Thanks, the number 2 has been confirmed at 165mm
tum tee tum.aint got 11000+ for the good of my health
isc Brake Models
Hope makes 4 different hydraulic disc brakes, each available with as either a Pro or Sport model, depending on the lever option you choose (see below for a description of the Pro and Sport levers). So, there are in fact 8 different models.
Depending on your requirements, Hope has a brake for you. Here are the 4 brake models:
1 - C2 - closed, 2-piston system;
2 - XC4 - closed, 4-piston system;
3 - O2 - open, 2-piston system; and
4 - DH4 (or O4) - open, 4-piston system.
Previously known as the Hope Pro, this brake has stood the test of time and can do it all - from DH runs to XC races. The C2 uses a closed system consisting of two pistons. The caliper is designed for free flow of air, water and mud to aid cooling. The caliper houses piston-return springs to pull the pistons away from the disc, thereby totally eliminating drag. Because the C2 is a closed system, it offers on-the-fly pad adjustability, giving you total control over how far the pads sit from the rotor, as shown in the picture below.
The front brake is available in two rotor sizes: 165mm for cross country and 185mm for downhill. The rear brake is only available in a 165mm rotor.
Note: The #3 engraved on the caliper is explained in the section Deciphering Caliper Numbers
This is a new XC-specific disc brake offered by Hope that uses a closed system consisting of four pistons.
The front and rear rotors are only available in 150mm and 130mm diameters, respectively.
Note: The XC4 must be used with Hope hubs. Other disc-compatible hubs (King DiscGo Tech, Hugi, Shimano, etc.) are not compatible with the XC4. Using hubs other than Hope will place the caliper into the spokes.
This is a new disc brake offered by Hope that uses an open system consisting of two pistons. The caliper uses the seals instead of the springs found in the C2 to draw the pistons back into the caliper. Because the O2 uses seals instead of springs in the caliper, the O2 caliper is slighter narrower than the C2 caliper which may be beneficial to those wanting to use non-Hope hubs where spoke/caliper clearance might be an issue. Unlike the C2 which offers on-the-fly pad adjustability, the O2 features a metal diaphragm inside the lever reservoir. This allows the brake to self -adjust to account for fluid expansion due to increasing operating temperatures, as well as pad wear. This is the real benefit of an open system design, no loss of braking power on even the longest descent.
The front brake is available in two rotor sizes: 165mm for cross country and 185mm for downhill. The rear brake is available in two rotor sizes: 165mm for cross country and 185mm for downhill.
The DH4 is Hope's DH brake. It uses an open system, 4-piston system that self -adjusts to account for fluid expansion due to increasing operating temperatures, as well as pad wear. This is the real benefit of an open system design, no loss of braking power on even the longest descent.
The front brake is only available with a 185mm rotor. The rear brake is available in two rotor sizes: 165mm and 185mm.
Open vs. Closed Systems
Hope offers two types of disc brakes: open and closed. Each system type has its advantages and disadvantages. Each system type will be described to help you choose which system is right for your riding style.
Hope's open system disc brake, shown in the picture below. This system is used in the O2 and DH4 (aka O4). Although it is called an "open" system, this does not mean that it is open to the atmosphere. The brake fluid is contained within the system with seals. During an extended DH run, the fluid inside the brake system will heat up and expand. The open design automatically compensates for this fluid expansion. Otherwise, the fluid expansion would force the caliper pads out to the rotor, possibly locking the rotor.
The disadvantage of an open system is that you have no control over pad adjustment (unlike the on-the-fly adjustment knob on the closed system brakes). The pad position is determined by the special caliper seals which pull the pistons away from the rotor as you release the lever. This means there is the slight possibility of a little pad rub on the rotor. If this occurs (most likely it will run with no drag), then it will not slow you down, nor will it be noticable when riding.
Another feature of the open design is that the brakes will come on sooner than the closed system because there are no piston return springs to compress and the pads run closer to the rotor.
