Campagnolo EPS/Chain catchers with SRM magnet hacks (on page 2)

Discuss light weight issues concerning road bikes & parts.
AlexC
Posts: 15
Joined: Thu Oct 11, 2007 8:24 pm

by AlexC

Gentlemen,

I’m building up a 2015 Colnago C60 with Campagnolo Record EPS V3 and fear I may have a compatibility issue with my Campagnolo SRM.

The Campagnolo SRM is a 5 bolt pattern with threaded chainrings, making it circa 2011-2014 (I think). I assumed, perhaps falsely, that it was compatible with all Campagnolo 11 speed components.

Only yesterday did I learn about Campy’s ‘A’, ‘D’, and other designations for specific generations of their 11 speed components.

My BB cups (IC15-RE41) are EPS compatible, but have an ‘A’ marked on them. Will they work with my pre-2015 Campagnolo SRM?

If not, can I simply use the older cups (IC11-RE41) or do I have to pony up and get a 4 arm Campagnolo power meter?

If I use a pre-2015 crank with post-2015 BB cups and components, what are the issues I’m dealing with? Chain-line? Clearance against the chain stay? Are there any other post-2015 components, like the derailleurs, that aren’t compatible?

Thanks for your help
Last edited by AlexC on Sun Jun 24, 2018 12:14 am, edited 2 times in total.

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

by Calnago

You are totally fine. It’s really the one component that is perfectly interchangeable between the groups with no issues. The only functional difference is that the teeth profiles on the 2015+ are a little more aggressive. Just make sure you have the slightly modified C-clip that comes with the SRM, the standard one won’t fit in the recess around the crank spider.
And for sure always use the newest cups which are your IC-15... versions. Oh, you may have to be a little creative with magnet placement for the SRM using EPS, since I don’t think there’s a compatible SRM/K-edge chaincatcher/magnet combo that works with the funky front derailleur bolt on EPS.
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

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AlexC
Posts: 15
Joined: Thu Oct 11, 2007 8:24 pm

by AlexC

Calnago,
Thanks for the reply, that’s a huge relief!

I’m all set with the SRM c-clip, but have been struggling with the k-edge chain catcher with SRM magnet.

Most, if not all, of the Lotto-Soudal team runs Campagnolo EPS, SRMs, and k-edge chain catchers with SRM magnets, despite this being listed as an incompatible setup on k-edge’s website.

https://cdn-cyclingtips.pressidium.com/ ... endt-6.jpg

https://cdn-cyclingtips.pressidium.com/ ... 120583.jpg

I asked a k-edge tech rep if he could explain this phenomenon and he said as long as the front derailleur’s braze-on tab is curved, necessitating the use of the supplied k-edge silver spacer, the front of the derailleur cage will clear the chain catcher. He made no mention of the stud sticking out of the EPS derailleur body...

However, a google image search of the Lotto-Soudal team bikes of Greipel, Roelandt, De Gendt doesn’t show and weird or outlandish modifications to the chain catchers. They all look stock.

http://www.velonews.com/2015/07/gallery ... -sl_376643

How do they achieve this? Any idea what sort of nut threads onto an M5 stud yet fits in the top hole of the chain catcher? Two of the nuts supplied with the Campagnolo V3 battery fit the bill, but the stud is too long, blocking the Allen key from gripping. Did they just cut the stud short?

Is it possible to unscrew the stud from the derailleur body and use the M5 bolt supplied with the chain catcher? They’re both M5 threads but I’m hesitant to try that on such an expensive component.
Last edited by AlexC on Wed Jun 20, 2018 10:49 pm, edited 1 time in total.

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Calnago
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by Calnago

AlexC wrote:Calnago,
Thanks for the reply, that’s a huge relief!

I’m all set with the SRM c-clip, but have been struggling with the k-edge chain catcher with SRM magnet.

Most, if not all, of the Lotto-Soudal team runs Campagnolo EPS, SRMs, and k-edge chain catchers with SRM magnets, despite this being listed as an incompatible setup on k-edge’s website.

https://cdn-cyclingtips.pressidium.com/ ... endt-6.jpg

https://cdn-cyclingtips.pressidium.com/ ... 120583.jpg

I asked a k-edge tech rep if he could explain this phenomenon and he said as long as the front derailleur’s braze-on tab is curved, necessitating the use of the supplied k-edge silver spacer, the front of the derailleur cage will clear the chain catcher. He made no mention of the stud sticking out of the EPS derailleur body...

However, a google image search of the Lotto-Soudal team bikes of Greipel, Roelandt, De Gendt doesn’t show and weird or outlandish modifications to the chain catchers. They all look stock.

