Originally Posted by Vo2min
I'm changing my old single pivot Shimano 600 brakes to newer 600 dual pivots, hoping for better braking performance. Do I need to change the old levers (slotted Shimano 600 non aeros) with no spring return) to something newer with springs like SHimano 105s of Tektro 200s? Also, is the amount of cable pulled different on the newer levers?
Upgrading the levers would actually improve braking more than changing the calipers. Modern "aero" brake levers have less friction and improved geometry, which makes for much better braking from the hoods (about the same from the drops.)
You don't need to upgrade the levers, but it would be highly worthwhile. If money is tight go for the new levers and cables with your existing calipers.
However, if you choose to ignore my advice, the Shimano dual pivot brakes are designed to be compatible with old-style brake levers: Where the spring presses against the caliper arm, there's a little nylon lubrication block the spring presses against. If you're using old fashioned levers, you need to remove this block and flip it over so the thicker side is betwixt the spring and the caliper arm.
Sheldon "Options" Brown
P.S. I get asked about this a LOT, so I have a canned boilerplate email response I send out a couple of times a week. Here it is:
A caliper brake system consists of 4 parts:
•The brake shoes
All of these parts are upgradable. Many people think first of replacing the calipers, but, in fact, this is the least likely part to make any real difference. A caliper is a simple leverage unit, and there's not all that much to one.
In the case of older bikes, it can be difficult to find a new caliper that will even fit.
The other 3 parts are much more likely to yield real improvement.
Older designs had the cables exit up from the front of the brake levers, arching over the
handlebars. The newer style, where the cable exits out the back of the lever and runs under the handlebar tape is referred to as "aero" because it eliminates the wind drag of the exposed cables.
Aero levers are generally a major improvement over the older type. The pivots are located differently, making it possible to get fairly serious braking from the position where the rider's hand is on top of the lever hood. Traditional levers would permit the use of this position for gentle deceleration only.
Additionally, the better aero levers have better internal cable routing, so there's less cable friction. I particularly recommend the Shimano Tiagra units we sell for $39.95, including cables. See: http://sheldonbrown.com/harris/brakes.html#leversdrop
Older cables used metal-to-metal contact as the inner cable slid through the spiral-wound steel housing. Lubricant was by grease, if the mechanic was conscientious.
Modern cable housings have a Teflon or similar lining. The better inner cables are stainless steel, and are "die drawn" to make them smoother. The result is greatly reduced cable friction, so more of your finger strength is transmitted to the caliper, rather than wasted overcoming cable friction.
•The brake shoes
Modern high-performance brake shoes also make a considerable difference. The very best is the ugly salmon-colored material originated by Scott-Mathauser, and now sold under the Kool Stop name. See: http://sheldonbrown.com/harris/brakeshoes.html
All the best,