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

Two different top-mount shifter bosses? Really?

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.

Two different top-mount shifter bosses? Really?

Old 06-01-20, 11:32 PM
  #1  
madpogue 
Senior Member
Thread Starter
 
Join Date: Jan 2004
Location: Madison, WI USA
Posts: 4,817
Mentioned: 30 Post(s)
Tagged: 0 Thread(s)
Quoted: 1511 Post(s)
Liked 583 Times in 452 Posts
Two different top-mount shifter bosses? Really?

Who knew? Both these bikes came with Suntour top mount shifters with braze-on mounts. Same year. First one is an '84 Miyata Seven Ten. Second one is an '84 Schwinn Le Tour.



A shifter mount for the first type will obviously not fit the second type of boss. Square peg in a round hole, literally. It looks like MAYBE a mount from the second type would fit the first type of boss.

Question is, why? The Miyata was no doubt a more expensive bike BITD than the Schwinn, so presumably it got a higher-end version of the shifters. So was it intentional not to allow someone to mount a higher-end shifter on the lower-end frame?

I guess it's obvious that my only option for the Schwinn, unless I do something drastic like round off the corners of the mount, would be to find a mount with a square cavity. I guess I'm just wondering what the rationale for this would have been.
madpogue is online now  
Old 06-01-20, 11:35 PM
  #2  
noobinsf 
Senior Member
 
noobinsf's Avatar
 
Join Date: Sep 2005
Location: Oakland, CA
Posts: 1,913

Bikes: CURRENT: '82 Univega Competizione, '72 Motobecane Grand Record, '74 Campania Professional, '83 Mercian KOM Touring, '91 Univega Alpina Comp PAST: '72 Puch Bergmeister, '72ish Peugeot UO-8, '86 Univega Gran Premio, '85 Univega Viva Touring

Mentioned: 41 Post(s)
Tagged: 0 Thread(s)
Quoted: 583 Post(s)
Liked 284 Times in 204 Posts
Symmetric shifters had the cam auto front trim mechanism, the second boss type.
noobinsf is offline  
Old 06-02-20, 06:54 AM
  #3  
RobbieTunes 
Half drunk? Finish!
 
RobbieTunes's Avatar
 
Join Date: Dec 2007
Location: Very Southern Indiana
Posts: 26,385
Mentioned: 34 Post(s)
Tagged: 1 Thread(s)
Quoted: 378 Post(s)
Liked 943 Times in 596 Posts
I think the first one tended to twist, and counted on the concavity backwards tube-grabbing principle, which was less than satisfactory. So they went square. Then Klein really tossed a wrench into it.

Shoulda bought an Ironman.
RobbieTunes is offline  
Old 06-02-20, 07:15 AM
  #4  
madpogue 
Senior Member
Thread Starter
 
Join Date: Jan 2004
Location: Madison, WI USA
Posts: 4,817
Mentioned: 30 Post(s)
Tagged: 0 Thread(s)
Quoted: 1511 Post(s)
Liked 583 Times in 452 Posts
Originally Posted by noobinsf View Post
Symmetric shifters had the cam auto front trim mechanism, the second boss type.
Yeah, I think I see that in a pic of one for sale on the 'Bay. How well does that system work, BTW?

Originally Posted by RobbieTunes View Post
I think the first one tended to twist, and counted on the concavity backwards tube-grabbing principle, which was less than satisfactory. So they went square. Then Klein really tossed a wrench into it.
Yeah a square mount does make sense, in that regard.

Shoulda bought an Ironman.
Um, I did. In fact, the day I picked up the IM, the shop dude talked me into buying three old frames, including the LeTour.

