Author Topic: A non chainglider option  (Read 235 times)

ourclarioncall

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A non chainglider option
« on: April 08, 2021, 06:51:51 PM »
Currently looking at everything thing I would need for rohloff chainglider 38 x 16 setup

I would also like to figure out an option without a chainglider

ourclarioncall

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Re: A non chainglider option
« Reply #1 on: April 08, 2021, 06:54:26 PM »
Part of my enquiry is inspired by a quote from MartinF

“ A possible alternative for long transmission life without a Chainglider might be:

https://www.kmcchain.eu/10000km

Not tried these KMC components myself, and I am unlikely to ever need them for most of my bikes, which already have Chaingliders. “

ourclarioncall

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Re: A non chainglider option
« Reply #2 on: April 08, 2021, 06:57:07 PM »
Also a quote from Thorn bible on gearing ...

“ We like to send our bikes out with a 17t , or even better a 19t sprocket - because the chain will last longer than if you use a 16t sprocket and much longer than if you choose a 15t sprocket! “

45 x 19 is recommended


ourclarioncall

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Re: A non chainglider option
« Reply #3 on: April 08, 2021, 06:58:51 PM »
Another quote

“ I had some threaded 19t sprockets made for us. 19t is still an option with the
NEW SPLINED SPROCKETS.
These give a significantly longer service life. there are more teeth for a start but the greatest benefit is that, as the chain doesn’t have to perform such a tight bend, there’s less opportunity for grit to get behind the side plates. The chain lasts significantly longer and therefore there’s less wear on the sprocket. I believe that the difference may prove to be, the difference between the cube of the number of teeth of the smaller sprocket, compared to the cube of the number of teeth of the larger sprocket - for example, 173 compared to 193 (To save you reaching for your calculator) this is 491 compared to 685, or about 40% more miles for the whole transmission.
There’s a small upcharge - if you choose the 19t option - but it is nevertheless, a real bargain! “

ourclarioncall

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Re: A non chainglider option
« Reply #4 on: April 08, 2021, 07:04:06 PM »
So.... if i go chainglider I’m restricted to a 15,16, or 17 sprocket , but would probably opt for the 16 to got with the 38 x 16 recommendation.

But with no chainglider , IF a 19 offered the benefits mentioned in the quote, but mainly longer life than smaller sprockets then maybe go with that ? Or even higher ? If there is more benefit

The KMC comes in a wide variety of rohloff sprocket sizes from 15T to 21T

The chainrings are 38T OR 42T

martinf

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Re: A non chainglider option
« Reply #5 on: April 08, 2021, 07:54:17 PM »
Thorn are right that using bigger sprockets and chainrings is easier on all the transmission components.

I have 22T sprockets with 38T chainrings on several family bikes fitted with Nexus 8 Premium hubs. This combination also allows a Chainglider, but the ratio wouldn't really suit a Rohloff hub, too low for most people.

On my Raven Sport Tour I have not fitted a Chainglider, for two reasons:

- the Chainglider would need a bit of surgery to avoid interference with the seatstay on this bike.
- I have a fairly large stock of non-Chainglider compatible chainrings to use up.

The Chainglider is also slightly less useful on this bike, as I tend to use it in good weather. Also, as I don't tour on this bike, the shorter maintenance interval is less of an issue (easier to do maintenance at home than on tour).

So instead of being restricted to 38 x 16 or 17 as I was with my "loaded touring" bike I went with the largest available sprocket at the time, which was 19T.

I have a selection of NOS TA Cyclotouriste chainrings in various sizes, picked up when an LBS closed for retirement. I'm currently using a 50T, which gives slightly higher gearing than on my "loaded touring" bike, which is OK for me as I use the Raven Sport Tour for lightly loaded day rides. If I need lower gearing as I get older I can fit smaller rings (down to 42T) and now also have the option of a bigger sprocket. I even have some unused 1/8" rings, so could try the KMC wide sprockets and their (claimed) long-lasting chain. But even without a Chainglider I reckon it will be quite a long time before I wear out the current sprocket and chainring.