The Open system is the first choice for downhill riders and for cross country riders who want a fuss free brake that takes care of itself in all riding conditions.
Hope's closed system disc brake, shown in the picture below. This system is used in the C2 and XC4. Unlike the open system which automatically compensates for fluid expansion due to overheating, the closed system uses an on-the-fly adjustment knob to extend/retract the pads. The adjustment knob allows for fine tuning of the lever 'feel' (pads further from rotor = more lever pull; pads closer to rotor = less lever pull) and can also be used to eliminate any rotor drag. Instead of the seals used in the open system, springs are used to retract the pads.
With a closed system, there is the possibility of "pump out" during extended DH runs. This phenomenon occurs as the heat builds up in the system and causes the fluid to expand, thereby forcing the pistons out and causing the levers to lock-up. For standard cross country riding, this is not usually a problem.
Hope Lever Types (Pro vs. Sport)
Hope offers two different leverblades: Pro and Sport. Each leverblade will be described to help you choose which option is right for you.
The Pro lever is shown in the picture below. The Pro lever is Hope's new 2-finger style brake lever. The Pro lever offers: a lighter design; improved ergonomics; a cleaner profile; slightly more power; and easier to adjust lever reach. However, these improvements result in a slightly more expensive lever.
The Sport lever is shown in the picture below. The Sport lever is the original Hope lever and has been around for some time. Works just fine from a braking point of view. It is less easy to set the finger reach and the longer lever is a little awkward and is not best suited for 2-finger braking. The Sport lever is slightly heavier then the Pro, and is therefore, slightly cheaper.
Installing Hope Disc Brakes
What you'll need to install your brakes:
- 2.5, 3, 4 and 5mm allen keys (2.5mm for the finger reach adjustment bolt inside the lever; 3mm for the rotor bolts; 4mm for the lever clamp bolts; and 5mm for the caliper bolts).
Note: Do not operate the brake lever until the caliper is fastened to the bike. Since one of the mounting bolts also clamps the caliper halves together, brake fluid may be lost if the lever is operated with only one bolt holding the caliper together.
The brake is supplied fully bled from Hope and should not require bleeding, provided the hose is not disconnected. If you need to disconnect the hose, please read the section on Bleeding your brakes.
Attach the brake lever unit to the handlebar. Route the hose along the frame or fork. Ensure that the handlebars can be turned through 180 degrees without being obstructed by the hose. Then, fasten the caliper assembly to the fork/frame mounts. A 5mm aluminum spacer is provided with each mounting bolt. These are to be used on the outside face of the mounting brackets to ensure that the mounting bolts do not touch the rotor. Also, 4 or 5 thin 0.2mm shims are provided to ensure proper alignment between the caliper and the rotor. These may or may not be required on the inside face of the mounting bracket. This will depend on your fork/frame and hub.
With the caliper installed (it may need adjusting once the rotor has been attached to the hub), you'll need to install the rotor on the hub. Depending on which hub you have selected, you may need a spider that attaches the rotor the hub. The new-style rotors/hubs are 6-bolt and the rotors attach directly to the hub. The older-style rotors are either 4- or 5-bolt. These require a spider to attach the rotor to the hub. The spider has splines which should match the splines used on the hub. If you have a spider, gently push the appropriate spider onto the hub. Then, carefully thread the lock-ring onto the hub and tighten the spider to the hub. With the spider tightened, attach the rotor to the spider. One side of the rotor has countersunk holes for the bolt heads. Make sure you have the rotor facing the right direction otherwise the bolt heads will not be flush with the rotor. Now, carefully install the front/rear wheel and check the alignment between the caliper and the rotor. The caliper pistons should be centered directly over the rotor. You may need to add/remove some of the thin shims to get the proper alignment.