Last edited by madpogue; 06-02-20 at 08:34 AM.
madpogue is online now  
Old 06-02-20, 10:11 AM
  #5  
noobinsf 
Senior Member
 
noobinsf's Avatar
 
Join Date: Sep 2005
Location: Oakland, CA
Posts: 1,913

Bikes: CURRENT: '82 Univega Competizione, '72 Motobecane Grand Record, '74 Campania Professional, '83 Mercian KOM Touring, '91 Univega Alpina Comp PAST: '72 Puch Bergmeister, '72ish Peugeot UO-8, '86 Univega Gran Premio, '85 Univega Viva Touring

Mentioned: 41 Post(s)
Tagged: 0 Thread(s)
Quoted: 583 Post(s)
Liked 284 Times in 204 Posts
Originally Posted by madpogue View Post
Yeah, I think I see that in a pic of one for sale on the 'Bay. How well does that system work, BTW?
It's actually effective, and the shifters themselves are pretty smooth. If you come across a spare set of shifters, you can butcher them to make a cable stop and mount bar ends or brifters, and there is a thread on these forums to show how. The only drawback is that the mounting bolts for the shifters are hex bolts, not d-rings, so you have to have a tool with you to adjust tension lest they loosen.
noobinsf is offline  
Old 06-02-20, 10:25 AM
  #6  
79pmooney
A Roadie Forever
 
79pmooney's Avatar
 
Join Date: Oct 2014
Location: Portland, OR
Posts: 8,442

Bikes: (2) ti TiCycles, 2007 w/ triple and 2011 fixed, 1979 Peter Mooney, ~1983 Trek 420 now fixed and ~1973 Raleigh Carlton Competition gravel grinder

Mentioned: 99 Post(s)
Tagged: 0 Thread(s)
Quoted: 2298 Post(s)
Likes: 0
Liked 716 Times in 499 Posts
I am pretty certain the Miyata is for a Superbe shifter, the Schwinn for the auto-trim. My custom has a boss for the Superbe. (It doesn't look quite like either because the builder simply made a titanium boss to fit the shifter I gave him. He didn't go on-line to see what it was "supposed" to look like. (It's been rock solid for 12 years so I'm not complaining.)

This isn't about Miyata and Schwinn, Each just built their bikes to accommodate what SunTour made. This is one of the very few times when I wonder "what was SunTour thinking when they designed those shifters to different mounts?

Edit: I've used both shifters. The auto-trims are sublime in feel. The front derailleur cable pull acts like the Simplex Retro (?- I never had thenm and forget what they are called) with the opposing spring in the lever. Very little pressure needed to shift in back. That is as nice as the auto-trim, The Superbes are just the finest straight friction sifters ever made.

Ben

Last edited by 79pmooney; 06-02-20 at 10:30 AM.
79pmooney is offline  
Likes For 79pmooney:
Old 06-02-20, 10:32 AM
  #7  
seedsbelize 
smelling the roses
 
seedsbelize's Avatar
 
Join Date: Nov 2010
Location: Tixkokob, Yucatán, México
Posts: 13,887

Bikes: 79 Trek 930, 80 Trek 414, 84 Schwinn Letour Luxe (coupled), 92 Schwinn Paramount PDG 5

Mentioned: 102 Post(s)
Tagged: 1 Thread(s)
Quoted: 6232 Post(s)
Liked 527 Times in 361 Posts
I have a small collection of symmetric shifters. I'll have to dig them out and look at the mounts.
__________________
Well look what the cat dragged in. Such a fine addition to the thread





seedsbelize is offline  
Old 06-02-20, 10:47 AM
  #8  
noobinsf 
Senior Member
 
noobinsf's Avatar
 
Join Date: Sep 2005
Location: Oakland, CA
Posts: 1,913

Bikes: CURRENT: '82 Univega Competizione, '72 Motobecane Grand Record, '74 Campania Professional, '83 Mercian KOM Touring, '91 Univega Alpina Comp PAST: '72 Puch Bergmeister, '72ish Peugeot UO-8, '86 Univega Gran Premio, '85 Univega Viva Touring

Mentioned: 41 Post(s)
Tagged: 0 Thread(s)
Quoted: 583 Post(s)
Liked 284 Times in 204 Posts
Oh, and if you think you can mount Shimano top-mount shifters on the square boss... the Shimano square boss of the era has different dimensions, about a mm smaller on each side. I think these aero mount shifters simply didn't have the chance to mature and drift toward standardization since other ideas came along. They just petered out instead.
noobinsf is offline  
Old 06-02-20, 02:02 PM
  #9  
Miele Man
Senior Member
 
