Author Topic: How do my teeth look?  (Read 4558 times)

martinf

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Re: How do my teeth look?
« Reply #15 on: July 19, 2021, 07:58:20 PM »
I'll replace with brand new Truvative 42 steel chain ring, a new Connex 808 (purchased as on hand spare when I mounted the current one 11,000 km ago) and a new splined carrier with new sprocket to replace the old style sprocket still in use.

Be careful when ordering the splined carrier.

There are two different models. The thinner one gives the chainline closest to the screw-on sprocket:

https://www.rohloff.de/en/service/handbook/speedhub/workshop/splined-carrier-conversion

Deviating from the current chainline "might" cause the Chainglider to rub on the seatstay, less risk of this with the #8540s.

steve216c

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Re: How do my teeth look?
« Reply #16 on: May 03, 2022, 02:59:11 PM »
Although I reckon I could have squeezed up to 15,000km on this combo of sprocket and chain, I decided to replace all the running gear yesterday as I wanted to investigate an annoying creak on my UN-BB55 bottom bracket that had covered only around 5,000km. It wasn't wobbling, and after checking it wasn't the pedals, realized that the crank would have to come off for further investigation.

Turns out the BB had simply loosened itself by an estimated 1/32 of a turn. A quick tighten, and creak was go. So my spare is back in the box for when it is really needed.

While I would have loved to have pushed this experiment a bit further, I've been plagued with medical matters since Christmas and am about to go under the knife for the 5th time in as many months in the coming days. So I decided to get it all changed now while I have my strength, so bike has no expected upcoming maintenance expected- hopefully until the next oil change.

The reversed sprocket, chain wheel and chain managed a proud 14,027 km recorded. The first 5,000km were exposed, after which I bought a Chainglider. I believe a lot of wear occured pre-Chainglider due to riding in all weathers and commuting on an unpaved forest path which threw up a lot of debris. I suspect the same combo with Chainglider from the offset would not have worn out so quickly. I did need to shorten my chain by a couple of links due to chain stretch. But got over 3,000km out of the shorter chain. I did notice a couple of times where the chain slipped as the sprocket got 'rounder' and I had begun to need to adjust my rear slider (no eccentric as not a Thorn!) every 600-800km to stop the sliding/jumping.

What did I learn?
1) I was unable to use my chain whip to hold the sprocket for removal as there was little for it to grip against. Nothing a bike shop and a EUR 10- donation couldn't fix. They had to extract the sprocket for me with better quality tools. So if you plan to run your cog down- be prepared for difficulty removing unless you are running a splinted carrier.

2) The whole running gear was getting audible towards the end. Not loud, but that might have bugged some of the purists. The chain no longer sat flat on the chainwheel due to the elongation, and I believe the noises riding was probably friction on the chainwheel struggling with a stretched chain

3) There was some mystery wear on the hub exterior itself. I don't recall if that was there when I purchased the bike. Biks shop suggested it could have been if the chain had been slipping on and off causing a groove to form. Or it might have been the Chainglider with the wrong size Chainglider rear end fitted? When I fitted the new parts, I struggled to see where the Chainglider might have rubbed. The bike shop had a look too and agreed the Chainglider end was in fact correct for the sprocket. Perhaps the chain had been slipping onto the hub and back onto the sprocket (the slipping I had occasionally had?) They were not sure. But I will touch up the groove with some black paint to help me spot if it starts wearing again as a safety precaution.

4) Is it feasible to travel around the world on a Rohloff without needing to purchase new chainwheel or sprocket? https://en.wikipedia.org/wiki/Around_the_world_cycling_record suggests 29,000km would need to be covered. I think it is not unreasonable to believe it possible to get 30,000km+ from a new chain/sprocket/chainwheel if you can keep debris from accelerating chain wear (e.g. Chainglider). So in your pannier of tools to take on the journey, only a spare chain would be needed for when you flipped the sprocket the first time.

Finally- some pics of the worn components:




Having fitted brand new replacement components, it is like a brand new bike feel (albeit with a well run in Rohloff hub). It didn't ride badly before, but it rode beautifully on my 10km test run yesterday. Having said that, it just shows what a marvel the Rohloff system is when you can get a chain/sprocket/chainwheel combo costing approx GBP 50- to take you half way around the world. I'd estimate for the same distance using my derailleur bikes I would have spend 10x that on replacing worn components- notomention more lost hours on repairs/maintenance than the Rohloff would need.

Hats off to this robust and amazing bike innovation which does not cease to impress me and many of you guys too!

If only my bike shed were bigger on the inside...

energyman

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Re: How do my teeth look?
« Reply #17 on: May 03, 2022, 03:09:41 PM »
Anybody got any long distance data on a belt ?

