Author Topic: What's your Rohloff combo (chainring, cog)?  (Read 59461 times)

Danneaux

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #15 on: July 21, 2012, 07:13:37 PM »
Quote
My Garmin only reads gradients up to 15% then it goes blank.
So do I, Jim, so do I!  :D

Yes, this helps greatly, too.  (Special note to Andre: I think I am beginning to "get it"; there's hope, I'm trainable, and your patience may yet be rewarded).

42x16...I'm now beginning to wonder if I might eventually "move up" from an initial 40x17 to something higher with use and practice, rather than down. Time -- and use -- will tell. I am so looking forward to seeing how the Rohloff combos compare to my derailleur offerings in practice, and have "budgeted" a good-long time for evaluation. It's only fair, given the nature of the hub and how it differs from what I have experienced to date. It now seems entirely reasonable that one might own essentially two Rohloffs -- one during the break-in period (during which time the owner also "breaks-in" to the idea of this IGH), then an indefinite long-term period (the rest of ownership) where the hub becomes more and more transparent to the user and use becomes second-nature.

Coming to this from the derailleur world, I had already prepared several little 1-14 "gear charts" for my handlebars, depending on the gearing I would choose...which I think I am going to toss in the rubbish. A gear chart just isn't needed (Yes, Andre, I am beginning to see what you meant). No cross-chaining, no "forbidden" combos, no double-shifts and loss of forward momentum to get from the gear you're in to the gear you need.

Ah.  ...Ah!

Best,

Dan. (the light is beginning to dawn...)

JimK

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #16 on: July 21, 2012, 07:28:20 PM »
No cross-chaining, no "forbidden" combos, no double-shifts and loss of forward momentum to get from the gear you're in to the gear you need.

Yeah, you probably already know from previous experience what bottom gear you need, and that's about the end of it. Nice even regular steps up from there. Simple, elegant.

Stopping and starting on hills is great. I too find it very difficult to get going in 1. So I move up to 4, push hard for a few strokes to get a bit of momentum, then switch back down to 1 to get back to grinding up the mountain. I down to maybe 2.5 mph for the real slogging.

Around here it can be steeply uphill for 50 yards and then steeply downhill. With derailleurs I would be switching both front and back and would barely get the chain settled down before I needed to switch again. When I am exhausted my brain works even worse than usual and I would get really frustrated and constantly get the chain crossed etc. With the Rohloff it is really simple. I can switch from e.g. 3 to 12 in just a couple twists of the wrist, with maybe a couple pedal strokes along the way in whatever intermediate gear I find myself in.

triaesthete

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #17 on: July 21, 2012, 08:38:43 PM »
There are some practical upsides to smallish chainrings and sprockets:

More ground clearance when straddling kerbs or going down a few steps, or lifting the bike over rocks.

Smaller gaps between chain and chainstays to swallow up trailside vegetation.

Shorter chain and less teeth so less to clean and lube. (Lighter too ;) That one is for Pete ;D),

Less vertical drop for the chainring into the trajectory of all the crud thrown up by the front wheel.

Less is more?
Ian

Andre Jute

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #18 on: July 22, 2012, 01:26:18 AM »
There's an additional small complication with the gears. If you want a chaincase or may ever want one, only certain combinations of gears will fit. Since Rohloff gear sets are expensive items, you don't want to throw out a half worn gear train when you fit a chain case.

There are some long articles on the forum in which I detail ten or twelve years of experience with all the major types of chain case. They can all be summarised as, "The only chain case Andre will now recommend is the Hebie Chainglider," among other reasons because it is the least fragile in utility/touring/commuter service. But the Chainglider works only with certain cogs and certain tooth counts on the chainring. (The modular Chainglider adds nothing to this; it's purpose is to adapt the casing to different lengths of wheelbase; it is just a different way of marketing the same parts.)

It's a niggling detail but it is something to keep in mind. I must sleep now, but tomorrow, if you haven't looked it up yet, I can check my records for the permitted Chainglider combinations. I do however remember that 40 tooth chainrings are not catered for. (38, 42 and 44 are permitted, IIRC.)

Andre Jute

Danneaux

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #19 on: July 22, 2012, 01:43:11 AM »
Andre!

I dont' want to keep you up any later, but (for morning) I can tell you the Hebie Chainglider -- and your account of it on this forum, and comparison to other chain cases including the Utopia -- looks ideal for my needs. It would be especially nice, it would seem, in the desert playa, where it would greatly protect the chain from the talc-like dust wheb dry, and the clay-ike goo when wet.

However, I hestitate due to several impediments that worry me --

1) The potential for noise in use. I like my bikes as quiet as possible, and I am concerned a chain case that effectively glides over the chain might also be noisy. It'd be kinda neat of it sort of "hovered" over the chain instead.

2) The difficulty in getting a good fit for the gearing combos I might find best.

