malcala622 

BFisher 

Ha! You need one of these:

scarlson 

My first Biopace!

Gonna see if they help my knees. Lifting weights and switching to different pedals/shoes seem to be helping, but maybe these too will help? Always game to try a new thing



The small ring has yet to arrive.

TXsailor

This Vetta saddle for my 87 Miami Vice courtesy of seypat Thanks Patrick!

NHmtb

Some old French cleats and tape

xbit05

I would really like to ask a question but it requires me to have atleast 10 post

madpogue 

You can ask a question, you just can't post links or pictures, yet. If you're fixin' on staying, nose around at the other forum sections, leave a few posts today and a few more tomorrow (IIRC you're limited to 5 posts/day), until you pass the 10-post "probation".

merziac

Welcome aboard, don't be shy, ask away.

Mad Honk 

Didn't really come in the post but when dropping off a rebuilt Nishiki mixtie to the co-op, I looked down on the floor. Seems there had been a loose Campy oil dust band hiding under one of the benches. Just what I needed to do a rebuild of a record front hub! Smiles, MH

HPL

I'm curious about just that! Is the overall stress reduced on the the knee during an average to hard ride. I can pick them up at my collective for $5 or less and most are in very good or better condition in regards to teeth wear. They were original on my '80s "funny" bike, but had been removed although I'm considering putting it in stock condition and seeing how things feel after a ride with those rings. It's my back that feels "wrong" on that bike though.
I'd like to hear your feedback as there are other "oval" rings that purport similar advantages.

scarlson 

I will let you know, whenever the little ring arrives and I get out on the Vitus. I have high hopes because the way Shimano designed the rings, the crank rotation slows down through the ends of the stroke, where the knee is changing direction and also at its most-flexed point. They're also not technically ovals, as I read on Sheldon Brown's biopace page.

The specific issue I have is joint hypermobility. I'm way too flexible, my shoulders have dislocated getting out of bed (they pop right back in, which is also unusual) and I can touch my hands flat on the floor with my legs straight. Lifting weights, specifically squatting and split-squatting, I've found my knees wobbling side to side when at more extreme angles. Now I'm noticing it in my pedal stroke. Standing to climb doesn't hurt (even when everything else does), but spinning too fast makes my knees follow erratic tracks and injure easily. And before anyone says I've just got bad technique, I've been cycling for twenty years and gone on twelve months of loaded tour. I could always spin properly. I've just become progressively more flexible and loose-jointed as I've aged.

So my situation is atypical, but I'm thinking Biopace and/or shorter cranks might be helpful.

HPL

Thanks scarlson,
I remember in the 80s when I thought that it would be the trend, but Shimano didn't stick with it, so I never thought about it until I got a frame with them as OE parts. I've read up some on the "Osymetric" brand rings which probably look the oddest of all I've seen. I tend to crank in higher gears (my technique is "not correct") so it would seem that the consistency of stroke would alleviate some joint stress.

Here's a snippet from one manufacturer: "With oval rings, rear tire traction improves greatly on loose and slippery terrain. Smoother power delivery to your rear wheel means that you will be able to maintain better, constant cadence; get less stress on the joints (knees) and therefore be able to keep a certain level of effort for longer. This results in higher average speed. Moreover, 11 studies made by various Universities in the World show that using oval chainrings human legs utilize more muscle groups (compared to round one), but each of them to a lesser degree. Load from pedaling an oval chainring is spread over greater muscle mass which in effect gives you the feeling of fresher and more relaxed legs.” – absoluteBLACK

I'm going to try out the stock set-up on my bike just to see how it feels, but I live in a flat environment and would like to know how they perform on a hilly terrain when in and out of the saddle; the same terrain I cycle in New England. I imagine that after 40 years of cycling with "standard rings" that it might be a bit odd at first depending on how "aggressive" the design is.

HPL

Old stock "Speedy" set for an '80s Gion "Italia" build. Luckily I have a new set of Modolo gum hoods I bought in the '80s for my old bike back in the day, but never got used; now they will. Kept the hoods in some talc, no deterioration.

daviddavieboy

Need better gearing for Eroica CA so I picked this rear derailleur up. The bottle cages were just a bonus. I originally bought this just for the long cage and non broke original pulleys but now I am tempted just to see if it will clean up and use the whole thing. If this is a mash up they did some fine work on the rivets. I think it is original.

HPL

That's a decent "Rally", mine had the long cage swapped out (common). I'd have to see if my rivets have hollow ends on that generation; my 2nd gen variant has that type of rivet though. It is the reinforced variant, but I cannot tell which one (there are 2, subtle difference at reinforcement). I still need that long cage, just don't like the cost for the OE Campy parts; but you need the long cage for over 28t (?).

daviddavieboy

I am using a 30t right now on a Bob Jackson with the wheel all the way back and a short cage NR I am hoping to go to a 34t and then put it back to normal when I get home. Then this Rally? - Nuovo Record ? will go on a touring build I am collecting parts for. There is a NR with the long cage and the original short cage on a facebook group for $130US but I got this for almost half.

Mad Honk 

Good looking derailleur. But like most that come in to me, it needs a complete break down and cleaning. If the movement of the body is solid, I would not do anything to the rivets. I think you will like the look of the cleaned up unit. Most of the ones that come to me look like new after a good cleaning. If you need new jockey pulleys I have been buying sealed bearing units from Chaser Tec that work well. Smiles, MH

jackbombay

I believe that modern oval rings are clocked "opposite" of biopace. Biopace is a lower gear when your cranks are at 9 and 3, and a higher gear when your cranks are at 6 and 12, the idea is that your legs gain some momentum through your power stroke to carry over the top of the crank stroke. I found they were more likely to break traction as you have a lower gear when you have your greatest power thus sending a large torque spike to the rear wheel.

Modern oval rings are generally set up so the gear is higher when the cranks are at 3 and 9 which reduces the torque spike of your pedal stroke to the rear wheel and then the gearing is lower when the cranks are at 6 and 12 when you have much less power.

HPL

I noticed the outer NR plate in the one photo and it didn't even register with me that it was from the same derailleur (duh!); that would certainly explain the disparity of the pivot pins if it is indeed built from the parts of 2 or more units. I have one or more NR derailleurs for nearly every year they were made, and plenty of SRs so no more buying RDs. I could easily fabricate some long cage plates from some billet stock if I want to run a larger rear sprocket, but it's nice to have the real thing. I wrote 28t because I know I've used the short cage NR unit on a gear of that size. If you can feasibly use it on a 30t sprocket then I would probably not need a long cage if the NR unit can cover that range since I rarely use anything over 30t. I think the long cage plates were going for around $50. I'd say you did well in the purchase, even for a "rebuilt" unit.

JaccoW

A second-hand Lepper Tourer in black.

madpogue 

This is going on very faint memory, from BITD when it was introduced, but doesn't Biopace have five phases, actually?

jackbombay

Yea, I don't doubt it, they are severely messed up! :-P

Looking at a BP ring I can sort of make out 4 lobes/peaks, but all in all they are fairly close to oval.

If the BP rings do help your knees scarlson, I have some I'll send along to you for the cost of postage.

Wildwood

Includes Clement Futurox 22mm

bark_eater 

This stuff has been trickling in for a while now. Anyone guess the theme?

billnuke1 

Tourin’...