Super73 Brake Service: Hydraulic & Mechanical Brake Adjustment Guide

The first thing to know before you touch a wrench is which brake system your Super73 uses. Super73 ships with two fundamentally different braking platforms: Magura hydraulic disc brakes (most common on RX and newer S models) and Tektro mechanical disc brakes (found on Z models and earlier S-series bikes). Hydraulic and mechanical brakes require different tools, different adjustment techniques, and different maintenance intervals. Identifying your system is straightforward – look for the brake caliper logo or check your model’s spec sheet. If you see a small mineral-oil reservoir on the lever and a hose running to a caliper with “Magura” stamped on it, you have hydraulics. If you see a bare brake cable entering the caliper and a threaded barrel adjuster at the lever, you have mechanical cable-actuated brakes.

This guide covers the service tasks that matter most for both systems: pad inspection and replacement, cable tension adjustment (mechanical), brake bleeding (hydraulic), and rotor replacement. Each section includes specific steps, practical checkpoints, and clear thresholds for when to stop DIY work and seek professional help.

Identifying Your Super73’s Brake System (Magura vs Tektro)

Before you buy pads, fluid, or a bleed kit, confirm which parts your bike uses. The table below summarizes the key visual and functional differences – look at the lever, caliper, and rotor.

Feature	Magura (Hydraulic)	Tektro (Mechanical)
Lever type	Integrated reservoir with bleed port	No reservoir; cable barrel adjuster
Caliper	Two-piston, sealed hose	Single-piston, cable-actuated arm
Rotor attachment	6-bolt or centerlock (varies by model)	6-bolt (most common)
Brake fluid	Mineral oil (Magura Royal Blood or compatible)	None (cable only)
Typical models	RX, S-series (2021+), some Z models	Z-series, older S models

If you’re unsure, remove the wheel and check the caliper body for stamped branding. Magura also places a small “MT5e” or “MT4e” marking on the inside face. Once you know which system you have, you can proceed with the correct service procedure.

Inspecting and Replacing Brake Pads

Pad condition is the single biggest factor in braking performance. Worn pads not only reduce stopping power but can also damage rotors – and on an e-bike that can weigh over 60 lb, worn pads are a safety issue, not just a convenience one.

How to check pad wear

Look through the caliper gap from above. Most Super73 pads have a visible wear groove or a red indicator layer. If the groove is nearly gone or the red layer is showing, replace the pads immediately. Measure the friction material with a small ruler: new pads typically have 2–3 mm; replace at 1 mm or less. If the pad material is misaligned or one pad is worn significantly more than the other, the caliper may be sticking – address that before installing new pads.

What about contaminated pads?

If pads have been exposed to oil, lubricant, or cleaning solvents, replace them even if they still have plenty of material. Contaminated pads lose grip unpredictably and cannot be effectively cleaned. A quick test: rub a clean finger across the pad surface – if it feels greasy or leaves a dark residue, swap them.

Pad replacement for Tektro mechanical brakes

Remove the wheel to access the caliper. Use a 5 mm hex key to remove the two pad-retaining bolts (or the single cotter pin on very old models). Slide out the old pads, push the piston back using a plastic tire lever or a flathead screwdriver wrapped in tape (this prevents piston damage). Slide in new pads – note the orientation: the friction side faces the rotor, and the steel backing plate sits outward. Re-tighten the bolts to 4–6 Nm (check your manual; over-tightening can crack the caliper body). If the piston doesn’t push back easily, open the bleed port on the lever to release pressure – this is rare but can happen when pads are very worn.

Pad replacement for Magura hydraulic brakes

Magura calipers use a clip-and-pin retention system. Remove the small retaining clip and pull out the pad pin. The pads slide out laterally. Use a plastic tire lever to gently push the pistons back – do not use a metal tool directly on the pistons, as ceramic pistons can crack. Install new pads, re-insert the pin, and clip it in place. Magura pads are keyed; if they don’t slide in easily, check that you have the correct pad shape (e.g., Magura M4 vs M7). If the pistons refuse to move, the system may be overfilled – open the lever bleed port slightly to release pressure, then retract the pistons.

