Initially, I thought no way, but then I read that one of Sheldon Brown's bike used has biopace.

I'm trying to do a very budget FG and have a biopace chainring. I have been riding "SS" in the 42-16 for a little while now and think I'm ready to go fixed with that ratio. I had planned to get a new chainring, but if I don't have to then I'm that much better off.

Also, I really don't want this to be a discussion about how pathetic biopace is, but more informational as to what problems I may run into or whether or not it will work at all.

theres a bike on fgg that was put up in the last couple days with a biopace ring.

I had one. I couldn't notice a difference with it compared to a normal chainring either... my $.02

BTW I was running 38 / 14, or maybe it was 15..

Watching someone ride a fixed with a biopace ring is kinda weird since the chain goes slack, tight, slack, tight... every revolution. Otherwise, it seems to work ok.

everytime biopace is brought up i throw up in my mouth a little

it will work but there's no real benefit in my own honest opinion - its supposed to help with rotation but it almost seems mute considering you're on a fg which in its own, helps you learn better rotation. i'd avoid it, not enough beneficial properties if you ask me.

in theory its not supposed to do this.. but ive never seen one in action

I would imagine that on a geared bike the derailleur would take up the slack, but on a singlespeed or fixed, it is definitely noticible.

Yeah but that happens anyways when someone rides fixed gear without biopace and is lazy on the pedal stroke.

or if the chainring isn't centered properly, or if it's warped at all... there's a lot of things that'll do that

Biopace is feasible and some like it. Go thru some old posts of Ken Cox and you will find what you are looking for.

Thanks for the replies. The main reason I want to go with biopace is that I already have it.

To me, that seems like the only reasonable reason to use it.

I ride a 53t biopace with 17t, 18t and 19t cogs, which give me 82, 77 and 72 gear inches, respectively.

I have lots of chainrings and cogs, and I periodically put on a round ring and a cog that will give me gear inches comparable to my biopace combo, just to refresh my mind on the differences.

I prefer the biopace on subjective grounds.
It feels better to me.
My spin feels rounder and less up-and-down, and the overall effect seems like it buys me two free gear inches.

I tighten my chain so that I have just a tiny bit of play at the tightest point, which gives me about 5/8" play at the loosest point.
I really focus on my spin, and so I don't feel any slack anywhere.

For winter, I ride with the 19t cog at 72 gear inches, so I can stay off my front brake.
At 72 gear inches and a biopace ring (feels like 70 gear inches), I can easily brake with just my legs, without skidding.
I just slow down and stop.

So-called "scientific studies" indicate that the watts work out the same, whether biopace or round, but subjectively, to me, the biopace feels smoother, rounder, and easier.

If I wear out this biopace ring and can't replace it, I'll go back to round rings and enjoy riding my bike.

it almost seems MOOT, not mute. Sorry, I am on a crusade here.

FWIW: had a 42 ramped biopace first off on my conversion, but found a round non-ramped dura-ace 43 and upgraded for the skid patches.

my chain fell off quite a bit with the biopace going over rough ground and had the unfortunate tendency to wrap around the chainstay (nice gouges!). Since the round ring, the chain's stayed on quite a bit better, either because it's non-ramped, or round--I don't know.

It will benefit camy's wallet: if he uses Biopace it means he doesn't have to buy a new chainring.

If biopace is so cool...why don't they make it anymore?

It got replaced. Now you can by cranks that ELIMINATE the "dead-spot" in your pedaling rotation! Why drop just a few coins on new chainrings, when you can spend major bank on new cranks?

One is o-symmetric, the other is power cranks. Power cranks won't work with a fixed gear though.

sorry teach, i'll make sure i study up for the next thread.

Biopace = worse than suicide hub in terms of safety, if you do it use a brake or two. It'll work but it will be VERY easy to throw the chain. And also loud, not smooth & generally a sh***y set up.

I have a totally dead silent chain.
When I ride through a half round underpass I can hear my tires echoing off the walls but not a hint from my chain.
I sneak up on deer and ride right through the midst of them.

It helps to have a perfect chain line, and for a perfect chain line it helps to have a Phil Wood or Miche crank bearing with adjustable cups.

As for a chain coming off easier with a biopace ring than a chain on a round ring, I don't see it.
My chain won't come off unless I loosen the chain tug and the axle nuts.

With a bad chain line and a too-loose chain, I can see a biopace throwing a chain before a round ring would, but with a good chain line and proper tension, no hay problema.

I especially like my biopace on hills, both uphill and downhill.

Going uphill, out of the saddle, the slight delay at the bottom of the spin let's me pull earlier, and I mash less and pull more.
I literally pull myself uphill.
I can do this with a round ring, but even easier with a biopace.

Coming downhill, I tend to ride slower than perhaps most of my fellow fixed gear riders.
Or so I think.
I don't have anyone with whom I can compare myself.
I see another fixed gear rider about once a year.
Anyway, I go slow enough downhill so that I can stop myself without a front brake or skidding.
Again the slight delay at the bottom of the biopace spin lets me put back pressure on the rising pedal earlier in the spin.

From the very first time I rode a biopace ring, it felt rounder to me than a round ring.
A round ring feels like it has more vertical in it than does a biopace.

I think if some of my fellow fixed gear riders rode a biopace without anyone pointing it out to them, they would describe the bike as unusually smooth, but otherwise a fixed gear bike.

If anybody comes to Bend, look me up in the phone book and I'll let you ride my bike.
I think you'll like it.

"I tighten my chain so that I have just a tiny bit of play at the tightest point, which gives me about 5/8" play at the loosest point."

If you have this much slack how will the chain not come off more easily?

"As for a chain coming off easier with a biopace ring than a chain on a round ring, I don't see it.
My chain won't come off unless I loosen the chain tug and the axle nuts."

I had to set one of these up for a customer, with the chain tight enough to pop I could easily derail it in the stand.

I glad Biopace works well for you. I just dont think it should be recommended for fixed riding.

I would think that it would cause the chain to stretch faster because of the increase in load each revolution. Just opinion though...