Go Back  Bike Forums > Bike Forums > Classic & Vintage
Reload this Page >

How foolish would this be?

Notices
Classic & Vintage This forum is to discuss the many aspects of classic and vintage bicycles, including musclebikes, lightweights, middleweights, hi-wheelers, bone-shakers, safety bikes and much more.

How foolish would this be?

Old 05-28-20, 01:10 AM
  #1  
Andy_K 
Senior Member
Thread Starter
 
Andy_K's Avatar
 
Join Date: Jan 2008
Location: Beaverton, OR
Posts: 12,495

Bikes: Yes

Mentioned: 323 Post(s)
Tagged: 0 Thread(s)
Quoted: 1927 Post(s)
Liked 345 Times in 185 Posts
How foolish would this be?

Unrelated (mostly) to my other effort to replace the spring in a LePree derailleur, and inspired by previous efforts by The Golden Boy (here) and coolkat (here), I've been trying to transplant a 3 pulley cage onto a SunTour Superbe Pro rear derailleur. The Superbe Pro uses the same pulley cage spring mechanism as their 3 pulley derailleurs, so I thought it might work. It bolts on easily enough, but there's a problem. The pivot stop on the body of the Superbe Pro derailleur is about 90 degrees rotated from the stop on the 3 pulley derailleurs, so it stops here (see pivot stop pin in the red circle):



The result is that it doesn't give me the extra chain wrap I need to use a triple crankset.

So, I was thinking about how I could solve this problem. My first idea was to tap another hole in the cage and move the stop pin right next to where it says "3 pulley system". I think that would work, but it would require me to figure out the threading of the stop pin, buy a tap, drill a hole, etc.

Then a second idea came to me. What if I just removed the stop pin. The chain will stop the pulley from folding back too far as long as the chain is engaged. Bad things could happen if I dropped the chain, but possibly(?) not too bad. So I tried it out.



It looks (!) like it's going to work. What could possibly go wrong?

What do you think?
__________________
My Bikes
Andy_K is offline  
Likes For Andy_K:
Old 05-28-20, 01:23 AM
  #2  
merziac
Senior Member
 
merziac's Avatar
 
Join Date: Oct 2015
Location: PDX
Posts: 5,937

Bikes: Merz x 5 + Specialized Merz Allez x 2, Strawberry/Newlands/DiNucci/Ti x3, Gordon, Fuso/Moulton x2, Bornstein, Paisley,1958-74 Paramounts x3, 3rensho, 74 Moto TC, 73-78 Raleigh Pro's x5, Marinoni x2, 1960 Cinelli SC, 1980 Bianchi SC, PX-10 X 2

Mentioned: 128 Post(s)
Tagged: 0 Thread(s)
Quoted: 1767 Post(s)
Liked 662 Times in 487 Posts
I think you need to dial it in and go for a test ride, cautiously.
merziac is offline  
Likes For merziac:
Old 05-28-20, 05:13 AM
  #3  
Prowler 
Senior Member
 
Join Date: Nov 2013
Location: Near Pottstown, PA: 30 NW of Philadelphia
Posts: 1,522

Bikes: 2 Trek Mtn, Cannondale R600 road, 6 vintage road bikes

Mentioned: 60 Post(s)
Tagged: 0 Thread(s)
Quoted: 233 Post(s)
Liked 130 Times in 79 Posts
IIRC the stop pins/screws are a convenience vs a necessity. Convenient for the original assembler and for the owner while maintaining the bike. During operation it does nothing so, as you know about RD rotation and can accommodate that while removing and installing the wheel and while changing the chain, then you should be fine. "Weight reduction". However check to be sure nothing is damaged if the cage ever pops back (broken chain, fumble fingers while out on the bench, etc). Does the cage hit some other part of the RD hard and damage it or does it catch a finger and damage that? If so, think on that one a bit.

On the RDs I've worked on or overhauled, some cages relax gently after that pin is removed. Others have much stronger torsion springs and can snap back quite smartly. Could even pinch a finger badly in a scissor action. I don't recall one that would "wap" the RD body and damage it. It also depends on how the high limit screw is set.
Prowler is online now  
Likes For Prowler:
Old 05-28-20, 05:38 AM
  #4  
nlerner
Senior Member
 
Join Date: Dec 2005
Posts: 13,093
Mentioned: 287 Post(s)
Tagged: 0 Thread(s)
Quoted: 1572 Post(s)
Liked 664 Times in 386 Posts
I had a Shimano Deerhead RD in use some time back in which the stop pin had gone missing. As you note, it was all fine as long as I didn’t have to remove the rear wheel, say like when on a long ride and I got a flatted rear tire and putting it all back together was an origami experiment that failed. So, yeah.
nlerner is offline  
Likes For nlerner:
Old 05-28-20, 05:47 AM
  #5  
SurferRosa
Senior Member
 