Success check and escalation threshold

After installing new pads, spin the wheel. The rotor should not rub the pads more than a faint whisper. If you hear a constant metallic scrape, the pads may be too tight – back off the caliper alignment (see rotor section) or adjust the lever reach and bite point on hydraulic systems. If the rubbing persists after alignment and you can see the rotor is visibly bent (more than 0.5 mm wobble when spun), stop – do not ride. A warped rotor cannot be trued reliably with DIY methods on e-bike loads. Replace the rotor or take the wheel to a shop.

Adjusting Mechanical Brakes (Cable Tension and Centering)

Mechanical disc brakes on Super73 bikes drift out of adjustment as cables stretch and pads wear. A quick cable-tension tweak can restore lever feel without replacing anything.

Step 1: Check the lever free play

Squeeze the brake lever. It should move about 1/8 inch (3–4 mm) before the pads contact the rotor. If it moves more than 1/4 inch, you need more cable tension.

Step 2: Use the barrel adjuster

Turn the barrel adjuster at the lever (counterclockwise to increase tension, clockwise to decrease). You can also use the barrel adjuster at the caliper, but start at the lever for finer control. Turn in small increments (quarter turns), then test.

Step 3: Center the caliper

After adjusting tension, the caliper may sit crooked, causing one pad to rub the rotor. Loosen the two caliper mounting bolts (usually 5 mm hex) just enough to wiggle the caliper. Squeeze the brake lever firmly and hold it – this self-centers the caliper over the rotor. While still holding the lever, tighten the mounting bolts to 6–8 Nm. Release the lever and spin the wheel. The rotor should run clear of both pads.

Step 4: Check pad clearance (if needed)

Some Tektro calipers have a two-wheel adjuster on the inside of the caliper arm. Turning this adjuster can fine-tune pad-to-rotor clearance without affecting cable tension. Turn clockwise to push the inner pad closer to the rotor; counterclockwise to pull it back. Use this only after tension and centering are correct.

Common mistake and escalation threshold

Over-tightening the cable clamp bolt at the caliper can strip the aluminum clamp or damage the cable. Tighten to the torque listed on the caliper, typically 5–6 Nm. If after adjusting tension and centering the brake still drags heavily or the lever feels too soft even under full force, inspect the cable for fraying, kinking, or corrosion. A damaged cable can snap under braking. Replace the cable immediately. If the caliper arm doesn’t spring back after release, the caliper may be seized internally – that is not a DIY repair; replace the caliper or visit a shop.

Bleeding Hydraulic Brakes (Magura)

Hydraulic brakes lose feel over time as microscopic air bubbles work their way into the system. A bleed restores a firm lever and consistent modulation. Magura systems require mineral oil – do not use DOT fluid, which will destroy the seals.

Tools you’ll need

Magura bleed kit (or a syringe with a bleed fitting compatible with Magura’s banjo bolt), fresh mineral oil (Magura Royal Blood or equivalent), a catch bottle, and a 2.5 mm hex key for the bleed screw.

Step 1: Remove the pads

This prevents oil from contaminating the friction material. Use the same pad-removal steps from the earlier section.

Step 2: Attach the bleed hose

Screw the bleed fitting into the bleed port on the lever (the small screw on the lever body near the hose entry). Attach the syringe filled with fresh oil to the bleed hose.

Step 3: Open the caliper bleed screw

On Magura calipers, the bleed screw is a small hex fitting on the caliper body, typically on the outboard side. Use the 2.5 mm hex key to loosen it one full turn.

Step 4: Push fluid from lever to caliper

Slowly push the syringe plunger – you are forcing fresh oil into the lever and down the hose, pushing bubbles out through the caliper bleed screw. Watch the stream at the caliper bleed port: you should see clear oil with no bubbles after 10–15 ml. If air shoots out, continue until the stream is steady.

Step 5: Close the caliper bleed screw

Close the caliper bleed screw while still pushing on the syringe to maintain pressure. Tighten to about 2 Nm (snug, not torqued hard). Over-tightening can strip the aluminum threads.

Step 6: Remove the syringe and close the lever bleed port

Replace the lever bleed screw and tighten gently. Wipe up any oil spills immediately – mineral oil is less corrosive than DOT fluid but can still damage paint and plastic.

