eTap/Di2 Hacking

Discuss light weight issues concerning road bikes & parts.
DirtyKolache
Posts: 19
Joined: Sun Feb 23, 2014 7:41 am

by DirtyKolache

Let's enjoy a little science experiment here. Say on a road bike I want to enjoy SRAM's eTap shifting but I want Shimano's hydraulic braking. What parts would be needed and what parts would need to be hacked in order to make a Shimano ST-R9170 shift a SRAM eTap derailleur.

I know how impracticable this is, but that is not the point of the question. Have fun!

by Weenie


2focused
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Joined: Wed Jul 19, 2017 9:27 pm

by 2focused

use etap hydro shifters with shimano rotors and caliper assembly?

uraqt
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Joined: Mon Apr 03, 2006 8:53 am

by uraqt

There is a thread about this but I am not sure that anybody has done any hacking.. there are pix at the patent US office of the etap electronics and it looked very easy to re-package them. I was thinking about putting the etap electronics in campy 10 speed shifters... but in the end decided to stay with old school mechanical

C

DirtyKolache
Posts: 19
Joined: Sun Feb 23, 2014 7:41 am

by DirtyKolache

uraqt wrote:There is a thread about this but I am not sure that anybody has done any hacking.. there are pix at the patent US office of the etap electronics and it looked very easy to re-package them. I was thinking about putting the etap electronics in campy 10 speed shifters... but in the end decided to stay with old school mechanical

C


Can you point me to that thread, I'm having trouble finding it.

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ergott
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by ergott

2focused wrote:use etap hydro shifters with shimano rotors and caliper assembly?


Different and incompatible fluids.

motorapido
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Joined: Fri Jul 30, 2010 7:08 pm

by motorapido

Not that easy,

As Shimano use mineral oil and SRAM use Hydraulic DOT 5 brake fluid, mixing systems will cause the seals to swell and wreck them.

You might be lucky and get seals the right size and material to swap for the calliper pistons but i doubt it will be that straight forward.

However if you have enough spare cash, and the inclination, i reckon you could probably buy some Etap hydro shifters and some Shimano Di2 hydro shifters, gut all the electronics from both systems and modify the Sram levers to activate the Shimano master cylinders. Not sure why you would want to do this but it is possible.

I've made several set that go the other way, Fitting Shimano Di2 lever assemblies and electronics into Sram mechanical shift hydroR brake systems.

Mainly on the HydroR rim brake systems to give Electronic shifting with Hydraulic rim brakes, not an option that Sram seem to make.

Have also done the same with a HydroR disc system, when Planet X where selling them off cheap,

I also have an Etap like system for 1x11 on my CX bike where the Doubletap levers have had the internals removed and they operate momentary switches, which are wired up to a single Shimano Di2 climbing shifter electronics. A junction 'A', rear XT Di2 mech and internal battery is all you need to make about the lightest clutched Di2 system you can build.

kwakekeham
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Joined: Fri Jul 22, 2016 8:03 pm

by kwakekeham

Having seen the guts of all of these, the problem is more about not being able to return to anything else and the sacrificial element is going to be the ST-9170 shifters. You'll also need a SRAM blip box plus sacrifical blips. How it would work is ST-9170 + a blip box + soldering iron + wire strippers. I am basing this on the ST-68xx and ST-90xx shifters. I haven't seen a disassembled 9170 yet.

The way DI2 works is that the "brains" of the shifter (yes, there are brains, 2 wire communications over powerline) is in the shifter body BUT the shifter buttons are on the levers with a small wire. Cutting this wire should reveal either 3 or 4 wires (I can't remember if they have a common). So you cut a blip off and solder into this to make pretty then it's just an input to your blip box. I believe these are Normally open, which is also what SRAM uses. I think everyone uses normally open switches. Also, the cable on the Shimano levers are short, so there isn't any repairing this without adding cable and you'll just end up with a mess.

This doesn't change any of the braking system so it's all mineral oil. The main issue is this cable is in the groove of the brake lever so it's hard and annoying to running it. It might be possible to run the wire through the body and have it come out where the normal di2 wire does if you've planned.

Also, no idea how to access to the top buttons on the 9000 and 9100 series electronic shifters. It's in there, I've just never gone this deep. 8000 did

L3X
Posts: 277
Joined: Wed Feb 25, 2009 8:39 pm

by L3X

I think the only reasonable option for this is to replace the seals in eTap shifters and then use mineral oil + shimano calipers. As far as I'm aware the issue only happens when mineral oil comes in contact with seals that used DOT fluid before.

TobinHatesYou
Posts: 605
Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

Are Shimano calipers even better than eTap HRD calipers? At least with the rotors, the IceTech/Freeza rotors have not impressed me. I've tried the RT-99s, the RT-900s, the Campy H11s, the SRAM Centerline X CL and Centerline X 6-bolt. The 6-bolt Centerline X have been by far the best rotors for me in terms of staying quiet and true under heaving braking. The centerlock version is a distant second. Next are the Campy H11s which warp temporarily after heavy braking and also produce Chewbacca noises under braking. Then come both IceTech rotors. They temporarily warp considerably as well as make wub-wub-wub sounds under light braking.

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ergott
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by ergott

Funny, the Sram rotors that came with the Etap hydro I built up were really out of true and too flimsy to get acceptably better. Ice Tech rotors have worked much better for me.

pwork
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Joined: Wed Mar 02, 2011 7:12 pm

by pwork

I also liked "gen 1" shimano road hydro braking and etap functionality. I've basically done that with Di2 1x setup on my 2018 Diverge. 785 shifters w/ flat mount calipers, XT der, 46t chainring, with either a 11-40 xt cassette on my road wheels with a 11-46 xt cassette on my gravel wheels for my 2018 diverge. I've reprogrammed my shifter buttons to shift like etap, faster/harder with all three right buttons, slower/easier with my left bottons. Soldered sprint shifters into climber switch and buried everything into a aerofly bar. Very clean install with the bar end A junction (even though it took ~6hrs to route everything lol).

Talked with a rep this weekend that etap won't go 1x for a while...and I hate front ders. The hydro Etap braking setup does feel a lot better to me though. Both shimano and sram gen 1 hydro felt the same in the drops to me, but the sram setup was a harder pull from the hood with my little hands.

motorapido
Posts: 241
Joined: Fri Jul 30, 2010 7:08 pm

by motorapido

L3X, its not quite that simple, with the Etap shifters there is a piston seal and bladder in the reservoir that would need changing.

The OP asked about fitting Etap shift to Di2 brakes,
So the solution is to fit momentary N/O switches activated by the Shimano lever paddles after removing all the Di2 electronics, and to wire these up to plugs that then go into the TT blip box, a mod that a few people on here have done to add extra sprint or climbing shifters (see Sugercane or jih posts on the subject) That should be job done.

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ergott
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by ergott

Pretty sure the original example is a hypothetical you guys are overanalyzing. I can't think of any practical reason to go through all the time/effort.

Now wiring up buttons from one group to another group's levers on the other hand...

uraqt
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by uraqt

@DirtyKolache

Sorry I couldn't find it ... But I am 100% sure it's on the net some where... It was patent office pix

C

by Weenie


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sugarkane
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by sugarkane

ergott wrote:Pretty sure the original example is a hypothetical you guys are overanalyzing. I can't think of any practical reason to go through all the time/effort.

Now wiring up buttons from one group to another group's levers on the other hand...



thats pretty straight forward :wink:

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