SurferRosa's Avatar
 
Join Date: Dec 2018
Location: Pac NW
Posts: 2,519

Bikes: old school 531c & Campy

Mentioned: 45 Post(s)
Tagged: 0 Thread(s)
Quoted: 1072 Post(s)
Liked 749 Times in 462 Posts
Yeah, rear flats are enough of a problem without compounding it.
SurferRosa is offline  
Old 05-28-20, 09:52 AM
  #6  
Andy_K 
Senior Member
Thread Starter
 
Andy_K's Avatar
 
Join Date: Jan 2008
Location: Beaverton, OR
Posts: 12,495

Bikes: Yes

Mentioned: 323 Post(s)
Tagged: 0 Thread(s)
Quoted: 1927 Post(s)
Liked 345 Times in 185 Posts
It turns out that if I use the chain hanger braze-on, the cage stays put pretty well even with the wheel off.
__________________
My Bikes
Andy_K is offline  
Likes For Andy_K:
Old 05-28-20, 12:53 PM
  #7  
dweenk 
Senior Member
 
dweenk's Avatar
 
Join Date: Mar 2013
Location: Maryland
Posts: 3,478

Bikes: 1971 Fuji Finest, Royale, S-10-S, 1976 Motobecane Mirage, 1989 Trek 330, 1100, 1970 Raleigh Sport, and more

Mentioned: 47 Post(s)
Tagged: 0 Thread(s)
Quoted: 707 Post(s)
Liked 97 Times in 71 Posts
You've done it!
__________________
"The man who does not read has no advantage over the man who cannot read." –Mark Twain
dweenk is offline  
Old 05-28-20, 01:08 PM
  #8  
3alarmer
Friendship is Magic
 
3alarmer's Avatar
 
Join Date: Nov 2010
Location: The Big Tomato
Posts: 18,754

Bikes: old ones

Mentioned: 258 Post(s)
Tagged: 0 Thread(s)
Quoted: 17973 Post(s)
Liked 1,651 Times in 1,206 Posts
.
...they laughed at Galileo, too. Well, actually they stopped laughing after a time and sent him before the Inquisition. YMMV
3alarmer is offline  
Likes For 3alarmer:
Old 05-28-20, 01:20 PM
  #9  
masi61
Senior Member
 
masi61's Avatar
 
Join Date: Oct 2005
Location: SW Ohio
Posts: 2,595

Bikes: Puch Marco Polo, Saint Tropez, Masi Gran Criterium

Mentioned: 21 Post(s)
Tagged: 0 Thread(s)
Quoted: 601 Post(s)
Liked 83 Times in 63 Posts
Is it possible to wind the spring another (almost) full turn and use the existing stop screw in order to get the chain wrap you need for your triple? Or is the spring too stiff?
masi61 is offline  
Old 05-28-20, 02:04 PM
  #10  
Andy_K 
Senior Member
Thread Starter
 
Andy_K's Avatar
 
Join Date: Jan 2008
Location: Beaverton, OR
Posts: 12,495

Bikes: Yes

Mentioned: 323 Post(s)
Tagged: 0 Thread(s)
Quoted: 1927 Post(s)
Liked 345 Times in 185 Posts
Originally Posted by masi61 View Post
Is it possible to wind the spring another (almost) full turn and use the existing stop screw in order to get the chain wrap you need for your triple? Or is the spring too stiff?
No, the problem isn't spring tension. The problem is that the pin stops the derailleur where it's shown in my first picture regardless of spring tension. You can't even manually move it past that point.
__________________
My Bikes
Andy_K is offline  
Old 05-28-20, 02:07 PM
  #11  
Andy_K 
Senior Member
Thread Starter
 
Andy_K's Avatar
 
Join Date: Jan 2008
Location: Beaverton, OR
Posts: 12,495

Bikes: Yes

Mentioned: 323 Post(s)
Tagged: 0 Thread(s)
Quoted: 1927 Post(s)
Liked 345 Times in 185 Posts
Originally Posted by dweenk View Post
You've done it!


Spaghetti Legs sent me this picture when I told him what I was doing.