Join Date: Jun 2014
Location: Ontario, Canada
Posts: 4,096

Bikes: iele Latina, Miele Suprema, Miele Uno LS, Miele Miele Beta, MMTB, Bianchi Model Unknown, Fiori Venezia, Fiori Napoli, VeloSport Adamas AX

Mentioned: 11 Post(s)
Tagged: 0 Thread(s)
Quoted: 1101 Post(s)
Liked 647 Times in 452 Posts
Originally Posted by noobinsf View Post
Oh, and if you think you can mount Shimano top-mount shifters on the square boss... the Shimano square boss of the era has different dimensions, about a mm smaller on each side. I think these aero mount shifters simply didn't have the chance to mature and drift toward standardization since other ideas came along. They just petered out instead.
Shimano downtube side shifter brazeons were also different from Campagnolo and Suntour at one time and thus the shifters weren't interchangeable. On top ofthat the Shimano ones used a 4.5mm bolt instead of the more common 5mm bolt. Then Shimano finally got on board with what Campagnolo and Suntour were using.

Cheers
Miele Man is offline  
Old 06-02-20, 04:45 PM
  #10  
The Golden Boy 
Extraordinary Magnitude
 
The Golden Boy's Avatar
 
Join Date: Aug 2009
Location: Waukesha WI
Posts: 12,138

Bikes: 1978 Trek TX700; 1978/79 Trek 736; 1984 Specialized Stumpjumper Sport; 1984 Schwinn Voyageur SP; 1985 Trek 620; 1985 Trek 720; 1986 Trek 400 Elance; 1987 Schwinn High Sierra; 1990 Miyata 1000LT

Mentioned: 76 Post(s)
Tagged: 0 Thread(s)
Quoted: 2029 Post(s)
Liked 355 Times in 244 Posts
Wasn't there also a top mount shifter boss that the shifters threaded into? it kind of looked like a Miyata rack eyelet- but where DT shifters would be.
__________________
*Recipient of the 2006 Time Magazine "Person Of The Year" Award*

Commence to jigglin’ huh?!?!

"But hey, always love to hear from opinionated amateurs." -says some guy to Mr. Marshall.
The Golden Boy is offline  
Old 06-02-20, 09:51 PM
  #11  
madpogue 
Senior Member
Thread Starter
 
Join Date: Jan 2004
Location: Madison, WI USA
Posts: 4,817
Mentioned: 30 Post(s)
Tagged: 0 Thread(s)
Quoted: 1511 Post(s)
Liked 583 Times in 452 Posts
Originally Posted by 79pmooney View Post
This isn't about Miyata and Schwinn, Each just built their bikes to accommodate what SunTour made. This is one of the very few times when I wonder "what was SunTour thinking when they designed those shifters to different mounts?
Yeah, I knew it wasn't about the bike brand, that was just for context. I just posted because I had the same thought -- what were they thinking?

Edit: I've used both shifters. The auto-trims are sublime in feel. The front derailleur cable pull acts like the Simplex Retro (?- I never had thenm and forget what they are called) with the opposing spring in the lever. Very little pressure needed to shift in back. That is as nice as the auto-trim, The Superbes are just the finest straight friction sifters ever made.
Interesting, thanks for the feedback (pun slightly intended).
madpogue is online now  
Old 06-02-20, 10:14 PM
  #12  
cudak888 
www.theheadbadge.com
 
cudak888's Avatar
 
Join Date: Sep 2005
Location: Southern Florida
Posts: 25,222

Bikes: https://www.theheadbadge.com

Mentioned: 52 Post(s)
Tagged: 0 Thread(s)
Quoted: 992 Post(s)
Liked 831 Times in 534 Posts
Word to the wise about the Symmetric mounts (#2), especially on Schwinns: They weren't always brazed to the frame well. This problem is compounded as Schwinn did not drill the frame tubing below the boss. Any bolt substitution in excess of the factory Suntour length (the Suntour bolt may even be an issue) may bottom out on the frame, causing the braze-on to get pulled up as if it were being jacked up from the bottom, and possibly snap.

