Hi folks,

I need a Stronglight 122 BCD chainring with 39 or 40 teeth to accommodate my vintage legs. It seems these are hard to come by and when available are expensive. If I can’t find one, I have several different BCD rings with the right tooth count and wonder if I could modify one to get 122 BCD. I checked 118 & 110 BCDs, but they won’t work. Haven’t had a chance to check others, like 130 & 135.The co-op where I volunteer, has a mill and a drill press that I could use for the mod.

Thanks & regards,

Van
AKA: Senior Ryder 00

You might want to also search for Stronglight 49D cranks/rings. For the inner rings, they used the same 122 BCD as their road doubles, presumably to save on chainring costs. The smallest chainring was a 38. I bet a bunch of 40s would have been used in the classic 52/40 x 14-17-20-24-28 'Alpine' double, as well.

39s might be a lot harder to find... I didn't start seeing 39t chainrings until the early 90s, when the 53/39 took over from 52/42 on road bikes. (Plus the bike industry has an irrational hatred of odd-toothed chainrings.)

TL;DR... You might have to buy a crankset.

--Shannon

Paging bulgie , who may have some chainrings that should suit.

Yeah I'm pretty sure I do. I know I have several 38t, know I don't have 39t (never seen one), and probably do have at least a couple 40t.
They're in the basement though, and I had abdominal surgery yesterday, still am not ready to walk down a flight of stairs.

Price for a NOS 38t is $60, sorry so expensive but that's the most popular size for most anyone old enough to be into SL93. Old dudes tend to want lower gears. Early-'70s PX-10 for example often (usually?) came with a 45t inner and that's not low enough for me and my ilk. My supply of 38s is intended for my bikes, I'm not a dealer just a hoarder.

Oh and if that's not low enough, I can sell a 36t for $100. That's not a size SL made in 122 mm BCD, so I made a couple using 36t SL 99 rings. I drilled new holes at 122, counterbored them, and cut the old 86 mm BCD holes off. The outer tips of the 5 spider arms on the crank have to be trimmed to use a 36t, else the chain hits there. Pics on request. Clearly, this is going to have limited appeal for anyone but a confirmed Stronglight geek. I am one of those of course, but there probably aren't many others, not gonna sell a lot of those at that price! Just thought 'd mention it.

Not sure if I have any used 38t but if I do they'll be less, down to maybe $15 for well-used, maybe $40 for lightly used.

If I have used 40t rings, those prices will be lower than for 38t due to being less in-demand. I don't have an inventory in my head and can't go look right now, so hopefully you're not in a hurry.

BTW check out Spa Cycles in the UK. I haven't looked lately but as of a few years ago they were selling SL 122 mm BCD rings that were recently made, like in modern hard alloy (7075) and anodized, technically excellent though they don't look right on a vintage crank. If you just want a rider not a concours-caliber restoration, then that's the smart way to go. Though what with tariff and whatever handling fee the parcel company tacks on for taking your money, it might be expensive — sorry I don't know. And if Spa could get them from SL, then other retailers probably could to, I just haven't seen any.

If someone here knows of a source in the US, do let us know.

Oh here's a couple pics of the 36-45 crank I made for myself recently, and the drilling jig I made to do them on the mill. I can make other sizes too, the limiting factor being availability of the "raw material", which is SL 99 rings in the size and condition you want. If you have a 99 ring you want converted to 122 mm BCD, I'm your guy.





That's not the finished pic of the jig, that's a work in progress. As I drilled the 5 new holes at the 122 BCD, I drilled right through the jig as well as the ring. So the jig can now be used in any old drill-press, doesn't need a milling machine. Just filp it over, and the holes in the steel jig act as drill bushings to align the drill, to drill through the ring bolted to what's now the bottom of the jig. I did a second one that way on the drill press as a proof of concept, went super fast compared to using the digital readout on the mill to position the holes. Pics of the finished jig on request, once I can walk down the stairs...

Oh and I also used that jig to make Triplizer rings, to replace the inner on a 93. It becomes the middle ring of the triple, which also has holes at 86 mm to take a granny down to 28t. This is one I made for me, 28-38-45, not for sale, but I can make more triplizer rings if there are lunatics like me who like the idea.





