Hydraulic Rim Brakes System Manual

1. Introduction

Your braking system is one of the most important set of components for a trials bike. A properly maintained braking system can help you be a bit more confident on your bike while being assured that your brakes will be as snappy and as responsive as possible whenever you’ll need them.

This comprehensive service manual is designed to guide users through the maintenance and care of the entire hydraulic rim brakes system, covering key elements such as slave cylinders, brake pads, and master cylinders. Understanding the significance of each component and their collaborative function is essential for bike trial riders seeking optimal performance and safety.

2. Safety Precautions

Safety is paramount when working with hydraulic brake systems. Whether handling brake fluid, inspecting slave cylinders, or replacing brake pads, users must prioritize personal safety. Always wear appropriate protective gear, secure the bike in a stable position, and follow the provided guidelines meticulously. These precautions apply to all aspects of the hydraulic brake system maintenance covered in this manual.

More specifically, although the ξ /ksi/ cycling hydraulic rim brakes system has been designed to be bled with water be aware of the potential hazards that can be caused by the use of third-party brake fluids, solvents, and greases and take the appropriate measures to prevent them. Please read carefully the relevant safety datasheets of such third-party materials and be prepared for any unfortunate situation that may happen. In case of emergency, ensure quick access to emergency equipment such as an eye-wash station and a first aid kit.

Moreover, keep your workspace and any tools involved in the maintenance of your braking system clean to avoid any unwanted contamination with dirt or dust. Also, any bike parts such as wheels and brake pads that shouldn’t be contaminated with oils and greases should be safely kept away from the workspace.

Additionally, practice proper disposal methods for used brake fluid, in case that you do not use water, as well as other materials according to their respective safety datasheets and manuals. Be environmentally conscious and adhere to regulations to minimize the impact on the environment.

By incorporating these safety precautions into your maintenance routine, you create a secure environment for yourself and others while promoting the longevity and effectiveness of the hydraulic brake system. Always prioritize safety to enjoy a reliable and safe biking experience.

3. Tools and Equipment

To efficiently and effectively service the ξ /ksi/ cycling hydraulic rim brakes system, assemble a set of essential tools and equipment as specified below. Third-party components may require specialized tools, so consult their respective manuals for any unique requirements.

More specifically, for the ξ /ksi/ cycling hydraulic rim brakes system, you will need the following tools for each component.

Slave Cylinders:

  • 2.5mm and 5mm Allen keys
  • 8mm open-ended spanner
  • A torque wrench with a measuring range of 2-4Nm
  • The ξ /ksi/ cycling piston plug tool, see picture below (a pick could also be used alternatively, but be careful as it may scratch the components and damage the intricate threaded piston plug)
  • A pick to carefully remove and install the used o-rings and seals
The ξ /ksi/ cycling piston plug tool

Brake Pads:

  • A pick to carefully remove and install the used o-ring

Also, you’ll need the ξ /ksi/ cycling bleeding kit with the relevant fittings for the slave cylinders and the master cylinder, see picture below. Keep in mind that the slave cylinder bleeding port features an M8x0.75 thread and needs the relevant ξ /ksi/ cycling bleed fitting to successfully bleed the hydraulic system. Also you may need a hose cutting tool in case you want to shorten or completely replace the hoses of your braking system.

The ξ /ksi/ cycling bleeding kit

Additionally, it is highly recommended to use a torque wrench for every bolt that specific tightening torque requirements are specified in the following chapters of this manual.

Moreover, you will need brake cleaner, seals grease, anti-seize grease, and water (or a water based brake fluid) to clean each component, lube the seals of your pistons, protect the threaded connections from galvanic corrosion, and bleed your braking system respectively.

The use of the tungsten disulfide (WS2) enhanced SLICKOLEUM grease, see picture below, is highly recommended for all piston o-rings used in the ξ /ksi/ cycling hydraulic rim brakes system.

The ξ /ksi/ cycling tungsten disulfide (WS2) enhanced SLICKOLEUM grease

Additionally, the ξ /ksi/ cycling hydraulic rim brakes system has been designed to be bled with water, but mineral oil or water-based solutions can be also used as long as they do not affect the seals of the system. If you are in doubt, please contact the manufacturer of the brake fluid that you want to use to check its compatibility with NBR o-rings, PTFE seals and PET-P pistons.

Finally, do not forget to wear safety glasses and gloves and keep your workspace as clean as possible.

4. System Overview and Components

The ξ /ksi/ cycling hydraulic rim brakes system is designed based on the standard configuration that a set of two slave cylinders are connected together and with a master cylinder in series. So, it’s important to give both an overview of the whole system and of each separate component before the explanation of their service and maintenance routine.