With the wheel installed and the caliper aligned properly with the rotor, check the function of the brake. If there is too much or too little lever travel, this can be adjusted if you are using a closed system Hope brake system (either C2 or XC4) via the silver adjustment knob on top of the master cylinder in the lever, as shown in the picture below. Turning the adjustment knob clockwise will move the brake pads closer to the rotor and reduce lever pull. Conversely, turning the adjustment knob counter-clockwise will move the brake pads away from the rotor and increase lever pull.
Hope brakes also offer finger reach adjustment via the 2.5mm screw found in the lever, as shown in the above. By turning the screw, this will either move the lever close to the handlebar or further away, depending on your personal preference.
Before disconnecting the hose from your brakes, please read the Warnings about Hydraulic Brake Fluid. Also, please thoroughly read and re-read this secion to gain a complete understanding of what is required.
In some instances when fitting the brake, due to routing problems, it may be necessary to disconnect the hose. Hope advises doing this at the caliper end. Use the pad position screw to set the pads in the fully retracted position. This ensures a zero pressure in the system. As a precaution you may want to remove the brake pads. Use an 8mm spanner to unscrew the aluminum shroud nut (brake line retaining nut), as indicated in the picture below. This exposes the brass olive that can be pried open with a screwdriver. Then using small pipe pliers, grip the hose firmly just below the olive and pull the hose off the connector. When removing the hose, you'll need to slightly twist it as you pull. If you pull the hose without pliers, the hose inner lining will remain attached to the connector. You will then need to cut the hose and fit a new length of hose if the hose is now too short. If care is taken, only a small amount of brake fluid will be lost. Carefully cut and re-route the hose, keeping fluid loss to a minimum. When you are ready to re-connect, screw the pad position screw clockwise until a small blob of fluid appears at the end of the hose. Quickly refit the connector and securely tighten the shroud nut (brake line retaining nut). If this method is used, bleeding of the brake may not be necessary. However, if you do need to bleed your brakes, go to the Bleeding section
What You'll Need to Bleed you Brakes:
- DOT 4 or DOT 5.1 hydraulic brake fluid;
- 8mm open ended wrench;
- adjustable wrench (or 26mm open ended wrench);
- 30cm (1 foot) of 3/16" clear tubing (available at the motorcycle store);
- pop can or other container for excess fluid; and
- 3, 4 and 5mm allen keys (3mm for the rotor bolts; 4mm for the lever clamp bolts; and 5mm for the caliper bolts).
Hydraulic Brake Fluid:
Use only glycol based DOT 4 or DOT 5.1 hydraulic brake fluid. Seals will be destroyed if mineral of silicone based fluid is used. Do not confuse DOT 5 with DOT 5.1, they are not the same. The difference between DOT 4 and DOT 5.1 is the point at which the brake fluid boils. DOT 4 has a lower boiling point than DOT 5.1. As such, DOT 4 is suitable for open brake system (O2 and DH4) since the effects of temperature are automatically compensated for. Only DOT 5.1 should be used with the closed system brakes (C2 and XC4) since they do not automatically compensate for fluid expansion.
Hope uses the brand name "Motul" (pronounced Mo-tool) hydraulic brake fluid, but this may or may not be available in your area. Go to your local motorcycle store and ask them for Motul (or equivalent) DOT 5.1 hydraulic brake fluid. If they don't have it (likely), have them order it for you. Using anything other than DOT 4 or DOT 5.1 brake fluid will destroy your seals.
Warnings about Hydraulic Brake Fluid:
1 - Do not spill brake fluid on the rotor. Brake fluid on the rotor will severely diminish braking power which could result in seriously bodily/bike harm. You should also avoid touching the rotor surfaces with your fingers because the oils from you skin will also diminish braking power. To remove fluid or oils from the rotor, use a clean cloth with some warm water and dish soap. Then clean with some alcohol.
2 - Do not spill brake fluid on the brake pads. Doing so will severely diminish their effectiveness. Damaged pads can potentially be salvaged by placing them on an oven element on top of a piece of aluminum foil. Allow the pads to sit on the element until the smoking has stopped, ie, the oil has been burned off.
