Just some general theory, since I have no personal experience!! Based on looking at the original French Constructeur bikes in Heine's book, many of them have rod and lever front mechs, and the chainwheel sets often look like 50/34 or so. The design in principle is capable of wide ranges. Whether a specific model can handle it, probably depends on cage depth and the rider's shifting technique. I'd expect to have to coax it into shifting by relaxing pedal pressure, and possibly to wait for a big upshift to catch.
On Mon, Dec 7, 2009 at 12:33 PM, Michael Allison <cyclo_one@verizon.net>wrote:
> Hi Jerry,
>
> Thanks for the information. Since it's an English bike, I'd like to go with
> a Cyclo rod op. derailleur. Does anyone else have experience with these
> derail??
>
>
> Michael Allison
> New York, NY
>
>
> On Dec 7, 2009, at 12:19 PM, Jerome & Elizabeth Moos wrote:
>
> You don't say what brand FD. I had the same concern, but the Simplex rod
>> FD on my 1954 Duravia shifts a 50-36 quite well. So, at least for Simplex,
>> I don't think the tooth spread is a significant problem. On the Simplex,
>> however, the range of movement is limited by the fact that the design has
>> the inner travel of the top of the rod stopped agianst the right side of the
>> seattube, so I don't think this design can shift a triple. Another thing I
>> found a little tricky was adjusting the FD so as to shift onto the large
>> ring without overshooting and dropping the chain outside the large ring.
>> There are no stop screws like a cable-operated FD, so you have to move the
>> cage in and out on the rod. But overall, these rod RD's shift a wider tooth
>> range than most people expect they would.
>>
>> Regards,
>>
>> Jerry Moos
>> Big Spring, Texas, USA
>>
>>
>> --- On Mon, 12/7/09, Michael Allison <cyclo_one@verizon.net> wrote:
>>
>> From: Michael Allison <cyclo_one@verizon.net>
>>> Subject: [CR] info needed on Suicide derailleur
>>> To: classicrendezvous@bikelist.org
>>> Date: Monday, December 7, 2009, 10:52 AM
>>>
>>> I'd like to use a rod operated front derailleur on my 1958
>>> Holdsworth restoration. Does anyone have experience on how
>>> well they handle large chainring differences? Will they
>>> shift the chain on a 46/32 (or smaller inner) combination?
>>>
>>> Michael Allison
>>> New York, NY
>>>
>>>
>>>
>>> _______________________________________________
>>>
>>>
> _______________________________________________
>
--
Ken Freeman
Ann Arbor, MI USA