Author Topic: A quick hello.  (Read 1014 times)

martinf

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Re: A quick hello.
« Reply #15 on: July 05, 2020, 08:35:10 AM »
I'll keep the change to splined hub until the current sprocket wears out and have it done then. SJS are only an hour up the road from me and will take it to them to have it done I think. Will ask their advice on changing the tooth count on the sprocket at that time, if the Current ones seem to have been a standard fit. I'll have a better idea of how it suits me by then.

My approach to wide range multi-speed gearing on a touring/utility bike like my Raven Tour is to choose the high gear to be about 80 inches, which corresponds to about 35 km/h at my target cadence of 90 rpm. For me, that gear is only useful on downhills, with a stiff tailwind or for very short periods sprinting to merge with traffic on a roundabout. In the latter case, I can sometimes get up to 50 km/h by increasing cadence. As for low gears, I can always use something lower than I've got, perhap only under special circumstances, for example a long climb with luggage in the Pyrenees, especially towards the end of a long day of cycling.

38x16 gives a high gear of 88 inches with my tyres, a fair bit higher than I would really like, so I rarely use gear 14. At the time I got the bike 38x16 was the lowest ratio permitted by Rohloff, they have since authorised much lower ratios.

Another constraint for me is the Chainglider, which will only take 15 to 17 tooth sprockets in the Rohloff version. 38x17 gives a high gear of 83 inches. I use a narrow stainless steel Surly chainring, which is supposed to wear less than aluminium, is reversible so you can get even more wear out of it and also fits the Chainglider well.

On my other Rohloff bike, a Raven Sport Tour, the frame geometry means a Chainglider won't fit without cutting bits off. So on this bike I have fitted the largest screw-on sprocket available at the time (19T) to minimise sprocket and chain wear.  With the current splined sprockets you can go up to 21T. I use this bike for fast day rides on good roads and with minimal luggage, so I currently have it set up with 50x19 and relatively narrow tyres to give a high gear of 93 inches (41 km/h at 90 rpm, 54 km/h at 120 rpm, again only really useful on downhills or for very short sprints). I have a stock of alternative chainrings to reduce the gearing as I get older, right down to 42x19 and a 78 inch high gear if necessary. I also have spare 52T and 54T chainrings, but I doubt if I will ever use these on a large-wheel bike.

On a utility bike with a more limited gear range I can do without the 80 inch high gear. My "new" (2014) utility bike has a Nexus 8 Premium hub, geared 38x22, which fits a standard Chainglider, giving a gear range of 23 inches to 71 inches. High gear corresponds to 31 km/h at 90 rpm, low gear is sufficient to tow a loaded trailer up the hill to the recycling centre, but hills near my home in South Brittany aren't as steep as those in Devon.

leftpoole

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Re: A quick hello.
« Reply #16 on: July 05, 2020, 09:11:00 AM »
I've attached a photo of the sprocket, am I right that this one needs the Rohloff tool to take the sprocket off and isn't splined. is it worth having it converted to splined?

After reading that Thorn don't like kickstands due to possible damage I'll be removing this one and getting a click stand at some point which seems to get great reviews though is a little more fiddly to use.


Hello,
I hope that you get much enjoyment from your recent acquisition.
Regarding the sprocket. I do not see any point in changing to a splined type for the sake of it. The sprockets last for what appear millions of miles.
As for 'Thorn' not 'liking' side stands...... It is purely to save any warranty claims for frame damage and because the particular designer does not like side stands. Leave it if you can use it. My opinion is simply my opinion and I would use a side stand but as I like the look of my bikes I do not fit side stands because I think they spoil the 'look'!
Anyhow, as I mentioned, enjoy riding it.
John

 

SafetyThird

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Re: A quick hello.
« Reply #17 on: July 07, 2020, 08:28:53 PM »
PS:  i've heard tell that it rains in Devon, so you might want to look into getting a Hebie Chainglider to cover and protect your chain. 'glider devotees are a little cult within the church of Rohloff, and there's several of us here on the Forum who can tell you about the myths and the various chants and incantations.

Oh yes, it does rain, I had no idea just how much until we moved here. Even my folks who spent 40 years in Ireland commented about it when they came to stay.

