Author Topic: What's your Rohloff combo (chainring, cog)?  (Read 180325 times)

PeteG

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #240 on: May 28, 2016, 09:08:27 am »
Quote
the new splined sprockets have a different chainline than the old thread on sprockets.  So, if you are calculating a spindle length for your bottom bracket, you might want to make sure you use the right data for your type of sprocket.

Thanks for that. Having had a quick measure up, it looks as though my chainline is closer to 58mm than 54mm ( outer ring position of a Shimano Hollowtech II external bearing triple chainset ), so I think my best bet is to return the 17t thread-on sprocket, once it arrives, and then order a splined sprocket + sprocket carrier.

neil_p

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #241 on: July 27, 2016, 01:26:08 pm »
I'm just about to switch to a 47x16 for unladen use. I'll switch back to my 40x16 when I do laden touring.

mickeg

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #242 on: July 27, 2016, 04:26:04 pm »
If you consistently use even numbered chainring and sprocket, this may be pertinent to you.  I cut a small notch in one tooth on my chainring and on the sprocket, I always put a link with outer plates on that tooth.
http://www.sheldonbrown.com/chain-life.html

This is why I use even numbers for both of my touring and for my around-home chainrings.  I also use a 16T sprocket.

Reuel

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #243 on: December 23, 2016, 08:45:54 pm »
Just started using 48 x 17 magic gear on a Soma Saga frame using the formula from: http://eehouse.org


Photo:
https://goo.gl/photos/FEj6KxqmfktTaBkr9

Danneaux

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #244 on: December 23, 2016, 09:22:52 pm »
Very nice, Reuel, and it worked out well for you.

How will you handle chain stretch? Do you presently use some half-links and then remove one or more as needed? Or will you swap chainrings or cogs as needed to take up the slack?

Best,

Dan.

Reuel

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #245 on: December 23, 2016, 10:02:55 pm »
Hi Dan, yes I'm not thinking long term at the moment! I'm considering the Rohloff DH Chain Guide, as using half links can get messy - plus maybe a dog fang chain catcher.

RST Scout

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  • Janet
Re: What's your Rohloff combo (chainring, cog)?
« Reply #246 on: January 16, 2017, 10:30:44 pm »
This has been a really interesting topic and I have enjoyed reading it.
My new bike has 44T/17T. I was thinking of swapping the rear to a 19T having read what Andy had to say about the subject in the Rohloff brochure (an extra £5). This would give me a range of 16.9-88.3 inches on a 160mm crank and a 26" wheel. My cadence is quite slow at between 60-70 rpm. My favourite gears are around the 51inch mark. On the 44/19 this would be around gear 10 (not the preferred gear 11).
Now having read the previous remarks, I'm wondering if I should keep the 17T and go for a  smaller front, say a 38T or 36T?
What do you think?

Janet
Scout & Bettina's slave!

mickeg

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #247 on: January 16, 2017, 11:09:04 pm »
This has been a really interesting topic and I have enjoyed reading it.
My new bike has 44T/17T. I was thinking of swapping the rear to a 19T having read what Andy had to say about the subject in the Rohloff brochure (an extra £5). This would give me a range of 16.9-88.3 inches on a 160mm crank and a 26" wheel. My cadence is quite slow at between 60-70 rpm. My favourite gears are around the 51inch mark. On the 44/19 this would be around gear 10 (not the preferred gear 11).
Now having read the previous remarks, I'm wondering if I should keep the 17T and go for a  smaller front, say a 38T or 36T?
What do you think?

Janet

You put less tension on the chain when you pedal with a larger chainring.  Thus, if you have larger front and larger back so that the ratio of front to back is the same, chains should last a bit longer.  And, chain wear occurs when each individual pin rotates within the adjacent chain link as the chain wraps and unwraps around a sprocket or chainring.  Thus, a larger sprocket and larger chainring means that the pin rotates slightly less each time the chain wraps around teh chainring or unwraps off the sprocket.  I am not sure if a chain will last longer with more teeth on the sprocket, but that might also occur but I think that would be very minor compared to the other issues.

I have a 16 in the rear, that is the normal size when you buy a Rohloff hub from most sellers, I did not buy my hub from SJS who usually sells 17 instead.  And I wanted to have an even number of teeth so I stuck with a 16.  But if they had made an 18 or 20, I might have bought that sprocket instead.

Whatever you switch to, keep your old parts in case you want them later.  I use smaller chainring for touring than I use for riding around home. 

