Ah! Of course. As you crank the pedals, for every tooth gained at the top you lose exactly the same at the bottom because the ring has radial symmetry. Very clever, those mechanical engineers. :D

Not that this has anything to do with bent forks.

I should have started this thread... :)

ROFL! So now you tell me... I was wondering why I was getting so many strange looks. I thought it was the inverted handlebar, but it is because everyone (other than me, at least) knows it means "busted for DWI". Doh!!

That's what I wanted to say. I agree that when you look at a perfect circle mated to a non-perfect cicle it doesn't look like it would play nice, but apparently it does.

Kinda like "preloading" the front suspension in rallye racing :D

That is toooo funny :lol:

Fortunately, I'm finished drinking coffee for the day; otherwise, I might have had a mess to clean up.

but isn't it an oval so that when the chain is wrapped around both "points" of the oval (the long ends are up and down) there's more contact than when only one long end is wrapped (when they're horizontal)? maybe I'm just thinking about it all wrong.

Its also for those who suffer from acid-reflux. :rolleyes:

Not wrong. Maybe just too hard. ;)

you are right.. it's just biopace rings are not really "oval".. they very close to round and the difference isn't enough to make the tension an issue.. the chain will not come off if you set the tension properly. I know cause i've made a fixed gear with the same biopace rings that guy is using (well not those exact ones, but the same model)

Biopace chain rings are not a true oval and overcome the deficiencies of oval chain wheels and Shimano described them as a "point-symmetric egg curve".

When you are in the power phase of the pedaling stroke and the cranks are horizontal you engage the smaller radius which allows you to accelerate your foot and then when the pedals are vertical and in the dead spot you are engaging the higher radius which smooths the transition speed as your legs changes direction.

Like Sheldon I agree that this was a great design that should have had broader acceptance among general cyclists and they are particularly nice when you use them on certain bicycles like tourers, mountain bikes, and utility bicycles.

You can spin them at high cadences just as easily and they can smooth things out for some but they really shine at lower cadence when you want to be able to lay down consistent smooth power.

This design has seen a rebirth as other companies are now offered similar designs and these have shown themselves to be quite successful in racing applications.

I suffer from neuropathy in my left leg and this causes some issues with maintaining a smooth cadence and can increase the stress to my right leg which does much more of the pedaling work under high loads. I recently installed a Biopace triple on my commuter / utility bike and also have one on my extracycle and can really notice the benefits this brings.

I have a nice collection of Biopace rings here and plan to retrofit my touring bike as besides the climbing advantage it will allow me to spin higher gears in a smoother fashion as this is where I have the most issues.

I have used Biopace on ss and fixed gear bicycles with no issues and have a Biopace single set up to install on my new winter bike as I think this will be a very suitable application.

this is a tricky one.. i dont think it is but kinda hard to tell

http://i818.photobucket.com/albums/z...i/SDC12646.jpg

http://farm4.static.flickr.com/3219/...fdfb0bee_z.jpg

I don't know. What do you guys think? Is it just the lens effect?

That's a southern hemisphere fork. It just looks odd to us NH people.

I've been riding this on my nightly training runs... Handling's a tad twitchy with its racing geometry and aggressive seating position.

http://www.greenephantom.com/yahoo_s...0632_large.jpg

hipster kids ain't got sh*t on them...... their little skids on fixed gear bikes are peanuts compared to the skills that these chicks possess...

pretty sure this one is bent and turned around lol

http://images.craigslist.org/5Y45W35...3d7a6d17e1.jpg

is this fork bent?

http://i430.photobucket.com/albums/q...t/DSCF9075.jpg
'70s competition gs
http://seattle.craigslist.org/skc/bik/3240215368.html

^ it kinda looks like it but if you look closely you can see the wheel is turned a tiny bit

Nah son that's an Hetchins.

I'd say yes. Though it's made for optional mudguards to be fitted, there is probably not enough space for it. Fork looks suspicious to me...

I would say yes.

Looks like a homage to a Bates Diadrant fork made from a Raleigh fork.

At least the rake is in the right direction - forward.