SRAM Red eTap FD chain drop

Discuss light weight issues concerning road bikes & parts.
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wheelsONfire
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by wheelsONfire

sfo423 wrote:
Thu Apr 04, 2019 4:02 pm
Quick Q; I am building an F10 disc w/eTap and was interested if most are opting for a chain catcher (w/their eTap builds)...regardless if you have had drop issues or not.
Sram Red chain catcher/ chain spotter or possibly Wickwerks Sentinel. However, Sentinel doesn't fit with my UP and Di2 and it doesn't on my Ax either.
I think it is reasonable to guess that it would not with many bikes.
So, what is the problem you may ask?
The Sentinel interacts with the seat mast tube bottle cage. No matter what cage i use. Either that, or the bottle will hit part of the Sentinel.
Last edited by wheelsONfire on Fri Apr 05, 2019 11:55 pm, edited 1 time in total.
Bikes:

Ax Lightness Vial EVO Race (2018.12.21)
viewtopic.php?f=10&t=156137
Paduano Racing Fidia (kind of shelved)
Open *UP* (2016.04.14)


Ex bike; Vial EVO D

by Weenie


bikeboy1tr
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by bikeboy1tr

Yeah I know that AB doesnt have a pin but the Rotor does. I find the AB big ring combined with the Rotor small ring work well together on etap as the ecentricity on AB is less than that of the Rotor which means the throw is not as far from the Rotor to AB (52T,38T). The rings are also closer together between the two as compared to having two AB inner and outer rings @ TobinHatesYou
"Life is like riding a bicycle. To keep your balance you must keep moving"-Albert Einstein
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wheelsONfire
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by wheelsONfire

I did set up another bike with Etap. Both my own bike and the other bike (not mine), have the lowest part of the cage 2mm from the top of chainrings tooths.
Even a hair less on some tooths.
This makes our chains run free from the "lump", in the "roof" of the FD cage.
The shifting works without rub, using all 11 gears with the 50T chainring and all 11 gears on the 34T and the 36T (my bike).
So, 22 gears you can use and you can cross chain how much you want.
No chain drops!
I have set both bikes with Sram Red chain catcher/ spotter. As mentioned above, i don't find Wickwerks Sentinel to work properly.
On my bikes, it interacts with the bottle cage and/ or the bottle itself.
Bikes:

Ax Lightness Vial EVO Race (2018.12.21)
viewtopic.php?f=10&t=156137
Paduano Racing Fidia (kind of shelved)
Open *UP* (2016.04.14)


Ex bike; Vial EVO D

alcatraz
Posts: 2054
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

wheelsONfire wrote:
Sat Apr 06, 2019 12:00 am
I did set up another bike with Etap. Both my own bike and the other bike (not mine), have the lowest part of the cage 2mm from the top of chainrings tooths.
Even a hair less on some tooths.
This makes our chains run free from the "lump", in the "roof" of the FD cage.
The shifting works without rub, using all 11 gears with the 50T chainring and all 11 gears on the 34T and the 36T (my bike).
So, 22 gears you can use and you can cross chain how much you want.
No chain drops!
I have set both bikes with Sram Red chain catcher/ spotter. As mentioned above, i don't find Wickwerks Sentinel to work properly.
On my bikes, it interacts with the bottle cage and/ or the bottle itself.
I'd like to give your setup a try.

Compared to the lines that sram says to use, how far and in which direction does your setup deviate?

Thanks

TobinHatesYou
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Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

I have more or less eliminated thrown chains, but I have about 6mm gap between the tallest tooth and FD cage in the outboard position. I also run the high limit to within .1mm of rubbing in big-small. The tail of the cage is also angled slightly in, maybe .5mm from the guide line.

The thing is this only applies to my bikes. Braze-on tab geometry and spatial positioning varies. If a braze-on tab positions your FD cage more onboard or outboard, the way the cage yaws will be slightly different. If the braze-on tab is in a different fore/aft position or pitched differently, the cage may have to be at a different relative height.

ArtV
Posts: 33
Joined: Tue Mar 01, 2016 3:23 am

by ArtV

My Wickwerks Sentinel hits my bottle but not my cage. I can still insert my bottle fully though so don't think it is an issue since the bottle is flexible and doesn't appear to exert much pressure.

Sent from my SM-T830 using Tapatalk



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wheelsONfire
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by wheelsONfire

alcatraz wrote:
Sat Apr 06, 2019 1:46 am
wheelsONfire wrote:
Sat Apr 06, 2019 12:00 am
I did set up another bike with Etap. Both my own bike and the other bike (not mine), have the lowest part of the cage 2mm from the top of chainrings tooths.
Even a hair less on some tooths.
This makes our chains run free from the "lump", in the "roof" of the FD cage.
The shifting works without rub, using all 11 gears with the 50T chainring and all 11 gears on the 34T and the 36T (my bike).
So, 22 gears you can use and you can cross chain how much you want.
No chain drops!
I have set both bikes with Sram Red chain catcher/ spotter. As mentioned above, i don't find Wickwerks Sentinel to work properly.
On my bikes, it interacts with the bottle cage and/ or the bottle itself.
I'd like to give your setup a try.

Compared to the lines that sram says to use, how far and in which direction does your setup deviate?

Thanks
I don't think it deviates at all. The markings on the FD should be parallel to the chainring as Sram says.

Slightly different, well, perhaps at the 34/36T and 28T at cassette. I have more clearance between chain and inner plate of cage.
This is needed to have enough clearance for the 50T to be able to be at 28T (cassette).
Even if you don't or won't use this combo, you may by accident.
The "lump" in the "roof" is supposed to be near chain. It's to prevent chain from over-lifting, causing chain to be thrown over.
Ofcourse chain should never rub this "lump".
I don't find angling the cage a good idea. At the 50/11 it should be close, but not so close that it rubs.

