Author Topic: What's your Rohloff combo (chainring, cog)?  (Read 169448 times)

rualexander

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #120 on: January 13, 2013, 05:08:20 pm »
......And I'd have to buy a new crankset too, as Surly doesn't make the 36T in 110mm diameter fitting.......
Surly stainless rings from 34t up available for 110 bcd here :
http://www.ukbikestore.co.uk/product/54/crsu10/surly-stainless-steel-chainring-110bcd-5-arm.html

julk

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #121 on: January 13, 2013, 05:13:25 pm »
Andre,
If you need to slow down on hills to give your physician a chance to keep up then you can always move to a 17 cog on the rear :)
Julian.

Danneaux

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #122 on: January 13, 2013, 05:26:18 pm »
Quote
I can go from 38x16 to 36x17 without changing my Chainglider. But only in several years time if I wait for the current parts to wear out.
Hi Martin!

"Careful" as I am to get full value from my purchases, I have occasionally found it worthwhile to make the jump to something else sooner if it better meets my needs. I pondered for some time whether I should stay with 40x17 simply because I already had it, and decided the extra "value in use" of going to 36x17 offset the sunk costs. As it happened, the Surly 'ring cost only USD$24 postpaid new from an eBay vendor, so USD$2/month additional for one year then paid-for, or fractional pennies over the expected lifespan.  

I'm riding the bike a lot and will more, so something that adds to my enjoyment while in the saddle has additional value beyond the cost of whatever it replaces.

I should probably put my near-as-new 38T Thorn 'ring and bash guard up on the Bits For Sale board once I get the Chainglider in place and see if it truly works for me.

Martin, a question for you if I may: Please, can you tell me the length of the chainstays on your RT? I'm pondering whether my Nomad's 470mm/~18.5in chainstays require an extra-long Chaingider or will do fine with the "regular" version. By some measurements, it appears the longer one might be indicated. I presume you're running a Surly 'ring as well?

Andre, Surly make their stainless ring in the following 110mm BCD sizes:
110mm BCD x 34t, 35t, 36t, 38t, 39t, 40t, 42t, 44t, 46t, 47t, 48t, 49t and 50t
Quote
The Deore that Dan and many others have isn't positively beautiful, it is merely negatively not as brutishly clunky as the rest.
No offense taken, Andre; 'tis true! In fact, the entire bike has the brutish appeal of a blunt instrument for getting the job done. Sometimes, beauty is more in a task well-performed; functional aesthetics rather than artistic.

All the best,

Dan.

martinf

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #123 on: January 13, 2013, 05:51:50 pm »
Martin, a question for you if I may: Please, can you tell me the length of the chainstays on your RT? I'm pondering whether my Nomad's 470mm/~18.5in chainstays require an extra-long Chaingider or will do fine with the "regular" version. By some measurements, it appears the longer one might be indicated. I presume you're running a Surly 'ring as well?

450 mm between rear hub axle and bottom bracket centre on the RT.

460 mm for my old 5-speed.

Both bikes have the "regular" Chaingider version, on both bikes measurements will vary somewhat with chain slack adjustment.

Surly ring on the RT after trying with a thicker ring on the old 5-speed.


Andre Jute

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #124 on: January 13, 2013, 05:54:18 pm »
Thanks to all who straightened me out on the availability of Surly SS chainrings in stump-publling tooth-counts.

Julian: I'd better not prod the fellow; he's fitter than I am!

Andre Jute

Danneaux

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #125 on: January 13, 2013, 05:58:03 pm »
Thanks very, Martin; I'll contact Hebie again to see what they suggest for my longer 'stays. The EBB is set to the shorter side at the moment, and I'm still getting ~47cm, which might leave too little at the ends for secure attachment of the end-piece cog cover.

All the best,

Dan.

pelago

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #126 on: January 29, 2013, 02:32:46 pm »




I am quite with my new custom made Rohloff. I found that my bike is rather similar with the one in the picture, and I too. I am a pastor in a city and mostly bike to my duties. In my bike there are vertical dropouts, no chain gilder, no EBB. The chain ring is 38, and the cog is 16. I will perhaps change to 17. During the summer I have a trailer, Bob Yak. A few times I had to walk up a hill last summer, especially in gravel roads with holes. The Bob Yak has a very small tire, 16 inch. But it is easier to drive even slowly than to walk with a trailer.

