Weak front derailleur clamp

Discuss light weight issues concerning road bikes & parts.
Daniel1975
Posts: 231
Joined: Sat Dec 31, 2005 2:46 pm

by Daniel1975

I have very bad shifting on my Simplon Kiaro bike. The SuperRecord 2011 group worked like a dream on my former bike, so I started to search for answers.
I've found out that the problem is the braze on clamp on my frame. I can move a bit under shifting pressure, causing the problems.
I'm afraid the best (only?) option is to remove the clamp (drill the rivets) and use a new front clamp like this https://www.bike24.com/1.php?content=7; ... ;orderby=2

Anybody a good other suggestion? My first choice would be to leave the frame intact and find a better solution using the original clamp.

by Weenie


sungod
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by sungod

with etap there are 'wedges' supplied that can be used to prevent the fd twisting if the clamp isn't stiff enough

perhaps you can improvise something similar

Daniel1975
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Joined: Sat Dec 31, 2005 2:46 pm

by Daniel1975

How do you attach those wedges? I cannot find them online.

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tommasini
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by tommasini

Campagnolo mechanical 2015 and after has 2 front der models. One of them ( it's called S2) has a small little arm that presses against the seat tube to reduce movement caused be the mounting tab flexing.

Shown at 5:42 of this installation video by Campagnolo https://www.youtube.com/watch?v=Y_1pkG2XfT0
Last edited by tommasini on Sat Dec 17, 2016 5:29 pm, edited 3 times in total.

Daniel1975
Posts: 231
Joined: Sat Dec 31, 2005 2:46 pm

by Daniel1975

Thnx! That looks like a solution, but not for my problem :-(. A 2011 shifter will not work with that front derailleur.
Good reason to buy a new groupset ;-)

sungod
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Location: it's raining, it must be uk

by sungod

Daniel1975 wrote:How do you attach those wedges? I cannot find them online.


they are supplied with the etap fd, also designed specifically for it, you can see one in the image below (not mine)

if the mounting bolt has a through hole, you may be able to use a long bolt and then use the protruding end to mount something that will press against the seat tube to prevent the fd twisting on the upshift - whatever you use, make sure the load is spread over a reasonable area of the seat tube otherwise it might cause damage

Image

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BRM
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Joined: Sun Mar 16, 2014 3:43 pm

by BRM

Daniel1975 wrote:I have very bad shifting on my Simplon Kiaro bike. The SuperRecord 2011 group worked like a dream on my former bike, so I started to search for answers.
I've found out that the problem is the braze on clamp on my frame. I can move a bit under shifting pressure, causing the problems.
I'm afraid the best (only?) option is to remove the clamp (drill the rivets) and use a new front clamp like this https://www.bike24.com/1.php?content=7; ... ;orderby=2

Anybody a good other suggestion? My first choice would be to leave the frame intact and find a better solution using the original clamp.


- Please make some clear pictures/vid of the issue.
- Did you contacted Simplon already?

em3
Posts: 888
Joined: Tue Dec 23, 2008 2:57 pm
Location: NYC

by em3

The OP is describing a problem with a front der TAB (riveted to frame) not a frt der clamp (bolted on frame)....he simply got the description incorrect.

Neither the Campy S2 frt der with the built in support arm or the SRAM eTap spacers/wedges will solve the poor shifting caused by the loose rivet. This is a frame repair issue. Some manufacturers will send their dealers a rivet kit to repair the frame, while other manufacturers will simply replace frame. If the downtube is perfectly round where the current tab is riveted, then using a bolt on clamp might be a solution, otherwise, a frame repair is the only solution. EM3
______________

Daniel1975
Posts: 231
Joined: Sat Dec 31, 2005 2:46 pm

by Daniel1975

It's not a loose rivet. Maybe we're lost in translation (i'm dutch).
I meant i have to drill the 4 small rivets to remove the clamp. In my opinion it's just poor design.
https://youtu.be/ZRUPgbl7O-A