3) This link, right here... http://yacf.co.uk/forum/index.php?topic=43859.0 ...where allusion is made to the Hebie Chainglider damaging Rohloff hubs. Apparently, their construction (perhaps glass-filled and therefore somewhat abrasive?) can ride directly on the side flange of a Rohloff and, with time, cut through it like a lathe.

That would not be good.

Andre, what are your thoughts on these concerns, and what suggestions do you have for overcoming them? I'd like to see a Hebie Chainglider in my future, but I am a bit worried. I'd hate to slice the end off the Rohloff like so much dry salami.

Best,

Dan.

il padrone

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #20 on: July 22, 2012, 02:48:52 AM »
The hub damage from a Hebie Chainglider was a very real problem.


That groove to the left of the sprocket..... should not be there  :o


Hebie now have a model of the Chainglider that has been specifically redesigned to suit Rohloff hubs and not cause any damage.

Problem solved.

Danneaux

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #21 on: July 22, 2012, 03:05:26 AM »
Quote
The hub damage from a Hebie Chainglider was a very real problem.
 
:o

Man alive, Pete!

This is *exactly* what I had feared, but my mental picture was not quite so...vivid.

Yikes!

Best,

Dan. (whose nightmares will now be based on the above photo)
« Last Edit: July 22, 2012, 03:07:20 AM by Danneaux »

il padrone

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #22 on: July 22, 2012, 04:00:02 AM »
Yes, it's pretty grim. However the description of damage as:

Quote from: Rohloff
scratching marks occasionally appeared on the hub case by the grinding touch of the Chainglider's rear side

does not seem to gel with that groove.... unless the smudges on the shell are the scratching and the groove is the join between the sprocket and the shell. I had a look at mine and it does not have such a pronounced groove. Puzzled.

Whatever the case the key thing to appreciate is:

Quote from: il padrone
Hebie now have a model of the Chainglider that has been specifically redesigned to suit Rohloff hubs and not cause any damage.

http://www.sjscycles.co.uk/hebie-chainglider-for-rohloff-15-17t-for-38t-black-prod22354/
http://www.sjscycles.co.uk/hebie-chainglider-for-rohloff-15-17t-for-42t-black-prod19788/
« Last Edit: July 22, 2012, 04:01:49 AM by il padrone »

martinf

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #23 on: July 22, 2012, 07:28:02 AM »
I seem to be the odd man out here, or possibly more reckless, as I have now moved to 43x21 to get gear 11 to be what suits me best.

43x21 would probably suit me well - I make that a 77" top with the tyres I use, which corresponds roughly to the highest gear on the Nexus Premium 8 I am currently using to test handlebar setups on my old bike (44x24, so 25" to 76").

As I "spin" short 150 mm cranks, the 76" gear is high enough for me in most situations. It corresponds to 33 kph at 90 rpm and I can push the speed up to about 45 kph for short periods, for example if I need to accelerate to keep up with traffic on a large roundabout.

But I am not too bothered about the warranty on the Nexus, whereas the Rohloff is a much bigger investment. And as I managed with 18" in the Picos de Europa, the 17" low with the "legal" 50x21 setup will be sufficient, although I wouldn't say no to even lower gears and might replace the 50 with something smaller once the hub has passed the initial running-in period.

NZPeterG

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #24 on: July 22, 2012, 09:49:35 AM »
Well my last Rohloff I run 40T to 17T and i'm going to run the same again on My new Nomad (which turned up this afternoon)

Pete..
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il padrone

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #25 on: July 22, 2012, 11:01:51 AM »
Danneaux's already posted that link, but Hebie have designed a version specifically to suit Rohloff IGH.

Cambirder

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #26 on: July 22, 2012, 11:05:40 AM »
I live in flat Cambridgshire and have gone with 44 x 17 with my RST. On the flat I tend to used 12 & 13 most. In the rolling terrain of north Cambs, Essex and Suffolk I seldom use anything below 7 so in theory I could up my gearing significantly, however from time to time I venture north. I found my current set-up is good enough to tackle the 20% gradients I encountered in the Yorkshire Dales (so far the only time gear 1 has been used in anger) so I will put up with the odd fast decent which has me spinning out at around 45 kph to allow me to get up the odd big hill I encounter on my travels, especially as I want to get some AAA audax points this year.

I know gear 11 is supposed to be the most efficient but in practice it think it makes little difference if you spend most of your riding time in another gear.

Cambirder

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #27 on: July 22, 2012, 11:09:03 AM »
How about going down the belt drive route Dan?

il padrone

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #28 on: July 22, 2012, 11:33:35 AM »
Don't confuse the poor man! Besides, belt-drive will require cutting through the Nomad's fine strong seat stay to instal a coupler.

Andre Jute

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #29 on: July 22, 2012, 04:55:06 PM »
How about going down the belt drive route Dan?

LOL! Robin Thorn will organise a shooting party all the way to Portland!