Spring tune-up time for ebike season
Spring is just around the corner. You've been itching to get back on your electric bike, but is your ebike ready for the spring riding season? Even if you did an end-of-season tune up a few months ago, your bike will still need to have the tires pumped, the battery charged, and probably some cleaning if it sat around collecting dust (or snow) all winter. The following is a comprehensive checklist to make sure that your bike functions properly and safely:
Clean the Ebike
If your bike has sat unused all winter, now would be a good time to clean off any dust that's accumulated on it. It's much easier to determine the bike's mechanical state when it's clean.
Inspect Wheels
If you rode in the snow with reduced tire pressure, check that the valve stems are straight. It's possible for the tire to shift in relation to the rim at low tire pressures, causing the valve stem to become angled. Re-inflate the tires to a pressure more suitable for riding on firmer surfaces. Underinflated tires will wear out prematurely, increase rolling resistance, and also make the inner tubes vulnerable to pinch flats. When inflating the tires, check that the bead is properly seated in the rim. The ideal tire pressure is personal to each rider. For fat tired bikes, we recommend starting with 20 psi, then incrementally bleeding some air until you've found a pressure that has the perfect blend of traction, compliance and comfort. The rear tire will always be at a higher pressure than the front. Once you've dialed in your perfect tire pressure, make a note of it, so you know what to inflate your tires to next time. The tires should also be inspected for tread wear and mechanical damage.
The wheels should be spun, and the rim checked for how true it is. Any wobbles should be corrected. Squeeze the spokes to check for spoke tension. The rear wheel tends to suffer more abuse (especially with a hub motor attached to it). A wheel that's undertensioned won't stay true for very long, it may suffer from premature spoke breakage, and cause handling issues.
The hub bearings should be checked for proper bearing preload. Cones too loose or too tight will accelerate bearing wear. The hubs used on DJ Bikes will need a 15mm wrench for the locknut, and a 17mm cone wrench for the cones.
This video covers the process of fine tuning a cone adjustment:
Calvin's Feast Part 3: The Hub Adjustment | Tech Tuesday #161 (8:00)
The quick release on the front wheel should be checked that it's tight. The handle on the quick release should be positioned in a way that it doesn't protrude from the bike, or interfere with the wheel or brake rotor. The rear axle nuts should be checked too. Loose axle nuts can result in expensive damage to the motor wiring. They can be tightened with an 18mm wrench to about 30 - 40 ft lbs.
Inspect Chain
Check the chain for wear. A chain worn well beyond its service limit will start skipping and accelerate wear on the rest of the drivetrain. When a chain is made, the rivets are spaced exactly 1/2" on center. When the rollers start wearing, the tolerances between parts start increasing, resulting in what's known as "chain stretch". You can find out if your chain has stretched using a 12" ruler. Place the edge of the ruler on the center of a rivet, and follow it to the 12" mark. The 12" mark should fall on the exact center of a rivet. If the rivet goes past this mark by 1/16" or more, you need to replace the chain. You can also purchase a chain wear gauge such as the Park Tool CC-3.2 Chain Checker.
If you haven't done any chain maintenance in months, now would be a good time to clean and lubricate it too.
Inspect Brakes
Squeeze the brake levers as hard as you can. You should be able to fully lock up the brakes without the levers coming in contact with the handlebar. You can rotate the pad adjusters on the calipers to compensate for pad wear. Noisy brakes can be a symptom of a warped rotor (it will make a rhythmic "ting" sound), or rotor contamination (loud squealing noise). Warped rotors can be gently tweaked with a small crescent wrench, or a dedicated tool like the Park Tool DT-2 Rotor Truing Fork. Contaminated rotors can be cleaned by wiping them down with a clean towel and isopropyl alcohol. Note that sintered metallic pads tend to be noisier than organic pads. They can be identified by a copper surface color.
Check the torque on the rotor and caliper mounting bolts.
For more info how to do brake servicing, please refer to our Knowledge Base article:
Inspect Cables
Check that the brake and shifter cables move smoothly and aren't frayed or damaged. Check the cable housing as well, especially where it enters cable ports in the frame, and around the frame hinge on the folding bikes. Any sharp edges around the cable ports should be deburred. Check that cables are properly secured so that they can't interfere with any moving parts. Check that the housing clamp screw on the fork is tight. A good practice is to add an extra zip tie here to ensure that the brake cable can't get snagged by the tire if the clamp should fail for some reason. A few extra zipties can be used to tidy up the handlebar cables. Make sure to fully turn the handlebars and confirm that no cables get snagged.
Inspect Headset
Lock the front brakes, and rock the bike forward and backward with the handle bar. You'll have play if you feel a subtle knocking sensation. Sometimes stanchion flex in the suspension fork can be confused for headset play. Wrapping your fingers around the headset bearing cups can help confirm where the play is coming from. To remove headset play on threadless headsets, loosen the pinch bolts on the back of the stem, and tighten the bolt on the stem cap to take up the slack, then retighten the pinch bolts. With threaded headsets, loosen the upper locknut, then use a headset wrench to tighten the upper bearing race. Tighten the locknut while stabilizing the upper race with the headset wrench. On the folding bikes, the stem cap is visible when the folding latch is opened.
This video covers how to check a headset:
Tech Tuesday #10: Troubleshooting the Headset (5:00)
Inspect Stem and Handlebar
Check that the stem face plate bolts and pinch bolts are tight. Check that the controls and accessories mounted on the handle bar are tight. You want to leave the bolts just loose enough that the part will move if it takes a strong impact.
