Biospace Cranksets, anything special about them?

[yoothgeye]

I walk past 2 Biospace cranksets in and outside of my shop everyday and really have no ideas of what to use them for and I was wondering if they had a following or if they are worth anything? These are the egg shaped chainrings right? What made (or makes) that design special, seems kind of like a gimic to me. One is on a 90s Schwinn mountain bike F&F I stripped down, it's a 3 speed. The other is on a complete Lotus road bike, 2 speed.

I'd thought about using the one with the smaller cogs and stripping it down for my SS mountain bike project, but I don't know how I feel about that egg shaped gear. Wait, my Schwinn road bike might have a Biospace too...

 

[colliwa]

i may be in the minority, but i really like biopace. I have a biopace triple crankset on my 87 schwinn high sierra and much prefer it to anything else i've ridden. It feels easier, and like i get more power with each down pedal. I'm starting a cruiser buildup and am keeping my eye out for another set to put on that one too. I would definitely give it a try

 

[yoothgeye]

i may be in the minority, but i really like biopace. I have a biopace triple crankset on my 87 schwinn high sierra and much prefer it to anything else i've ridden. It feels easier, and like i get more power with each down pedal. I'm starting a cruiser buildup and am keeping my eye out for another set to put on that one too. I would definitely give it a try

I might have the same(ish) bike, it's a High Sierra, frame and fork are a tan color, but the seat stays and chainstays are chocolate brown.

I wasn't sure about using the Biospace on a single speed, but I will be using a chain tensioner.

 

[Bendix]

biopace first arrived on the scene at a time when conventional wisdom said mountain bikers would ride at low rpms- and never ride strapped in like road bike riders. the egg shape was meant to deliver a smoother pedal stroke by more closely matching a 'left-right-left-right' pedalling style. as soon as mountain bike riders (not just the racers) started using toe clips and straps the higher 'spinning' cadences no longer matched the biopace shape and would result in a very weird, choppy pedal stroke. biopace got rounder over the years and shimano tried the less extreme version on road bikes as well but nobody cared...... :roll:

if anything, i would say biopace detracts from the value of a bike since many old mtbs are destined to be single speed projects and of course dedicated ss bikes require round rings for chain tension.....

i will admit i added biopace rings to my schwinn high sierra in 1985 (i think?) and at a low rpm i actually did think it would sort of 'smooth out' the power delivery. i can honestly say i felt a difference in wheel spin on the loose 'dobe dirt' climbs i rode regularly at that time. after i started running clips & straps....no thank you.

 

[colliwa]

Seems like you have the 87 too. I love mine. I think it's the best bike I've ever owned.

I will defer to bendix's opinion on whether biopace is appropriate for a single speed set-up, as i don't have any experience with that.

 

[Bendix]

I will defer to bendix's opinion on whether biopace is appropriate for a single speed set-up, as i don't have any experience with that.

if you're still running a derailleur or some sort of spring loaded tensioner i suppose it's fine- but by 'dedicated ss' i'm just referring to a ss specific frame with track/bmx style dropouts.

 

[yoothgeye]

Very interesting, I did notice that the Biospace on the Lotus looks less oval than on the older Schwinn MTB. I read somewhere that Shelton Brown used Biospace in a fixed gear configuration, so I looked again and now I know EVER MORE!

http://sheldonbrown.com/biopace.html

 

[Bendix]

Very interesting, I did notice that the Biospace on the Lotus looks less oval than on the older Schwinn MTB. I read somewhere that Shelton Brown used Biospace in a fixed gear configuration, so I looked again and now I know EVER MORE!

http://sheldonbrown.com/biopace.html

i remember that!

i don't suppose he'd have been as happy with it if he'd used a first generation mtb ring.... :mrgreen:

 

[yoothgeye]

i remember that!

i don't suppose he'd have been as happy with it if he'd used a first generation mtb ring.... :mrgreen:

True that, it's a huge difference now that I know to look for it. I'm gonna start counting teeth and I'll use the Bio on my SS if I have one that's small enough to keep my weak legs happy on hills.

 

[mojo66]

As stated earlier... you cant use a Biopace on a SS.. The chain will get loose and tight as the chainring goes through its rotatation... I saw one attempted, it wasnt pretty.. I had one on my Trek 830 Antelope MTB in around 1988...

 

[yoothgeye]

As stated earlier... you cant use a Biopace on a SS.. The chain will get loose and tight as the chainring goes through its rotatation... I saw one attempted, it wasnt pretty.. I had one on my Trek 830 Antelope MTB in around 1988...

Read through Shelton Brown's information and he explains how he used Biospacing on his fixed gear and explains why it works. As for my SS, I will be using a tensioner and it won't be a high speed bike, so I might get away with it, if not, start over.

 

[TornadoDave2]

I remember eleptical chainrings coming into vogue for road bikes in the 1970's.... then they went away for a time, only to come back later for mountain bikes. I actually used such chainrings on one of my bikes, and didn't find any advantage to them. They did however cause some shifting problems with the rear derailleur, since the chain slack has to be taken up and let back out by the derailleur twice per revolution of the crank.

I've got a copy of "Bicycle Science" and if I remember correctly, the author thinks that such chainwheels offer no advantage over a regular sprocket.

 

[Bigcam59]

I'm going to share a little known secret with everyone here atRatrodbikes, shared with my by a grizzled old bike mechanic, even older than me :shock: . The real reason Biopace cranks were used was because it helped Shimano's pre-shiftramp index shifting systems work.

 

[yoothgeye]

I'm going to share a little known secret with everyone here atRatrodbikes, shared with my by a grizzled old bike mechanic, even older than me :shock: . The real reason Biopace cranks were used was because it helped Shimano's pre-shiftramp index shifting systems work.

And look how influential they were with a mistake! haha

At this point the only reason I'll be using the Biospace on my single speed (I forgot to count teeth last night during long and tall bike building) is because the Biospace is only crankset I have with removable chainrings. haha

 

[aka_locojoe]

I had them on an old MTB of mine. I once heard that someone concluded they were bad for your knees.

 

[yoothgeye]

I had them on an old MTB of mine. I once heard that someone concluded they were bad for your knees.

Shelton Brown talked about this in his write up, I think this would be a concern for a high RPM extended cadence.

 

[TornadoDave2]

I liked Sheldon.... he was a great friend of mine..... but he was often wrong, you know. He was a huge proponent of Fixies, in spite of their inherent dangers and difficulties. Now after folks have been riding them for a while, they are switching over to single-speed freewheels in droves.

The same thing happened with the elliptical sprockets. Sheldon advocated them for a time, then when folks rode them for a bit, they switched back to plain old round ones. As far as I'm concerned, the Biopace sprockets and similar parts belong in the scrap-bin of inventions that we all tried and didn't like.