JohnR

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Re: A non chainglider option
« Reply #6 on: April 08, 2021, 09:05:14 PM »
I'll add that 42T chainring + 17T sprocket gives about 4% higher gearing than 38T / 16T. You need to figure out what gearing your legs are comfortable with and this is also affected by your choice of wheels and tyres. There's also the option of the open chainglider which protects the chainring and about 2/3rds of the upper part of the chain. However, I think this is more to protect trousers than protect the chain as I've noticed that my chainglider collects a lot of muck on the part which covers the bottom section of chain.

martinf

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Re: A non chainglider option
« Reply #7 on: April 09, 2021, 11:24:52 AM »
Also a quote from Thorn bible on gearing ...

“ We like to send our bikes out with a 17t , or even better a 19t sprocket - because the chain will last longer than if you use a 16t sprocket and much longer than if you choose a 15t sprocket! “

45 x 19 is recommended

50 x 21 with the 21T KMC wide sprocket (more teeth AND more width) combined with the KMC e101EPT chain should theoretically be even better, and still give the same gearing as 38 x16.

But it might be difficult to source a 50T chainring in the wide 1/8" width. The ones I have are unused track rings that fit the (very old) TA Cyclotouriste 5-pin crank design.

Using all KMC 10,000km+ components the combination with their largest chainring size closest to 38 x 16 would be 42 x18.

As JohnR says, you should start by working out what gearing you want.

My own take for a loaded tourer is to decide the biggest gear I really need (i.e. I do without a really big gear for downhills and strong tail winds) and put that as the highest gear, taking account of the limitations of available sprockets/chainrings, and (in my case) Chainglider compatibility.

In 2011-2012 (might be a bit lower now with advancing age) that was a top gear of about 80", which corresponds roughly to 38 x 17. At the time, this was less than the smallest recommended ratio for Rohloff, so I chose 38 x 16 in order to comply with the guarantee conditions. Rohloff have since changed their smallest recommended ratio to 1.9, so 38 x 17 is now OK and even lower ratios are possible.

With 38 x 16, I hardly ever use the highest gear of 88", but the lowest gear of 17" is very welcome on steep climbs at the end of a long day with a touring load and I could sometimes use even lower.

 

Andre Jute

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Re: A non chainglider option
« Reply #8 on: April 09, 2021, 01:13:03 PM »
With 38 x 16, I hardly ever use the highest gear of 88", but the lowest gear of 17" is very welcome on steep climbs at the end of a long day with a touring load and I could sometimes use even lower.

I found that on 622x60mm tyres with 29.45in diameter rolling surface, the utility of the lowest gearing (like the once best-permitted 38x16) was limited for the steeper hills not so much by their inclination but by my ability to keep my balance -- because I'm a masher who never learned to spin. It seems to me that spinning adds a gyroscopic force that aids balance. At
http://coolmainpress.com/BICYCLINGHebieChainglider.html
click the top table to see what I mean. On smaller wheels and tyres the problem of course grows. All the same I was perfectly happy with 38x16 because regular use soon taught me how to approach the piece of road before the difficult section, and soon I pushed nowhere. But a tourer of course doesn't enjoy the advantage of micro-familiarity with the contours of the land.

The coming, in two stages over the last decade or so, of lower permitted transmission chain ratios aggravated the balance problem by making lower speeds for anyone's best* cadence legal.

* not very good in my case!

Sometimes, reading this forum, and not excluding my own posts, I wonder if I've stumbled into a Jesuit seminary...

PH

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Re: A non chainglider option
« Reply #9 on: April 09, 2021, 01:20:21 PM »
But it might be difficult to source a 50T chainring in the wide 1/8" width. The ones I have are unused track rings that fit the (very old) TA Cyclotouriste 5-pin crank design.
You don't need to run a 1/8" chainring with a 1/8th chain, the 50T Surly SS would probably be fine.
What we're talking about here is the difference between something lasting a very, very, very long time and a very, very, very, very long time.
I'm quite keen on longevity, but there still come a point where I'll say that's long enough,  For my own bikes, and my usage, the chances are by the time I've been through a set of components (1 ring, 1 sprocket, 2 chains) I'm likely ready for a change.  On my most used bike that'll be around three years, on my least used around ten years, and my Thorn will be somewhere between those two.

martinf

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Re: A non chainglider option
« Reply #10 on: April 10, 2021, 09:22:25 AM »
You don't need to run a 1/8" chainring with a 1/8th chain, the 50T Surly SS would probably be fine.
What we're talking about here is the difference between something lasting a very, very, very long time and a very, very, very, very long time.

