Review: Formula RX Hydraulic Disc Brakes for Mountain Bikes | Bike198

Review: Formula RX Hydraulic Disc Brakes for Mountain Bikes

Formula RX Brake and 180mm Rotor

Over the past couple of months, we have been putting a beating on the new Formula RX hydraulic disc brakes for mountain bikes. The RX brakes from Formula are the budget brake out of the lineup that brings Formula performance at a lower price. During the review period, these brakes (tested in 180mm F/R) saw everything from smooth, twisty singletrack to big mountain, rocky, several mile long downhills in the attempt to see where the limit of these brakes were. With the XC and AM/Enduro crowd in mind, the RX brakes are designed for those applications, so let’s see how they performed on the trail.

Formula RX MTB Disc Brake Specs


The RX is a brand new offering for 2010 from Formula featuring a radial master cylinder combined with a 1 piece caliper which houses 22mm diameter pistons. This translates into lots of power and modulation while keeping the weight at a category leading 351g. The RX is the perfect brake for any XC or AM/Enduro application.

Master Cylinder/Lever
  • Radial Master Cylinder.
  • Patent-pending high capacity, integrated reservoir.
  • Removable handlebar clamp.
  • Flip-flop master cylinder assembly.
Caliper Assembly
  • 1-piece caliper body with 22 mm pistons.
  • Post mount style w/adaptors.
  • Top and bottom vented caliper body.

Available In – Painted matte black or gloss white
Lever blade – High tensile strength casting, painted silver
Hose Black – 100cm-165cm
Rotor 1-piece – 160mm, 180mm, 203mm, 220 mm
Brake Pads – Organic
Mounting – Standard PM 6”
Weight – 351 grams (Post Mount, including 800mm hose, 160mm rotor
Pricing: Click here for the best price

Formula RX Lever

Install and Adjust: Formula RX Disc Brakes

The first thing you notice about the RX disc brakes is the quality of the construction right out of the box. Even though these are Formula’s “budget” brakes, they are still above and beyond much of the industry. From the blue caliper caps to the solid lever construction, you are getting a high quality set of brakes with the RX’s, but you are forgoing some of the flashier elements of the other models and some adjustment features.

Installation of the RX disc brakes goes smoothly just like any other disc brake install and adjust on a mountain bike. The levers are a “flip flop” design so if you prefer to run your brakes moto-style, that is as simple as flipping the levers to the other side of the bars. With the two bolt design of lever plate, you are able to get the levers on and off your bars without removing grips or any other levers, however, Formula does use a T-25 Torx head bolt over the conventional hex head you are used to seeing on other mountain bike components and brakes. My Crank Brothers multi-tool has a T-25 for trail side adjustments, but I would have liked to see a conventional hex head.

Reach adjust on the RX levers is handled through a small hex head bolt on the top of the lever (as seen in the gallery below). While we would like to see a tool free adjust, it does get the job done easily and should be a set and forget adjustment once you get it right for your hands.

The calipers installation and adjustment also goes very easily with the aid of pivoting washers on top of the caliper to adjust for any angle differences on your frame or fork. This should help reduce any noise when dealing with varying tolerances.

Formula RX Caliper Back

On The Trail: Formula RX Disc Brakes

As mentioned previously, we tested the 180mm rotors front and rear during the review period. The 180mm rotor diameter is the perfect fit for bikes in the aggressive XC to heavy AM range and is the most popular combination for most riders.

Power and Modulation

The Formula RX disc brakes have a ton of power on tap. For any bike in the 4 inch to above 6 inch suspension travel category, the RX disc brakes will bring you to a stop in a hurry with the 180mm rotor combo. During longer, technical downhill runs, the RX brakes did a great job of staying cool and preventing brake fade. There was as much power and modulation at the end of the run as the brakes had at the beginning.

Power is delivered through a solid lever feel and comes on progressively through the stroke. While some hydraulic brakes on the market can exhibit a on/off feel, the RX brakes from Formula do a great job of delivering the power in proportion to where you are in the pull down process on the lever. This makes speed scrubbing and traction control in slow tech easier to handle.

Braking Noise

The Formula RX brakes came shipped with the stock organic pads and a set of the sintered replacement pads for review. The stock organic pads did a great job of preventing brake squeal, but there was a lot of active braking noise under load (sounds like two hard surfaces rubbing together). After some time on the organics, we switched over to the sintered pads to see if that got rid of the friction noise. The sintered were a lot quieter under braking but they seemed more prone to the high pitched squeal you sometimes get out of misaligned or wet brakes. At the end of the review period, we left on the sintered pads as they were the quietest set out of the group.

Overall: Formula RX MTB Disc Brakes

At around $142 each depending on where you shop, the Formula RX brakes are a bargin when compared to their more expensive competition with the Avid Elixir lineup and offerings from Hope or Shimano. With a full build weight of around 351 grams depending on which rotor you choose, it also makes them a great lighter weight option for the price with a ton of power for a wide range of riders. There were a couple of little things we would like to see added like tool free reach adjust and quieter braking with the stock pads, but overall…Formula has done a fantastic job of bringing their powerful, well modulated braking to a lower price point.

Positive: Formula RX Brakes
  • Tons of power on tap for a wide range of riding situations
  • Great modulation through the entire stroke
  • Durable construction
  • Great looks
Negative: Formula RX Brakes
  • No tool free reach adjust
  • Noisy braking with stock pads (friction sound…not high pitched squeal)

If you are looking for a high quality set of brakes at a lower price point, the Formula RX brakes are a great option for your XC/AM rig.

Click here to see the best price on the Formula RX disc brakes.