SRAM's Bleeding Edge technology is a change in standard which seems to be spreading to all SRAM's brake models from 2017-onwards including Guide, Code and Level brakes - it even features on the new Reverb 1x remote!
Specifically it means a change to the bleeding port on the new SRAM S4 brake caliper meaning that your good old threaded bleed fittings from your SRAM Bleed Kit will no longer fit. Here's what SRAM themselves have to say about it:
|"Bleeding Edge™ technology makes bleeding brakes quick and simple. An updated fluid path and bleed porting make it easier to push fluid through the caliper. A dedicated bleed adapter plugs into the bleed port and seals the system to minimise air contamination and fluid loss."|
|- SRAM USA|
Sounds harmful enough but it does mean you will now need new kit in order to perform a full bleed of any brake system equipped with the Bleeding Edge interface - inconvenient to say the least! So what does the new adapter look like?
The new SRAM Bleeding Edge tool with traditional Avid/SRAM bleed adapter circled.
Here you can see just how much the SRAM Bleeding Edge tool differs from the traditional bleed adapters (circled) which you would normally use to bleed older SRAM and Avid brakes.
There is now no need to remove the caliper bleed port screw in order to attach the bleed fitting since the Bleeding Edge tool is also used to open and close the system making the bleed process faster and cleaner.
Do I need a Bleeding Edge Tool?
In order to answer that we need to find out if you have the new SRAM S4 caliper or an older model. Below you can see two SRAM Guide brake callipers with the location of the bleed ports marked by arrows.
Left: SRAM Guide S4 caliper with Bleeding Edge bleed port; Right: Previous caliper design with traditional bleed port.
The one on the left is the S4 caliper with the updated bleed port, and on the right you can see the older design with the bleed port in its more traditional setting. The caliper on the right can be bled using the regular threaded bleed fittings found in your Avid Bleed Kit, whereas the one on the left requires the Bleeding Edge tool.