I'd not heard of the chain glider so I'm doing a little research, it does sound like a very good idea, does it cause much friction given that it rests on the chain?

SafetyThird

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Re: A quick hello.
« Reply #18 on: July 07, 2020, 08:38:14 PM »
A little bit of a change around today, I took off the thorn comfort bars and stem and put on a steeper stem with some knock-off Jones loop bars. A short test ride suggests I'm going to like them, though I may decide to shorten them a little, but I'll experiment for a while. the bar ends will go once I decide what length the bar will be and I have tape to tape up the bare areas once I'm happy with the gadget layout.

The bars are still a little lower than I'd like but I can't really change that without getting another fork with a longer steerer tube. Jones makes a 2" riser version of their bars and perhaps the folks that make the ones I have will copy that too. I'd buy the ones from Jones but at £150, they're a little unreasonable for what they are.

I'll have to change out my Arkel bar bag because that's far too far out in front with these but that's easily done.




leftpoole

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Re: A quick hello.
« Reply #19 on: July 07, 2020, 09:57:05 PM »
Itís very easy to raise the bars. Buy a riser stem. On EBay orcSJSC I believe. They fit into the current steerer and work like an old quill stem!
Iíve used them in the past and you donít know they are there.
John

SafetyThird

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Re: A quick hello.
« Reply #20 on: July 07, 2020, 10:02:59 PM »
thank you, I'd looked for, and bought a 45 degree stem to raise it but didn't know you could get a completely vertical one. Thanks very much, I'll be doing that shortly then.

martinf

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Re: A quick hello.
« Reply #21 on: July 07, 2020, 10:15:24 PM »
[quote author=SafetyThird link=topic=13858.msg103115#msg103115
I'd not heard of the chain glider so I'm doing a little research, it does sound like a very good idea, does it cause much friction given that it rests on the chain?
[/quote]

I was very sceptical until I got one. There must be some friction, but on my initial test rides it wasn't enough to notice, although the set up I used for the tests (1/8" chain, rather thick TA 1/8" chainring, 1/8" sprocket) was suboptimal for Chainglider use.

I now have Chaingliders on all the family bikes where it is possible to fit one (6 bikes).

Downsides as I see it:
- friction, not really perceptible in my case.
- some rubbing noise, not noticeable if the thing is properly adjusted.
- some extra weight. I'm not racing, so I don't care.
- only fits some specific chainring/sprocket combinations.
- will not fit on some frames, interference between Chainglider and seat stay.
- some chainrings are too thick and will rub, perhaps causing noticeable friction.

Advantages as I see it:
- keeps the chain much cleaner for much longer.
- as a result, significantly reduces time spent on maintenance.
- another result, significantly increases chainring, chain and sprocket life.
- prevents clothing from picking up chain oil. I don't care much, but my wife appreciates it. Also useful on my visitor bikes.

For fixing punctures I consider it neutral. I have to dismantle the rear part of the Chainglider, but leaving the front part on I find it organises the chain and makes it easier to deal with (less likely to fall off the chainring and dangle in the dirt).

It isn't a total answer, as it isn't completely sealed, so with intensive winter use on muddy tracks some water/mud will eventually get in.

A reasonably fair comparaison is between my current two visitor bikes, both with Nexus 8 Premium hubs and very similar chainrings/sprockets, these two bikes generally get a similar amount of use. One has a Chainglider, and has gone for more than a year without transmission maintenance, the other has vertical dropouts and a chain tensioner and has needed chainring, chain, sprocket and tensioner maintenance 4 times during the same period.

Optimal setup for a Chainglider is with a thin 3/32" chainring, I recommend the Surly stainless-steel reversible chainrings, ideally combined with a 3/32" chain designed for single-speed/hub gear use, although standard 8-speed derailleur chains also work, and a 3/32" sprocket.

Starting out with a new chain gives better results, with the SRAM or KMC chains I have used the factory lube lasts for several thousand kms in ordinary use (all weather commuting, utility riding, on-road touring).


SafetyThird

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Re: A quick hello.
« Reply #22 on: July 08, 2020, 10:38:48 AM »
Thanks Martin, that's really useful info. Currently I have a thorn 38t on the front and 16t on the back so it should fit if I go that route. The surley reversible steel sprockets seem to be highly recommended so when I next have to change a sprocket out I'll go with one of those.

martinf

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Re: A quick hello.
« Reply #23 on: July 08, 2020, 11:10:10 AM »
Currently I have a thorn 38t on the front and 16t on the back so it should fit if I go that route.

