104 4 bolt 42 ring in silver

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PT1029
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104 4 bolt 42 ring in silver

Post by PT1029 »

Does anyone know of a good quality 4 bolt 104 BCD 42t single ring (no ramps etc) available in silver?
A few (incl TA) are available in black, a few are available in silver but no bigger than 40t.
Intention is for a single ring on silver Middleburn square taper cranks/104 4 bolt Rohloff spider for Rohloff chain line.

I could use a 110 BCD 5 bolt spider, but that would require a long square taper axle (127mm?), which is in all probability a dieing breed in the long term, shorter axles are more likely to be available for some time I suspect.

Thanks.
brumster
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Re: 104 4 bolt 42 ring in silver

Post by brumster »

Surly stainless steel?
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andrew_s
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Re: 104 4 bolt 42 ring in silver

Post by andrew_s »

There are the Thorn own brand reversible single rings, but they are black only, as are most other options.
I suppose you could polish off the black if you are more style conscious than I am.

If you go 5-arm 110 bcd square taper, there are plenty of options that don't need a 127 mm BB. I used to use a Stronglight Impact triple, with the chainring in the middle ring position.
rotavator
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Re: 104 4 bolt 42 ring in silver

Post by rotavator »

This is not exactly what you are looking for but it is designed for Rohloff's chainline: Stronglight Impact R:
https://www.sjscycles.co.uk/chainsets/3 ... ard-170mm/

I can look up the BB length if you are interested.
slowster
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Re: 104 4 bolt 42 ring in silver

Post by slowster »

PT1029 wrote: 3 Oct 2022, 8:21pm I could use a 110 BCD 5 bolt spider, but that would require a long square taper axle (127mm?), which is in all probability a dieing breed in the long term, shorter axles are more likely to be available for some time I suspect.
My experience is that a Spa TD2 chainset (110 BCD 5 bolt spider) with a 122.5mm Shimano bottom bracket will give a ~55mm chainline for a chainring in outer position, which corresponds to the chainline with the Rohloff slim splined sprocket carrier 8540S fitted.

According to Brucey's Shimano bottom bracket stickout measurements (viewtopic.php?t=105385), it should also be possible to use a 118mm bottom bracket in combination with 3mm spacers between the chainring and spider to give the same chainline. That is providing there is sufficient clearance between the cranks and the chainstays.

Likewise 2mm chainring bolt spacers with a 122.5mm bottom bracket should give a ~57mm chainline corresponding to the standard splined sprocket carrier.

I think if using chainring bolt spacers as outlined above, it would be best to use double chainring bolts and additional spacers as necessary on the inside face of the spider, because I think single chainring bolts do not have enough thread engagement to tolerate spacers being added.
NickJP
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Re: 104 4 bolt 42 ring in silver

Post by NickJP »

You can use NaOH-based drain cleaner to remove black anodising. Here are a couple of Hope five bolt 110BCD rings that were both originally black before I used drain cleaner on the left-hand one to remove the anodising:
PXL_20211203_222029619.jpg
Instructions here: https://lixbmx.com/de-anodising - I'd reduce the time you leave a chainring in the solution from their suggestion - turn the chainring over every minute or so and check it each time to see if the anodising has gone. I found a couple of minutes was sufficient to remove the anodising, and I used the J-bend of a stainless steel spoke through one of the bolt holes to pick up the chainring and turn it over.
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simonineaston
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Re: 104 4 bolt 42 ring in silver

Post by simonineaston »

Does anyone know of a good quality 4 bolt 104 BCD 42t single ring (no ramps etc) available in silver?
I might have such a thing - Lord knows why... the boxes of stuff are still in the jam-jar after the last boot sale. I will potter over to the stables after the staff have served brekkers and have a shuftie.
S
(on the look out for Armageddon, on board a Brompton nano & ever-changing Moultons)
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Mick F
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Re: 104 4 bolt 42 ring in silver

Post by Mick F »

I said on here the other day that I removed the black off my Mirage Triple. The finish of the alu wasn't good, and I had to polish them up a tad. They faded off over a few weeks and needed another polish ad infinitum.

Silver stuff is still anodised. It's not plain alu.
Mick F. Cornwall
PT1029
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Re: 104 4 bolt 42 ring in silver

Post by PT1029 »

Thanks for helpful replies.
Surly stainless, I looked at that, they only go up to 36t (I'd rather bigger for aethetics plus longer transmission life/less wear).
Removing a black finish, I expect a resulting DIY polish finish not as good/durable? (as Mick F says on his chain ring).
I could go black, but I was planning on a black paint (frame), and I'm not sure if silver crank/spider with a black ring and frame would look "right", and for me, black frame/cranks/spider/rings is just, well, too black.

Middleburn is tempting as it reduces food miles of the bike (even if it also reduces my bank balance somewhat).
I could use their Rohloff specific spider and go for a 40t ring (TA available in silver) Middleburn only do this in 4 bolt 104 BCD - I find 5 arm a more pleasing design, though 4 arm has the benefit of rotating the ring 90 deg to even out wear).
Their customer service chap seemed very unkeen on a 5 arm spider (road chain line) as it would need a "very long" BB axle to get the Rohloff chain line (from the Middleburn review in the latest Cycle magazine, I'm guessing it would need 123mm BB which seems ok to me (Cycle article says 113 BB for 44mm chain line). I'm not sure of the Middleburn Q factor, but my frame builder says if Middleburn, he will not have to put intents on the curved chain stays for crank clearance.
Middleburn don't do 104 4 bolt rings in 42t, they suggested TA or Absolutely Black https://absoluteblack.cc/chainrings.html (who I think inhabit a different universe from me! - see their "Hollow cage carbon for Shimano"....)