If I seriously considered keeping any frame with this sort of braze on, I'd drill a hole a few sizes smaller through the tube (being super careful not to nick the threads), then file it open until flush with the threads - at which point I'd then tap the whole thing, fairly confident that it wouldn't pop off during the tapping.

-Kurt
__________________







cudak888 is offline  
Likes For cudak888:
Old 06-03-20, 12:00 AM
  #13  
madpogue 
Senior Member
Thread Starter
 
Join Date: Jan 2004
Location: Madison, WI USA
Posts: 4,817
Mentioned: 30 Post(s)
Tagged: 0 Thread(s)
Quoted: 1511 Post(s)
Liked 583 Times in 452 Posts
Originally Posted by cudak888 View Post
Word to the wise about the Symmetric mounts (#2), especially on Schwinns: They weren't always brazed to the frame well. This problem is compounded as Schwinn did not drill the frame tubing below the boss. Any bolt substitution in excess of the factory Suntour length (the Suntour bolt may even be an issue) may bottom out on the frame, causing the braze-on to get pulled up as if it were being jacked up from the bottom, and possibly snap.
Picturing this .
madpogue is online now  
Old 06-03-20, 12:32 AM
  #14  
79pmooney
A Roadie Forever
 
79pmooney's Avatar
 
Join Date: Oct 2014
Location: Portland, OR
Posts: 8,442

Bikes: (2) ti TiCycles, 2007 w/ triple and 2011 fixed, 1979 Peter Mooney, ~1983 Trek 420 now fixed and ~1973 Raleigh Carlton Competition gravel grinder

Mentioned: 99 Post(s)
Tagged: 0 Thread(s)
Quoted: 2298 Post(s)
Likes: 0
Liked 716 Times in 499 Posts
Or - measure how deep the bolt hole is, shoulder to tube, then how long the bolt is. Maybe file a little bolt off if it is close. (I've never run into this and didn't know it until now. My Symmetric was on a clamp band and my Superbe is on a custom where the builder had it in his hand when he made the mount. (And it's welded titanium, I doubt its going anywhere.)

Ben
79pmooney is offline  
Likes For 79pmooney:
Old 06-03-20, 01:41 AM
  #15  
Last ride 76 
1/2 as far in 2x the time
 
Last ride 76's Avatar
 
Join Date: Nov 2013
Location: Northern Bergen County, NJ
Posts: 1,881

Bikes: Yes, Please.

Mentioned: 13 Post(s)
Tagged: 0 Thread(s)
Quoted: 482 Post(s)
Liked 255 Times in 201 Posts
Originally Posted by noobinsf View Post
Symmetric shifters had the cam auto front trim mechanism, the second boss type.


Having spent a looking afternoon last week figuring out that Suntour "endless band" friction shifters have some parts which make some of the shift levers not interchangable and on the aero version, even the bodies cannot be swapped without doing some "modification".


Perhaps a highly developed sense of irony was intrinsic to what made Suntour engineers so unique. Or perhaps it was Suntour's marketing department, frustrated with the way their brilliant engineers would create a marvelous product, and them add another layer of complexity, one only appreciated by fellow engineers.


SYMMETRIC Shifters? HA, HA... That was a long afternoon, I didn't get the final adjustments done in time for a test ride! All I wanted was to use the light and elegant 2 hole regular shifters on the rounded, less clunky looking, endless band, aero body (from which they had incidentally removed the word "symmetic"). No, then no again, not my second choice combination, then not the third either. Finally, "success" on itteration #4 .

Then all I had to do(realizing that if I didn't, when I went to use them next, I would have forgotten what went with what), was reassemble the others and put them away. At least this went smoothly, having become recently familliar with their differences,,,
__________________
I seem to have lost what little mind I had left before this all started.
Last ride 76 is offline  
Old 06-03-20, 06:33 AM
  #16  
cudak888 
www.theheadbadge.com
 
cudak888's Avatar
 
Join Date: Sep 2005
Location: Southern Florida
Posts: 25,222

Bikes: https://www.theheadbadge.com

Mentioned: 52 Post(s)
Tagged: 0 Thread(s)
Quoted: 992 Post(s)
Liked 831 Times in 534 Posts
Originally Posted by madpogue View Post
Picturing this .
I've had it happen happen once.