3 - Do not spill brake fluid on your painted frame as the fluid will damage the paintwork.
4 - Do not get the fluid in your eyes and or on your skin. If brake fluid is splashed in the eyes, rinse with lots of water.
Bleeding your Brakes:
Open the pad adjuster all the way counter-clockwise. Then remove the wheel and place the bike in a stable position, preferably on a bike stand. It is important to mention that you may remove the brake pads to avoid spilling brake fluid on them, thereby destroying them.
Loosen the lever assembly and position it in a horizontal position on the handlebar. Once positioned, tighten the handlebar clamp bolts. With the adjustable wrench, remove the reservoir cap and piston assembly from the lever unit. Remove the bleed nipple cap at the caliper and attach the clear 3/16" tubing to the bleed nipple. Run the tube into the pop can/container to catch the bled fluid. Put a small quantity of brake fluid into the pop can/container and immerse the end of the tubing into the fluid. Ensure that the end of the tubing stays immersed in the fluid in order to prevent air from entering the caliper-end of the system during the bleed.
It is at this stage that it is best to set everything else up for after the bleed. Take the reservoir cap and piston assembly that has just removed and turn it upside down. You will see the bottom of the adjuster piston which looks like a silver disc with a smaller silver cylinder protruding from it, about 5mm long. Tightly grab the protruding cylinder and rotate the reservoir cap (black body) counter-clockwise. You will quickly notice that the piston you are holding onto will begin to unscrew from the reservoir cap. Twist the piston out until the lip of the silver piston is about 3mm past the edge of the reservoir cap, or until the black rubber seal, which is along the circumference of the silver disk is showing. Now the reservoir cap and piston assembly is ready for when the system needs to be closed. This is also a good time to adjust the lever reach so the brake is properly set-up once completed.
When bleeding the brake it is best to have a second person to help out - one to watch the reservoir and one to watch the caliper. If necessary, the bleed can be done by one person with a little caution. With the lever set in the horizontal position, the reservoir cap/piston assembly removed and the clear tubing attached to the caliper bleed nipple, you can begin bleeding the brake by opening the bleed nipple with the 8mm box wrench a half turn. You will notice, especially if using clear tubing, that fluid will begin to run from the disc quite rapidly since the reservoir in the lever is open. Quickly and carefully begin to pour fresh Motul DOT 5.1 fluid into the reservoir as it drains from the system. Be very careful to ensure that the fluid in the reservoir never goes empty during this process or you will be introducing air into the system (this is where having someone control the nipple while you do the fluid comes in very handy). Keep refilling the reservoir as it empties the during the bleed and let the fluid bleed out of the brake until you do not see any more air bubbles at the nipple, and the fluid looks clean and free of debris. Once you are sure that you have flushed the system with enough fluid, close the bleed nipple. Do not remove the bleed hose. Occasionally, the fluid will not flow from the caliper as readily as it usually does. In this case, open the bleed nipple a half turn and slowly, gently and steadily pull on the lever blade one full stroke to force the fluid from the reservoir into the lines and through the system. Be careful to use a slow and deliberate lever stroke, otherwise fluid will spurt from the reservoir. Then, tighten the bleed nipple screw and release the lever. Repeat this procedure a number of times and close the nipple when air bubbles are no longer present in the lines.
Next, top up the lever reservoir until the fluid level is ~2mm from the top. Hope recommends that to successfully bleed the system and ensure no air is introduced into the system that the system should almost be over flowing with fluid, so if you want you can fill the reservoir right to the top, it's your prerogative. Now take the reservoir cap and piston assembly, which you have already pre-adjusted earlier, and carefully insert the piston into the reservoir and slowly tighten the cap while simultaneously screwing the pad adjuster counter-clockwise. When you do this, you should have a rag to catch and wipe up any fluid overflow, which will likely occur if bleed and filled properly. Also, because the reservoir is so full, you will likely have to push down pretty hard on the reservoir cap while turning the reservoir body clockwise. Proceed until the cap is screwed down fully.
