Beside BTP clamps in the shifters the RD can be tuned quite a bit with new pulleys and bolt.

Original DA 7970 pivot bolt is 11 grams
Kronos from FWD is 6 grams.

222 grams to start- tuned to 208

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-Deacon Doctor Colorado Slim

wow...how much did saving those 14 grams cost you?

Really? That's not the point. Why not just tell him he should have gotten Ultegra 'cause it's "good enough"

Starnut

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Ummm... break out the Dremel and get to work.
Carbon plates?
Change out the mounting bolt.
You can probably bring it down to ~190g.

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Exp001

This is Weightweenies ...!

But... but... if people spend time reading threads like this, they won't have time to author more first-ever-post "Which wheelset" topics!

My first-ever post here was during a heated debate on the weights of dried tubular glue. Oh, the good ol' days...

I'm still psyched to find out about all the weenie-tuning options available for Di2. Lighter, custom batteries? Custom wiring? Total geeks taking apart and reworking the electric motors? Sunglass-mounted blink-sensitive shifting sensors? Bring it on!

The rear plate is pretty light to begin with at 5 grams.


A sexy ultra light one didnt save much and wasnt as stiff


I took off the limit screws and B screw and they weigh next to nothing so no real tuning there.

Custom battery is where its at though for real WW savings. 70 grams for a dual cel (size of AA batteries) and plastic shell. I am trying to half that with a half battery and different mounting option. It already lasts way too long for me. I would rather charge it more often (still almost never) and save 35+ grams.


There is not a lot to do with the FD without some custom fabrication


Internal/Extrenal harness can be hacked up a bit to save some grams too. The metal plate is removable and quite heavy.

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-Deacon Doctor Colorado Slim

colo,

Drill out the battery. Less weight, fewer shifts*

* Well, o.k., that might be 0 shifts now, but anywho. Just pick a low enough gear for climbing, and learn to spin as the terrain levels out and goes down. And if your bike catches fire, that will be even more weight savings.

Hahaha

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IIRC a lot of the Di2s performance benefit is due to added stiffness and changed profiles of the mechs, at what point does weightweenie tuning turn into missed shifts?

For the battery I would suggest to simply replace the 2 cells, with 2 other, but lighter, cells. Going back to 1 single cell will require a voltage booster, too much of hassle, especially when you aren't an EE.

Take a look here for example: http://www.all-battery.com/li-polyersinglecells.aspx
The lightest option weights only 0.95 grams. But don't shift to often, because the capacity is only 25 mAh Something a little heavier would be a better choice, for example one with a capacity of 160 mAh weights only 4 grams. For comparision when the orinal cells are of the AA format (14500), the capacity is 900 mAh and the weight is 21 grams a cell. So weight savings with the 160 mAh cells would be: 2*21-2*4=34 grams

And get rid of plastic housing, heat shrink tape is a lot lighter

thanks coloclimber for your innovation on this new di2 drivetrain. it will be interesting to see what you can do with the battery as that seems like it is the heaviest of the parts that can be modified. possibly the cables can be changed out too with less durable housing ones?

I would do a custom battery. You can make a small pack and shrink wrap it, but you may have to cut the battery connector and solder in another type of power connector.

I'm looking into that (smaller cables and junctions) as well. Waterproofness is pretty important.

The FD is frustrating me at the moment. There is a lot of mass but not much you can do about it since its part of the mechanical. The biggest gram savings is in the battery and cable system.

Thanks for all the PMs about volts/wiring/charging etc.
I am definitely no EE- environmental lawyer by trade- so this stuff is way beyond my expertise.

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-Deacon Doctor Colorado Slim

Is this the weight fully charged or empty?