The basic components of a hydraulic rim brakes system are the master cylinder, the fittings and hoses, the slave cylinders and the brake pads.

Brake pads

The ξ /ksi/ cycling hydraulic rim brakes system has been developed to be compatible with the majority of the commercially available rim brake pads. However, it is recommended to use the ξ /ksi/ cycling rim brake pads in order to get the full experience of using this braking system.

The ξ /ksi/ cycling rim brake pads are comprised by three parts – the backing, the polyurethane refill and a retaining o-ring. Thus, they are refillable and their polyurethane refills along with the retaining o-rings are considered to be consumables and they should be replaced as often as they needed. For more on these and their maintenance, please check out the relevant section later in this manual.

Fittings and hoses

The ξ /ksi/ cycling hydraulic rim brakes system has been designed to be compatible with all standard nylon non-braded hoses that have an outer diameter of 5mm. Also, it has been designed to allow the connection of the hoses using shroud nuts and olives.

More specifically, for each connection of a hose to another component such as a slave cylinder or a lever you’ll need a single use olive that will be compressed against the fitting port using a shroud nut. Also, it has to be noted that if you use third party levers you should check out the relevant user manual in order to determine the appropriate way to fit a hose to a lever.

At that point it has to be underlined that olives are meant to be single use components and should be discarder every time you want to shorten or replace your hoses.

Moreover, all components are compatible with all shroud nuts that have an M8x0.75 thread.  However, it is highly recommended that you use the ξ /ksi/ cycling olives and shroud nuts as specified and recommended by this manual.

Slave Cylinders

The ξ /ksi/ cycling slave cylinders have been designed to be compatible with all standard M8x0.75 shroud nuts and olives for hydraulic rim brakes that use 5mm nylon non-braded hoses. Also, they are compatible  with the majority of the commercially available rim brake pads. However, it is recommended to use the official ξ /ksi/ cycling components in order to get the full experience of using this braking system.

Moreover, they are compatible with the majority of the commercially available rim brake clamps and brake boosters that have been designed to mount slave cylinders with a mounting diameter of 23mm. However it has to be mentioned that they have been designed to be as compact as possible to allow for greater clearance between the crank arms and the slave cylinders when mounted on the frame. This may be an issue for some frames or forks with relatively large clearance between their mounting holes. So, if you’re in doubt please contact ξ /ksi/ cycling before purchasing these slave cylinders.

The ξ /ksi/ cycling slave cylinders are the first customizable and fully repairable commercially available slave cylinders. So, it’s important that you fully understand and familiarize yourself with the components that are involved in these slave cylinders as it will be easier for you to understand their purpose and their expected proper operation.

The following diagram shows the parts that comprise the ξ /ksi/ cycling slave cylinders and the brake pads as well as their respective names.

Also, it should be noted that three sets of components could be grouped together as they can simplify the way that you approach the slave cylinders assembly. The first obvious group is the set of seals and the scrapper of each slave cylinder as this can be considered as a consumable set of parts that should be checked and assessed every time you maintain your brakes. For more information about that please check the relevant maintenance section. The second one is the piston assembly as this is the most complicated subassembly of each slave cylinder and the third one is the set of fasteners and components that can be swapped with their titanium alternatives. The last one can make your slave cylinders a bit lighter (~6gr lighter per pair) but keep in mind that their operation and performance do not rely on these parts.

Moreover, it should be underlined that you can customize your slave cylinders to your liking by selecting between alternative components made out of different materials. As already mentioned, you have the selection between 316 Stainless Steel and Grade 5 Titanium (Ti-6Al-4V) for all fasteners and shroud nuts as well as the piston rod and the bleed plug. Also, you can select between 7075 T6 Aluminum alloy and PET-P for the material of your slave cylinders’ pistons. Additionally to these customization options you can also select between two different springs with two different spring constants in order to fine tune the lever feel and response to your liking.

So, additionally to the fact that you can take everything apart and maintain your slave cylinders you can see that you have numerous options to fully customize your slave cylinders to your liking.

To sum up regarding the different options you can have for each part of the ξ /ksi/ cycling slave cylinders, you can check out the following table that includes all different alternatives along with their respective weights in order to help you decide the custom configuration that fits your preferences.

5. Assembly Procedures

This comprehensive guide takes you through the step-by-step process of assembling all the components of the ξ /ksi/ cycling braking system. Whether you are a seasoned technician or a DIY enthusiast, understanding the intricate details of assembly is crucial for ensuring optimal performance and longevity of your hydraulic rim brakes. Each subsection provides detailed instructions, accompanied by visual aids, to simplify the assembly process. Before diving into these procedures, make sure you have the recommended tools, a clean workspace, and a thorough understanding of the safety precautions outlined in the manual.