I am now 60, 198cm and 82kg; well fit but I very seldom use even 11th gear.

In the snow the lower gears have been very useful even in the city.

I can not stand up when biking even in the hills, the bike feels too small.

This thread was interesting.
« Last Edit: January 29, 2013, 02:38:37 pm by pelago »

revelo

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Re: Hebie 38T with 36/17 gearing
« Reply #127 on: January 30, 2013, 10:36:06 pm »
I just finished changing over from my original 42/17 gearing, using a Thorn aluminum 42T chainring to 36/17, using a Surly steel 36T chainring. Chainline with the Thorn chainring was about 55mm, or just over the 54 recommended by Rohloff. Whereas chainline with the Surly chainring was about 52mm. So I added 1.2mm chainring spacers (available at sjscycles) and that brought the chain line to almost exactly 54mm. These measurements are done with a ruler and my measurement error is probably in the range of 1mm. I probably should have used 2mm spacers but I didn't order these, for some reason, and I can't make another order since I'm off on a trip soon.

Because of the much smaller chainring, I now remove 7" from a brand-new 57" chain, rather than 5" as previously. A 50" chain causes the EBB to sit just about in the middle position, so it will probably never be necessary for me to shorten the chain in the field, given that my tours are only about 3000 miles max and I replace my chain at the end of each tour. These are PC830 chains, which I can buy for under $10 (or about £6), so frequent replacement is not expensive for me.

Then I installed the Hebie chainglider for Rohloff 38T version (ordered from sjscycles). As you can see in the picture below, the 38T version is a little large for the 36T Surly chainring, but it seems like it will work. There is clearly some added friction, because before adding the chainglider, the cranks would turn when idling, whereas afterwards they would not. But the friction doesn't seem extreme. There is plenty of clearance at the rear, so no danger of rubbing against the Rohloff shell. Remains to be seen how this gizmo will work on dirt-road tours. My next bicycle tour will be in July.




Danneaux

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #128 on: January 31, 2013, 12:09:06 am »
Hi Frank!

Not to cast a metaphorical stick in the spokes, but I'm a bit concerned about the fit of your Chainglider on the rear portion of the front 'ring. I notice the rear of the chainring is well exposed and this obviates the purpose of the Chainglider. It appears it could pick up excess amounts of dust and grit in your desert use and will draw that inside the case where it will cause problems.

I have a 590M Nomad as well, and have been in contact with Hebie who have helpfully advised me the Extra-Long front unit is appropriate for my chainstay length, rather than the Standard size (they warn a bit of trimming will be needed, but the Standard will be too short for my 'stays). They also advised the 38T front section is appropriate for my 36T 'ring. Apparently, if the Chainglider is connected too tightly with the rear cog cover, the result can be excessive friction of the sort you describe.

Alternatively, if you're at the midpoint in your EBB adjustment, it there may be some length remaining to let the Chainglider out a bit and so better center the front half over the chainring.

All may be well in practice, but it seemed wise to sound a cautionary note in advance of your tour; if it proves to be problematic, it would still be possible to fix it before your departure in July.

Best,

Dan. (...whose comments are well-intended)
« Last Edit: January 31, 2013, 02:39:20 am by Danneaux »

revelo

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #129 on: January 31, 2013, 02:43:06 am »
Hi Dan,

Sounds like you don't know how the chainglider works. The chainglider I ordered from sjscycles is plenty long enough. However, the front part of the chainglider ALWAYS sits snug against the front part of the chainring, regardless of how long or short it is, because it is designed to wrap the chain. That is, there is a "lip" on the chainglider that encloses the chain. Because of this lip, you can't just push the chainglider forwards, since the lip will catch on the chain at the front of the chainring. So if you use the 38T chainglider with a 36T chainring, you will always have the back part exposed as in my photo, regardless of how long or short the chainglider is and regardless of how you attach the rear section.

BTW I didn't describe "excessive" friction. I said there is enough friction to stop the cranks from turning while idling. This crank turning is due to friction at the seal between sprocket and hub. Evidently, the friction of the chainglider is greater than this hub seal friction, but that is not saying much since the hub seal friction is supposed to be minimal. (Though minimal in a well-lubricated hub, the sprocket-hub seal friction is typically greater than BB internal friction, which is almost nil.) There will obviously be some friction given that the chainglider is resting on the chain.