JohnR

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Re: How do my teeth look?
« Reply #18 on: May 03, 2022, 09:49:26 PM »
Anybody got any long distance data on a belt ?
There's a comment at https://bikerumor.com/gates-belt-drive-goes-long-with-new-cdxexp-high-mileage-sprockets-plus-cheaper-cdn-models/ from someone who travelled 31,000km before the belt broke. However, I wouldn't want to embark on a long journey without a spare as I have a vision of some sharp object getting tangled in the belt and triggering premature failure. Fortunately, it's no longer a worry as I recycled my belt drive bike.

Andre Jute

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Re: How do my teeth look?
« Reply #19 on: May 03, 2022, 11:58:50 PM »
14K is already a most impressive mileage on a single chain, Steve.

I donít think much of the theory that the channel in the Rohloff was cut by a slipping chain running on and off the cog. Not impossible, I suppose, but Iíve never heard of such an event.

I think it is more likely that you when you bought the bike you had such stars in your eyes that you never noticed the previous owner had been careless.

When I was a young man, my girlfriend used to say I bought cars with my eyes closed, so I know the feeling of discovering the blemishes laterÖ

steve216c

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Re: How do my teeth look?
« Reply #20 on: May 04, 2022, 06:19:43 AM »
Ö I think it is more likely that you when you bought the bike you had such stars in your eyes that you never noticed the previous owner had been careless.

When I was a young man, my girlfriend used to say I bought cars with my eyes closed, so I know the feeling of discovering the blemishes laterÖ

This is a feasible option. Not sure about having stars in my eyes as I often pick out superficial blemishes on big purchases to intentionally get a better bargaining price when haggling. This is always  with the expectation  that any perfect item would look well blemished  after a week with my 3 kids at home chez Steve 😵‍💫

A week away from my silver wedding, Iíve come to the conclusion that true happiness comes not from seeking to keep everything in showroom condition but from accepting and embracing  blemishes and imperfections.

If only my bike shed were bigger on the inside...

Matt2matt2002

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Re: How do my teeth look?
« Reply #21 on: May 04, 2022, 11:54:52 AM »
Iíve come to the conclusion that true happiness comes not from seeking to keep everything in showroom condition but from accepting and embracing  blemishes and imperfections.


Happiness is the only thing that doubles when shared.
Never drink and drive. You may hit a bump  and spill your drink

PH

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Re: How do my teeth look?
« Reply #22 on: May 05, 2022, 11:35:08 AM »
Although I reckon I could have squeezed up to 15,000km on this combo of sprocket and chain,
Well done on an impressive amount of wear, I've never worn a sprocket down that far, not even close  :o
I'm a little surprised you've done so in the distance, particularly as much of it has been protected in a chainglider. 
I'm getting better than that with an exposed chain, though it may have an easier life than those commute photos you've posted indicate.  I replaced chain, sprocket and chainring when I rebuilt my Mercury two yeas ago, since then it's done 9,200 recorded km, plus a few unrecorded, it's been adjusted once and looks hardly worn.  It's hard to account for the difference, it's used in all weather, mostly on road though that includes some filthy lanes, kept reasonably clean with a wipe and well lubricated.  I wonder how much of a difference the components make?  I'm using the top of the range KMC chain and when I rebuilt it, I upped the size of chainring and sprocket to 47/19 to spread the wear.   
As always, such things are anecdotal, I don't know how it would be possible to account for all the variables.
« Last Edit: May 05, 2022, 12:39:17 PM by PH »

PH

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Re: How do my teeth look?
« Reply #23 on: May 05, 2022, 11:41:24 AM »


That does look like chain rub, my secondhand hub has a bit of that though not as much, I've assumed the chain has unshipped once or twice, it wouldn't take much to go through the anodising.  I'd be tempted to coat it in something to gauge if it reoccurs, nail varnish maybe?

mickeg

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Re: How do my teeth look?
« Reply #24 on: May 05, 2022, 01:25:15 PM »
I wonder if this would cover that up?
https://www.rohloff.de/en/shop/product-detail?tt_products%5Bproduct%5D=99&cHash=39ad2827473f82aa7d026b57497c13bd

I have never seen one so not sure how it is used.  I just remember reading of it when I was researching Rohloff before I bought.

At one time I accidently had the chain on the hub and moved the crank, that put a very slight scoring on the black hub that is noticeable when I clean it.  I just took a photo of it.  It has had a few hundred miles on gravel since last cleaning.  I have the thread-on sprocket.




steve216c

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Re: How do my teeth look?
« Reply #25 on: May 07, 2022, 09:34:51 AM »
@PH- when I purchased bike 2nd hand the previous owner had no idea how far it had been ridden. But the sprocket was visibly sharktoothed. So when I flipped it it was already well worn in one direction and it was only a 3-4000km on the flip side before I noticed that sprocket teeth began to lose their ends. I can only warrant the km I have ridden, of which the first 5000km was fully exposed, ridden in all weathers on daily commute including approx 10km of unpacked forest paths which threw up a lot of crud onto exposed chain. I suspect accelerated  wear occurred during this time. I am hopeful that new running gear all round with fitted Chainglider will see slower decay of new chain/cog.