Totally accurate, right down to me beating on this when it wouldn't work and then later hearing grumbling coming from the garage. (OK, that last part isn't entirely true.)
__________________
My Bikes
Andy_K is offline  
Likes For Andy_K:
Old 05-28-20, 02:19 PM
  #12  
stykthyn
Senior Member
 
Join Date: Nov 2012
Posts: 330
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 131 Post(s)
Liked 1 Time in 1 Post
What's the benefit of a 3rd pulley?
stykthyn is offline  
Old 05-28-20, 02:24 PM
  #13  
dweenk 
Senior Member
 
dweenk's Avatar
 
Join Date: Mar 2013
Location: Maryland
Posts: 3,478

Bikes: 1971 Fuji Finest, Royale, S-10-S, 1976 Motobecane Mirage, 1989 Trek 330, 1100, 1970 Raleigh Sport, and more

Mentioned: 47 Post(s)
Tagged: 0 Thread(s)
Quoted: 707 Post(s)
Liked 97 Times in 71 Posts
Originally Posted by Andy_K View Post
Totally accurate, right down to me beating on this when it wouldn't work and then later hearing grumbling coming from the garage. (OK, that last part isn't entirely true.)
It doesn't need to be true, it only needs to be repeated over and over and over, and then it'll be enough true.
__________________
"The man who does not read has no advantage over the man who cannot read." –Mark Twain
dweenk is offline  
Likes For dweenk:
Old 05-28-20, 02:59 PM
  #14  
Andy_K 
Senior Member
Thread Starter
 
Andy_K's Avatar
 
Join Date: Jan 2008
Location: Beaverton, OR
Posts: 12,495

Bikes: Yes

Mentioned: 323 Post(s)
Tagged: 0 Thread(s)
Quoted: 1927 Post(s)
Liked 345 Times in 185 Posts
Originally Posted by stykthyn View Post
What's the benefit of a 3rd pulley?
It provides extra chain wrap. When the derailleur cage is forward, the third pulley isn't engaged and it acts like a short cage 2 pulley derailleur. When the cage swings back, the third pulley engages to force the chain to cover more distance. A longer cage accomplishes basically the same thing, but this is weirder.
__________________
My Bikes
Andy_K is offline  
Likes For Andy_K:
Old 05-28-20, 05:04 PM
  #15  
nlerner
Senior Member
 
Join Date: Dec 2005
Posts: 13,093
Mentioned: 287 Post(s)
Tagged: 0 Thread(s)
Quoted: 1572 Post(s)
Liked 664 Times in 386 Posts
Three pulleys is 1/3 cooler than two.
nlerner is offline  
Likes For nlerner:
Old 05-28-20, 09:36 PM
  #16  
gugie 
Dilberteur at large
 
gugie's Avatar
 
Join Date: Jul 2014
Location: Portland, OR
Posts: 8,344

Bikes: It's complicated.

Mentioned: 906 Post(s)
Tagged: 0 Thread(s)
Quoted: 2765 Post(s)
Liked 703 Times in 399 Posts
Originally Posted by nlerner View Post
Three pulleys is 1/3 cooler than two.
Grant Petersen would say it's 0.333 cooler, because metric.
__________________
If someone tells you that you have enough bicycles and you don't need any more, stop talking to them. You don't need that kind of negativity in your life.
gugie is offline  
Old 05-28-20, 09:39 PM
  #17  
nlerner
Senior Member
 
Join Date: Dec 2005
Posts: 13,093
Mentioned: 287 Post(s)
Tagged: 0 Thread(s)
Quoted: 1572 Post(s)
Liked 664 Times in 386 Posts
Originally Posted by gugie View Post
Grant Petersen would say it's 0.333 cooler, because metric.
Who’s Grant Petersen?
nlerner is offline  
Old 05-28-20, 09:53 PM
  #18  
gugie 
Dilberteur at large
 
gugie's Avatar
 
Join Date: Jul 2014
Location: Portland, OR
Posts: 8,344

Bikes: It's complicated.

Mentioned: 906 Post(s)
Tagged: 0 Thread(s)
Quoted: 2765 Post(s)
Liked 703 Times in 399 Posts
Originally Posted by nlerner View Post
Who’s Grant Petersen?
He runs the local savings and loan
__________________
If someone tells you that you have enough bicycles and you don't need any more, stop talking to them. You don't need that kind of negativity in your life.
gugie is offline  
Old 05-28-20, 11:08 PM
  #19  
Spaghetti Legs 
Senior Member
 
