Classic & Vintage - Cycle Underground Chainrings

Has anyone used Cycle Underground to get hard-to-find sized chainrings in specific sizes?

http://www.cycleunderground.com.au/chainringdesigns.htm

I'm trying to get a 49T 86BCD chainring and they're hens teeth near as I can tell.
These guys seem interesting.

That does look interesting. I could get replacements for my Stronglight 93s for about what they're selling for on eBay and in sizes that aren't available.

i'm not sure what shipping runs, I've got an inquiry into them. I can't imagine its much more than 15 bux to ship

Hmmmmm. Hmmmmm.

I wonder if they'd be willing to tackle Herse-style 3-pin rings for my Stronglight TSsssesssss...?

Why no 118mm BCD (Zeus)?
Why no 128mm BCD (Nervar)? One can admittedly adapt a 130mm ring pretty easily.
Why no 41 and 42T 144mm?
Why no 6-bolt 152mm (TA) and 157mm (Simplex)?

I'd be VERY interested to know if they can reproduce the uber-rare 37t Stronglight 93 (122BCD) chainring?

Even cooler if they could do the drilled "bis" version.

Their site says they can do 122bcd, and their designs include the "look" for the 93 rings. BUT not the small teeth count versions...

Anyone interested in a "group" ask?

From their site:

We also have avaialble in any of the designs above the following bolt circle diameter (bcd) 58 64 68 74 86 94 102 120 122.
No doubt we have probably missed some bcd sizes that you may need.
Simple contact us (http://www.cycleunderground.com.au/contact.htm) and if need be we will add that size of bcd to our jig (http://www.cycleunderground.com.au/productcomingsoon1.htm) and specially cut that chainring for you......no extra charge.

I had a 151 BCD ring made a couple of years back. Very impressed, cool guys to deal with!

But it appears they are not machining for us gear hounds. These are really only for SS/FG and the occasional conversion of a 5 speed Collegiate. :lol:


Because our chainrings are not designed for front gear changes...

Batavus, are you using an FD with your 151 BCD?

Why no 118mm BCD (Zeus)?
Why no 128mm BCD (Nervar)? One can admittedly adapt a 130mm ring pretty easily.
Why no 41 and 42T 144mm?
Why no 6-bolt 152mm (TA) and 157mm (Simplex)?

....oh , you're just too old-fashioned, sir. :)
But I agree.

I'm reviving this dead but not yet badly decomposed thread because I'm wondering if these guys (Cycle Underground) are still in business. Google takes you to a static site that claims Cycle Undergrond has a new improved Web site in the works, but no other information. They don't answer email anymore.
I would like to try these guys again as part of my ongoing quixotic effort to get someone to make me a 122 BCD triplizer ring. They told me a year and a half ago that they could do it, but I stupidly didn't follow up and now maybe it's too late. Still waiting for the outfit in North Carolina that said they could make the ring to actually do it. I email them once a month and they always say "yes, we're going to make your ring any day now." At least I haven't paid them anything yet.
Also, FWIW, I asked the guy at CU about their tooth design--whether it was applicable to derailleur gearing or SS/FG only--and was told that they can make either tooth style. Except that now they're apparently not making anything....
Any of you Australians know what's going on with these guys?

This is a good thread, and a very worthy project.

There is a guy who is doing some amazing machine work. He's currently doing hubs. See this review! http://wheelfanatyk.blogspot.com/2011/10/hub-is-born.html

He sent a note saying that when he's done with this run of hubs, he's moving onto cranks and would consider a prototype triplizer for 122bcd.

I'm still hunting for a 37t 122bcd ring, should anyone discover one!!!

I was out riding my stronglight-equipped bike the other day and that totally reminded me that I want that triplizer badly.

Not sure what's happening with Cycle Underground but they've always been pretty bad with emails. Try phoning them (check the timezone first!).

Btw, the rings work fine with derailleurs as far as I'm concerned. They just don't have ramps and pins like modern chainrings for smoother shifting.

These guys in the UK do custom rings, too. Might want to check with them: http://www.highpath.net/

Might want to check with them: http://www.highpath.net/



Please note


I regret that I've stopped making chainrings and sprockets.

Thank you to all my loyal customers who have sent me so many interesting
orders over the past 25 years. I almost feel that I know some of you
personally - indeed some of you have become good friends!

On this page you can see some of the things I used to make...


:notamused: seems like it would have been a great option.

Hmmm, this all makes me curious - what would be a "fair" price on CNC rings in hard to find bolt circles? Does anyone know the ID of a 122 bcd ring. Not the bcd it self but the diameter where it meets the crank spider.