I have a black touch up stick for car paint which I will try to cover blemish to help identify if it starts rubbing again. But nail varnish would probably have done the trick too. Not sure how shocking pink or ruby red from Max Factor would look adorned on my hub. Good talking point though if I had gone that direction 😜

& Mickeg - I was not aware of that part existing. I will keep an eye on further wear and certainly consider such a fitting if I notice this happening again.

If only my bike shed were bigger on the inside...

PH

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Re: How do my teeth look?
« Reply #26 on: May 07, 2022, 10:10:35 AM »
@PH- when I purchased bike 2nd hand the previous owner had no idea how far it had been ridden. But the sprocket was visibly sharktoothed. So when I flipped it it was already well worn in one direction and it was only a 3-4000km on the flip side before I noticed that sprocket teeth began to lose their ends.
That might explain it.  I've wondered if there's an optimal time to flip a sprocket, in theory the chain should only be wearing a previously unused surface, though if it's been left long enough there might not be much left to wear away.
Likewise with chains, I've never used one to destruction, neither brave or stupid enough to try, I have a feeling it'd always be the sprocket that gave up first. I suspect it's another advantage of a  larger chainring and sprocket, having more teeth and links engaged at all times can't be a bad thing.

JohnR

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Re: How do my teeth look?
« Reply #27 on: May 07, 2022, 10:39:23 AM »
I've just noticed that titanium Rohloff sprockets are available. Do they last better or are they for those people who want to shave another ounce off the weight of their bike after weighing it down with a Rohloff hub?

PH

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Re: How do my teeth look?
« Reply #28 on: May 07, 2022, 11:27:27 AM »
I've just noticed that titanium Rohloff sprockets are available.
Doesn't make much sense - At the same thickness titanium will wear faster than steel, though of course there's different alloys of each and steel's hardness (Brinell) is also dependent on it's manufacture.  On the Brinell index it's usually quoted as 70 ti - 120 steel .
Designing from scratch and having all the wearing parts made in ti, dimensions could be increased to have something longer lasting for less weight, but no one has done that.

EDIT - I wrote the Brinell numbers the wrong way round  :-[
EDIT, EDIT - of course hardness isn't everything, checking the numbers I notice glass is 1,500 but I wouldn't recommend it as a sprocket material.  Which reminds me, when I worked in a tool place, diamond tipped circular saw blades were around twice the price of any other (Carbide?) and were reputed to last four times longer, diamond tipped sprocket anyone?
« Last Edit: May 07, 2022, 12:30:01 PM by PH »

mickeg

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Re: How do my teeth look?
« Reply #29 on: May 08, 2022, 01:43:37 PM »
I have replaced chains several times on my Nomad Mk II without reversing the sprocket, which might have been a mistake.  But when I finally flipped my sprocket, it was so worn that a new chain would catch on the hooked part of the worn teeth as the chain lifted off of the teeth as I pedaled.  It took a while to figure out exactly why I could feel something odd in the feel of it and the odd noise.  I run an even number of teeth (16) on my sprockets, not the Thorn norm of odd (17) number of teeth.  So every other sprocket tooth wears differently as only the chain links with outer plates elongate as a chain wears.

I used to replace my chains at 0.75 percent elongation (or stretch), but now only do that on my derailleur bikes, I run my chains much longer on my Rohloff bike.

I do not recall if anyone on this forum was going to experiment with KMC sprockets, but if my memory is correct, KMC makes a Rohloff sprocket that is thicker than the Rohloff sprocket, instead of an 8 speed chain it uses the wider single speed chain.  If they were both the same steel, I suspect that the wider sprocket would give longer life simply because more metal would have to wear off before it wears out.


I've just noticed that titanium Rohloff sprockets are available.

Doesn't make much sense - At the same thickness titanium will wear faster than steel, ...
...
Which reminds me, when I worked in a tool place, diamond tipped circular saw blades were around twice the price of any other (Carbide?) and were reputed to last four times longer, diamond tipped sprocket anyone?

Fully agree that titanium is softer, I suspect in all alloys would be softer than any steel that anyone chose to use for a sprocket.

I am a geological engineer by training.  Geologists think in terms of hardness on the Mohs scale, diamond has a hardness of 10.  The mineral corrundum is aluminum oxide with a hardness of 9.  Quart has a hardness of 7, tool steel further down the list.  But that is says nothing about brittleness, you hit a diamond with a hammer, the hammer won't break, instead the diamond will. 

But marketing departments love to use the word titanium.  I have even seen clothing listed as titanium even though there was no titanium added to the clothing.  And some razor blade manufacturers have added a titanium coating to the razor for reasons that I am clueless on.