4 piston calipers dissipate heat better due the greater surface area of multiple pistons. When more hydraulic fluid is pressed into the hose by pulling the brake lever the pistons push harder on the brake pads which in turn push against the brake rotor stopping the bike.
4 Piston Mountain Bike Brakes Buyers Guide Worldwide Cyclery
4 piston caliper vs 2 piston. Dual 2 piston calipers are usually sliding calipers with brackets but some 2 piston calipers are fixed position with opposing pistons one on the inboard and one on the outboard side. 2 piston the basic function of a 4 piston brake caliper is the same as a 2 piston. 4 piston on the front if you have 6 piston in the rear. For fast road track use the 4 piston 6 piston caliper cannot be touched. The more pressure the higher the braking power. Inherently 2 piston mountain bike brakes weigh less than their 4 piston big brother but at the same time a 4 piston caliper will give you more braking power.
Since 2 pistons are wider than 1 the brake pads are also typically wider which means the brake pads surface area is larger creating more friction and more stopping power. To sum up the stopping power of the xt four piston as compared to the two piston the difference is akin to that of braking with a proper gravity tread vs. You will find 2 piston brakes on cross country and trail bikes where weight is very important and you will find 4 piston brakes on enduro and downhill bikes where additional braking power is worth having at the cost of some added weight. Six and four piston brake calipers reason number two is that a four piston caliper with two sets of opposed pistons can be set up to squeeze the front two pistons slightly before the rear pair. Most rear engine cars dont need much front brakes. When they go wrong its alot more money to fix.
A 2 piston caliper has 1 piston on each side and a 4 piston caliper has 2 pistons on each side. Using a two piece alloy construction the calliper is sleeker and lighter than shimanos saintzeext 4 piston callipers though inside youll find the same 1517mm diameter ceramic pistons. 4 piston calipers are almost always going to have 2 inboard and 2 outboard opposing pistons. It feels like the reported 20 power increase is quite accurate and the performance is noticeably confidence inspiring. It is definitely easier to balance the brakes if the fronts are smaller than the rears. 4 piston calipers are usually a fixed position design.
Big rear brakes are nice especially if cutters are used often. An xc or semi slick tire. Down side is that they tend to need more attention cleaning to keep them operating.