There are a number of things that contribute to brakes feeling firm versus squishy. I'd say the order would be something like:
1. Pad alignment/centering. Pads that don't hit the rim squarely and don't contact the rim at the same time will feel squishy. Ideally, pads should be setup perfectly square for optimum feel, but if there is persistent squeal, sometimes they require toe-in, which sacrifices firmness somewhat, since you will be flexing the brake pads to achieve full contact. 2. Brake system mechanical advantage. On cantilever brakes, the other big determining factor for mechanical advantage is straddle cable length (i.e. height of the straddle hanger). It's a complex subject, Sheldon wrote a whole page on it, but the short answer is that the shorter the straddle cable, i.e. the closer the hanger is to the tire, the more mechanical advantage you have, thus shorter brake pad travel but higher force exerted after rim contact for a given lever pull. Longer straddle, higher hanger gives lower mechanical advantage, meaning that the brake pads will travel farther for a given lever stroke (so you can set them farther from the rim), but will exert less force for a given pull. The slightly hard part to wrap your head around is that there is an inverse relationship between firmness at the lever and mechanical advantage, i.e. lower mechanical advantage actually feels firmer, but you will have to pull harder on the lever to achieve the same braking force. Of course, there are other factors that limit straddle cable height, such as tire, fender, and rack clearance under the cable, and adequate clearance above the straddle hanger for the cable to travel without the hanger hitting the housing stop. Furthermore, overall mechanical advantage is also determined by the leverage ratios of the brake arms themselves and the brake levers themselves. To answer your question specifically, there might be a small difference between aero and non-aero levers here, but in theory they should be pretty close. My usual practice is to set the straddle cable as short as is feasible while still providing proper clearance, but I've also come to prefer the firmer feel of systems with lower mechanical advantage (I've got relatively strong hands), at least on road and all-rounder bikes. 3. Stiffness of brake arms/levers/frame or fork. Flex in any of these places is going to make things feel squishy. A lot of times, this is where you can feel the difference between lower-quality components and higher quality ones. Old non-aero levers often feel squishy because they aren't as stiff as more modern aero levers. In a frame, flex may be desirable for other reasons unrelated to braking, but when it comes to braking components I like stiffness. On Saturday, May 17, 2014 3:45:40 PM UTC-7, Deacon Patrick wrote: > > Compared with the brakes on my Hunqapillar, the Quickbeam’s brakes feel > squishy. They could use some tightening, but not by much (and are worn > about half way). Possible causes I could think of: > > — New pads (these are the stock Tektro pads), I’d put on the kwikstops > (qwikstops?). > — The QB has aero-levers vs. the Hunqapillar’s non-aero-levers. Could that > contribute to squish? > > Other ideas? I prefer to start simple first, of course. > > With abandon, > Patrick > > *www.MindYourHeadCoop.org <http://www.MindYourHeadCoop.org>* > *www.OurHolyConception.org <http://www.OurHolyConception.org>* > > -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To unsubscribe from this group and stop receiving emails from it, send an email to rbw-owners-bunch+unsubscr...@googlegroups.com. To post to this group, send email to rbw-owners-bunch@googlegroups.com. Visit this group at http://groups.google.com/group/rbw-owners-bunch. For more options, visit https://groups.google.com/d/optout.
