wear out, then if a carrier had to come off it would be a lot more difficult. His reply was that yeah in theory but most users will never remove one and they're Teflon coated to make removal easier and lastly probably someone like him would remove the carrier, i.e. someone who has training, a workshop and experience.

Good luck

Edit: Here's an image I found helpful when researching the splined carrier.

[mickeg]

I suspect most Rohloff owners do not have a good chain whip in their collection of tools.  Or the really big adjustable wrench.  Thus circlip removal to swap a sprocket is likely a big advantage to those owners.

When I pulled my sprocket off after three years, it was primarily to see how tight it was because I had read on this forum that they can be hard to remove.  I had no problem at all in removing it, but I used copious grease when I first installed it and I own the big wrenches that make the job easy.  I can see where smaller shorter wrenches could make it a more difficult task.

[Matt2matt2002]

Regarding the chain alignment; I recently shortened my chain and adjusted the BB.
It slides from side to side so how was I supposed to make sure the chain ran true?
I did it by sight but is there a better way?

Isn't this alignment problem what is being discussed here due to the new rear cog sitting further ' out'?
Matt

[TheShipwright]

Regarding the chainline, I admit to being a pedant!   Various sources have said running the chainline out of aligment by 5mm or so is nothing compared to what a regular externally geared chain can accomodate.   If you want to measure here's how I interpret it from Sheldon B,  I measure the width of my seatube divide by 2. Measure from the side of the seat tube nearest the chainring to the centre of the chainring and add the half of the seat tube measurement. so in my case my seat tube is 28.8 mm and from the seat tube the centre of chainring is now 42.5mm so 42.5 + 14.4 = 57mm the magic number for splined carrier.

At the hub, 135mm (hub oln) divided by 2 = 67.5mm. Measure from the inside of your rear DO to the centre of sprocket and subtract from 67.5mm. In my case I measured 10.5mm from DO to centre of sprocket so 67.5mm - 10.5mm = 57mm.

http://www.sheldonbrown.com/chainline.html

Re the sprocket being further out then yes you're correct, I damaged my hub and when repaired opted to have the new splined carrier installed which subsequently moved the chainline out a few mm, I think from 54mm to 57mm.  As it transpires my previous chainline was out by a few mm so on the splined carrier sprocket it was out even further out but as I've said I'm a pedant.

Good luck

[TheShipwright]

FYI, in response to a query I had, Dave Whittle has just confirmed that the old style screw on sprocket removal tool also works for removing the new splined style "carrier", should you wish to remove the carrier.