Egg chainrings, who remembers them?

[brant]

Zak is resting.
No pics of NEMBA that I can think of.
I've been going through a few old topics adding bits.

I've still got that CR7 in my shed you know - and at least one pair of RC35s, an Orange UFO (monocoque alloy URT frame), a Spinergy rear wheel, Hope mechanical disc brake (front) and a set of Box brake levers in my garage somewhere

 

[messiah]

I got Chris Bell to make me so some very odd rings for my Nicolai a couple of years ago. They are lasting very well and he was a pleasure to deal with.

 

[Crell]

Welcome Brant. I have some defective Mad Pads. I have grazed thighs. Am I entitled to a refund?

 

[GeoffApps]

Eggrings

Eggrings are still very much available ~ if you're prepared to pay the extra for quality, durability and your own exact requirements ~ in other words: value for money.
My choice of fairly radical ovality smoothes out the difference between powerstroke and top and bottom dead spots, getting me out of some tight situations.
When chugging along the road, the brain seems to click into the dead spots to tell the fingers which gear to select, so it's tempting to go too high, which make my bike feel sluggish; it still happens, even after 20 years.
It's a shame that Shimano flooded the market with that great cock-up, Biopace, at about the same time as Chris was bringing his rings onto the market. People did not realise that the two types of chainring design couln't be more different.

 

[GrahamJohnWallace]

Apart from trying the useless Biopace back in the 80s I have always used round rings. Well it made sence, if elliptical rings were any good everyone would use them. I wasn't prepared to trade the mechanical advantage of my 24 tooth inner-ring for a harder to push 28 tooth elliptical one.

Whilst walking behind a still cycling Geoff Apps last winter, my 24 tooth ring wouldn't push me through the freezing mud whilst his extremely elliptical equivalent made it look easy, I decided it was time for a rethink.

Only since trying out 45% elliptical EggRings myself have I found out how absolutely brilliant they can be in certain conditions. Nor did I realise how much energy is wasted in gaining enough momentum to move a crank through the deadspot when climbing or pushing through mud. Yes you can climb steeper hills with these rings. The strange thing is that your cadence actualy slows down to almost a walking pace, the deadspot disapears, and you winch the bike up the hill at a speed that keeps things within your lung capacity. No more spin and pray. It's more a case of controlled winching as the front wheel is less likely to lift and the rear is less likely to slip.

You can climb steeper and longer hills with these rings and your less likely to run out of energy or breath. I don't know if you can cycle up hills quicker, though I should do some tests to find out. I do know that these rings don't work at high cadences as your legs have to accelerate through the deadspots. Less elliptical or round outer rings can solve this problem. Though changing from an extreme elliptical, to a round ring and vice-versa, will feel strange for about two minutes as your brain needs time to adapt.

It is only a matter of time before someone influential in the cycling industry tries elliptical rings out and discovers the truth for themselves. We will then have the next big idea in cycling, though this one is actualy ages old and so not patentable. That is unless they do what Shimano did with the Biopace, namely, choose at random of an almost elliptical mathematical shape, and patent that instead. :twisted:

 

[Repack Rider]

During the "klunker" era, when we tried everything we could find, I used a Durham oval chainring as the inner ring with a round outer.

It shifted easily, but I found that whichever shape you had been on for a while, the other felt weird.

Of course I tried Biopace in the '80s. I haven't tried the Eggs, but the general problem with anything but round rings is when you are hitting your RPM limit at high speed. Your feet accelerate and decelerate twice per revolution and a high-speed spin is impossible.

 

[REKIBorter]

Charlie Kelly, Geoff Apps & Brant Richards all on one thread

 

[GrahamJohnWallace]

Charlie Said: 'I haven't tried the Eggs, but the general problem with anything but round rings is when you are hitting your RPM limit at high speed. Your feet accelerate and decelerate twice per revolution and a high-speed spin is impossible'.

The solution to the high cadence spin problem is a hybrid elliptical/round chainset like this one. Shifting is fine but be prepared for the two minutes of the weird sensation in your legs as your brain adjusts to the change from round to extreme elliptical.

This crankset is fitted with a 44 teeth middle ring and can take 45% elliptical inner as small as 23 teeth.

But you do have to make sure the front derailleur has enough capacity to cope with te very small minor axis of the ellipse.

 

[Neil G]

How about square chainrings...reckon that'll be the next 'craze'

I do remember Shimano Biopace BITD, my Muddy fox came with them. Does anyone know why there was a return to round rings if Biopace/oval rings were that good?

 

[GeoffApps]

In this thread, it is really important that you read carefully the posts that have gone before.
Not all oval (or, more correctly, elliptical) chainrings are the same; they're not even similar.
Biopace and Eggrings are opposite in their effects. Therefore, because Biopace was completely wrong, it is unwise to assume that all elliptical chainrings are wrong. It doesn't help that Biopace was brought out by Shimano, with many thousands of pounds brought into play to support the marketing of this design mistake. Eggrings, on the other hand, have been developed by a brilliant engineer buried in the depths of rural Wales with not much more than most people spend on a complete transmission to market his invention. (I might add here that Chris Bell didn't invent elliptical chainrings, but he did invent and develop the software to produce these economically as one-offs to fit all existing cranksets, something it was impossible to achieve prior to the introduction of CAD CAM programmes.)
As a society, we tend to follow the big money, without always questioning what it is actually giving us in return.
So, to answer the question: Does anyone know why there was a return to round rings if Biopace/oval rings were that good?
The answer: because the Biopace concept was crap and correctly designed ovals cannot be marketed in a way that would get manufacturers to fit them in any significant quantity to acheive 'critical mass' ~ a phenomenon vital to the take-up of any 'innovation'.