How do they achieve this? Any idea what sort of nut threads onto an M5 stud yet fits in the top hole of the chain catcher? Is it possible to unscrew the stud from the derailleur body and use the M5 bolt supplied with the chain catcher? They’re both M5 threads but I’m hesitant to try that on such an expensive component.
Hmmm.... I’m not sure the SRM guy you were speaking with understood what was really going on. The eps front deraileur has a stud on it (I’m sure you know this) that goes through the Brazeon tab and a 7mm square nut screws down on that stud. No idea why they made the attachement so completely different than every other front derailleur but in any case I’ve thought about the K-edge solution and without mods I couldn’t see an easy fix short of just attaching the magnet to the frame or bottom bracket, which would be no big deal either. But thanks for that link, they have definitely got something figured out there. I will look into what they are doing there to make it work. Because it is a nice solution.
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

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Calnago
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by Calnago

AlexC wrote: Is it possible to unscrew the stud from the derailleur body and use the M5 bolt supplied with the chain catcher? They’re both M5 threads but I’m hesitant to try that on such an expensive component.
It certainly looks like that’s what they’ve done there, doesn’t it. I just don’t know... either that or enlarged the hole in the curved thick washer but left enough that they attach a nut that would both fit and hold the washer on. I’d have to see one up close, and probably remove it to see the trick. But they definitely are doing something out of the ordinary.
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

AlexC
Posts: 15
Joined: Thu Oct 11, 2007 8:24 pm

by AlexC

Calnago, I think I figured it out.

Click on the photos to enlarge and apologies for my crappy photography

Here’s Greipel’s Ridley Noah SL:
C72D5DD7-CDFA-42EE-B115-4224323C2D42.png
Here’s a mock up of my C60:
99D63148-F721-47C7-AF1A-1D58A9B038E4.jpeg
Below is how I did it:
Campy supplies two nuts with their battery that are round:
6C7CC5AA-8BED-4D26-A283-D9B5B1D70F16.jpeg
I didn’t need these to install the battery, I just used their supplied studs and hex nuts.
The nut on the left is hex side up, the one on the right is thread side up. There are about 3-4 threads in the nut, which isn’t nearly as much as the original Campagnolo flanged 7mm nut for the FD, but probably adequate with some loctite (I hope).

The nuts have an outer diameter of 8.04mm:
9ED54BD8-4999-4473-921A-87BEADB56206.jpeg
But the inner diameter of the top hole in the chain catcher was only 7.99mm, so i had to bore it out with a 21/64” drill bit, producing an enlarged inner diameter of 8.28mm:
FE0080C1-4027-4216-9A93-CF499F625561.jpeg
D32AE138-60B7-406C-AA35-EB916A1AFEFA.jpeg
In the photo of Greipel’s bike it looks like the nut fit in the chain catcher without any modification. We’re only talking 0.05mm so it might just be due to manufacturing tolerances.

The only other mod I had to make was filing down the derailleur stud by 2 threads so the Allen key can fit in the nut when it’s fully tightened down. Here’s a pic of the original length of the stud next to the k-edge space and battery mounting nut:
B07F3A2D-7D40-4F3A-A046-DF81065D6897.jpeg
After filing off two threads:
D0F562B4-96EF-4552-9D99-1AF943B4EB93.jpeg
I was willing to make this modification because in the worst case scenario if the chain catcher doesn’t work and I have to revert to the stock Campagnolo mounting hardware, I only lose two threads so the Campagnolo nut would still have plenty of purchase on the stud.

When I mounted everything up it seemed ok. I can tighten down the nut plenty hard:
34C19AA1-55F3-489B-9E72-91D2584DF534.jpeg
B56DE3F8-11DB-4047-9E90-69DDC6F0D7A5.jpeg
And the chain catcher still clears the derailleur cage.
I think this what the Lotto-Soudal mechanics did because in the pic of Greipel’s bike, you can see the nut they used is also black while the stud is still silver.

My other idea of replacing the stud with one of the silver colored bolts supplied with the chain catcher is perhaps more elegant, but I didn’t want to risk damaging the front derailleur. This way the only thing I only lose is two threads. The upside far outweighs the downside.

Let me know if anything above jumps out at you as being wrong or dangerous before I tighten everything down with loctite.
Last edited by AlexC on Thu Jun 21, 2018 10:25 pm, edited 1 time in total.