-Andy

I'm reviving this dead but not yet badly decomposed thread because I'm wondering if these guys (Cycle Underground) are still in business. Google takes you to a static site that claims Cycle Undergrond has a new improved Web site in the works, but no other information. They don't answer email anymore.
I would like to try these guys again as part of my ongoing quixotic effort to get someone to make me a 122 BCD triplizer ring. They told me a year and a half ago that they could do it, but I stupidly didn't follow up and now maybe it's too late. Still waiting for the outfit in North Carolina that said they could make the ring to actually do it. I email them once a month and they always say "yes, we're going to make your ring any day now." At least I haven't paid them anything yet.
Also, FWIW, I asked the guy at CU about their tooth design--whether it was applicable to derailleur gearing or SS/FG only--and was told that they can make either tooth style. Except that now they're apparently not making anything....
Any of you Australians know what's going on with these guys?
The link in the first post (and others on the site) seem to work... not sure if that means anything or not.

Hmmm, this all makes me curious - what would be a "fair" price on CNC rings in hard to find bolt circles? Does anyone know the ID of a 122 bcd ring. Not the bcd it self but the diameter where it meets the crank spider.

-Andyfair price to me is whatever TA is charging for theirs, plus whatever time it takes to program the machine. Price out cad/cam time and you'll see that you can't afford a fair price. People that run this kind of business almost never charge a fair price, which is why they don't usually last past their tolerance for unreasonable customers.

Only have to program it once per design... This gets absorbed by running multiple parts. Small shop, low overhead, and "freedom of expression" can go a long ways when it comes to making cool stuff...

Only have to program it once per design... This gets absorbed by running multiple parts. Small shop, low overhead, and "freedom of expression" can go a long ways when it comes to making cool stuff...

And small "tabletop" CNC rigs are pretty cheap nowadays.

Does anyone know the ID of a 122 bcd ring. Not the bcd it self but the diameter where it meets the crank spider.

-Andy


117mm.

This falls into the "Holy Crap!" category:

Peter B from here and CR list fame, passed this web site onto me. They will manufacture rings "on demand" but it is apparently not cheap. Real problem: the site is in Chinese. Anyone read this?

http://homepage1.nifty.com/ct-seizan/sub03.html

Check out the 36t 122bcd under the 105bis header!!!

Someone, Anyone, tell what that would cost!?!?!?!!??

117mm.

Not sure on that...

But I do have a stronglight 104(?) with a 122 bcd(?)down at the shop. I'll have to grab that before I can get the needed dimensions. I really think this is a doable project for me. I just have to be a little patient waiting for a weekend that a)I'm free and b) the mill's open/between jobs.

Anyone want to post a pic or two for aesthetic purposes?

Check this out! A 122bcd triplizer! ! !

http://i120.photobucket.com/albums/o191/LeicaLad/122adp4232.jpg

here: http://homepage1.nifty.com/ct-seizan/122adp4232.jpg

LeicaLad; I'm wondering what it would take to get these cut in China ???? Might be too much trouble given the relatively small demand.
Certainly would/should be less expensive than the above Japanese site.

Check this out! A 122bcd triplizer! ! !

http://i120.photobucket.com/albums/o191/LeicaLad/122adp4232.jpg

here: http://homepage1.nifty.com/ct-seizan/122adp4232.jpg

Is that a 110 BCD small ring? That only gets you what, four teeth smaller than the smallest 122 ring?
I'm holding out for a 26-tooth granny.
In any case, I'm pumped that other people are getting involved in this. I've wanted one of these things for a long time!

117mm.

Maybe, but measuring that diameter with a regular old metric ruler I get about 106 mm. This is a Stronglight 93 ring we're talking about? I don't see any dimension that looks like 117 mm.

222085Here's a pic of the hypothtical triplizer I've been trying to get someone to make for the past 6 months.

Maybe, but measuring that diameter with a regular old metric ruler I get about 106 mm. This is a Stronglight 93 ring we're talking about? I don't see any dimension that looks like 117 mm.

Uuuh. I pulled a NOS 40t ring for a 93 from my box 'o parts and laid a ruler across it. This was not from bolt holes, but from the inner rim. Not a precise measurement, but it sure looks like 117mm to me.

Am I missing something here?

http://i120.photobucket.com/albums/o191/LeicaLad/IMG_0247.jpg

I don't know if these will display right. If not, I'll be editing the entry.