Brake Pads Assembly

Assembling the brake pads in the ξ /ksi/ cycling hydraulic rim brakes system is a straightforward yet crucial process to ensure optimal braking performance. The brake pads consist of three components: the backing, the refill, and a retaining o-ring. Both the polyurethane refill and the retaining o-ring are assembled on the aluminum backing as described in the following steps.

  • Press-Fit ξ /ksi/ Cycling Refills
    The ξ /ksi/ cycling refills are being installed by press fitting them on the aluminum backings. Keep in mind that they have been designed and manufactured to ensure a very tight fit with the aluminum backings and hence, no cyanoacrylate (CA) glue or any other compound is needed to safely fit them on the backings.
  • Third-Party Refills (if applicable)
    Compatible third party brake pad refills can be also installed on the  ξ /ksi/ cycling aluminum backings, but you may need to use a bit of CA glue to ensure that they are properly fit on the backings. Note that this step is unnecessary when ξ /ksi/ cycling refills are being used.
  • CA Glue Removal (if needed)
    If CA glue is applied and you want to remove it from the backings, for example before replacing the refills with new ones, the best option you have is to soak the brake pad backings in acetone for as long as it’s required to make it easier to gently remove the CA glue using a pick or a scraper without damaging the anodized surface of the backings.
  • Install Retaining O-Ring
    To install the retaining o-ring on the aluminum backings you’ll need a pick and a bit of patience to carefully position the o-ring in its respective groove as shown in the figure bellow. Please make sure that the retaining o-ring has been fully seated inside the groove as this will ensure the proper installation of the brake pad on the slave cylinders.

Once you have followed the previous steps and everything is properly assembled together the brake pads are ready to be used.

Fittings and Hoses Assembly

The ξ /ksi/ cycling hydraulic rim brakes system has been designed to allow the connection of all standard nylon non-braded hoses that have an outer diameter of 5mm, using shroud nuts and olives.

As already described in a previous section you can select between two different material options both for the ξ /ksi/ cycling shroud nuts and the olives. So, you can select between 316 Stainless Steel and Grade 5 Titanium (Ti-6Al-4V) shroud nuts and between Steel and Brass olives. Be cautious with combinations, as Steel olives can only be combined with 316 Stainless Steel shroud nuts.

Moving on to the assembly of the fittings and hoses, the following figure shows the proper sequence of assembling a hose to the slave cylinder using a shroud nut and olive connection.

After the fitting of the hose make sure that the connection is secure and not leaky when fully engaging the brakes. Moreover, you shouldn’t be able to pull the hose out of its position and also the hose shouldn’t be forced out of its place when you fully engage your brakes.

Assembly tips

  • The tightening torque of a shroud nut depends on the material of the used olive. Generally for brass olives the tightening torque is much lower than the torque that is required when using steel olives. The applied torque depends on the application of lubricants between the fittings and the relevant port of the component but generally the result should be a properly sealed fitting and the finally deformed olive should look like the one pictured bellow.
  • A properly fitted hose can be disassembled and reassembled without the need of replacing the deformed olive. However, olives should be considered as single use parts so you have to safely discard used olives every time you need to shorten or replace your hoses.
  • When installing a hose using a shroud nut and olive connection it is a matter of good practice to apply a bit of anti-seize grease on the threads of the shroud nut and on the olive before fitting the hose. This will make it easier to manipulate the rotational position of the hose once it’s been fitted and at the same time it will eliminate the risk of galvanic corrosion between the fitted parts. It is highly recommended to use the ξ /ksi/ cycling anti-seize grease as it is compatible with all possible combinations of materials that are used in this brakes system.

Slave Cylinders Assembly and Disassembly

This section will guide you through the process of assembling the slave cylinders. Whether you are replacing consumables, exploring customization options, or performing routine maintenance, a clear understanding of the assembly procedures is essential. Prior to beginning the assembly, gather the required tools, consult the system overview, and ensure a well-lit, clean and organized workspace to facilitate a smooth assembly process.

The assembly procedure for the ξ /ksi/ cycling slave cylinders will be divided into 4 subsections to make it easier to organize the assembly operations and ensure that everything will be properly assembled together.

A. Piston Assembly

The main subassembly of a slave cylinder is the piston assembly and the following figure shows its exploded assembly drawing.

In order to properly assemble the ξ /ksi/ cycling slave cylinder pistons you will need a pick and the ξ /ksi/ cycling piston plug tool (a pick could also be used alternatively, but be careful as it may scratch or even damage the components). Also you will need a bit of seals grease to lubricate the o-ring and the piston before installing it into the slave cylinder. It is highly recommended to use the WS2 enhanced SLICKOLEUM grease to ensure the best possible piston response while braking.

