Di2 cable length for ultegra 6870

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vtspot
Posts: 48
Joined: Mon Jun 02, 2014 4:34 am

by vtspot

Greetings,
My frame size is 520mm and attached is the bike geometry.

According to the starbike website, I should get the following measurement:
1) Down Tube Wire - 700mm
2) FD Wire - 300 mm
3) RD Wire - 500 mm
4) Battery Wire - 300 mm (+50mm for internal battery)
5) Left Shifter - ??
6) Right Shifter - ??

Should I go for the cable length for S size frame (47-52cm) or the M (54-56cm)?
Which cable length for left & right shifter do I need?

Thank you.
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bike-geometry.png

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rmerka
Posts: 618
Joined: Wed Mar 06, 2013 4:23 pm
Location: Austin, TX

by rmerka

I used 350mm wires on my 42 c-c bars. Was a good fit. I'd recommend doing the measurements on the actual frame and if in doubt adding a little extra length won't hurt. Too short and you're buying a new wire.

by Weenie


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Gearhead65
Posts: 110
Joined: Sat Jan 23, 2010 1:24 am
Location: Evansville, IN, USA

by Gearhead65

rmerka wrote:I used 350mm wires on my 42 c-c bars. Was a good fit. I'd recommend doing the measurements on the actual frame and if in doubt adding a little extra length won't hurt. Too short and you're buying a new wire.


+1...everything rmerka said.
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toiyuet
Posts: 174
Joined: Wed Dec 14, 2011 2:47 pm
Location: Hong Kong

by toiyuet

At least 350mm each, wonder who need the 300mm wire for shifters?

ProEvoSLTeamHighMod
Posts: 65
Joined: Wed Feb 19, 2014 6:13 am

by ProEvoSLTeamHighMod

350 on shifters, suggest a bit longer, ~800 to be safe on downtube, and internal battery also should be ~800, not "+50" as suggested there...

vtspot
Posts: 48
Joined: Mon Jun 02, 2014 4:34 am

by vtspot

Thank you for all the replies. :)

So, I should have get the cable length for the M size frame instead?

1) Down Tube Wire - 800mm
2) FD Wire - 350 mm
3) RD Wire - 550 mm
4) Battery Wire - 350 mm
5) Left Shifter - 350 mm
6) Right Shifter - 350 mm

rma
Posts: 169
Joined: Mon Apr 21, 2014 9:17 pm
Location: Belo Horizonte, Brazil

by rma

I use a 42cm C-to-C handlebar and 300mm cables from the shifters. It works, but they are a few mm away from total stretch... Totally wrong according to Shimano docs... 350mm would be perfect.

vtspot
Posts: 48
Joined: Mon Jun 02, 2014 4:34 am

by vtspot

Thank you.

I just realized that starbike is not selling 800mm di2 wire. It is not saying out of stock, but instead, there is totally no option for 800mm. May I know if there is really no 800mm di2 cable in the market?

The next measurement would be 950mm? Is it too long if i go for 950mm? or I can go for 750mm di2 cable?

ProEvoSLTeamHighMod
Posts: 65
Joined: Wed Feb 19, 2014 6:13 am

by ProEvoSLTeamHighMod

Too long is always preferable to too short, go longer!! Even on external wiring builds it's easy to hide, and a good thing to have for future moves.

clarkson
Posts: 190
Joined: Sat May 07, 2011 12:23 am

by clarkson

Seriously... If your install is primarily internal, extra cable has no downside. You just tuck it in there, and it will have exactly zero influence on your shifting performance. Order long, have a nice stress free install, life's pretty good.

aaric
Posts: 430
Joined: Thu Jun 09, 2011 4:10 pm

by aaric

An extra 50-100mm of slack internally per cable is worth the maybe 10 grams of weight unless you are going for a super weenie build. And honestly, if you were that concerned about weight, you'd be running mechanical SRAM ;)

Fishing around inside the frame to find a cable that popped off due to no slack isn't fun. I made the mistake of going too short on my internal battery / seatpost wire initially, so there wasn't reasonable slack to pull the seatpost out.

vtspot
Posts: 48
Joined: Mon Jun 02, 2014 4:34 am

by vtspot

Thank you for everyone advice. I will go for longer cable. :)

ricks123
Posts: 4
Joined: Fri Sep 19, 2014 1:53 pm

by ricks123

This is discussed on their stec site, but sadly, no info on si.shimano.com

by Weenie


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