Between digging in the archives, and help from the CR list, the maker has been found in Japan. BUT, it is still unclear if he's still making rings or not. The main page displays code rather than Japanese (as if that'd help!), but the images are amazing. SO, I understand, are the prices. Think $175 or so per ring. But these are custom made per order, so, according to the deep pocketed collectors, reasonable. Sigh. Anyway...

Check out these tasty photos:

1957 49x36 - perhaps chrome plated steel?
http://homepage1.nifty.com/ct-seizan/stronglight1-12h4936.jpg[/url]
... [ Stronglight made similar looking 5-pin steel chainrings http://www.velo-pages.com/main.php?g2_itemId=11532 ]

1957 type 49d 5-pin 48x36
http://homepage1.nifty.com/ct-seizan/57d4836.jpg

105-bis 36t
http://homepage1.nifty.com/ct-seizan/105bis36.jpg

mod 63/93 50x37
http://homepage1.nifty.com/ct-seizan/6393d5037.jpg

Here's a mod 105/93/63 adapteur. In this case for 42x32 inner rings
http://homepage1.nifty.com/ct-seizan/122adp4232.jpg

More, as we discover more.

:D

Am I missing something here?

http://i120.photobucket.com/albums/o191/LeicaLad/IMG_0247.jpg

My eyes are not that great, but that measurement appears to me to be 107 mm, not 117. Maybe there's something I don't understand about what's happening at the other end of the ruler?

222085Here's a pic of the hypothtical triplizer I've been trying to get someone to make for the past 6 months.

Ah, wasn't sure what a "triplizer" was! Pretty obvious now that I see it. The granny needs spacers, yes? What's the inner bcd we're after here?I'm thinking outer and granny rings to match of course. Something like 52/38/28? Do you have this drawing in a cad format (something other than a *.jpg). I can copy/paste/scale/vectorize in my software so not a deal breaker if you don't. I'm off to the shop to grab my crank after I get some coffee in me. Then I can get back to work on it.

PS looks like 107 to me too.

Well. Duuuh! was right.

107mm.

:o

Ah, wasn't sure what a "triplizer" was! Pretty obvious now that I see it. The granny needs spacers, yes? What's the inner bcd we're after here?I'm thinking outer and granny rings to match of course. Something like 52/38/28? Do you have this drawing in a cad format (something other than a *.jpg). I can copy/paste/scale/vectorize in my software so not a deal breaker if you don't. I'm off to the shop to grab my crank after I get some coffee in me. Then I can get back to work on it.

PS looks like 107 to me too.

My plan was to go for 42 triplizer ring, so traditionalists could go with 52/42/30, half-step true believers (like me) could go with something like 46/42/24 with a five-speed 14-17-21-26-32. (I want a gear low enough to climb Mt. Ascutney--long stretches of 19 percent grade.) I think a 47-42 also works well as straight crossover gearing with a 13-15-17-19-21-24-28 in back. I may have gotten the 47 and 46 switched--I charted both of those out once, but don't have the numbers in front of me now.

Cad work is done! This has a 122 bcd with a 74 bdc for the inner. Got that from Sheldon as the "standard" inner for a triple. Would allow for a 24t granny, again from Sheldon. Inside diameter is 60cm as per jonwvara's drawing. Any input before I move on to the CAM side of the work?

Cad work is done! This has a 122 bcd with a 74 bdc for the inner. Got that from Sheldon as the "standard" inner for a triple. Would allow for a 24t granny, again from Sheldon. Inside diameter is 60cm as per jonwvara's drawing. Any input before I move on to the CAM side of the work?

Wow! You're all over this. Yes, you're right about the ring bcds and tooth counts. The 60 mm inside diameter is kind of arbitrary--it just looked good to me. The important dimension is the 107 mm larger inside diameter where the cranks spider fits against the ring, just inside the 122 mm bcd bolt holes.
Assuming that it really IS 107 mm, that is. That measurement is just based on a rough-and-ready measurement with a ruler--not sure it's precisely right. I would be more than happy to let you borrow a standard Stronglight 93 ring so you won't have to guess on any of the dimensions. Send me a PM with your address and I'll drop it in the mail.
JV

I'm trying to decide which siren call to heed: a 36t inner ring on a double, or a triplizer.

For me, the 42 middle is almost a deal-breaker, because I'm already finding my 38 inner ring so useful.

I think a compact range with the mid ring at 40 makes more sense. 48-50 for top end. But that's just me.

Amazing progress, eh?

