Glennr134

Any input on shamano 600 biopace crank sets. Do most get replaced by conventional sets ? The 1987 Schwinn super sport i just acquired has the 600 biopace. I was wondering if its better left on the bike or switched out for a conventional 600 crank set which i have in the parts box. All the info i seem to read about it is that it did not get good press when it was released. Any suggestions or thoughts would be great!!

bikemig 

I’d just ride it. I doubt you’ll notice it much.

icemilkcoffee 

I purposely sought out Biopace chain rings to put on my Lemond and I think they are great. Very good for hard stomping and stand up pedaling. I wish Shimano didn’t give up on it so soon.

scarlson 

I'm a devotee. I experimented a bunch with them last winter after some knee hypermobility issues and they worked well enough that I installed them on a racing bike, a touring bike, and a tandem. Lon Haldeman and Pete Penseyres set the record for fastest bike ride across the USA on a tandem that was all Biopace. In 1987. And that time still hasn't been beaten.

Try them out. You may really like them.

zukahn1 

Check to see if there good take apart if there are no major lips bad looking spots ride them if not feel free too mix a single bad ring with a conventional ring. I actually switched out a rough small normal ring 28t alloy for a 28t steel no issues actually got a bit better climbing.

polymorphself 

I was skeptical but they’re on my 86 Voyageur and honestly they feel just fine. Can’t personally notice the difference.

79pmooney

Those chainrings use standard bolt patterns. If so you can simply buy circular chainrings and try them. That will tell you far more than pagers of answers to your thread will.

I took a quick look at Sheldon Brown's website and saw that Biopace was made in 130 BCD and 110 BCD. Very popular standards, Finding circular rings shouldn't be hard.

Ben

Lascauxcaveman 

^This^

It's the rings that are BioPace, not the cranks. Use the rings, swap them out for round ones; doesn't matter. The cranks can stay. I have two late 80s Schwinns with BioPace rings. I forget they are BioPace until I look down at them while I'm pedalling. I don't see any reason to change them out.

top506

I would change the 42t small ring for the hard to find 40t, but that's just me.
Love Biopace.

Top

Glennr134

Thank you for the posts. I have only had the bike out on one very short ride . Not long enough to really tell how they are. Its very good to know that i can just change out the rings if i do not like them. Depending on the weather today after work i plan on going out.

Classtime 

I have put quite a few miles on Biopace and go back and forth between them and round rings. I think I can feel the difference pedaling but I can't describe it. Same with front shifting. Leave em.

Trakhak

Biopace chainrings are optimized for riding with a moderate cadence. People who maintain a high cadence seem to prefer round rings (or Rotor rings, in the case of people like Chris Froome).

The Golden Boy 

I've been thinking about hunting down some Biopace II rings for a bike or 2.

FWIW- there's Biopace and Biopace II- and it's my understanding that the Biopace II have a more gentle elliptical shape. My High Sierra ATB has regular Biopace- at 28-38-48- and aside from seeing them, I don't notice that the big rings aren't round, but I do notice the small ring- because it is SO out of round. I had a set of the the SR Ovaltech rings on a bike- and I had to remember that they weren't round.

Also FWIW- I remember a thread here about someone flipping out about how whoever made their crappy bike couldn't even make the chainrings round and got angry when he looked down and saw them...

jdawginsc 

Having had three different sets, I will tell you that the first iteration was uncomfortable (105 version), but the more pronounced Deore was great on MTB cranks. The second “600” version was gentler in ellipse, and I hardly notice it is there.

High cadences were messy.

Doug Fattic 

Yes, recreational riders with a slower cadence liked them just fine. When you are in a fast pace line or racing, the not round chainrings upset your higher rpm cadence. I think the negativity from the highest profile users killed Biopace. Shimano has always been very sensitive to marketing and what they made was based on how well it sold and not on whether the technology was superior.

If I was out for a cruise by myself or with my wife and I was probably pedaling at 70/80 rpm (maybe a bit more), I liked Biopace rings just fine. If i was on a training ride and trying to stay with the big boys with my modest talent, I hated them. To control my speed so I could stay as close as possible to the wheel in front of me (every mm mattered to reduce my effort or I was off the back riding by myself) as well as be prepared to accelerate out of corners or when someone jumped, I had to keep my cadence way up.