The following steps show you the proper assembly sequence for the ξ /ksi/ cycling slave cylinder pistons:

  • Properly align and drop the piston rod inside the piston
  • Drop the spring on top of the piston rod that is already into the piston
  • Secure the assembly by threading a piston plug using the relevant special tool or a pick
  • Apply a bit of WS2 enhanced SLICKOLEUM grease on the o-ring groove and along the outside surface of the piston
  • Carefully slide the o-ring in place and smear the excess seal grease on the outside surface of the piston

Having followed these steps your piston assembly is ready to be installed in a slave cylinder body.

Be careful when tightening the piston plug as it is a very thin walled part with fine threading and it should not be overtightened. There are no specific torque specifications for this one but you should keep in mind that you should stop tightening it when you feel that it is fully threaded and flush with the back surface of the piston.

B. Seals Assembly

Each ξ /ksi/ cycling slave cylinder features at most 3 o-rings and a scraper. In this subsection we’ll discuss on the proper way to install the seals and the scraper of the ξ /ksi/ cycling slave cylinder.

  • O-rings installation

Each ξ /ksi/ cycling slave cylinder has two standard o-rings, one for the piston and one that seals the pocket that connects the piston to the body of the slave cylinder. Also, the slave cylinder that is at the end of the hydraulic chain features another o-ring for the bleed plug screw.

You can carefully remove and install all o-rings by using a pick. However you should be careful to ensure that all o-rings have been properly seated on their respective groves.

The following image shows the position of each o-ring.

  • Scraper assembly

Each ξ /ksi/ cycling slave cylinder features a piston scraper that serves its purpose to keep large dust and dirt particles outside the area between the piston and its cylinder as this can result to issues such as sticky pistons or even damage your brakes.

In order to install a new piston scraper you will need to use a pick to push it along its periphery of its groove and then carefully bent the PTFE scraper until it gets into its groove. The ξ /ksi/ cycling PTFE piston scraper is designed to withstand acute bending without being damaged. However, you should be careful when installing a scraper to avoid excessive bending as this would affect its form and dimensions.

Proper Piston Scraper Positioning

Also, it has to be noted that even if the ξ /ksi/ cycling piston scrapers are being considered as single used parts, you can possibly remove them and reinstall them multiple times as long as you are careful enough and there is no gap between the scraper and the piston after it’s being assembled.

Anyway keep in mind that both the used o-rings and the piston scraper should be properly discarded once their service life has come to an end.

C. Slave Cylinder Final Assembly

Once the piston has been properly assembled and the seals are all properly seated in their grooves, you are ready to assemble the ξ /ksi/ cycling slave cylinder. To do so you will need a torque wrench with a 2.5mm allen key attached and the relevant screw.

Here are the steps that you have to follow in order to complete the slave cylinders assembly:

  • Before you assemble the piston inside the slave cylinder, make sure that the internal face of the cylinder is clean of any debris and dirt
  • Smear a bit of WS2 enhanced SLICKOLEUM grease on the surface of the cylinder using a cotton bud or a similar applicator that cannot damage the anodized surface of the slave cylinder
  • Push the piston assembly into the slave cylinder and use the 2.5mm allen key to guide it into its mounting hole.
  • Once the piston rod is properly positioned in the mounting hole of the slave cylinder, push the piston in position
  • Start screwing the M4 countersunk bolt at the rear end of the slave cylinder in order to fully pull the piston rod into position. Note that the tightening torque should not exceed 2.5Nm.
  • Once you feel that the piston is properly seated and the M4 bolt is well tightened, your slave cylinder is ready to get connected to the rest of the hydraulic system of your brakes.

Slave Cylinders Assembly Tips

  • If you feel that your piston starts to rotate when you tighten the M4 bolt and you cannot get it to full tighten, it means that the friction between the piston rod and its mounting hole is not adequate to facilitate the fastening of the piston assembly to the slave cylinder body. So, one thing that you can do to overcome this issue is to try to bend a bit the allen key as it gets tightened. This will make sure that one side of the piston rod gets in contact to the sides of the mounting hole and provide adequate friction to fully tighten the M4 bolt and fasten the piston assembly to the slave cylinder body.
  • You should not overtighten the M4 bolt. The max tightening torque should not exceed 2.5Nm.
  • If you use the Titanium M4 bolt, it is a good practice to use a Stainless Steel or Steel bolt to fully pull the piston assembly into its mounting position and then remove the Stainless Steel or Steel bolt and replace it with the Titanium one. Once the Titanium bolt is installed you can tightening it according to the given specifications.

D. Bleed Plug and Hose Fittings

The final assembly step to fully connect a slave cylinder to the hydraulic system of your rim brakes is to connect it with the proper fittings with the hoses of the hydraulic system. For this one please refer to the relevant section of the assembly procedures.