Join Date: Dec 2014
Location: Central Virginia
Posts: 3,743

Bikes: Numerous

Mentioned: 84 Post(s)
Tagged: 0 Thread(s)
Quoted: 1074 Post(s)
Liked 386 Times in 194 Posts
Originally Posted by nlerner View Post
Three pulleys is 1/3 cooler than two.
Its actually 150% cooler. That’s OK though, I know you’re an English major.
__________________
N = '96 Colnago C40, '04 Wilier Alpe D'Huez, '10 Colnago EPS, '85 Merckx Pro, '89 Merckx Century, '85 Moser, '86 Tommasini Professional, '04 Teschner Aero FX Pro, '05 Alan Carbon Cross, '86 De Rosa Professional, '82 Colnago Super, '95 Gios Compact Pro, '95 Carrera Zeus, '84 Basso Gap, ‘89 Cinelli Supercorsa, ‘83 Bianchi Specialissima, ‘85 Pinarello Record
Spaghetti Legs is offline  
Likes For Spaghetti Legs:
Old 05-28-20, 11:21 PM
  #20  
rhm
multimodal commuter
 
rhm's Avatar
 
Join Date: Nov 2006
Location: NJ, NYC, LI
Posts: 19,381

Bikes: 1940s Fothergill, 1959 Allegro Special, 1963? Claud Butler Olympic Sprint, Lambert 'Clubman', 1974 Fuji "the Ace", 1976 Holdsworth 650b conversion rando bike, 1983 Trek 720 tourer, 1984 Counterpoint Opus II, 1993 Basso Gap, 2010 Downtube 8h, and...

Mentioned: 483 Post(s)
Tagged: 0 Thread(s)
Quoted: 1692 Post(s)
Liked 154 Times in 115 Posts
Originally Posted by Spaghetti Legs View Post
Its actually 150% cooler. That’s OK though, I know you’re an English major.
No. It's 150% as cool, AKA 50% cooler. Five pulley wheels, now, that would be 150% cooler.

But that's assuming that a derailleur's coolness is directly proportional to the number of pulleys. I submit that though those three-pulley derailleur's are pretty cool, the S-1 (with only two pulleys) is cooler still.

Well, at least it's weirder.

Last edited by rhm; 05-28-20 at 11:28 PM.
rhm is offline  
Likes For rhm:
Old 05-28-20, 11:54 PM
  #21  
Dfrost 
Senior Member
 
Dfrost's Avatar
 
Join Date: May 2013
Location: Pacific Northwest
Posts: 1,549

Bikes: ‘87 Marinoni SLX Sports Tourer, ‘79 Miyata 912 by Gugificazione

Mentioned: 130 Post(s)
Tagged: 0 Thread(s)
Quoted: 335 Post(s)
Liked 68 Times in 51 Posts
Originally Posted by Spaghetti Legs View Post
Its actually 150% cooler. That’s OK though, I know you’re an English major.
Well @Andy_K can write the code to keep a running count on the relative coolness, depending on how many pulleys are engaged.

I think it’s extremely cool and a worthy quarantine project.

Last edited by Dfrost; 05-28-20 at 11:58 PM.
Dfrost is offline  
Old 05-29-20, 01:23 AM
  #22  
Andy_K 
Senior Member
Thread Starter
 
Andy_K's Avatar
 
Join Date: Jan 2008
Location: Beaverton, OR
Posts: 12,495

Bikes: Yes

Mentioned: 323 Post(s)
Tagged: 0 Thread(s)
Quoted: 1927 Post(s)
Liked 345 Times in 185 Posts
Originally Posted by rhm View Post
No. It's 150% as cool, AKA 50% cooler. Five pulley wheels, now, that would be 150% cooler.
I had to fight really hard not to cnlerner 's math. I knew I could count on someone else to come along and do it.
__________________
My Bikes
Andy_K is offline  
Old 05-29-20, 01:24 AM
  #23  
Andy_K 
Senior Member
Thread Starter
 
Andy_K's Avatar
 
Join Date: Jan 2008
Location: Beaverton, OR
Posts: 12,495

Bikes: Yes

Mentioned: 323 Post(s)
Tagged: 0 Thread(s)
Quoted: 1927 Post(s)
Liked 345 Times in 185 Posts
Originally Posted by Dfrost View Post
Well @Andy_K can write the code to keep a running count on the relative coolness, depending on how many pulleys are engaged.
Nah, that's a hardware problem.
__________________
My Bikes
Andy_K is offline  
Old 05-29-20, 01:30 AM
  #24  
Andy_K 
Senior Member
Thread Starter
 
Andy_K's Avatar
 
Join Date: Jan 2008
Location: Beaverton, OR
Posts: 12,495

Bikes: Yes

Mentioned: 323 Post(s)
Tagged: 0 Thread(s)
Quoted: 1927 Post(s)
Liked 345 Times in 185 Posts
Originally Posted by rhm View Post
I submit that though those three-pulley derailleur's are pretty cool, the S-1 (with only two pulleys) is cooler still.




Yeah, that's some next level stuff right there.
__________________
My Bikes
Andy_K is offline  
Likes For Andy_K:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information

Copyright © 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.