If you buy the 19 and if you do not have any extra chain links you might have to buy a new chain because the two extra teeth might need more chain.  I am not sure which bike you have or how much more room you have in your eccentric for adjustment. 

If I recall one Thorn model has a smaller eccentric and if you have that bike you might need to ask SJS what will work.

julk

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #248 on: January 17, 2017, 10:12:42 am »
Janet,
I would recommend the 38x17 setup plus a chainglider.
That way you will never have to buy another chain…
Julian.

Neil Jones

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #249 on: January 17, 2017, 10:49:29 am »
That would be a good chainring, cog combo although I've heard that you can't fit a Chainglider on an RST (especially small frame sizes) due to the tight clearances, although I have not tried it myself.

Neil

Matt2matt2002

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #250 on: January 17, 2017, 11:40:35 pm »
Janet,
I would recommend the 38x17 setup plus a chainglider.
That way you will never have to buy another chain…
Julian.

I have 38*17 and a Chaingliger.
And I am buying a new chain this week!
Old one done 6,000 miles I think.
I'll check and confirm this tomorrow.

Great piece of mind, having the Chaingliger. Keeps 99% of muck off.
Easy to fit and remove after a few times. Tricky at first to be honest.

Cog combo is great for touring with weight. A bit over geared otherwise.
Never drink and drive. You may hit a bump  and spill your drink

RST Scout

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #251 on: January 19, 2017, 06:33:54 pm »
That would be a good chainring, cog combo although I've heard that you can't fit a Chainglider on an RST (especially small frame sizes) due to the tight clearances, although I have not tried it myself.

Neil
Oh! I was specifically thinking about a chainglider with the 38/17 combination but my RST will be a 461S, the smallest there is. Maybe I should forget about the chainglider and just go for 44/19.
Scout & Bettina's slave!

lewis noble

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #252 on: January 19, 2017, 08:05:46 pm »
Hello Janet - I suppose the fact that the RST has tighter clearances etc is part of what contributes to it being a lighter and feeling a more nimble bike. People with chain guards seem very keen on them, but I'm not sure if the folks without them really miss them.  Oops . . . I'll have started a storm here . . . .

I had a Rohloff Raven Tour for 4 years, no chainguard.  The fact that the chain runs in a fixed line, and never falls off (until very worn) means that the whole system keeps clean, in my experience, and is so much easier to keep that way.  Choose the gearing that suits you, likely use etc (i.e. chainring, sprocket) and you will be fine.

I think most Thorn users would say that if you are torn between two ratios / gearings, go for the lower one, and that is certainly my own view.  I reckon it is far worse to run out of low gears when tired or on a hill that to run out at the top end down hill - a personal view.

Good luck

Lewis
 

julk

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #253 on: January 19, 2017, 10:52:07 pm »
Janet,
my expr has tight clearances, the chainglider was pushed off vertical at the rear top by the seatstay.
i took a round surform file to that part of the chainglider which was getting pushed over by the seatstay.
Cutting away at the plastic seemed quite brutal and I eventually cut right through at one point.
I used black duck tape to cover the small gap in the chainglider from both sides making it watertight.
The result is a chainglider which fits and works…
Julian.

RST Scout

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  • Janet
Re: What's your Rohloff combo (chainring, cog)?
« Reply #254 on: January 20, 2017, 12:53:04 am »
Hello Janet - I suppose the fact that the RST has tighter clearances etc is part of what contributes to it being a lighter and feeling a more nimble bike. People with chain guards seem very keen on them, but I'm not sure if the folks without them really miss them.  Oops . . . I'll have started a storm here . . . .

I had a Rohloff Raven Tour for 4 years, no chainguard.  The fact that the chain runs in a fixed line, and never falls off (until very worn) means that the whole system keeps clean, in my experience, and is so much easier to keep that way.  Choose the gearing that suits you, likely use etc (i.e. chainring, sprocket) and you will be fine.

I think most Thorn users would say that if you are torn between two ratios / gearings, go for the lower one, and that is certainly my own view.  I reckon it is far worse to run out of low gears when tired or on a hill that to run out at the top end down hill - a personal view.

Good luck

Lewis

I rather think I'll go with the 44/19 combo. It gives me a low gear of just under 17". Of my current bikes, the lowest gear is 22" (which my LBS said would climb the wall of a house  ::) so 17" is considerably lower. If I need anything lower, I will just have to get off and push and I've done that enough times in my life  ;) I can always alter it at a later date if I need to.
I've never used anything like a chainglider before so I guess I won't miss what I've never had (I hope).
Scout & Bettina's slave!