I use a flashlight and look at both sides to see precisely what happens.

Regarding Sentinel, i don't appreciate this feature of Sentinel (rubbing bottle)
Personally it annoys me so i can't recommend this piece. The Red chain catcher is perfectly executed though!
Bikes:

Ax Lightness Vial EVO Race (2018.12.21)
viewtopic.php?f=10&t=156137
Paduano Racing Fidia (kind of shelved)
Open *UP* (2016.04.14)


Ex bike; Vial EVO D

TobinHatesYou
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Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

That lip is there to prevent the chain from jumping too high on downshifts, not upshifts.

When I follow the SRAM guides/videos/manuals exactly as instructed, I get regular overshifts. I'm sure others can chime in with similar experiences.

Yes I've tried using the wedges.
Yes I've tried using the angled shims to rotate the tail of the cage down.
I've also tried bringing the cage as low as possible (causing the lip to contact the chain in big-big combos.)
I've tried rotating the tail out so it barely clears the crankarm during the temporary overshift.

What works for me is a 6mm gap for cage height, having the yaw of the FD so the tail is .5mm closer to the frame rather than lined up with the chainring, and setting the high limit to the point where there is almost hesitation in the upshift...literally .1mm from rubbing the chain.

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wheelsONfire
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by wheelsONfire

Hey THY, i believe you! But the thing is, there are guys who have followed the video and end up with great working bikes. I have been trying to figure why there is such a diversity between bikes. There are several guys here who have had serious issues and those bikes seem to have been at dealers and even Sram have been involved. But a few of them still have an unsolved issue.
It would be interesting to have some flat out fact, saying this was the problem.
My current bike would probably be in the region of a potential issue. Chainstays are only 403mm. My ex bike had same. Only difference between my new EVO compared to the previous is BB drop (5mm difference).
I wonder if it has something to do with alignment of the FD towards the chainrings (not just rear or forward)!?
I guess it can be a slight offset which is probably nothing we could do anything about!?
Bikes:

Ax Lightness Vial EVO Race (2018.12.21)
viewtopic.php?f=10&t=156137
Paduano Racing Fidia (kind of shelved)
Open *UP* (2016.04.14)


Ex bike; Vial EVO D

bikeboy1tr
Posts: 367
Joined: Thu Mar 21, 2013 3:19 am
Location: Southern Ontario Canada

by bikeboy1tr

I have done much the same as THY with the FD set up but originally I set mine up via Sram instructions and no luck so the last time I did the set up I eyeballed the FD with the big ring trying to keep it in parallel with the big ring and the height was set to just clear the chain when in third largest cog rear and big ring front. The min max for inner and outer is very tight with a little rub when again in third largest rear cog and big ring and a little rub when small ring, small cog rear. I got two hours in today with no dumps and lots of shifting. My rear chain stay according to geometry charts for the V2R is 411mm.
Feel like I got horse shoes up the arse at the moment.
"Life is like riding a bicycle. To keep your balance you must keep moving"-Albert Einstein
2018 Colnago V2R Rim Brake
2014 Norco Threshold Disc Brake
2012 Time RXRS Ulteam Rim Brake
2008 Time VXR Rim Brake
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wheelbuilder
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by wheelbuilder

See my post in SRAM 2019 thread for observations on AXS shifting and set-up.

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wheelsONfire
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by wheelsONfire

bikeboy1tr wrote:
Sun Apr 07, 2019 1:03 am
I have done much the same as THY with the FD set up but originally I set mine up via Sram instructions and no luck so the last time I did the set up I eyeballed the FD with the big ring trying to keep it in parallel with the big ring and the height was set to just clear the chain when in third largest cog rear and big ring front. The min max for inner and outer is very tight with a little rub when again in third largest rear cog and big ring and a little rub when small ring, small cog rear. I got two hours in today with no dumps and lots of shifting. My rear chain stay according to geometry charts for the V2R is 411mm.
Feel like I got horse shoes up the arse at the moment.
What size of cassette and chainrings?
Bikes:

Ax Lightness Vial EVO Race (2018.12.21)
viewtopic.php?f=10&t=156137
Paduano Racing Fidia (kind of shelved)
Open *UP* (2016.04.14)


Ex bike; Vial EVO D

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wheelsONfire
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Joined: Mon Jul 07, 2014 8:15 am
Location: NorthEU

by wheelsONfire

When the chain climb up from small to big, the lump in the "roof" of the cage, force the chain down on the big chainring tooths. If the distance is too high, the chain may overshift.
You could easily see this if you look at how the chain moves when you upshift.
Bikes:

Ax Lightness Vial EVO Race (2018.12.21)
viewtopic.php?f=10&t=156137
Paduano Racing Fidia (kind of shelved)
Open *UP* (2016.04.14)


Ex bike; Vial EVO D

Tarmacian
Posts: 14
Joined: Thu Feb 18, 2016 9:00 pm

by Tarmacian

Hi all,

Next week my new bike will be build. It’s running red AXS. Does anyone experience chain drops with AXS or not?

I’m considering a chain catcher just to be sure but maybe it’s not necessary.

Regards

by Weenie


TobinHatesYou
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Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

Tarmacian wrote:
Wed Jun 05, 2019 3:22 pm
Hi all,

Next week my new bike will be build. It’s running red AXS. Does anyone experience chain drops with AXS or not?

I’m considering a chain catcher just to be sure but maybe it’s not necessary.

Regards
Ask Bauke Mollema about that.

Basically yes. You need to set up your FD so that it will shift to the big ring during the overshift. If I’m in one of the four largest cogs on my cassette and miss the overshift, my chain will just chatter along in the small ring. Just make sure you are actually pedaling during a shift...

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