Nevertheless, if a slave cylinder is the last component of a hydraulic system, it means that you will need to use a bleed plug to properly shut the system. The ξ /ksi/ cycling slave cylinders use a special lightweight bleed plug that uses an o-ring to fully seal the system.

The o-ring is considered as a consumable part and you should check it for damage every time you bleed your brakes and replace it if required.

Also, you should not overtighten the bleed plug as it is the o-ring that seals the system and not the plug. The tightening torque should not exceed 3Nm.

E. Disassembly Procedure

Now that you have a deep understanding of the assembly procedure, you can follow the steps in reverse to disassemble the ξ /ksi/ cycling slave cylinders.

The only tip that should be noted is that once to unscrew the M4 bolt to take the piston assembly apart, you can use the 2.5mm allen key to push the piston rod out of its socket and release the piston assembly from the slave cylinder body.

Keep always in mind that you should take appropriate precautions as once the slave cylinders are disassembled grease and brake fluid (if water is not used) will drip out of them. So, wear the appropriate protective equipment and make sure that you properly discard the used lubricants, brake fluid and any consumable components.

6. Maintenance Protocol

This section includes all the information you need to properly maintain the ξ /ksi/ cycling braking system. The provided maintenance protocol is separated into three subsections that include the routine maintenance procedures that do not require the re-bleeding of the hydraulic system, the full maintenance routine that imply the re-bleeding of the system and finally the bleeding procedure of the ξ /ksi/ cycling braking system will be also given.

Keep in mind that all safety precautions should be taken in account before proceeding with any maintenance procedure. Wear the appropriate safety equipment such as gloves and safety glasses and work on a well-ventilated area to avoid contact with brake fluids (if water is not used) and brake cleaners during the maintenance of your braking system. Also, be aware of the safety guidelines of each third party brake fluid, cleaner or grease and avoid direct exposure on these substances as much as possible.

  • Routine Maintenance (Minor or No Disassembly Required)
    There are some maintenance bits of work that you can do in order to keep the ξ /ksi/ cycling braking system working as perfectly as possible between your scheduled full maintenance jobs. In this section we are going to discuss about these quick maintenance activities that you can perform even daily to ensure that everything works as good as possible for longer.

So, before each ride:

  1. Fully engage your brakes and make sure that the hydraulic system is well bled and there are no damaged or leaky hoses and fittings
  2. Feel the responsiveness of the lever and observe for any inconsistences along the travel range of the lever
  3. If the available travel range of the lever has been significantly decreased, you may need to proceed with a full brake bleed as specified in the relevant section

In case that during the daily pre-ride check a decrease is observed in the responsiveness of the slave cylinders pistons, the following maintenance activities can help you fix it temporarily and avoid having sticky pistons during your next training session. However, keep in mind that once the responsiveness of your brakes start to decrease, you have to schedule your next full maintenance job.

Preventing Sticky Pistons

Sticky pistons are mainly caused when dirt and dust particles are introduced in the area between the pistons and their respective cylinders. These dirt and dust particles can obstruct the smooth movement of the pistons and this can be prevented by keeping the slave cylinders clean. The frequency that this one can happen mainly depends on the type of terrain you ride as training at terrain with a lot of loose dirt can accelerate the reappearance of this issue.

To properly clean your slave cylinders:

  1. You have to remove the wheel and the brake pads to allow for unobstructed access to the pistons.
  2. The removed brake pads  should be cleaned with a clean tissue and if needed with a bit of brake cleaner. Also, keep track of the position and the orientation of each brake pad so as to properly reinstall them after the slave cylinders cleaning procedure.
  3. Use tissues, cotton buds or brushes to clean the area of the slave cylinders that faces the brake pads.
  4. Spray a light oil such as WD-40 to loosen any persistent dirt while engaging and disengaging your brakes so as to make the pistons move as they are getting cleaned. Be careful to protect any components that may be contaminated while you spray towards the slave cylinders. More specifically, keep your rims and brake pads out of reach of the sprayed oil droplets.
  5. Keep spraying and cleaning with tissues, cotton buds and brushes until no dirt is getting out of the slave cylinders.
  6. When everything is free of dirt and dust, use a clean tissue to wipe off any oil from the slave cylinders until they are well dried and free of excess oil as this can contaminate your brake pads or the rims.
  7. Check that both slave cylinder pistons are moving together and their response is up to your expectations.
  8. Reinstall the brake pads and the wheels and you are ready for your next ride! However, keep in mind that this is a temporary solution and you will have to schedule a complete maintenance procedure sooner or later.