Step 7: Check lever feel

Pump the lever a few times. It should be firm, with a short free stroke. If the lever pulls to the bar, there is still air – repeat the process. Magura often requires a second pass to purge small bubbles trapped in the lever chamber.

Hydraulic tip

Magura levers have a reach-adjust dial (a small plastic wheel near the lever pivot). If the lever feels spongy after a bleed, try adjusting reach inward – this can sometimes move air trapped in the lever cavity toward the bleed port.

Escalation threshold

If after two full bleed attempts your lever still feels spongy or pulls to the bar, stop. Internal seals may be damaged or the lever body may have a hairline crack. Continued bleeding will not fix a seal failure – take the bike to a Super73 dealer or a qualified bike shop. Riding with a spongy lever risks complete brake failure.

Replacing Brake Rotors

Rotor replacement is less common but necessary when a rotor is warped, excessively worn (below the minimum thickness stamped on the rotor), or you want to upgrade to a larger size for better heat dissipation.

Rotor type

Super73 uses both 6-bolt and centerlock rotors depending on the hub. Most Tektro-equipped bikes use 6-bolt; Magura-equipped bikes often use centerlock. Check the hub before ordering a rotor. A simple way to tell: if the rotor is held on by six small bolts, it’s 6-bolt. If you see a single large ring with splines or a lockring tool interface, it’s centerlock.

6-bolt rotor replacement

Remove the wheel. Use a T25 Torx driver (or 5 mm hex, depending on your rotor bolts) to loosen the six bolts securing the rotor to the hub. Bolts are usually secured with threadlocker; apply even pressure. Remove the old rotor. Clean the hub flange. Place the new rotor with the braking surface facing outward (some rotors have a directional arrow – follow it). Thread the bolts finger-tight, then torque to 6–8 Nm in a star pattern. If your bolts didn’t have threadlocker, apply a drop of medium-strength (blue) threadlocker before final install.

Centerlock rotor replacement

You’ll need a centerlock tool (or a cassette lockring tool plus a large wrench). Remove the axle nut or quick-release, then unscrew the centerlock retaining ring counterclockwise. Lift off the old rotor. Install the new rotor, tighten the retaining ring to 40 Nm (typical for Shimano/SRAM standard). Over-tightening can warp the rotor or damage the hub.

Success check and warped rotor diagnosis

After installing a new rotor, re-install the wheel. Spin the wheel and listen for rubbing – a new rotor may have slight surface irregularities that wear in after a few rides. If rubbing persists, re-center the caliper as described in the mechanical brake section (the same centering process works for hydraulic calipers). If the rotor wobbles visibly more than 0.5 mm when you spin the wheel, it is warped. Do not attempt to straighten a rotor on an e-bike – the forces are too high and a bent rotor can cause sudden brake failure. Replace the rotor or take it to a shop.

Frequently Asked Questions

How often should I replace brake pads on my Super73?

Pad life depends on riding habits, terrain, and weight, but expect to inspect pads every 200–300 miles. The rear pad often wears faster on e-bikes because the motor delivers power to the rear wheel and regen braking also adds wear. Replace once the friction material is down to 1 mm.

Can I switch from Tektro mechanical to Magura hydraulic brakes on my Super73?

Yes, but it is a significant conversion. You’ll need new levers, hoses, calipers, rotors (if the rotor diameter differs), and often new cables or adaptors. The labor cost and complexity make it worthwhile only if you ride aggressively or in wet conditions where hydraulic modulation is a clear advantage. Many owners prefer to stay with mechanical for simplicity and lower maintenance cost.

What brake fluid does Magura use, and can I substitute?

Magura recommends Royal Blood mineral oil. Do not use DOT 3, 4, or 5.1 – those are incompatible with Magura’s rubber seals and will cause swelling and failure over time. Compatible alternatives include Shimano mineral oil or other fully synthetic mineral brake fluids labeled for bicycle use.

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– Aventon E-Bike Brake Service: Hydraulic & Mechanical Adjustment Guide
– Velotric E-Bike Brake Service: Hydraulic Brake Adjustment & Pad Replacement
– Sondors E-Bike Brake Service: Adjustment, Pad Replacement & Bleeding Guide
– How to Adjust & Replace Brakes on Lectric E-Bikes: Step-by-Step Guide