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Calnago
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by Calnago

Nice work Alex, I think that’s exactly that they’ve done. And your pics and explanation describe it perfectly. I’ve but one concern and that’s how large you made the hole in the catcher. It’s almost 0.3mm larger than the bolt diameter. So what? Well, the original bolt is well within 0.1mm... and it is intended to provide support for the actual bolt and leverage against it moving. Meaning you want the edge of the bolt head butted right up against the inner diameter of the hole in the chain catcher. The K-edge instructions even say to make sure it’s against that Edge, which made me pause and think about why that’s so critical. The smaller bolt merely keeps the thing in place but if the chain gets wedged in between I’d bet it could easily force its way through because the opposite end isn’t being supported so well if there’s potentially a 0.2-0.3mm gap there. Even though that’s a small gap it is at the pivoting point so the gap at the other end would be larger and probably enough to allow the chain through with a little force.

It’s clear that on Griepels bike they didn’t alter or drill the catcher. I measured the hole in one just now and came up with 8.00mm diameter, close to your measured 7.99mm. You measured the EPS nut at what... 8.04mm? For that amount of difference all you need is quick twist with some Emory cloth until you have a perfect fit, either on the nut head itself or the inside diameter of the hole in the catcher. Not sure the force of just screwing in the nut wouldn’t be enough to just draw it in, it is aluminum after all. I suspect you’ll be fine but experiment a bit when you get closer to see how much play there could potentially be at the point where the chain passes.
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

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Miller
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Joined: Thu Sep 21, 2006 8:54 pm
Location: Reading, UK

by Miller

Hmm. EPS front mechs exert a lot of force. Is there a magnet mounted on the end of that K-edge chain catcher? The Campag dedicated chain catcher works well with the EPS front mech mounting, perhaps you could have got one of the Campag ones and fixed a magnet to the end of it.

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Calnago
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by Calnago

Yes, that’s the other thing I forgot to mention... the force from that front derailleur is a lot, which means the support around that bolt is even more critical. You’ve definitely drilled out some slop in there.

As for the Campy catcher, I really do prefer the K-Edge design, and yes... the magnet is on an adjustable extension at the end of the chain catcher. Works perfectly and is very clean. And for whatever reason... Lotto Soudal seems to have chosen it as well. With Campy as their sponsor main group sponsor, I’m sure they could use either.

@Miller: do you have the Campagnolo chain catcher on your bike? If so, and it’s not too much trouble, could you post a pic of it. I’ve never actually used it as I’ve preferred the K-Edge, even after comparing the two. The Colnago chain catchers I just toss because the adjustment and tightening bolt are one and the same, like the first gen K-Edges used to be. Especially with how precise the front derailleurs today need to be aligned, having to worry about also getting the chain catcher perfectly adjusted using the same tightening bolt makes the process a pain in the ass, like a kids Walmart bike.
Last edited by Calnago on Thu Jun 21, 2018 10:08 pm, edited 1 time in total.
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

AlexC
Posts: 15
Joined: Thu Oct 11, 2007 8:24 pm

by AlexC

Calnago,

Good call! I admit I didn’t read k-edge’s directions, so thanks for explaining the necessity of having a tight fit.

I’ll order another chain catcher, leave the top hole alone, and just rub the nut with some Emory cloth until it fits.

Your suggestion makes the whole hack simpler as well as safer, since filing down the front derailleur stud is really the only modification that needs to be made.

I wonder if I should re-title this thread so more people running this set-up know about this trick we figured out.
Last edited by AlexC on Thu Jun 21, 2018 10:28 pm, edited 1 time in total.

AlexC
Posts: 15
Joined: Thu Oct 11, 2007 8:24 pm

by AlexC

Miller,

Yeah, absolutely. I think Calnago’s suggestion of leaving the top hole in the k-edge catcher alone is exactly what the Lotto-Soudal mechanics did.

If they’re confident enough in the strength of this set-up to run an entire pro team on it, I’m comfortable running it on my bike.

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Calnago
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by Calnago

Sure. Renaming the thread would be good. This is a good tip you’ve come up with. It bothered me a bit that I couldn’t put a K-Edge on the last EPS I did, so this is good to know. If it’s good enough for Greipel, it’s good enough for me.
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

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Miller
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by Miller

Calnago wrote:
Thu Jun 21, 2018 10:08 pm
@Miller: do you have the Campagnolo chain catcher on your bike? If so, and it’s not too much trouble, could you post a pic of it.
I do, I'll get round to posting a pic. Adjustment of the actual chain catcher is independent of the fixing bolt.

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Calnago
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by Calnago

Yes, I know they have independent adjustment too, I admit I haven’t given it a try since I’ve been using the K-Edge but I’d like to see your setup for cases where an SRM isn’t involved and no magnet is necessary.
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

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Miller
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by Miller

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