You might have an issue with the Thorn chainring, IIRC these are relatively thick.

38x16 is one of the combinations that work with the Rohloff version of the Chainglider.


SafetyThird

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Re: A quick hello.
« Reply #25 on: July 08, 2020, 12:29:33 PM »
Thanks for that. I've also seen these which might be an option, not sure if the different heights are the difference in vertical height or horizontal length of the stem.

https://www.sjscycles.co.uk/stems/100-humpert-comfi-1-18-inch-stem-318mm-clamp-black/

leftpoole

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Re: A quick hello.
« Reply #26 on: July 08, 2020, 12:52:15 PM »
Thanks for that. I've also seen these which might be an option, not sure if the different heights are the difference in vertical height or horizontal length of the stem.

https://www.sjscycles.co.uk/stems/100-humpert-comfi-1-18-inch-stem-318mm-clamp-black/

I have seen one and I did not like it. But of course it depends how much higher you want to go. It has only a sort rise.
Personal opinion.
John

spoof

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Re: A quick hello.
« Reply #27 on: July 08, 2020, 02:32:44 PM »
As a help, here is one that I described.

 https://www.ebay.co.uk/itm/Alloy-Bicycle-Quill-Stem-Adapter-Extender-Riser-22-2-25-4mm-28-6mm-Adaptor-UK/324204397847?hash=item4b7c168517:g:a6gAAOSws-xe7auY

https://www.amazon.co.uk/Deda-Elementi-Adapter-22-2mm-25-4mm/dp/B0083QRHAE/ref=pd_sbs_200_1/262-2339586-2917953?_encoding=UTF8&pd_rd_i=B0083QRHAE&pd_rd_r=c44f0fc0-d4c4-40f0-8f0c-c3c3d320d19b&pd_rd_w=anMvR&pd_rd_wg=kFBLz&pf_rd_p=2773aa8e-42c5-4dbe-bda8-5cdf226aa078&pf_rd_r=2SRSKE3NB288F031KS1E&psc=1&refRID=2SRSKE3NB288F031KS1E

Do these quill stem risers work with the gentlemans bicycle headset? I thought one must have the threaded type headset in order to use quill style stems that secure via wedge clamp. The picture of the bicycle looks to have a threadless headset with star nut inside the steerer as such the ergotec one linked by the new owner will be suitable.
Maybe the product linked below be another option to help dial in adjustment for both height and reach. Do check the safety information in the datasheet first before making decision because there will likely be a minimum amount of available steerer required for the riser to clamp safely to.

https://www.amazon.co.uk/Satori-400441-Height-Adapter-Black/dp/B005PM5S5A/ref=asc_df_B005PM5S5A/?tag=googshopuk-21&linkCode=df0&hvadid=341145103353&hvpos=&hvnetw=g&hvrand=6096169901531691737&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9045649&hvtargid=pla-562688850427&psc=1&th=1&psc=1

Kind Regards,
Kyle

PH

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Re: A quick hello.
« Reply #28 on: July 08, 2020, 02:44:46 PM »
Plenty of ways to raise the bars, but if the bike is a keeper, I'd bite the bullet and get a framebuilder to extend the steerer.  I've never needed it done, but Dave Yates did it for a friend a few years ago and did so without disturbing the paint, also claimed it was stronger than the original.  Several builders have replacement steerer on their repair list, Bob Jackson for example charge £60. You could easily spend more than that experimenting with other options.

SafetyThird

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Re: A quick hello.
« Reply #29 on: July 08, 2020, 04:09:08 PM »
This bike's definitely a keeper, everything else is the correct size. Most of the photos I've seen of various Raven Tour bikes show a longer steerer tube with higher bars. I didn't know you could extend a cut steerer tube, I'd been looking as a longer term option to replace the fork but if I could just have the steerer extended, that would be a cheaper route and remove any strength worries for the long term.

I wonder if SJS Cycles offer it as a service at all..
« Last Edit: July 08, 2020, 04:12:20 PM by SafetyThird »