Bodge for di2 to get lower gear?

On Jan 27, 2:54*am, Andreas Oehler wrote:
Wed, 26 Jan 2011 14:26:26 -0800 (PST), mtb Dad:



Thanks. *We discussed that. *The coach said he was concerned about
trying to shift with the hands when they are on the pedals. *Like us
trying to shift with our feet. How would you prevent inadvertant
shifts during hard efforts?

Why not simply ask someone riding a handbike with twist grip shifter?

Andreas

Not sure if I understand, but twist grips won't work for Karen because
she doesn't have that much grip strength. So hinged or otherwise
articulated pedal axles sound like they might be difficult to control
under effort. Was that what you meant?

On Jan 27, 11:49*am, Qui si parla Campagnolo
wrote:
On Jan 25, 1:56*pm, mtb Dad wrote:

A friend coaches a quadreplegic handcyclist, who has trouble with
shifting. *we're thinking a bite valve might be rigged to make di2
work. *But the 50-34 by 27 max cog is too high. *I've heard the front
and rear shifting is linked, but can anyone sugest a way to run di2
with two smaller chainrings? *Right now she uses 28 (triple) by 28
lowest cog.

Other suggestions, such as cable shifting options welcome too.

16t difference, just get a crank with similar CR differences, like a
MTB crank(2 rings), smaller BCD and say 46/30. BTW-largest shimano cog
is a 28(11-28)

Thanks Peter. So the front di2 deraileur will still work over the
smaller rings? Shimano says a minimum I think; is that just because
that's what they sell?

On Jan 28, 11:39*am, mtb Dad wrote:
On Jan 27, 11:49*am, Qui si parla Campagnolo
wrote:

On Jan 25, 1:56*pm, mtb Dad wrote:

A friend coaches a quadreplegic handcyclist, who has trouble with
shifting. *we're thinking a bite valve might be rigged to make di2
work. *But the 50-34 by 27 max cog is too high. *I've heard the front
and rear shifting is linked, but can anyone sugest a way to run di2
with two smaller chainrings? *Right now she uses 28 (triple) by 28
lowest cog.

Other suggestions, such as cable shifting options welcome too.

16t difference, just get a crank with similar CR differences, like a
MTB crank(2 rings), smaller BCD and say 46/30. BTW-largest shimano cog
is a 28(11-28)

Thanks Peter. *So the front di2 deraileur will still work over the
smaller rings? Shimano says a minimum I think; is that just because
that's what they sell?

I think as long as the total difference is about the same(max of 16t
for 7950 compact) and the big ring isn't too small, I'll bet a 30/46
would work fine with the Di2 FD.

On 2011-01-26, mtb Dad wrote:

There's a rumour someone has cracked a di2 and made it work over
both rings + rear with one button

http://jeffr-tech.livejournal.com/23467.html

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