Re: [CR]Max freewheel cog size for Campag rear der.

(Example: Framebuilders:Dario Pegoretti)

Date: Thu, 26 Jan 2006 07:47:26 -0700
From: "Mitch Harris" <mitch.harris@gmail.com>
To: Jerome & Elizabeth Moos <jerrymoos@sbcglobal.net>
Subject: Re: [CR]Max freewheel cog size for Campag rear der.
In-Reply-To: <20060126132541.95129.qmail@web81111.mail.mud.yahoo.com>
References: <20060126031614.71645.qmail@web30212.mail.mud.yahoo.com>
cc: classicrendezvous@bikelist.org
cc: classicrendezvous@bikelist.org

No experience with the Gran Sport, but I've had a N. Record shift well to a 28 cog but I needed to have the wheel all the way back in long drop outs so that the der. hanger was in front of the hub spindle.

Mitch Harris Little Rock Canyon, Utah

On 1/26/06, Jerome & Elizabeth Moos <jerrymoos@sbcglobal.net> wrote:
>
> There is no hard and fast number for how large a rear cog a given RD will
> handle. It's all a matter of geometry. I believe a Campy NR was also
> supposed to handle only a 26T, but I've used them with a 14-28 FW and 52- 42
> chainrings lots of times. There are lots of factors involved, including not
> only the geometry of the RD, but the chainstay length, the model of chain ,
> the front chainwheel sizes, the chain length, the type of rear DO, and th e
> position of the wheel in the DO's. In general, a smaller spread on the
> chainrings makes it easier to find a chain length that works with a large r
> rear cog. With a 46-50 front, I'd guess it shouldn't be that hard to hand le
> a 14-28 on the rear. Be sure you have a good chain tool. You'll probabl y
> have to try several chain lengths before you find the right one.
>
> Regards,
>
> Jerry Moos
> Big Spring, TX
>
>
>
> scott Baxter <rg500g@yahoo.com> wrote:
> My Gran Sport rear derailleur clearly states on the
> back that the largest rear cog permitted is 26 tooth.
> I've got a 151 BCD crank and my small ring is 46
> teeth. I need all the mechanical advantage I can get.
> I was about to buy a Regina 14/28 freewheel, but held
> off until I got feedback from the list. I don't want
> to spend $60 only to have the derailleur pulleys slam
> into the big cog when I try to grab the lowest gear I
> can.
>
> SO, how compatible is a 28 tooth rear cog with a
> Campagnolo rear der that says max 26 teeth? I've had
> a couple of folks tell me that it's doable if you are
> careful with the chain length, undoubtedly to flatten
> out the pulley cage as much as possible. My
> chainrings are a 46/50, so there's no big jump there.
> Feedback from the list would be greatly appreciated.
>
> Regarding chainrings, if anyone has a Campagnolo 151
> BCD chainring in a 52 tooth size or greater for sale
> please contact me offline, rg500g@yahoo.com.
>
> Scott Baxter
> St. Louis, MO
>
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