Help Needed - Frame Specs for Di2/EPS

dan_hudson · #1 02-22-2023, 08:14 PM

Specifically, hoping to find specs regarding the location of the wiring port for the front derailleur. Stuff like elevation along seat tube from center of bottom bracket, acceptable angle locations off of centerline, etc.

I’ve found this doc from Campy online that includes the drawing below. This shows a max offset (but no min) as well as an angle. Thinking there might be an even more detailed doc, from Campy or especially Shimano (as I asked for Di2 routing), that they share with bike manufacturers and frame builders.

Asking as I recently received a new custom frame that has what to me seems like an unconventional placement of the port. Will require an extended external run of wire potentially threatened by the tire or road debris. Has been a struggle to have a productive exchange regarding the placement + how to keep the wire safe/secure from the builder and their LBS representative.

Hoping finding such docs will facilitate a more constructive discussion of the issues.

Thanks!

BdaGhisallo · #2 02-23-2023, 04:54 AM

I just scanned all 450 pages of the Shimano "Products Technical Information" manual from 2017-18 that I have and there's info about the dimensions of the frame holes for internal DI2 routing but nothing that I can see about where those holes should be located.

dan_hudson · #3 02-23-2023, 07:00 AM

Thanks for flipping thru all that! I'm hoping there may be a frame builder/manufacturer-specific doc that does have that info. Was pleasantly surprised to find the linked doc from Campy.

While possible the industry settled into the now common "few inches above the BB, 45 or 135 degrees off of front center", my gut is the hand of Shimano setting the layout.

To be clear, the port in my new frame is in a radically different location than in the Campy drawing or what we usually see. It's not a question of being a few mm or degrees different.

Quote:

Originally Posted by BdaGhisallo

I just scanned all 450 pages of the Shimano "Products Technical Information" manual from 2017-18 that I have and there's info about the dimensions of the frame holes for internal DI2 routing but nothing that I can see about where those holes should be located.

BdaGhisallo · #4 02-23-2023, 07:20 AM

Quote:

Originally Posted by dan_hudson

Thanks for flipping thru all that! I'm hoping there may be a frame builder/manufacturer-specific doc that does have that info. Was pleasantly surprised to find the linked doc from Campy.

While possible the industry settled into the now common "few inches above the BB, 45 or 135 degrees off of front center", my gut is the hand of Shimano setting the layout.

To be clear, the port in my new frame is in a radically different location than in the Campy drawing or what we usually see. It's not a question of being a few mm or degrees different.

There could be something like that floating around. This doc has some pretty detailed information pertaining to frame building and manufacturing specs, though.

If you're interested in it, PM me your email and I'll send it to you.

prototoast · #5 02-23-2023, 07:37 AM

Sorry, Shimano leaves this one up to the builder (from the 2013-2014 Products Technical Information).

charliedid · #6 02-23-2023, 07:42 AM

I'm confused as to what's happening here.

Dan - You took delivery of a bike and you are concerned it was improperly built?

Blown Reek · #7 02-23-2023, 08:08 AM

Quote:

Originally Posted by dan_hudson

Asking as I recently received a new custom frame that has what to me seems like an unconventional placement of the port.

The Paceline formally request that you attach a picture of the area in question. No need for frame specifics, just the location of the hole in relation to the bottom bracket area.

dan_hudson · #8 02-23-2023, 09:51 AM

Hole/port is in the bottom bracket dead-center between the chain stays.

batman1425 · #9 02-23-2023, 10:11 AM

Physically it should work, but, depending on tire/frame clearance, I share your concern about debris from the tires damaging the wire over time or even ripping it out if you got something big stuck in there. Def need to secure it with a stick on guide or zip tie to the seat tube. Either option is not something I’d expect to have to do on a custom frame.

Is the frame material amenable to relocating the hole easily?

Id not be crazy about that placement.

Sent from my iPhone using Tapatalk

Blown Reek · #10 02-23-2023, 10:19 AM

Quote:

Originally Posted by dan_hudson

Hole/port is in the bottom bracket dead-center between the chain stays.

That is quite an atypical location.

Dave · #11 02-23-2023, 10:44 AM

Sounds like a typical location for a water drain hole or cable guide bolt.

I have carbon frames with two holes in the side of the seat tube. I guess they support electronic or mechanical FD. Another has a hole about 3cm below the FD mount and pointing about 45 degrees toward the front of the bike. It's also got one under the chain stay, about 6cm ahead of the axle.

None of them get used with SRAM AXS.

dan_hudson · #12 02-23-2023, 11:57 AM

Thanks to all for the info. While this Shimano doc is not everything I was hoping for, the highlighted areas do help illustrate their intent that the port be on the side of the seat tube in proximity to the FD.

To be clear, the hole in the BB that the shop + builder say is the wire port is literally between the chain stays, not on the bottom where a cable guide would attach. Of course it can work with a zip-tie or two to secure the cable. The discussion I'm trying to have is on the appropriateness of that.

Also, we are talking about a custom frame from a renown builder with multi-year lead-time.

Quote:

Originally Posted by prototoast

Sorry, Shimano leaves this one up to the builder (from the 2013-2014 Products Technical Information).

Blown Reek · #13 02-23-2023, 12:22 PM

Quote:

Originally Posted by dan_hudson

Also, we are talking about a custom frame from a renown builder with multi-year lead-time.

Interesting. I wonder if it's one of those "artistic foibles" that a builder would do just because they can and that's what you get (which is a thumb of the nose to the customer). However, that location is just stupid and no framebuilder with a modicum of common sense would put it there. I mean, really... what's the thinking?

charliedid · #14 02-23-2023, 02:39 PM

What does the builder have to say?

prototoast · #15 02-23-2023, 02:43 PM

Quote:

Originally Posted by dan_hudson

Thanks to all for the info. While this Shimano doc is not everything I was hoping for, the highlighted areas do help illustrate their intent that the port be on the side of the seat tube in proximity to the FD.

To be clear, the hole in the BB that the shop + builder say is the wire port is literally between the chain stays, not on the bottom where a cable guide would attach. Of course it can work with a zip-tie or two to secure the cable. The discussion I'm trying to have is on the appropriateness of that.

Also, we are talking about a custom frame from a renown builder with multi-year lead-time.

I definitely wasn't expecting the hole in the bottom bracket shell, that's for sure. When I've drilled holes for di2, I put them on the front side of the seat tube to keep the wire away from the rear wheel/mud splatter, but also the rear derailleur di2 cable is pretty exposed coming off the chainstay, and I've yet to hear of a problem related to that, so this will probably be fine--albeit a little weird.