There would still be openings for dust even with a 38T chainring, though perhaps slightly smaller openings.

I'm going to give the thing a shot and see how it works. I doubt it will make things worse. If it does, I just yank it off and throw it in the trash and I'm back where I was originally. I was planning to carry my usual bottle of chain lube (white lightening epic ride, which is silicone-based) anyway.

Andre Jute

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #130 on: January 31, 2013, 09:29:18 am »
Hi Frank!

Not to cast a metaphorical stick in the spokes, but I'm a bit concerned about the fit of your Chainglider on the rear portion of the front 'ring. I notice the rear of the chainring is well exposed and this obviates the purpose of the Chainglider. It appears it could pick up excess amounts of dust and grit in your desert use and will draw that inside the case where it will cause problems.

I have a 590M Nomad as well, and have been in contact with Hebie who have helpfully advised me the Extra-Long front unit is appropriate for my chainstay length, rather than the Standard size (they warn a bit of trimming will be needed, but the Standard will be too short for my 'stays). They also advised the 38T front section is appropriate for my 36T 'ring.

It seems clear to me, Dan, that if teeth are showing, the thing is misfit. What Hebie is in effect saying is that you should cut the length of the extra-long struts (for want of a better name for the two long sections where only the chain runs) to centre  the Chainglider over the chainring. This is marketing field manure; they must be blushing in the engineering department. Together with Frank's photo it is in fact Hebie's admission that the 36T ring doesn't fit the 38T Chainglider. It is quite clear from Frank's photo that, however carefully you fit the Chainglider, in the best fit all the teeth will show at least in part, rubbing off oil on your trousers, taking in dirt. That defeats both purposes of the Chainglider, cleanliness and low maintenance, as you have noted. More, the Chainglider isn't fixed in any way on the chain, it glides as the name tells you, and therefore there's a millimetre or two of play each way, and that guarantees that no matter how carefully you cut the struts, at one time and another, the slippage might amount to a quarter inch, and the bad fit you're starting with means you end up where Frank is, with teeth showing.

Shame on Hebie for giving this sort of shockingly misleading advice.

Andre Jute

Andre Jute

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #131 on: January 31, 2013, 09:53:07 am »
Hi Dan,

Sounds like you don't know how the chainglider works. The chainglider I ordered from sjscycles is plenty long enough. However, the front part of the chainglider ALWAYS sits snug against the front part of the chainring, regardless of how long or short it is, because it is designed to wrap the chain. That is, there is a "lip" on the chainglider that encloses the chain. Because of this lip, you can't just push the chainglider forwards, since the lip will catch on the chain at the front of the chainring. So if you use the 38T chainglider with a 36T chainring, you will always have the back part exposed as in my photo, regardless of how long or short the chainglider is and regardless of how you attach the rear section.

Frank, the lip you describe runs the complete circle around the Chainglider chainring cover, and is flexible enough to part of the chainring and to glide over the thinner ends of spider spokes. It is therefore theoretically possible to centre the Chainglider for 38T chainrings over a 36T chainring, as Hebie claims. But it would be a satisfactory solution only if you never rode, pushed or otherwise disturbed your bike. Under any dynamic condition, sooner or later teeth would show whole, as on your bike.

BTW, I've just been to inspect my bike, and even on the 38T chainring, perfectly fitted and proven satisfactory in 4K of rough roads, the 38T Chainglider is not precisely centred: at rest it sits right on top of the chain and is vertically uncentred by about 3mm. In motion it soon centres itself, which is why I haven't before this noticed the minor asymmetry at rest.

There would still be openings for dust even with a 38T chainring, though perhaps slightly smaller openings.

Theoretically correct, but in practice nothing noticeable gets in. I published photographs, on this forum I think, showing how clean the inside of my Chainglider is. I was quite amazed.

I'm going to give the thing a shot and see how it works. I doubt it will make things worse.

Don't you have a bike with cheaper transmission you can try that on? Just asking... I think it possible that the lip will rub off most of the dirt the oil on the exposed teeth pick up. So you may be right, the Chainglider may still offer a good measure of protection, and a Surly chainring is in any event virtually indestructible. I was thinking more of the expensive, and sometimes difficult to get off, Rohloff sprocket.

Good luck.

