Epicus07 

I just installed some new Kore Race+ cantilevers. I have the straddle cable about 2 inches above the front tire. I have the brake shoes pretty close to the rim and they both contact at the same time. I'm also able to fully engage the brake lever without bottoming out on the handlebar.

The problem?

Even though it feels great in the stand it doesn't stop quickly without squeezing the brakes much harder than is necessary.

I'm feeling like i need more mechanical advantage...so i should lower the straddle cable?

What do you guys think?

fietsbob

actually lengthening the straddle cable increases the MA power.

Sheldon did the math, to show it's true ..
has to do with the angle that the end of the lever is pulled from..

xenologer

*checks online photos of kore race+*

Yes, get the straddle wire as close as possible to the tire.
Also if possible rearrange the brake pad spacers so the thin ones are on the inside -causing the brake arms to angle inwards more; this will raise the ends of the straddle wire thus complimenting the effect of lowering the center of the straddle wire.

Also keep in mind that this is a wide profile canti brake, and these are inherently weaker than medium profile canti brakes. I find them to work best when used with road levers -not mtb flat levers, as road levers have higher leverage built into them. examples of medium profile canti brakes: avid shorty 6, tektro oryx -note that with medium profile design, the arms initial position is higher up than with your current brake; this allows the straddle wire to be closer to horizontal for more mechanical advantage, the straddle more easily clears the tire at the center....

Epicus07 

I'll give that a shot. Thanks

I'm using them with Ultegra 9 speed shifters so hopefully they'll work out.