To be clear, you need a 99 ring to make it out of, and if you have a 99 crankset, you should just use it. Or use any other good triple crank, if triple is what you want. There's no advantage to tiplizing a 93 that I can think of, other than to say you did. It's a little crazy. (I like 'em though!)


.

Only newer-vintage 49 rings will go on a 93 crank. Older 49s used 7 mm chainring bolts, so the holes in the ring are too small to take the 10 mm bolt on a 93 crank.
I don't know when the spec changed, anyone here know? My guess is early '70s.

Here's a 49 crank of the older style with 7 mm holes; note the bolts are not hollow, don't use an allen wrench, so that's your quick visual clue.



Here's Bob Hanson's pic showing the dimensions, valuable for anyone who wants to make repros:

Can you make a big difference by changing the freewheel to a larger 28T sprocket? PastorBob set me up with a 14-28 to make things a bit easier.

One of our list members has them here on his site, Red Clover Components - Red Clover Components - Bicycle Triplizers and Chainrings

Personally I installed an 86 bcd Stronglight crank on my 1982 Peugeot PX 10 with 50/34 rings and a 14-28 6 speed freewheel. It is easy peasy to get low gears with a stronglight 99. Spa Cycles used to sell (and probably still does) new 86 bcd rings.

I still really like a triple, in order to get a wide gear inch ratio range, such as the 100:24 on my mountain bike, along with a 6 or 7 percent ratio progression through the mid and high ranges.

What works best for me is a classic 1.5step Alpine with a crossover to a granny. With a 3x8 setup, I can get about 20 usable gears, omitting the large-large crossover and the first few granny-small combinations.

I am currently running 46-38-28 / 12-13-15-17-20-23-26-30, with plans to swap in a 26 next time I overhaul the bottom bracket and need to pull the cranks, anyway. I tried 48-40-24 in the past, but that 24-to-40 step was a bit much, even for my SunTour XCD front changer, so I ran 48-40-28 instead. I figure 46-38-26 should still shift OK.

I see the inner ring as one cost of aging.

I've got one of these Stronglight 49 (Marque?) with the outer ring mounted on the 50.4 BCD crank.



Every time this subject comes up I go through the posts, and I end up doing nothing.
I'd like to get smaller than my current 52/40. It appears that the TA or VO Grand Cru Outer can fit, but require the matching brand inner.
The tariff situation pretty much makes overseas ordering out of the question.
Does anyone have a simple solution, available from one vendor in the US?
Thanks

FWIW, I'm running a 46/30 on a Nervar 631/633. V/O outer, TA inner. (The V/Os were used hard, and I had wicked chainsuck on the 30.) 50.4/80 BCDs, so TA specs, but as long as your inner BCDs match, you're good to go. (The OG rings on a Nervar are 50.4/128, so I had to change both.)

--Shannon

Peter White is the US vendor of TA rings. https://www.peterwhitecycles.com

Or do a WTB post in the classic and vintage sales forum

or do a search on eBay.

Beauty shot! Circa '74 Moto GJ I assume? Man I love those.

I can sell a TA Pro 5-vis double in most any size combo for probably $120, that's two rings plus all the bolts and spacers. Or could be half that or less, if you can accept used parts.

I can't do an inventory of my TA rings at the moment but I'll dig them out in a day or two after I heal from my surgery. There's a chance that I may be down to my last one of the size you ask for, and these are being hoarded for use on my own bikes, but as long as I have multiples I'll sell them. I have accumulated a decent sized stack o' rings over the last 50 years, sometimes buying close-outs like when a shop goes out of business, or they ditch all this slow-moving "obsolete" stuff. I have bags of chainring bolts that still have French air in them.

Got any for the three-arm TA crank?

bulgie I'll send you a pm.

Hello again,
Thanks for the feedback.

Just a bit of additional info. I’m planning on using my Stronglight cranks, which I have 3 of, on two builds that I will be using as regular riders. Unfortunately, they all have 52/42 rings. Even at my age,I think I can get by with 50/40 tooth rings & a 14-28 freewheel with the terrain around here. The plan is build a rather scruffy mid 70s Raleigh International & nice 1961 Mondia using bin parts. I was given both of these bikes. Trying to keep the initial cost reasonable.
Regards,
Van

Alas no, sold my last 3-attaches a couple years ago.