Also, another quick and simple maintenance activity that can improve your braking performance is to visually check your brake pads every time you remove them, for example during the cleaning of your slave cylinders. Once you remove the brake pads you can always clean the slave cylinders and the brake pad backings, but you can also check if the braking surface is clean enough. If dirt, tar or rosin has been adhere to the brake pads surface you can rub them on a coarse sandpaper to remove any contaminants from the braking surface. This will immediately improve the braking performance as any contaminants on the braking surface of the brake pads can directly affect the braking response and effectiveness.

To sum up, the cleaner you keep the components of your braking system the better your brakes will perform for longer.

  • Comprehensive Maintenance

There are two main reasons that you’ll need to schedule a complete maintenance job on the ξ /ksi/ cycling braking system.

The first reason is due to the fact that braking fluid sips out of the seals as the brakes engage and disengage and this can be observed as the lever travel distance decreases over time and no lever adjustment can fix it. This one can be fixed by just re-bleeding the hydraulic system as no full disassembly is required. To proceed accordingly please check the following section of this manual.

The second one as it has been already mentioned is whenever the performance and the response of the ξ /ksi/ cycling braking system start to decrease and your pistons start to get a bit sticky and no temporary solutions can fix them. This can be solved only by disassembling the ξ /ksi/ cycling braking system, thoroughly clean and visually inspect all of its components, replace any damaged parts and finally reassembling everything according to the provided specifications. To proceed accordingly please check the relevant Assembly and Disassembly Procedures section of the present manual.

  • Bleeding Procedure

The ξ /ksi/ cycling braking system has been designed to be bled with water. However, mineral oil or water-based solutions that do not affect the seals and parts of the system can be also used. So, keep that in mind before you select the brake fluid of your choice. If you are in doubt, please contact the manufacturer of the brake fluid that you want to use to check its compatibility with NBR o-rings, PTFE seals and PET-P pistons.

Also, make sure that your braking system and the involved components are as clean as possible before start bleeding your brakes to avoid contaminants from entering your hydraulic system.

To proceed with the proper bleeding of the ξ /ksi/ cycling braking system, you have to follow the next steps:

  1. Prepare for bleeding by thoroughly clean your slave cylinders, the levers and the bleeding ports in order to remove any dirt or other possible contaminants.
  2. Gather the appropriate tools for the job. You will need the ξ /ksi/ cycling bleeding kit that is comprised by two syringes fitted with the appropriate fittings for the slave cylinders and the levers. Note that you will need the specialized M8x0.75 barbed fitting in order to properly bleed the ξ /ksi/ cycling slave cylinders. You will also need a 5mm allen wrench, an open-ended 8mm spanner and any other tool that is required from the rest of the used components.
  3. Prepare your workspace by arranging your tools on a clean workspace and take any safety precautions (wear gloves and safety glasses) before start the bleeding procedure. Also, make sure that your bike is secured and positioned in such a way that any trapped air can travel freely from the slave cylinders to the levers.
  4. Load the syringes with brake fluid until they are half full.
  5. Remove the bleed plugs from the lever and the slave cylinder one at a time and attach the relevant syringe once you remove each bleed plug.
  6. Push and pull each syringe and force the brake fluid to flow inside the hydraulic system and repeat this process until all trapped air escapes from the system. Also, if your brake fluid is contaminated and dramatically changes color once you start forcing the flow of new clean brake fluid into the system, you should consider scheduling a compete maintenance job as soon as possible as this discoloration implies that dirt and dust particles have been introduced into your hydraulic system.
  7. In order to ensure that any trapped air has escaped from the system, you should pressurize the syringes in order to move the pistons as this will aid the escape of any air bubbles that are trapped inside the pistons. Also, you can knock lightly the brake hoses as this will force any small bubbles to move towards the levers. Moreover, you can rock your bike back and forth and from side to side to further ensure that all air bubbles have been escaped towards the syringe that is located at the highest position of the hydraulic system.
  8. Once all trapped air has been escaped you can start removing the syringes one at a time and plug the bleed ports of the lever and the slave cylinders. Be careful not to introduce any air to the freshly bled hydraulic system. Keep in mind that it is better to have a bit of brake fluid overflow when you plug each bleed port than introduce any small air bubble to the system.
  9. After closing the bleed ports of the hydraulic system, engage the brakes and make sure that both ports have been properly sealed and no break fluid leaks out of them.
  10. Check that the system has been properly bled by slightly touching your lever. In a properly bled system, the pistons of the slave cylinders should slightly move when touching the brake lever and slightly move the piston of the master cylinder. Otherwise, if the slave cylinders pistons are even slightly unresponsive after a full bleeding procedure, it may indicate that a bit of air may have trapped into the hydraulic system and in that case you may have to repeat the bleeding procedure a bit more carefully this time.
  11. After the successful bleeding of the ξ /ksi/ cycling braking system, safely and properly dispose the used and possibly contaminated brake fluid.
  12. Now you are ready to reinstall the brake pads and the wheels and take your bike for a ride enjoying the freshly bled and fully responsive brakes.