Andre Jute
« Last Edit: January 03, 2016, 12:59:17 am by Andre Jute »

Danneaux

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #132 on: January 31, 2013, 05:38:31 pm »
This is going to require a rethink and further research....

...for Science!

Best,

Dan. (...who is rethinking and researching as he writes this)

revelo

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #133 on: January 31, 2013, 07:48:42 pm »
Frank, the lip you describe runs the complete circle around the Chainglider chainring cover, and is flexible enough to part of the chainring and to glide over the thinner ends of spider spokes. It is therefore theoretically possible to centre the Chainglider for 38T chainrings over a 36T chainring, as Hebie claims. But it would be a satisfactory solution only if you never rode, pushed or otherwise disturbed your bike. Under any dynamic condition, sooner or later teeth would show whole, as on your bike.

You can certainly center the chainglider on a 36T chainring WITHOUT a chain mounted. WITH a chain mounted, the chain will hold the chainglider snug against the front of the chainring because of the lip. This wasn't obvious to me either at first. It took me a while of tugging and pushing with the chainglider half-installed to figure out why I couldn't push it forwards, until I noticed the lip.

Quote
Don't you have a bike with cheaper transmission you can try that on? Just asking... I think it possible that the lip will rub off most of the dirt the oil the exposed teeth pick up. So you may be right, the Chainglider may still offer a good measure of protection, and a Surly chainring is in any event virtually indestructible. I was thinking more of the expensive, and sometimes difficult to get off, Rohloff sprocket.

No, just one bike. I live in motels now and my storage bin is too small to comfortably store a spare bike, so I sold my old derailleur MTB and with it the cassette removal tool. I had some fond feelings for the former but good riddance to the latter!

Anyway, my whole bike was filthy for most of my three tours so far. For the Lassen tour, the chain was making horrible squeaking noises, it was so filthy, until I got to town and had a chance to clean it with some sort of spray stuff from the discount store. Despite all this dirt, the Rohloff sprocket shows little wear after 5000 miles. I think the secret is that I change the chain after each tour, which is never more than 3000 miles and I soak the chain liberally with lubricant (white lightening epic ride silicone lube) while on tour. My chain has never exceeeded the .75% mark on the chain wear gauge after a tour.

I believe those horribly worn sprockets you sometimes see are due to people running a very worn chain, and they do this with Rohloff systems because they can, not because it is such a great idea. It goes against the old derailleur wisdom which was to replace chains frequently so as to avoid changing chainrings and cassettes. Andy Blance apparently runs his chain into the ground, but he also notes that using a succession of cheap chains is also possible. And SRAM PC830 chains ARE cheap here in the United States. I get mine for under $10, including tax and shipping, and I could get them for $8 if I ordered in bulk. So that's $30/year if I take 3 tours, or about £20/year. Aside from sparing the sprocket and chainring, I think frequently replacing the chain is good simply because the chain has more moving parts than the rest of the bike combined and is subjected to a lot of wear and tear even if kept immaculately clean and well-lubricated. Frequent replacement means less likelihood of the chain breaking in the field. Not that I've had this happen to me, and of course I carry some spare links and spare master links just for this contingency.

My main concern about this chainglider was the potential for rubbing the Rohloff hub shell, but that problems seems completely fixed with the current version. As is, the chainglider will protect me from most filth on the chain and that alone probably justifies the weight (250g), since I was already considering getting the Thorn chain guard for this purpose, which supposedly weighs 135g (and also requires changing the bottom bracket, which is a PITA), but that would only have protected me from part of the filth. I keep my pants secured against my legs with velcro straps I sewed to the pants, but I sometime find myself leaning the chain against my leg while stopped and fiddling with the GPS or items in my handlebar bag, and the Hebie will protect against soiling when that happens. So for 115g more than the Thorn chain guard, I get much better protection from dirt. If the Hebie also allows me to dispense with my toothbrush and bottle of chain cleaning fluid (20g + 140g = 160g) by reducing if not eliminating chain filth, then it is a net reduction in weight.

Matt2matt2002

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #134 on: January 31, 2013, 09:43:29 pm »
Sorry to jump in here at the tail end.....
Is there an alternative the the Chainglider?
Something that fits to the frame rather that sit in the chain?

Matt ( who knows little but is eager to learn )
Never drink and drive. You may hit a bump  and spill your drink