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Simplex LJ rear derailleur mount on a Campy hanger

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Simplex LJ rear derailleur mount on a Campy hanger

Old 11-25-16, 02:10 PM
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Dboyle
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Simplex LJ rear derailleur mount on a Campy hanger

Hi all: how does a simplex LJ rear derailleur mount on a Campy rear dropout hanger?

Thx!
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Old 11-25-16, 02:48 PM
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Narhay
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I was wrong

Last edited by Narhay; 11-26-16 at 12:25 AM.
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Old 11-25-16, 02:51 PM
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Same as it does on a Simplex dropout. The hanger tab that prevents a Campagnolo-style derailleur from rotating forward is superfluous for the Simplex derailleur. The Simplex derailleur has a tab that sits in front of the hanger to prevent this, and the upper pivot spring pulls the body back.

Important points, if you're not familiar with Simplex: the mounting bolt inserts from the inside of the dropout; the allen socket on the upper pivot is to set the spring tension, not to mount the derailleur (many time a plastic plug is stuck into that socket to prevent you from trying to use it to mount the derailleur). You can ruin the upper pivot spring if you go cranking on it trying to mount the derailleur.



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Old 11-25-16, 07:16 PM
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^^ @JohnDThompson has it right. Do be alert to possible chain interference on smallest cog, though. May need to respace the axle/re-dish the wheel to accommodate.
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Old 11-25-16, 11:36 PM
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Simplex

Originally Posted by JohnDThompson View Post
Same as it does on a Simplex dropout. The hanger tab that prevents a Campagnolo-style derailleur from rotating forward is superfluous for the Simplex derailleur. The Simplex derailleur has a tab that sits in front of the hanger to prevent this, and the upper pivot spring pulls the body back.

Important points, if you're not familiar with Simplex: the mounting bolt inserts from the inside of the dropout; the allen socket on the upper pivot is to set the spring tension, not to mount the derailleur (many time a plastic plug is stuck into that socket to prevent you from trying to use it to mount the derailleur). You can ruin the upper pivot spring if you go cranking on it trying to mount the derailleur.



Thanks. This is really helpful. DB
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Old 11-26-16, 12:47 AM
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So, the mounting bolt that screws in from the inside of the dropout can be tightened down, while from the outside (where the plug is) you use a light touch to adjust the tension? I've been having problems with the upper pivot tension on a 637 Criterium on a Campy dropout.
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Old 11-26-16, 10:08 AM
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Originally Posted by kroozer View Post
So, the mounting bolt that screws in from the inside of the dropout can be tightened down, while from the outside (where the plug is) you use a light touch to adjust the tension? I've been having problems with the upper pivot tension on a 637 Criterium on a Campy dropout.
No, no, no, no.... Ne touche pas!!!
@JohnDThompson nailed it. Take his advise.

"Nisi fractus noli sarcire" If it ain't broke - don't fix it! In other words unless there is a problem don't mess with the upper pivot screw.

Reassembling the upper pivot on a Simplex RD can be a 3 handed job!

Over the years Simplex used several different methods for adjusting the tension on the upper pivot screws.

The 637 Criterium dates back to the mid 1960's. The old Prestige used the same design.

If the IS a problem, the post below can help you adjust the upper pivot tension or diagnose the problem:

clink on link...
https://www.bikeforums.net/6465151-post6.html

Delrin derailleurs didn't have a spring hole in the travel stop plate. There were 2 spring stop holes inside the plastic body. The tang on those spring could break off.

Later versions of Simplex RDs were not really adjustable. They had 2 positions for the spring to fit through on the travel stop plate, one for short pulley cages and one to long arm pulley cages.

Eventually Simplex did away with the 2 holes and only had one.

Some last suggestions, Delrin plastic is supposed to be a self lubricating material for low speed bushings under light loads. But... Simplex derailleurs need to be clean and well lubricated.

Make sure that the body can move freely back and forth in the dropout so that it can wrap up chain. If it hangs that will affect shifting and you may have to place a thin shim between the back of the mounting area and the dropout.

When properly lubed and adjusted with good quality shift cables they will out perform most Campy derailleurs made before the late 80's!

verktyg

Chas.
Attached Images
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File Type: jpg
File Type: jpg
SimplexStopPlate.jpg (8.1 KB, 66 views)
File Type: jpg
SimplexStopPlate2.jpg (9.2 KB, 67 views)
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SimplexSX410T-SP-Parts.jpg (16.4 KB, 65 views)
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Last edited by verktyg; 11-26-16 at 10:18 AM.
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