Agree, but if someone really wants the "best possible longevity" they might as well try and go the whole hog!

A 50T Surly SS chainring with one of the biggest available standard 3/32" sprockets combined with one of those (claimed) long-lasting 3/32" chains mentioned by another poster should also be very long lasting.

The "buy relatively cheap chains, not bother about cleaning them, replace them often to save wear on sprockets and chainrings" method could also be a good alternative, it may well be cheaper than getting "the best", whether chain or belt drive. With the right tools, it is quick and easy to remove or fit a chain, wiping one sprocket and one chainring clean before fitting a new chain is easy to do even on tour.

If I ever find an opportunity to use these (claimed) KMC long-lasting sprockets/chains on one of my bikes, for me it will be more a matter of using up my stock of obsolete 1/8" chainrings. Might be worth doing on one of my Bromptons, these have particularly fast transmission wear (relatively small sprockets, chain close to the ground with the small wheels, no way of fitting a Chainglider), but my folding bike mileage has dropped significantly since retiring and the end of daily commuting.

martinf

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Re: A non chainglider option
« Reply #11 on: April 10, 2021, 10:07:34 AM »
I found that on 622x60mm tyres with 29.45in diameter rolling surface, the utility of the lowest gearing (like the once best-permitted 38x16) was limited for the steeper hills not so much by their inclination but by my ability to keep my balance -- because I'm a masher who never learned to spin. It seems to me that spinning adds a gyroscopic force that aids balance.

Another factor is that in a given gear, spinning rather than mashing makes you go faster.

So you can use a lower gear without having balance problems. The lowest gear I have yet used is 15", on a Brompton with double chainrings. That gives me a speed of about 6.5 km/h at 90 rpm, or 4.3 km/h at 60 rpm if I am tired and drop my pedalling cadence. Lowest gear on my Raven Tour tourer is 17" or about 7.5 km/h at 90 rpm, this is with the 38x16 combination.

Lowest gear on my wife's bike is 23", which is good for about 7 km/h at 60 rpm. But she sometimes prefers to walk on some of the steeper local hills, if this happens and I am using my Rohloff-equipped Thorn Raven Tour I can put it into 1st gear and cycle at her walking speed (4 to 5 km/h), which I find easier than pushing.

The top gear on my Raven Tour tourer is 88", which equates to 39 km/h at 90 rpm. Going to 38x17 would lower that to 83" (= 36 km/h at 90 rpm), which is still more than enough for me on a touring bike. Apart from downhill, when I am usually happy to stop pedalling, generally the only time I need to go faster than 36 km/h is to merge with the traffic on roundabouts, for this situation I can up my pedalling cadence to about 120 rpm, which gives 49 km/h with an 83" gear. But only for a very short time!

When touring on a reasonably good road on the flat without a tailwind or headwind, I would generally be in Rohloff gear 9, 10 or 11 with my current setup (20, 23 or 26 km/h at 90 rpm).
.

PH

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Re: A non chainglider option
« Reply #12 on: April 10, 2021, 09:39:46 PM »
Agree, but if someone really wants the "best possible longevity" they might as well try and go the whole hog!
Maybe and a more likely maybe if you're sacrificing chains to achieve it.  If like me you're swapping together, then as I may have said upthread, the ideal is for the three to wear at the same rate. Having one wear less is of no benefit, if it's still too worn to take a new chain the extra wear is wasted when you turn or replace it anyway.
it isn't easy to gather your own data, there's half a dozen variations and it'd take a few years using each before you could make a decent comparison, by which time the product you concluded would be the best is probably long obsolete and you'd have to start again... So at best we're guessing on incomplete data, which leaves me happy to say what works for me, but not to say it's any better than something that works for someone else.