Notice that the square is brazed only on the left and right edges, not the center. The example above isn't even brazed up to each end.

-Kurt
__________________







cudak888 is offline  
Old 06-03-20, 07:30 AM
  #17  
Ex Pres 
#39
 
Ex Pres's Avatar
 
Join Date: Dec 2007
Location: Mountain Brook, AL
Posts: 7,222
Mentioned: 24 Post(s)
Tagged: 0 Thread(s)
Quoted: 400 Post(s)
Liked 45 Times in 33 Posts
Originally Posted by The Golden Boy View Post
Wasn't there also a top mount shifter boss that the shifters threaded into? it kind of looked like a Miyata rack eyelet- but where DT shifters would be.
Is this the one you're thinking of?
https://www.phred.org/~alex/pictures/bikes/shiftboss.jpg
__________________
72 Frejus, Holdsworth Record & special CNC / 74 Italvega NR / c80 ?French? / 82 Raleigh Intl MkII / 83 Trek 620 / 87 Centurion IM MV / 03 Casati Dardo / 08 BF IRO / 09 Dogma FPX / 10 Vassago Fisticuff

Ex Pres is offline  
Old 06-03-20, 09:38 AM
  #18  
The Golden Boy 
Extraordinary Magnitude
 
The Golden Boy's Avatar
 
Join Date: Aug 2009
Location: Waukesha WI
Posts: 12,138

Bikes: 1978 Trek TX700; 1978/79 Trek 736; 1984 Specialized Stumpjumper Sport; 1984 Schwinn Voyageur SP; 1985 Trek 620; 1985 Trek 720; 1986 Trek 400 Elance; 1987 Schwinn High Sierra; 1990 Miyata 1000LT

Mentioned: 76 Post(s)
Tagged: 0 Thread(s)
Quoted: 2029 Post(s)
Liked 355 Times in 244 Posts
Originally Posted by Ex Pres View Post
Yes!!!
__________________
*Recipient of the 2006 Time Magazine "Person Of The Year" Award*

Commence to jigglin’ huh?!?!

"But hey, always love to hear from opinionated amateurs." -says some guy to Mr. Marshall.
The Golden Boy is offline  
Old 06-03-20, 10:28 AM
  #19  
noobinsf 
Senior Member
 
noobinsf's Avatar
 
Join Date: Sep 2005
Location: Oakland, CA
Posts: 1,913

Bikes: CURRENT: '82 Univega Competizione, '72 Motobecane Grand Record, '74 Campania Professional, '83 Mercian KOM Touring, '91 Univega Alpina Comp PAST: '72 Puch Bergmeister, '72ish Peugeot UO-8, '86 Univega Gran Premio, '85 Univega Viva Touring

Mentioned: 41 Post(s)
Tagged: 0 Thread(s)
Quoted: 583 Post(s)
Liked 284 Times in 204 Posts
Originally Posted by cudak888 View Post
I've had it happen happen once.

Notice that the square is brazed only on the left and right edges, not the center. The example above isn't even brazed up to each end.

-Kurt
Hmm, I guess if I ever wanted to remove it...
noobinsf is offline  
Old 06-03-20, 10:35 AM
  #20  
cudak888 
www.theheadbadge.com
 
cudak888's Avatar
 
Join Date: Sep 2005
Location: Southern Florida
Posts: 25,222

Bikes: https://www.theheadbadge.com

Mentioned: 52 Post(s)
Tagged: 0 Thread(s)
Quoted: 992 Post(s)
Liked 831 Times in 534 Posts
Originally Posted by noobinsf View Post
Hmm, I guess if I ever wanted to remove it...
I learned the hard way about involuntary removal of that specific braze-on.

-Kurt
__________________







cudak888 is offline  
Likes For cudak888:

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.