If your e-bike’s brake track is split, the fix is almost never “repair the crack.” A split brake track usually means the rim (or disc rotor) has structurally failed, and the safe solution is replacement, not patching, bending, or gluing. Keep reading for how to identify what’s actually split, what to do immediately, and the right way to replace the damaged part.
What “brake track split” means (and why it’s urgent)
Brake track usually refers to the machined sidewall of a rim that rim brakes rub against. On an electric bike, a split here is especially dangerous because e-bikes are heavier and often faster than acoustic bikes.
Common signs:
- A visible crack running along the rim’s braking surface (sometimes a long hairline, sometimes a gap)
- The rim sidewall looks bulged, wavy, or “opened up”
- Pulsing brakes, sudden rubbing, or a new “tick… tick…” sound per wheel rotation
- A blowout or sudden loss of air (the tire bead can unseat if the rim fails)
Do not keep riding to “see if it gets worse.” Rim failures can become catastrophic without much warning.
Confirm what’s actually split: rim brake track vs disc rotor
Rim brake e-bike (most common “brake track” wording)
- The rim sidewall is the brake surface
- A split here usually means rim wear, heat damage, or fatigue
- Safe fix: replace rim or entire wheel
Disc brake e-bike (sometimes people call the rotor a “track”)
- The brake surface is the disc rotor
- Cracks often appear near the holes or spider arms
- Safe fix: replace the rotor (and sometimes pads)
If you’re not sure, look at where the pads touch:
- Pads touch the rim sidewall → rim brake track
- Pads clamp a metal disc near the hub → disc brake rotor
What to do with E-Bike Brake Track Split immediately
1. Stop riding. Walk the e-bike to a safe spot.
2. Inspect the damage in good light.
- If you see any gap, bulge, or crack you can catch with a fingernail, treat it as a failure.
3. Do not inflate the tire further.
- Higher pressure can force the crack open.
4. Don’t attempt a temporary repair (epoxy, tape, hose clamps, welding, bending).
- These don’t restore rim strength and can fail suddenly.
If you’re far from home, the safest move is walking the bike or getting a ride. A split rim can turn into a crash fast, especially downhill.
Why brake tracks split on e-bikes
These are the usual causes, and knowing them helps prevent a repeat:
Rim wear from braking grit
If you ride in rain, dust, or winter grit, rim brakes grind away material. Over time the rim wall becomes thin and cracks.
How to check:
- The rim sidewall may look concave instead of flat
- You might see a wear indicator groove is gone (some rims have one)
Heat buildup on long descents
Dragging rim brakes heats the rim. Heat plus tire pressure can push a weakened rim over the edge.
E-bike factor:
- More weight, more speed, more braking heat.
Brake pads set too low or misaligned
Pads that hit the tire or ride off the braking surface can create hotspots and damage.
High load and low spoke tension
Cargo, heavier riders, or loose spokes can flex the rim more, encouraging cracks.
Corrosion or manufacturing defect
Salt air, winter roads, or a bad rim batch can shorten life.
The real fix for a rim brake track split: replace the rim or wheel
Option A (most common): Replace the entire wheel
This is usually the fastest, cleanest, safest path.
What you need to match
- Wheel size (for example 26 inch, 27.5, 700C)
- Rim brake type (rim must have a braking surface)
- Axle type (quick release, thru axle, solid axle)
- Rear spacing and drivetrain (freewheel vs cassette)
- On hub-motor e-bikes: motor type, cable routing, axle diameter, torque arms, connector style
High-level replacement steps
- Power off the e-bike and remove the battery.
- If it’s a rear hub motor, carefully disconnect the motor cable (do not yank wires).
- Remove the wheel.
- Move tire and tube to the new wheel (or install new ones if worn).
- Install the new wheel and ensure it’s seated straight in the dropouts.
- Reconnect motor cable (hub motor), reinstall battery, then do a slow test.
If your e-bike has a hub motor and you’ve never removed the wheel before, it’s very normal to use a bike shop. Hub motor wheels can be fiddly because of torque arms, washers, and cable alignment.
Option B: Rebuild the wheel with a new rim
This can be great if you have a nice hub (or an expensive hub motor), but it requires correct spoke length, tensioning, and truing.
In practice:
- For most riders, a wheel rebuild is a bike shop job unless you already have wheelbuilding tools and experience.
If the split is on a disc brake rotor instead
A cracked rotor is also replace, not repair.
Basic rotor replacement outline:
- Remove wheel.
- Remove rotor bolts (or lockring, depending on rotor type).
- Install a new rotor of the same diameter.
- Tighten to the manufacturer’s torque spec.
- Reinstall wheel, align caliper if needed, and bed in the brake pads with controlled stops.
If your pads are contaminated or worn thin, replace pads too.
After the fix: brake setup and safety checks
Rim brakes
- Align pads so they hit the rim flat and do not touch the tire
- Make sure both arms move freely and return evenly
- Spin the wheel to confirm no wobble and no brake rub
- Do several slow stops before riding normally
Disc brakes
- Check rotor runs true (no major wobble)
- Center the caliper if you hear rubbing
- Bed in the pads: a series of controlled stops builds proper bite
Prevention: make brake tracks last longer on an electric bicycle
- Clean rims and pads after wet or gritty rides
- Replace rim brake pads before they get embedded with metal shards
- Avoid dragging brakes on long descents; use firm, intermittent braking
- Periodically check spoke tension and wheel true
- If you routinely carry cargo or ride steep hills, consider switching to or prioritizing disc brakes when upgrading
Final Thoughts
A split brake track is one of those problems that feels small until it suddenly isn’t. The good news is the “fix” is straightforward once you confirm whether the damage is on the rim’s braking surface or the disc rotor: replace the compromised part, set the brakes up correctly, and you’re back to smooth, predictable stopping. After you’re rolling again, build a quick habit of checking rim wear or rotor cracks during regular cleanings—on an fat tire-bike, that tiny inspection can prevent a big failure later.
FAQs
Can I glue, epoxy, or weld a split brake track?
No. Those don’t restore the rim’s structural strength and can fail without warning.
Is it ever safe to ride “a little” on a cracked rim?
If it’s truly a split brake track, treat it as unsafe. Walk the e-bike or arrange transport.
How do I know if my rim was worn out before it cracked?
Concave sidewalls, missing wear indicators, frequent broken spokes, and gritty braking wear are common clues.
Will a warranty cover a brake track split?
Sometimes, if it’s a defect and the wheel isn’t worn out. If the rim is clearly worn thin from use, it’s usually considered wear-and-tear.
Should I replace just the rim or the whole wheel?
Whole wheel is simplest for most riders. Rebuilding makes sense if you have a valuable hub motor or premium hub and a shop you trust.