Inspect Bottom Bracket
The forces from pedaling can eventually work the bottom bracket loose, resulting in an annoying creaking sound. Grab both crank arms, and try to shake them side to side, feeling if there's any lateral play present. Tightening the bottom bracket will require removal of the crank arms, and the use of a Shimano style bottom bracket tool. Please note that the drivetrain side bottom bracket cup is reverse threaded.
Inspect Crank Bolts
Use an 8mm hex wrench to check that the crank bolts are torqued to between 30 and 40 ft lbs.
Inspect Pedals
Just as the bottom bracket can come loose, the pedals can also work themselves loose from pedaling as well. While a loose bottom bracket can be annoying, loose pedals can be very dangerous. Loose pedals can cause the threads in the crank arm to shear out, leading to a potentially catastrophic loss of control situation. The pedals can be easily tightened with a 15mm wrench. They should be fairly firm. You're aiming for about 30 ft lbs. Please note that the left side pedal spindle is reverse threaded.
Inspect Shifters and Drivetrain
With the bike elevated, turn the cranks, and run through the gears to ensure that it shifts gears easily. The shifter cable can stretch over time, leading to sloppy shifter performance. Rotating the barrel adjuster on the shifter or derailleur a click or two is often all that's needed to properly re-index shifting.
This video covers the basics of derailleur operation:
How a Rear Derailleur Works (Park Tool 4:21)
This video goes through the whole procedure of derailleur adjustment:
How to Adjust a Rear Derailleur - Limit Screws & Indexing (Park Tool 16:07)
Inspect Electrical Connections
Start by pulling the battery and inspecting the power terminals on the battery, as well as the terminals inside the cradle/mounting base. The terminals should be straight, clean and free of corrosion. Tighten the screws used to attach the battery cradle, battery rail, and controller compartment door. If you have a mid-drive, make sure that the lockring and mounting bolts for the motor are tight too.
Inspect the power connector to the motor (located under the drive side chainstay). It's in a location vulnerable to weather exposure. We like to put dielectric gel on the terminals pins, making sure the plug is firmly inserted, and then wrap the connection with electrical tape to keep water and dirt out.
Examine the wiring behind the bottom bracket and under the chainstay. Because of the proximity to the rear wheel, it's possible for wires to get damaged if they come in contact with the tire.
This is an example of how the rear wiring can be secured:
This is an example of damage from tire rub. This was easy to fix. Anything worse than this (such as bare wires) become complicated or expensive to repair.
Finally, inspect all the connections on the main wiring harness. The connectors can be disconnected by giving them a firm, straight tug. A good practice is to put a small dab of dielectric gel on the connectors to seal out corrosion. Reinsert the connectors back together. The plugs have a keyway on the inside, as well as an alignment mark on the outside, to ensure they only go on one way. The pins are delicate and can be damaged if the plug is forced in the wrong position.
On the folding bikes, remove the cable wrap that's near the handle bar, and ensure that all the connectors from the handle bar are firmly connected to the wiring harness. It's possible for the wires to get snagged and disconnected.
Power On Test
With the bike elevated, turn the power on. Ensure no error message shows up on the LCD. Turn the cranks and confirm pedal assist operation. Push the throttle lever, and confirm that it works.
Turn the headlight on to confirm that it operates. Squeeze the brakes, and confirm that the brake light works (where equipped).
Inspect Motor Inhibitor Circuit
With the bike still powered up, slowly turn the crank, and lightly squeeze the front brake. Power should immediately cut to the motor. Repeat for the rear brakes.
Inspect Magnet Wheel and Cadence Sensor
When the magnet wheel is manufactured, the process of pressing the magnets can cause small fractures to form in the plastic wheel. This can cause the individual magnets to fall out, or even contribute to the magnet wheel completely falling apart. Check that the magnet wheel spins true on the bottom bracket spindle. Check that the cadence sensor bracket isn't bent. There should be a 2mm space between the magnet wheel and the cadence sensor. You can use the shaft of a 2mm hex wrench as a go/no-go gauge to confirm this. The sensor has a red LED that blinks when a magnet passes by it.
Inspect Fasteners
Check that all the bolts and fasteners are tight. Using some thread sealant on them can keep them from rattling loose again. Specific areas to check are rack, fenders, and lights.
Inspect Accessories
Check for damage to accessories. Chipped paint and cracks can be signs of metal fatigue. The fenders and derailleur hangar are the most vulnerable to this. If your bike has any bags, make sure all clamps are tight, and any straps are out of the way. If you've installed any aftermarket accessories make sure these are tight too.
Folding Bike Specific
Check the condition of all the latches. The latch on the main frame hinge should be very tight. A loose latch can produce a creaking sound. It can be tightened by stabilizing the latch nut with a 10mm wrench, and spinning the latch handle. If the hinge is excessively tight, squirt a little oil into the hinge pivot. Check that the latch mechanism moves freely, and isn't interfering with the metal on the frame. The latch handle should point down when it's closed, so that you can't accidentally catch your foot on it.
Check that the latches on the stem mast are tight too. The tension on the handle bar folding latch can be adjusted by opening the latch, and rotating the turnbuckle inside with a 6 mm wrench. Use about 1/8 of a rotation at a time. Turn CCW to tighten the latch, CW to loosen.
