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LastKraftWagen 03-10-14 08:56 PM

Profile Carbon Cobra Wing Inside diameter?
Wondering if anyone who has the profile Carbon Cobra Wing Base/Stoker bar knows the inside diameter at the bar ends? I'm hoping to fit the DI2 bar end/TT shifters (SW-R671) in the stoker position (ask if you're a glutton for punishment for it is a long story). Also is there any unusual curves at the bar ends that would prohibit fitting the TT shifter provided that the diameter is not a factor?


twocicle 03-11-14 09:35 AM

We have a set of these bars, but at the moment they are all taped up so can't go measure. They do appear to be of normal diameter.

Problem you will have is that the bar ends are curved upward, very near the ends. Usually TT end shifters require a straight tube, so my guess is that attempting to install shifters on these bars will not work.

It would seem that giving shifter controls to the stoker is like having a car passenger control the gas pedal.

waynesulak 03-11-14 09:47 AM

There is a blind stoker on the old Tandem Hobbs list that had a tandem set up that way. Stoker controlled all shifting. Captain had brakes.

He was a Para Olympic competitor and is very strong rider. He used to live in Austin, ride, and sometimes win with various captains on the "Tuesday nighter" A very competitive weekly ride famous for a certain pro rider's participation.

Austin, TX: Cycling Training Rides & Guide | Bicycling Magazine

Tuesday Nighter Austin training race - YouTube

I suppose he was so in tune with the bike and the ride that like an automatic transmission he didn't need to see ahead to shift.

LastKraftWagen 03-11-14 11:10 AM

It would seem that giving shifter controls to the stoker is like having a blindfolded car passenger control the gas pedal.[/QUOTE]

I know of a few teams that set up this way, and they all have their reasons. Many blind stokers (and probably many sighted as well) have a pretty good feel of changes in terrain, and the shift to adjust is reasonably close to the pilot's reactions.

My reasoning is different, as I don't have a dedicated pilot, and very few of the pilots I do get have experience with the DI2 shifters, and distinguishing between the two shift "levers." This weekend we entered a TT where I had a pilot swap at the last minute, his first time on a tandem ever was about an hour before our start time. Shifting was an issue, and it would be easier (both in races and with other non-DI2 users), if I could just smack the pilot in the back of the head :) and temporarily take over shifting duties. I already have a normal drop bar and second set of shifters set up, but my frame size means I can't always run these as they hit the pilot in the back of the legs. For my bull bars I can avoid this mostly and install the climber shifter, but it only control the RD, and the K-Edge option is a bit pricey. Nothing like spinning out the downhills at 29mph because the pilot can't find the FD upshift, or doing a turn around back uphill in your 53/11. And I could hear the FD trying to downshift to that third imaginary ring and cogs somewhere outside my frame.
(We managed both)

twocicle 03-11-14 01:17 PM

Not sure which version of Di2 you are running, but it's my understanding with the E-tube versions it is possible use the E-tube software to program the climbing shifters for either FD or RD. This is part of what makes Di2 E-tube "plug & play" so great because component usage/assignment is very flexible.

Reference: Shimano Ultegra and Dura-Ace Di2 Electronic Shifting ? Everything You Need to Know
ROAD magazine ? June 2013 : Shimano 11Spd Di2

LastKraftWagen 03-11-14 02:45 PM

Possibly, and would be a better option, but my local LBS and other sources have said the climb shifter can be reprogrammed for multiple shifts but no one knew for sure if they (two in a series) could be programmed front and back. For the sprint shifter while they can be reprogrammed for the FD and/or the RD, it is also a "two switch system whereas the climbers are only one. The LBS wasn't sure if the software would recognize a single use switch twice (climbers) like it does all the other multi-pod setups. Again, hope it would work because this would be the easiest option...Waiting patiently awaiting response from Shimano tech.


Finally heard back from Shimano...They don't know either...And didn't seem too willing to just send a tech to the back and try it. First it couldn't be done, then you could have one climb shifter for either the FD or the RD, but not both; Then the climb shifters could only be plugged into the STI shifters and not an independent junction box; Then you could plug them into an independent box but then it would be two separate systems and wouldn't work; Then I would have to unplug the STIs and program the R600s then reattach (which may have been quickly dismissed when I asked about the climbers working without the STIs); Then...then...then...
Final tech support from Shimano- You could always buy two shifters and give it a try...
PS- The etube software is not blind/screenreader accessible (in case anyone was wondering).

Thanks to all for your input, may just have to grab a newspaper and smack the pilot on the schnootz...Bad pilot bad pilot.

twocicle 03-11-14 05:42 PM

FWIW, I just took another look at the Wing bars on our bike. The straight part of the extension ends before they bend, do seem long enough to accomodate the TT shifters. Just a guess - on par with Shimano Tech ;)

Wish I had a pair of climbing switches to test for you. If anything, I'll be getting the TT shifters and bar extensions (replacing the Pi Wing).

LastKraftWagen 03-11-14 08:08 PM

Appreciate it Twocicle... I just don't want to buy two switches to find it doesn't work and then return one (or both) for something that I consider not to be the fault of the equipment. May have to bite the bullet and eBay the impending disaster eh?

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