On Mon, 13 Nov 2006, boyd wrote:
> On Mon, 13 Nov 2006, Sheldon Brown wrote:
>> Tektro has been teasing us with pictures of these for a loooong
>> time, but now they have arrived, and they were worth the wait!
>>
>> http://sheldonbrown.com/
>
> So, could I replace cantis with those brakes on my Cannondale? The
> tires are 700x38 and I have SKS fenders. It seem like they might be
> long enough, but are they wide enough to clear the (45mm?) fender.
Yes. To keep the same mechanical advantage you need to scale up
the whole brake. There are pictures of various calipers side by
side in this blog entry:
http://blogs.phred.org/
The cantis will probably work better. I have a lot of experience with long reach dual pivot sidepulls, but haven't installed this particular brake yet. The dual pivot with a reach of much over 60mm tends to be more flexible and thus doesn't stop as well as a cantilever. They are simpler to setup and people like them for that reason.
Making the caliper long also requires making the arms thicker to resist bending over a large distance. Brakes rarely do this. With simple (probably non-machined) designs they are limited by how thick the arm can be. They can make the arm thicker and recessed in the area for the pad mounting bolt, but this doesn't work with some bolt designs and is pretty uncommon.
Just to be clear I think 47-57mm reach calipers are great (but the maximum 30mm tire (measured) with fenders is limiting on a touring bike). I don't like 57mm+ reach calipers. Different people have different definitions of the word "long".
alex