Spa TD2 chainset says 116 BB for triple (so I guess 116 BB for outer ring in Rohloff chain line(?). I was hoping for a single ring crank which would have much cleaner lines for a single ring than an under used triple, and I would probably mutter every time I cleaned the crank.....).
Spa say 159mm Q factor

Stronglight Impact R (I guess is Sugino?), available in 42t (Thorn website) with a 5 arm spider, says 110 BB for Rohloff chain line. Probably a straight forward way to go!

Sometimes I wish I didn't over think things!
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andrew_s
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Re: 104 4 bolt 42 ring in silver

Post by andrew_s »

Surly stainless chainrings exist in 42T 110mm 5-arm
slowster
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Re: 104 4 bolt 42 ring in silver

Post by slowster »

PT1029 wrote: 4 Oct 2022, 5:28pm Spa TD2 chainset says 116 BB for triple (so I guess 116 BB for outer ring in Rohloff chain line(?). I was hoping for a single ring crank which would have much cleaner lines for a single ring than an under used triple, and I would probably mutter every time I cleaned the crank.....).
Spa say 159mm Q factor
The TD2 is available in both double and triple versions. Spa used to recommend a 113mm BB for the triple version of the TD2. I can imagine a few possible reasons for the change, mainly to do with issues particular to derailleur gears, e.g. 116mm might be more versatile and work with MTB front derailleurs.

As for "so I guess 116 BB for outer ring in Rohloff chain line(?)", based on my own bike the answer to that is no.
PT1029 wrote: 4 Oct 2022, 5:28pm Stronglight Impact R (I guess is Sugino?), available in 42t (Thorn website) with a 5 arm spider, says 110 BB for Rohloff chain line. Probably a straight forward way to go!
Normally I would trust Thorn/SJS implicitly on something like this, but 110mm seems way too short. I think the Impact is the same as the Spa XD2, i.e. a rebadged Sugino XD. Stronglight recommend 127mm and Holland Bike Shop 118mm, and I suspect to get the chainline spot on with a Rohloff, 127mm would be the right choice, combined probably with chainring washers to fine tune the chainline.

http://www.stronglight.com/stronglight/ ... uit?id=308

https://hollandbikeshop.com/en-gb/bicyc ... hloff-hub/

I still think the TD2 with a 122.5mm BB is a better choice, especially if using the default splined sprocket carrier as opposed to the slim model. That would be with the chainring in the outer position, rather than the inner position required if using a chainguard, which I think both looks better and gives a better (lower) Q factor (assuming there is no need to accommodate extra wide chainstays).

Bear in mind that it is unreasonable to expect millimetre perfect frame alignment. If you want to get the chainline perfect with a Rohloff, you need to be prepared for a bit of trial and error and to modify a set up which nominally should be spot on. Thus it might be necessary to replace the BB with one of a different length, use chainring washers and/or fit the slim splined sprocket carrier to fine tune the front and/or rear chainlines.
PH
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Re: 104 4 bolt 42 ring in silver

Post by PH »

Mick F wrote: 4 Oct 2022, 9:10am Silver stuff is still anodised. It's not plain alu.
Not all. I have both Rohloff and SON hubs that are polished rather than anodised. To keep them looking good they need a polish every couple of years. I wonder if the quality of the original polishing effects the time it takes for them to become tarnished.
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Re: 104 4 bolt 42 ring in silver

Post by PH »

slowster wrote: 4 Oct 2022, 7:44pm Bear in mind that it is unreasonable to expect millimetre perfect frame alignment. If you want to get the chainline perfect with a Rohloff, you need to be prepared for a bit of trial and error and to modify a set up which nominally should be spot on. Thus it might be necessary to replace the BB with one of a different length, use chainring washers and/or fit the slim splined sprocket carrier to fine tune the front and/or rear chainlines.
I'm not sure a mm or two matters, Rohloff used to say to try and get the chainline within 1mm, but seem more relaxed about it now.
I's a one off job, so I try and get it perfect, as you suggest that involves some trial and error, whatever it says on the tin. Another couple of tools in the arsenal are BB spacers, and if using a plan insert EBB (As in not a wedge type) then running this a couple of mm off centre does no harm.
Last edited by PH on 4 Oct 2022, 8:16pm, edited 1 time in total.
PH
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Re: 104 4 bolt 42 ring in silver

Post by PH »

and back to the OP - I don't know of such a ring in silver. I was a couple of years ago looking for a bling silver chainset for a Rohloff, I had a couple shortlisted including the Middleburn, but also a BCD110 VO and one from White Ind (Though I can't find it on the current website) none of them were cheap and in the end I spent the budget elsewhere and got the excellent though BLACK Thorn one! I wasn't put off by using a 120+ BB having done so for several years without issue. I tend to run triple cranks with the ring in the middle position and a bashguard on the outer, mainly because I prefer a wider Q factor.
slowster
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Re: 104 4 bolt 42 ring in silver

Post by slowster »

PH wrote: 4 Oct 2022, 8:01pm I'm not sure a mm or two matters, Rohloff used to say to try and get the chainline withing 1mm, but seem more relaxed about it now.
I's a one off job, so I try and get it perfect, as you suggest that involves some trial and error, whatever it says on the tin.
Indeed. For a couple of years I ran my Rohloff believing it had perfect chainline, having measured the front chainline to be almost exactly 57mm. It was only when I checked with the straight edge of a 24" steel rule held up against the chainring and sprockets that I found that the front and rear chainlines differed by a couple of millimetres, I guess because the frame alignment was not millimetre perfect.
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