dddd

I believe those "butt fairing" saddles were banned from competition, making them obsolete only in the rulebook sense, and thus also making them prized by collectors as they are rare.

FBinNY 

yes, competition rules generally ban any kind of faring or added aerodynamics. Aerodynamic shapes are allowed only if they' re the structural elements themselves --- ie, aero tubing, seatposts, and rims --- not anything added.

long john

This was on my shelf.. I have all the parts! It's brand new!I rode the bike with the crank about a 1/4 mile. That's why it's off the bike. Peddling feels like stumbling as you walk.

Chombi

You forgot to add that they are mostly quite fugly too.....

The Golden Boy 

How about the triple pivot Suntour LeTech derailleur.




So, you're thinking- "what's so odd about that?"

There's the normal in/out of the slant parallelogram- and the normal pivot of the cage- but that pivot is on a pivoting arm!

DiabloScott

I don't think the aero part was the reason they were banned though, I think it was because it was an extra point of contact - because you could push against it with the back of your butt. The "three contact points" (feet, butt, hands) was the reason they didn't even allow TT handlebars for a long time. -

Darth Lefty 

How soon until we can put the Elliptigo, Cyco Cycle, and those side-to-side skate-motion trikes whose name I don't know, into this thread?

What about those BMX-style scooters with the 12" wheels? I loved those things but the fad was killed stone dead by the Razor.

willydstyle

Like, I can tell that's not a normal crank set, but what does it do?It looks like the pedal has some ability to move independent of the cranks? What for?

FBinNY 

It's a cam driven chainring advance/****** system * that offers the "benefits" of oval chainrings and other power curve modifiers, without the darwbacks of oval rings. Of course it has it's own issues, but that's a different story.

* that's "re tard", come on censors, really?)

repechage

Nobody has offered up the Facet Biocam yet?

dddd

It creates the "BioPace" effect of varying the effective gear ratio throughout each half-revolution of the cranks.

Using the PowerCam mechanism allowed a similar effect using round chainrings, the better to keep a front derailer functioning as it should, among other considerations.

I've used and raced on the milder "BioPace HP", "BioPace II" and "BioPace SG" versions of BioPace, which have both (or all three) rings in the same 3.5% shape that the largest ring of a BioPace chainset always is.

Regular (earlier) Biopace chainsets use a much wilder shape for the smaller ring(s), with fully 8% variation of the gear ratio.

I have to say I really like the effect of the rounder (3.5%) BioPace rings, the better to bridge larger gaps in one's gearing, so potentially requiring fewer shifts while racing.
I can't spin the original 8% versions of the smaller rings well at all though, and they also limit the smallest chainring size for any given bolt circle diameter.

repechage

Tell that to Scott and those bars Greg used.
If they were not patented, they would still be around, gotta love the UCI.

How Cinelli got the Cinelli Laser passed is beyond my full comprehension. Maybe the first frames were all metal, the ones I have been able to take a magnet to failed that test. Bondo babies.

repechage

Trying to watch all the monkey motion as a bike with that rear mechanism was shifted on the work stand was wild. I guess it worked, but the regular Suntour design worked well enough.

David Newton

I cannot believe this thread has gone 3 pages without the Bicycle Bungee

https://www.youtube.com/watch?v=uLKBy5ioPbg

dddd

Looking back, perhaps the "dual sprung" A and B pivots of the Shimano (Simplex apparently used this also) "Servo-Panta" mechanism were patent-protected at this time(?).

Combining "Shimano's" Servo-Panta dual-springing with Suntour's "Slant Parallelogram" architecture produces the modern, high-capacity derailer.
But before this was done, there were Mountech/LeTech Suntour derailers and Huret Duopar derailers, both of which could cope with the widest-ranging freewheels of the day.

Oh, and the Campagnolo Gran-Turismo was dual-sprung, and with an unusually heavy offset between the guide pulley and the "A" (cage) pivot, so it too can handle huge-ranging gearing strategies, as shown below during my personal Turismo research odyssey:

long john

The POWERCAM device could be retrofitted to any standard bicycle (unlike BioCam) and used very large chain rings and a cam at the center of the cranks facing the bottom bracket cup. This device theoretically allowed the effort to be reduced where the muscles were weakest and to alternately be increased where the muscles were strongest.. not altogether unlike the purpose of the Shimano Bio Pace chain rings.

long john

nice photo

The Golden Boy 

I can't take credit for the LeTech in use- pilfered from the internets- if it's yours- it's a great pic that shows both the cage pivots.

I keep saying I'm going to put my LeTech on a bike (probably my Trek 720). I got it on my Voyageur SP- The bike shifted flawlessly when I got it- tore it apart, cleaned everything up, put it together. When I took it apart, I didn't pay attention to how the derailleur was set up- it's a rear derailleur- how hard can it be? But for whatever reason, the chain tension pulled farthest pulley down pulling the upper pivot down so that the upper pulley didn't make contact with the chain. It didn't matter a whole lot because I had two other derailleurs (1st gen Cyclone, XC Pro) that I really wanted to use on that bike anyway.

The Golden Boy 

What was the reason the DuoPar had such a huge cog capacity? With the Tech derailleurs, it's easy to see that the upper pulley gets pivoted down to make cog clearance. The DuoPar- without a slant parallelogram- shifts very nicely (I can't believe I just wrote that) but I don't know how that both shifted smoothly AND had huge cog capacity without lowering (or raising, for performance) the upper pulley.

Where does the AG Tech fit in that pantheon of 38T cogs?

JohnDThompson 

Yeah, that was SunTour's implementation of an idea that first appeared on the Huret Duopar derailleur, several years earlier:



The additional articulation allows the upper pulley to track the cluster profile more closely than even the SunTour "slant parallelogram." This made it particularly suited for wide range clusters where the single, arbitrary angle of the slant parallelogram would be inadequate.

okane

Just for those who wanted a close up look at the Bummer.

Was on a bike I purchcased last year and tried to ride it once...once!

Now I'm hoping someone will offer me a small fortune for this valuable, rare, one of a kind, vintage, and sure to be a wonder to everyone you meet testament to American cycling technology (sound CL enough?).

KonAaron Snake 

Basically everything on this bike is extinct, and rightfully so!

Aero bottles? X
dynadrive? X
Aero tubing? X
toe clips? X
Dura Ace AX? X

I do think it's a very cool bike.



The Merlin grease guard bottom bracket:

The Golden Boy 

Don't hang me on a hook, my mother hung me on a hook once... Once.

The Golden Boy 

Duh... yes, the DuoPar DOES have that extra pivot.

And yes, the smoothest shifting that I can think of was with barcons, a DuoPar Titanium and a 5 speed Helicomatic freewheel.

clubman 

Weinmann brake bolt adjusters...I hope. edit. Actually whole brake can just disappear. Bad.