I could live with 42 in the middle and that'd leave my 52 for the occasional overdrive gear or two and I'd have enough on the low end just using a 28 tooth inner ring. It turns out on both the stronglights I have the 52 rings are basically toast anyway so I'd happily run a 42-28 compact double and eventually snag another 52 ring off ebay or something... 'course there will be derailleur issues to sort out too. Anyway this is an exciting thread now!

Amazing progress, eh?[/QUOTE]

You've got that right. Things were barely smoldering before. Thanks for blowing on the coals and getting an actual fire going.

I could live with 42 in the middle and that'd leave my 52 for the occasional overdrive gear or two and I'd have enough on the low end just using a 28 tooth inner ring. It turns out on both the stronglights I have the 52 rings are basically toast anyway so I'd happily run a 42-28 compact double and eventually snag another 52 ring off ebay or something... 'course there will be derailleur issues to sort out too. Anyway this is an exciting thread now!

I was going to say that I didn't think you could run the granny gear of a triple as half of a compact double, but I guess you can if you use some kind of a "bash guard" instead of an outer chainring. Not sure how you'd find one in 122 BCD. Maybe you could grind/machine the teeth off a 52-tooth chainring? They seem to be abundant and pretty cheap.

You want the bash guard?

http://www.ebay.com/itm/STRONGLIGHT-CHAINRING-COVER-W-BOLTS-/250905962132?pt=LH_DefaultDomain_0&hash=item3a6b292694

This is its second time around. It has one bid this time. It's light, but puts a big "face" on the crank. I tried one once, but then took it right off. Doing the compact double, tho, might make it worthy.

Here's what it looks like mounted:
http://i120.photobucket.com/albums/o191/LeicaLad/IMG_2597.jpg

That measurement is just based on a rough-and-ready measurement with a ruler--not sure it's precisely right. I would be more than happy to let you borrow a standard Stronglight 93 ring so you won't have to guess on any of the dimensions. Send me a PM with your address and I'll drop it in the mail.
JV

Shouldn't need it. I got the measurment off my SL 104 ring, came out to 107.5 or so. I got the CAM side of things last night. Now I just have to get some material and some free time in the machine! There's a fair amount of real-state in the triangle area over the inner bolt circle. Should we skelatize this. Or we could do some "drillium" work on the whole thing. Or custom "panto" work.... Thoughts?

Nice bashguard, I'll try and keep an eye on it.

I was planning to just leave the 52 on as a vestigal ring but I had also ready to leave the outer ring off as gauche as that may be. I've given even less thought to the derailleur situation but I'm currently trying to resurrect the triplex sport that was shifting the crank.

edit: or run this triplizer on the outer part of the ring?

edit: or run this triplizer on the outer part of the ring?

I think the crank spider would be in the way.

Why no 118mm BCD (Zeus)?


118mm is SR Apex, not Zeus. Zeus was 119mm and unique. Why is it so hard to find a really complete BCD reference chart? I've never found one.

Shouldn't need it. I got the measurment off my SL 104 ring, came out to 107.5 or so. I got the CAM side of things last night. Now I just have to get some material and some free time in the machine! There's a fair amount of real-state in the triangle area over the inner bolt circle. Should we skelatize this. Or we could do some "drillium" work on the whole thing. Or custom "panto" work.... Thoughts?

I'm a pretty utilitarian guy, so my opinion is that "skeletalization" of the ring or any other elaborate treatments are likely to be more trouble than they're worth, given that this is a middle ring--it's not like it's a main design feature. Also, I think we want it to be pretty robust, since the load on the granny gets transmitted through it. Trying to lighten it too much might reduce its stiffness enough to cause problems.
I say build a simple one, see if it works, then get fancy later if it seems worth it.
Of course, you can also design something by making a prototype that's as light as it can possibly be, run it until it breaks, make a new one that's stronger in the broken area, and repeat as many times as necessary until it no longer breaks. That works, too, but it costs more and takes longer.
JV

Sounds good. first part(s) will be made like the above drawings. As far as 'more trouble then it's worth", almost no trouble at all! the materials aleady in the machine and it doesn't care if i wanted to drill one hole or turn the whole thing into chips. I'll be making this out of 7075 T6 aluminum which is far tougher stuff than the alloys of days past. Should hold up all kinds of abuse and last a long time...

Or do FEM to determine strenght requirements.

Who else wants one of these? I'll be making a few. Once set up, CNC's really show their worth when making quantities. Other designs (hopefully) to follow, feel free to PM or post with inquiries. This is pretty cool, "I love it when a plan comes together!"
-Andy