Dura Ace made some Biopace rings for a short period which only had a modest amount of ovalness that were designed for the fast crowd. I'll attach a picture.

John Nolan 

I'm a recreational rider: I have biopace on several of my bikes, and like them fine. I certainly wouldn't bother changing them out...I don't really notice them in use.

daverup 

I recently overhauled and started riding a Biopace set on a 89 Diamondback Axis XT. This is my first experience with Biopace as well.
A short ride probably isn't enough time to decide on them. Just looking down at the silly thing while riding makes my comfort level go down.
The longer ride should show you more. I've noticed a bit more noise when chain angle is high, and slight inconsistency on FD shifting.
I still have not decided to keep mine Biopace or change them after 60 miles or so.
Good luck,
Dave

ryansu

I have replaced the bio pace chain rings (not the whole crank) on one bike and I have left them in place on another and I am not sure I can really tell the difference, as bikemig said ride them first then worry about changing them. New Sugino chain rings cost about $30 a piece so swapping them out isn't cheap but you could probably find rings at the co-op if you really felt the need to go round versus oval.

canklecat

Try 'em. I did last year and liked 'em.

For me, it worked best when I slowed down my cadence and pushed harder gears. And it felt better with a shorter crank than I'm accustomed to.

Normally I'm comfortable with cranks from 170 to 175, and usually spin around 90 rpm.

With the 52/42 Biopace rings, it felt better with 170 cranks and cadence around 60-75 rpm.

I also tried the trick of reorienting the Biopace rings to move the lobes around. But eventually I went back to standard orientation. Same trick with other eccentric chainrings -- some folks prefer to reorient them to move the lobes around to better suit their power/rest strokes. Just gotta experiment and see what works for you.

icemilkcoffee 

It depends on how high a cadence. When you are going downhill and you are spinning furiously, you notice your butt is bouncing off the seat. This is because you are overpowering the downstroke. In other words, you are still pressing down on the pedal even when it reaches 6 o'clock. This is what causes your butt to come off the seat. Biopace is designed expressedly to counter this tendency to over-stomp 6 o'clock. And this tendency occurs both when you are spinning fast, and when you are stand-up pedaling.
Now if you have a perfect circular pedaling motion, then you don't need Biopace. For the rest of us, Biopace+ short cranks takes the harshness out of riding.

scarlson 

Yeah I noticed that with Biopace I could maintain a higher cadence without my knees giving me trouble. I know I know, your knees are supposed to hurt less with a high cadence, but I'm not normal. Hypermobility sucks. But spinning with biopace is good for me. I can use longer cranks with biopace than without, because my feet move slower through the points where my joints are at extreme flexion, and things stay together better.

clubman 

You sound like a good candidate for short cranks. Great for mashers.

dunkleosteus

Cool! I'm just getting into vintage bikes and I've been riding around on biopace chainrings on a new old bike (a miyata triplecross) and didn't even notice they were ovalized. I have an oval chainring on my modern mountain bike and I love it. I mainly notice it on steep sandy climbs, which on round chainrings I would tend to spin out and have to put a foot down, maybe even hike-a-bike. I wouldn't even consider taking the triplecross on a trail like that though. I wonder what Shimano's motivation was for putting them on the bike. Maybe in the 90s people really were crazy enough to take such bikes up those steep sandy trails...

LittleGinseng 

Just acquired my first Biopace crank. I've been away from steady riding for a few years now and looking to get back into shape. Have always been a masher so I thought I'd give 'em a try. My 60 year old knees might appreciate the change.

Saw a short vid on youtube where the rings were rotated clockwise (IIRC) 72 degrees. Was supposed to improve the power stroke? Might give it a shot.

Glennr134

I went for a short ride today on the Schwinn and did not see much difference between my Bridgestone with round rings. The big thing was when i would look down and see the rotation. Its a bit odd and am not used to that. I am going to leave them on for now and see where it goes. The bike is a dream to ride and its the highest level bike i own now. 1987 Schwinn super sport. Columbus tenax frame . 600ex group. It is very good to know that i can swap out only the rings if i have to. I have thought about moving the rings around to see if any changes can be felt. But for now she will stay stock. Lol