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Calnago
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Joined: Sun Nov 07, 2010 9:14 pm

by Calnago

Yes, your English is fine. I didn't read it as a loose rivet problem, but rather simply there's some flex in that area, be it due to a soft brazeon tab, a thin walled or flimsy frame tube, or a combination of the two. The newer long arm derailleurs have either a support screw (Shimano) or a little arm that you can butt up against the frame tube (newer Campy S2 front derailleur). But sounds like you're using the 2011 SR Front derailleur, which does not have the support arm, as it's the old style without the new longer arm which can exert significantly more leverage in the system. You've pretty much thought through your options already. Just make sure the cause of your poor front shifting is indeed due to the flex in the braze-on tab area and not simply due to something you may have overlooked like improper adjustment, worn chain, rings, etc. Good luck. But indeed, contact the manufacturer and ask their opinion first of all.
Colnago C64 - The Naked Build; Colnago C60 - PR99; Trek Koppenberg - Where Emonda and Domane Meet;
Unlinked Builds (searchable): Colnago C59 - 5 Years Later; Trek Emonda SL Campagnolo SR; Special Colnago EPQ

Daniel1975
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by Daniel1975

Does anybody know if this support bolt really works? The wedge from Sram as seen a few posts above looks like something that works, but I cannot find good pictures of the Shimano-solution.
Looking at Sram and Shimano, I think they have a better solution than the S2-system from Campy.

Image

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Calnago
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by Calnago

Yes, it works, in the sense that it provides exactly what it says... a little more "support" when the derailleur wants to naturally twist that way. It doesn't change anything about your brazeon tab or your frame however. The little tabs are simply there to protect your frame from the screw going right into it. Many derailleur tabs have an appropriate spot that the screw will butt up against and making the stick on tabs redundant. But if your entire frametube/brazeon is flexing, the derailleur will move right along with it, as will the support screw.
And see that last image at the bottom of the page you posted above... especially where they say to set it up initially with a 0.5-1mm inward angle, then to use the support screw to push it out so that it's parallel with the chain ring. Be very careful with that guideline as I think it's way too much. Rather, I would try to get the cage set as parallel as possible with the chain rings from the get go, and only then turn the support screw so that it barely touches the support plate or brazeon tab, but still has contact so it can do it's thing.
Here's an example of what happened with a 2012 Cannondale Evo brazeon tab, which was not designed to be used with the newer long arm front derailleurs and the new support screw...
Image
Old design (pre 2013) on the left. You can see where the support bolt made contact, but due to both the angle it made contact with the tab and perhaps the weakness of the tab itself, when the new Shimano 9000 front derailleur was being installed, as in the instructions you posted above, that 0.5mm of necessary final adjustment was all it took to snap the tab and break it. The tab on the right is the updated beefier version and also includes a flat "shelf" that the support screw can butt up against. The key in that last instruction is to just "tentatively" tighten the derailleur at this position, so that it can still move a bit on the tab without taking the tab with it as that final adjustment of the support screw is made.
Colnago C64 - The Naked Build; Colnago C60 - PR99; Trek Koppenberg - Where Emonda and Domane Meet;
Unlinked Builds (searchable): Colnago C59 - 5 Years Later; Trek Emonda SL Campagnolo SR; Special Colnago EPQ

Daniel1975
Posts: 231
Joined: Sat Dec 31, 2005 2:46 pm

by Daniel1975

I think my best and easiest option is to remove the tab and use a 34,9mm clamp.
The seatpost is exactly that size.

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BRM
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by BRM

Maybe in the end yes. But I would contact Simplon first. Possibly they have an other solution for you and also with an eye on warranty issues in the future.

drhex
Posts: 21
Joined: Sat Feb 13, 2016 7:49 pm

by drhex

Can't see what is flexing in your video, but if it is the frame, it is broken. Should not move a bit under the pressure you seem to be exerting. Just having a similar issue with a Canyon where the frame is being replaced without question(thanks Canyon!). Tab was way more stable in the beginning and has deteriorated over one year of use.
Florian

by Weenie


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