Classic & Vintage - 120 BCD Chianrings
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07-04-08, 09:16 AM
My Univega viva Touring (believed to be a 1985 model) has 5 bolt, 120 BCD Chainrings that need to be replaced. My Delima is that this pattern has been out of production for about 10 years now :(
So far, my only choice is to replace the cranks for an estimated $70-$80.
Does anybody know of any suppliers or manufacturers that are still offering these Chainrings? I need a 52 and a 42.
Thanks for any info.
07-04-08, 09:19 AM
Do you not mean 110 or 122?
07-04-08, 09:33 AM
Nope, it is a 120 BCD. The LBS mechanic checked it with BCD gauge.
07-04-08, 11:16 AM
Are you absolutely sure it is 120? I have seen 110, 118, 122 and 130, but I have never seen or even heard of a 120bcd crank. What make of crank is it?
If it really is 120, you can elongate the mounting holes of a 122mm Stronglight chainring inward by 1mm each. I have done this very successfully when mounting 130mm rings on a 128mm Nervar spider.
07-04-08, 12:01 PM
John E, thanks for the idea.
I was going to post a link to the B.C.D topic that Sheldon had posted on his site, but I don't see 120 on the list, I'll set the gauge to it again.
07-04-08, 12:12 PM
How old is the LBS mechanic? I bet it is a 118.
07-04-08, 12:46 PM
The LBS mech/owner is 60. I suspect that it is user error more than enything else. The gauge is from Park Tools, and it has markings for all known BCD patterns that have been in production. The gauge landed dead on 120. Before I put it on my bike again, I'll meassure a known 130 BCD crank first to make sure I'm reading it correctly.
07-04-08, 12:49 PM
Given that you said the bike in question is a Univega and assuming it has the stock crankset, I'd say the bcd is likely 110 if it's a triple or 130 if it's a double. You don't need the LBS mechanic to measure it for you; simply measure the centre-to-centre distance b/w two adjacent bolts and then check the conversion table on Sheldon Brown's site.
07-04-08, 02:33 PM
I would definitely check again as the 118bcd Sugino crankset was found on Univegas. Still, that size isn't so easy to find either!
07-04-08, 07:58 PM
118s are tough to come by (My SR Silstar uses one). 122s are relatively easy and I even have some extra 42s (I think).
07-04-08, 08:08 PM
I have to agree that 118mm BCD chainrings are rare, I needed a set for my SR Custom crank and ended up buying a parts bike to get the chainrings.
07-07-08, 10:38 PM
If you confirm these are 118s, which I'm pretty sure they are, let me know. I might have a set of chainrings for you.
Zeus made a proprietary size chainring that was something like 119bcd!
07-09-08, 01:18 PM
I measured and re-measured, they 120 BCD, without a doubt. Since 120 is rarer than the 118 size, I guess I'm replacing the cranks, O'well.
Thanks for the input.
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