This picture is just an example of what I have. Mine has some major sharktoothing going on. I have spent some time sourcing cobbled together new non oval rings for this and it would cost about $60 for three rings. The smallest one being pretty expensive. Would I be better off just buying some cheap Shimano riveted together $30 cranks set to replace this? Im kind of new at this so it’s a lot of information to process and figure out. Any help would be appreciated!
by Imnothere1980
4 Comments
A new Shimano Acera triple crank with chainrings is $45 shipped (eBay). If you want higher end, used good XT is as low as $60. Lucky for you there are a lot of 1980s bikes being parted, so parts are cheap. Looks like complete crankset is cheaper than replacement rings.
I’ve rebuilt my old bikes twice now, and parts are cheaper with each rebuild.
Did you like the Biopace? I rode a bike with it once, was strange
You don’t need to do anything special when choosing a ring, besides making sure it’s for 3/32″ chain, multi gear (not single speed), and has the correct BCD. Whether you can do that for less than $60, not sure. But I would suspect *maybe*. That said, it’s not like it’s a super nice crankset or anything. I personally hate the riveted ones, but I suppose at the end of the day… If you’re never going to end up replacing the rings and just buy a new crankset with rings anyway… Might as well get the cheap one.
Shimano has not made Biopace rings in decades – they were a bit of a joke at the time because they were poorly designed for doing the thing they claimed to do. If you do want to replace the rings it will be with round rings and the cost is likely more than a cheap new crank. Just make sure the new one you buy is a “square taper” crank like the one you have or you will need a new bottom bracket too. The methods of attaching cranks to spindles have changed a couple of times since these cranks were new in the 1980s
personally, if it were me, i would invest in some decent chainrings and keep the cranks.
i like old cranks. they are usually made of tough alloy, look good (shiny silver > black any day imo), weigh significantly less than a cheap new crankset, and usually have nothing *wrong* with them except for the great consumerism sin of being aged*.
the reason i’d spend money to get decent chainrings is because it’s one part of your drivetrain setup that lasts the longest. keep up on your chain and your cassette, and a chainring can last thousands of miles. plus i think it pays to spend a little on chainrings to avoid the shitty stamped ones that wear out (and wear out your chain!) so quickly.
* ok sometimes old alloy can get a little brittle, yes yes that’s a concern, but not a huge one!