Have a 1989 Fuji with a Shimano FC A452 biopace crankset. Any one know options for switching to regular 42 and 52 chain rings? I was told the FC 6503 might be an option, but can't confirm.

Any chainrings with the correct BCD should work, they don't need to be Shimano rings. I have a pair or 52/42 round rings in 144 BCD I would gladly trade for your Biopace.

you'll need to check the bolt-circle diameter of your crank/current chainrings. Your 400 series "exage" double is probably a 130mm bcd, if it has 52/42 rings, but double check before you buy; it may be 110mm. any rings with a 130mm bolt circle diameter will fit. Things to watch out for: make sure the rings you get are 3/32" for use with derailer systems. (not 1/8" for singlespeed) If you get ramped/pinned rings, make sure they're aligned properly for optimal shifting. (Once you get them, come back on here for help.) If you wish to change ratios, now is the time. It may be easier to source a 39t inner ring, but 42s are plenty common. Here's a fine example of a compatible ring that'd look "right" on your late 80s ride:
https://www.treefortbikes.com/eurl.ax...22346928___325

I'm guessing that your fuji is a 6 or 7 speed system; 8 speed rings shall work fine.

if your biopace rings aren't beat up too bad, pm me. I'd like to buy them.

-rob

Many of us will want the biopace rings, i suspect. Unfortunately, there's no way that the OPs crank has a 144mm bcd.

-rob

Here's another source: https://www.jensonusa.com/store/produ...Chainring.aspx

As it mentions, if using Shimano, match inner and outer ring types.

That's what I figured, but I thought it worthwhile to ask. I wasn't sure if Biopace ever made it to the unusual 144mm BCD size.

Many thanks for the guidance. I’m Canadian and while trying to find someone who will ship to me I came across this comment from Excel Sports, Boulder on their Shimano Ultegra 42 T ring.

“Although it features a 130mm bolt pattern, it should only be used with triple cranks because the tooth profiled and ramping are specifically designed to have this ring sandwiched between two other rings.”

It seems everything I look at is for triples. Is this likely to be a problem?

on your Fuji I would not worry too much about the rings being for triples. as long as you get the correct BCD and make a slight adjustment to your FD you should be fine.

I am going to be out of town for a few more days but I would not mind facilitating a shipment to the great white north.

Shimano uses a 130 BCD for their road cranksets, has for a longtime..
the triple crank was a 110 74, as I recall ..
non round chainrings are a variable radius, so chainring is like several sizes at once.

perhaps a smaller round ring will give a better set of ratios with your rear cluster,
130 cranks can use a 38t small gear, or of course anything larger
Its a common size, so aftermarket chainring sources abound.

Other Non Round chainring suppliers : Highpath Engineering in Wales UK
will make any size and shape you wish, custom

Rotor is a Spanish company that makes non round chain rings, now...
many on the Pro Circuit use them, they have mounting holes all around the inside,
so you determine where the larger and smaller portions of the oval are
in that rotation.... Useful for recumbents as I understand..

Those only fit on much older Campy cranks and a few track cranks.

i have an old set of sugino road cranks that take 144bcd rings...

Forgot about those. I knew Suguino made 144 bcd track cranks but forgot about the road version. Anyway, they are old!

Ah, but there is at least one more! The crank I was referring to is the Sakae that came stock on my 1984 Trek 460 road bike. I was disappointed when I found out I couldn't put a Biopace ring on it (it's been converted to FG/SS.)

Sugino used to be near-perfect copies of Campy. Sugino made 144BCD road and track cranks when Campy did, and 151mm BCD road and track cranks before that (early '70's).

Only in the sense that a "triple" ring will have extra pins and ramps that you don't need. Your Exage cranks are 130mm bolt pattern. This is very common, and you should be able to find them through most online stores, including Canadian, eh?

Surly makes 130 chainrings in 42 and many other tooth counts,
great as a single or an inner chaintring on a double, theyre Stainless steel.
Long wearing..

Salsa another QBP brand name, has Replacement rings Aluminum 7075.
Sugino makes spare chainrings on the cheap end,
TA on the jewelry level of the spectrum, also a 7075 alloy..

Superbe Pro used 144 BCD for a while but switched to 130 at some point AFAICT since ebay has lots of Superbe Pro 130 rings.

If you have a MEC nearby they stock chain rings in a wide variety of sizes.

Pffff.

Absolutely no drama. As Jeff Wills says, it just means there'll be unused shifting aids.

Although it does mean slightly less metal in some of the teeth, which by rights would lead to shorter life.

So you'd be paying a bit extra for fancy bits that won't be used and it won't last quite as long as a plain one.