Shimano Dura Ace 11s Downtube Shifter (hack)

[Look585]

Shimano does not provide downtube shift levers for its 11s groupsets. However, with a bit of work you can remove the guts of the rear 11s bar-end/time-trial shifters and fit the indexing unit into the rear 7900 downtube shift lever.

Parts required:
SL-BSR1 11s TT shifters
SL-7900 10s DT shifters

Tools required:
Dremel with a tiny burr bit
Patience

Diagram: I'll refer to the part numbers below for both DT and TT shifters. "4tt" would be the time-trial lever body, "3dt" would be the down-tube indexing unit.

Process:

1) Remove the indexing unit (3tt) from the TT lever body. It simply pulls out with a bit of force. You will likely dislodge the two funny looking washers on the backside (5tt and 6tt) in the process. That is fine as they will follow the indexing unit to its new home.

2) Remove the indexing unit (3dt) from the DT lever body as above.

3) Have a look at "stop washers" 5tt and 5dt. You'll note that they are slightly different. The shorter distance between the "stop tabs" in 5tt allows the lever to rotate about 10 degrees further around to make room for the 11th detent position in the 3tt indexing unit.

4) Turn the now empty lever (4dt) over and look at the "backside". The raised section (yellow oval) in 4dt needs to be "shortened" with a dremel burr so the stop washer (5tt) from the TT shifters fits. You need to remove about 1.2mms of material. I started with a flat diamond needle file to remove the "proud" portion and then switched to a dremel burr to hollow out the "recessed" portion. Go slow and check the fit of your 5tt periodically to ensure you don't go past what needs to be removed. You can also measure the same feature on part 4tt as that is the dimension you are targeting for 4dt.

5) Once you have shortened the limiter on 4dt and the 5tt washer fits in the recess, simply assemble the bits in the following order and you are ready to mount to your DT shifter boss: 7dt>6tt>5tt>4dt>3tt>2dt>1dt

I have been running the 7900 DT lever as 11s for a few weeks now, perhaps 250 miles and 100s of shifts. It works fantastic, nice positive clicks in the lever and the indexing is spot on.

[m_sasso]

Thanks for the write up, knew this was possible however unaware how it was done.

Are you using a 10speed rear derailleur, if so witch one?

[bbobway]

Nice write up, thank you!

[Cicli]

Originally Posted by m_sasso

Thanks for the write up, knew this was possible however unaware how it was done.

Are you using a 10speed rear derailleur, if so witch one?

The indes is for 11 speed. You need an 11 speed derailuer.

OP, very nice job.

[stien]

Thanks for the write up! Anyone know if this will work with a Shimano 600 tricolor shifter?

[Mr_Gimby]

Originally Posted by stien

Thanks for the write up! Anyone know if this will work with a Shimano 600 tricolor shifter?

Why would you need to adapt that for a downtube application? It comes already setup for DT mounting...

[stien]

Convert the 6s lever to 11s?

[Look585]

RD, Cassette, Chain are all 11s.

No idea on the 600 Tricolor. Pull it apart and if it looks like the above...

One last note, you can test your setup without any modification by simply dropping the 3tt indexing unit into your existing dt lever (no other parts from the BSL1 unit). It should index perfectly with your 11s setup, but not rotate far enough to reach the 11th index detent. If that works, get out the dremel to extend the throw.

[guido]

Fantastic! Thanks so much!

[Ti Designs]

With a single micro switch I could make a Di2 downtube shifter which will work just fine with 11-speed...

Sometimes you have to think forward to work backward.

[Look585]

Originally Posted by Ti Designs

With a single micro switch I could make a Di2 downtube shifter which will work just fine with 11-speed...

Sometimes you have to think forward to work backward.

Yep, it is easy to make auxiliary Di2 buttons and stick them somewhere, but the vestigial DT shifter mounts on your old steel (or Ti!) frame will still look silly.

Sometimes you want to do something that cannot be done.

[stien]

Originally Posted by Ti Designs

With a single micro switch I could make a Di2 downtube shifter which will work just fine with 11-speed...

Sometimes you have to think forward to work backward.

I have a picture in my head: a momentary two way toggle coming out the top of a DT cable stop. That would be so cool. I may have to do it.

Looks like you need shifter guts that house the all important a-d connected to a switch. Anything other than 7970 is digital.

[chiasticon]

cool writeup! knew it was possible, just didn't know the details of HOW

[Look585]

Originally Posted by stien

I have a picture in my head: a momentary two way toggle coming out the top of a DT cable stop. That would be so cool. I may have to do it.

Looks like you need shifter guts that house the all important a-d connected to a switch. Anything other than 7970 is digital.

Yeah, I considered this, but you need the "brains" somewhere. You could probably bury everything in the seat tube (battery, a&b junctions, and shifter brains) and then run wiring inside the downtube to the DT bosses with a hole drilled on either side where the mounting bolt runs. Then you have to find mom-off-mom rocker switches that aren't huge and would jive well with the rest of the build. Then you'd need to build housings/mounts for those rockers.

The dremel work on the 7900 lever keeps everything looking stock and crisp and gets my retro ride on the 11s wheel standard. I'm not saying the eDT-Di2 project isn't worth doing, just that it is going to be pretty involved.

If anyone wants to take this to the next level (eDT-Di2), I have a pair of shifter brains from a crashed set of 6870 levers I'd donate to the cause.

[Look585]

Originally Posted by chiasticon

cool writeup! knew it was possible, just didn't know the details of HOW

While I really appreciate the Breadwinner project, that is a stunning and cool ride with amazing attention to detail, they fell a bit short with the use of the "flat" DT shifter boss covers. For ~$10 and some dremel time, they could have re-profiled some "radiused" DT shifter boss covers and achieved a better aesthetic. Details!