7. Advanced Maintenance Tips

In this section we are going to discuss about some more advanced slave cylinder issues that have to do with the asymmetrical piston response that sometimes can be observed as well as the maintenance routines that you can follow in order to get the ξ /ksi/ cycling braking system working as perfectly as possible.

Asymmetrical piston movement is a common issue that can be observed at all hydraulic rim brakes systems and implies that when a connected pair of slave cylinders is engaged and their pistons move, sometimes one of the two pistons move first or generally more than the other one.

Common reasons that may cause this issue are listed bellow along with their suggested solution:

  1. The pistons of your slave cylinders move a bit asymmetrically. While this can be considered quite normal, a common issue that may cause an asymmetrical movement of the pistons is the case that you have overtighten the bolts of the brake clamps. A torque wrench should be used for the tightening of the bolts of the brake clamps and the tightening torque should not exceed 4Nm.
  2. One of the two pistons is sticky and doesn’t move at all. This can be a sign that you need to perform a full maintenance job on your slave cylinders as dirt and dust may have been entered the area between the slave cylinders and the pistons. However, before you schedule a full maintenance job you can try to temporarily solve this issue by performing a quick piston and slave cylinder clean up by following the process discussed previously. Also, sometimes a piston may be sticky when this particular brake hasn’t been engaged for a while and so any seal grease or brake fluid has been expelled from the area that the piston seals comes in contact with the cylinder. In that case you can get your pistons working as responsively a possible just by engaging the brake repeatedly a couple of times and force the pistons to move independently in and out of the slave cylinders. This will force the existing seal grease to relubricate the piston o-rings and your brakes responsiveness will be restored right away.
  3. The slave cylinders are freshly maintained, do move but they are not as responsive as they used to be. This may be a sign that you have to clean and relubricate the seals of your master cylinder. Please refer to the service manual of your lever’s manufacturer for the specific maintenance protocol that you have to follow in order to complete this maintenance task.
  4. Your slave cylinders are fully maintained, cleaned and regreased but they are not as responsive as they used to be when they were brand new. This may be a sign that the slave cylinders or their pistons have been worn out and their anodized surface may have been scratched or worn. In that case you may have to replace your pistons or the whole assembly of each worn out slave cylinder.
  5. Your slave cylinders are fully maintained, cleaned and regreased and their anodization is still intact but they are not as responsive as they used to be when they were brand new. The easiest way to solve this issue is to replace the o-rings and the scrapers of your pistons as they may have been worn out or contaminated with dirt and dust particles and act abrasively against the slave cylinders sockets increasing the dynamic friction and hence affecting the responsiveness of your brakes.
  6. Your slave cylinders are fully maintained, cleaned and regreased with brand new o-rings and scrapers, and their anodization is still intact but they are not as responsive as they used to be when they were brand new. Brand new ξ /ksi/ cycling slave cylinders have been internally coated with Tungsten Disulfide (WS2) and this coating wears out with use. In that case you have to reapply a coat of WS2 on the surface of the cylindrical socket of the ξ /ksi/ cycling slave cylinders. To do so you can resend your slave cylinders back to the ξ /ksi/ cycling workshop and we can do it for you. However, keep in mind that if you regularly use the WS2 enhanced SLICKOLEUM grease for the lubrication of your slave cylinders, the coating is being maintained as your pistons move in and out of the slave cylinders. So, we highly recommend you to use the WS2 enhanced SLICKOLEUM grease as it will make your brakes feel as responsive as possible while maintaining the low friction coating on the slave cylinders and the pistons.

To sum up, it can be perfectly normal if the pistons of your slave cylinders move slightly asymmetrically but keep in mind that it can also indicate other issues of your braking system if everything is well maintained according to the given protocol. So, setup and follow a regular maintenance schedule in order to keep your braking system working as perfectly as possible for as longer as possible. Please consult the maintenance protocol that is described in this manual in order to optimize your maintenance routine.

8. Upgrades and Customization

The ξ /ksi/ cycling braking system and especially the ξ /ksi/ cycling slave cylinders have been designed to be upgradable and customizable in order to fine tune your brakes based on your personal preferences.

Upgradability implies that you can fine tune the weight of your slave cylinders by selecting different materials for some of the parts. Please refer to the following table to see the different slave cylinder versions as well as the different parts variations along with their relevant weight as an aid to select the perfect combination for your brakes. Note that weight values are given considering a pair of slave cylinders, including three shroud nuts and a bleed plug.