When the reservoir cap is screwed completely tightened, the caliper pistons may be extended such that the pads are touching. In order to open the pads, loosen the bleed nipple screw until just a drop of fluid is released from the bleed tube (this is why we left the hose still attached). You may have to turn the adjuster knob clockwise just a little bit to get enough fluid to come out. Do this only until you have enough clearance between the pads to put the wheel/rotor back in place to run drag free. Do not remove any more fluid at this point or the brake will not have enough fluid in the system to get enough pressure on the rotor. When this is done, carefully remove the hose from the bleed nipple, making sure not to spill any excess fluid.
Finally, clean everything up, replace the wheel and go ride, because everything's done. Just be sure to properly dispose of the excess DOT fluid.
Different Pad Types
Hope disc brakes come standard with EBC disc brake pads. These pads are manufactured with high quality Kevlar based compounds and high performance sintered metal for maximum durability.
Hope/EBC pads are available in 3 different colors (compounds): green, gold and red. Each color has a different purpose, as explained below.
- Green: These are the standard pads used in Hope brakes and are intended for all-purpose riding. The pads are made from Dupont Kevlar Fibre with a medium to high friction level with medium durability.
- Gold: These pads are intended for dry, mud, dirt or wet conditions. The pads are made from a high friction sintered bronze metallic compound that provides excellent durability but with a good strong brake effect. These pads will cut through the mud and slurry but will generate more heat in downhill or hot dry conditions.
- Red: These pads are intended for downhill racing only. The pads are Kevlar based with a very high coefficient of friction that deliver very strong braking....even up to 500 dgrees!
It doesn't get much easier than this:
1) Remove both split retaining pins at the top of the caliper;
2) Remove brake pads; and
3) Put new pads in being careful not to touch the pads with your finger. It is adviced to new split retaining pins, available from Hope or in any package of new pads.
Deciphering Caliper Numbers
Hope disc brake calipers come with different numbers engraved on them, depending on which fork, rotor size and whether they are installed on a fork or frame. Determining which number caliper you need for your particular fork/frame is not an easy task.
Here's what I've determined so far:
Caliper #1: This is a special caliper that is used when no disc mounting tabs are on the frame/fork. Example: 1998 Pace fork, with tapered leg, and 155mm disc.
Caliper #2: This caliper is to be used on frames with no rear disc brake mount. The rear rotor is 155mm.
Caliper #3: This caliper is to be used on the front with 185mm rotors or on the rear with 165mm rotors.
Caliper #4: This caliper is to be used with 1997 Marzocchi Z1 and Z2 forks with a 185mm rotor.
Caliper #5: This caliper is to be used on the front with 165mm rotors.
Caliper #6: This caliper is to be used with '98-'00 Rock Shox Boxxer forks. Rotor = 185mm.
Caliper #7: This caliper is to be used with Answer X-Verts that do not have Hayes mounts and a 165mm rotor.
Caliper #8: This caliper is to be used on the rear with 185mm rotors.
Caliper #9: This caliper is to be used with Manitou forks w/ 68mm hole spacing with 165mm rotors (??). No adapter is required (bolts directly to the fork tabs).
Caliper #10: ???
Caliper #11: This DH4 caliper is to be used with Manitou X-Vert Carbon forks. No adapter is required (bolts directly to the fork tabs).
For a list of which 1999 Hope calipers are required for which fork, please go here. - http://www.oocities.org/ti_guy.geo/hope_calipers.html
"Real" Hope Brake Weights
No, Hope brakes are not the lightest disc brakes on the market. If you want the lightest, look elsewhere.
Click here for a tabulated list of "real" weights for Hope disc brakes, rotors and spiders. All brake weights include the following items: lever, caliper, line, fluid, pads, and mounting bolts and shims. Rotor weights include: rotor and mounting bolts. The spider weights are listed seperately.