VersionTi/SS PartsPistonSpringWeight
Ti-PET-NGrade 5 – TiPET-PNormal78.3gr
Ti-PET-HGrade 5 – TiPET-PHard79.0gr
Ti-Alu-NGrade 5 – Ti7075-T6Normal84.7gr
Ti-Alu-HGrade 5 – Ti7075-T6Hard85.3gr
SS-PET-N316 SSPET-PNormal85.9gr
SS-PET-H316 SSPET-PHard86.5gr
SS-Alu-N316 SS7075-T6Normal91.2gr
SS-Alu-H316 SS7075-T6Hard91.8gr
*actual weight may vary ±1gr given the typical accuracy of our scales

Also, the response of the ξ /ksi/ cycling slave cylinders can be customized by selecting between different piston materials and between two different springs with different spring constants.

More specifically, you can select between two piston variations one made out of PET-P polymer and one made out of anodized 7075 T6 aluminum alloy. Both pistons work great and have a very low friction coefficient between them and the slave cylinders. However, you may feel that the aluminum pistons that are a bit stiffer as they eliminate their influence on the brakes response due to their deformation when they are engaged. On the other hand polymer pistons feel a bit more giving and the lever feel is a bit softer. However, these differences are quite marginal and so it’s up to you which piston material suits best your needs and your way of riding.

Moreover, you can select between two different springs with the one being a bit stiffer than the other. Stiffer springs imply that your brakes response will be snappier but it may make your lever feel a bit heavier. This is another decision that you have to make to fine tune the ξ /ksi/ cycling slave cylinders to your liking.

Note that all ξ /ksi/ cycling products can be directly purchased only via our e-shop at bikecave.eu

To sum up, it is up to you to experiment with the different options you have to upgrade or customize the ξ /ksi/ cycling braking system according to your personal preferences and your way of riding. Also, we’ll be pleased to assist you in case you have any questions or you need any additional information about the ξ /ksi/ cycling braking system. So, do not hesitate to contact us and we’ll try our best to help you get the most out of our braking system.

9. Environmental Considerations

At ξ /ksi/ cycling, we’re committed to not only delivering high-quality bike tools and components but also fostering a sustainable cycling community. As you enjoy the longevity of your ξ /ksi/ cycling braking system, we encourage responsible practices for the disposal of its components.

Disposal Guidelines:

When the time comes to bid farewell to your braking system components, consider the following guidelines for environmentally conscious disposal. To ensure proper recycling, disassemble the components and separate them according to their materials. Check with local recycling facilities for specific regulations and guidelines.

Eco-Friendly Practices:

Embrace eco-friendly practices during the disposal process. Identify recycling centers that specialize in bicycle components or in the materials that are used for each component. Responsible disposal ensures that materials are reclaimed, contributing to a healthier environment. Remember, every small effort counts.

Reusing Components:

Explore the possibility of reusing individual components by adopting a discerning approach. Instead of purchasing complete slave cylinders for example, consider buying only the damaged parts that need replacement. This practice not only reduces waste but also extends the life of non-damaged components. Explore opportunities to contribute to sustainability by selling or donating salvageable parts. Your conscious decision to selectively reuse components aligns with a commitment to environmental responsibility and promotes a circular economy within the bike trials community.

ξ /ksi/ cycling Take-Back Program:

As part of our commitment to sustainability, ξ /ksi/ cycling offers a take-back program for used components. By participating in this program, you contribute to responsible disposal and recycling. Contact us via e-mail or direct message to our social media accounts for details on how to return components to us, ensuring they are handled with care.

To sum up we’d like to thank you for choosing ξ /ksi/ cycling braking system. By adopting responsible disposal practices, you contribute to a greener bike trials community. Let’s collectively embrace sustainability, ensuring the joy of bike trials extends to future generations. For any queries or additional information, feel free to contact us—we’re here to support your journey towards a more sustainable ride.

10. Contact Information and Support

Should you have any inquiries or encounter challenges with the ξ /ksi/ cycling braking system, we are here to assist you. Reach out to us through our social media accounts or via email for prompt and dedicated support. Your satisfaction and successful experience with our products are our top priorities, and we look forward to addressing any concerns you may have. Stay connected with us for the latest updates, maintenance tips, and announcements via our social media channels. Thank you for choosing the ξ /ksi/ cycling braking system, and we appreciate your trust in our commitment to quality and service.

11. Connect with Us on Social Media

We invite you to share your ξ /ksi/ cycling braking system experience with the bike trials community! Tag our social media accounts and use the hashtag #ksicycling to showcase your training sessions, maintenance success, or any tips you’d like to pass on. Your stories inspire us and fellow trial riders. Let’s build a community that thrives on passion, performance, and shared adventures.
Ride on, share on! 🚴‍♂️🔧 #ksicycling