Check the bolts on your e-bike

E-bikes are heavy and fast, so a loose bolt matters more than on a light bike. A quick bolt check once a month catches problems before they turn into a crash or a broken part. This guide follows Rad Power Bikes' owner's manual schedule, Park Tool's torque guide and Shimano's care advice. Your own bike's manual has the numbers that count.

How often

• Rad's RadWagon 5 manual lists a hardware torque check in its weekly schedule (every 100 to 200 miles) and a crankset and pedal torque check in its monthly schedule (250 to 750 miles). It also says to check bolt torque after the first 50 to 100 miles of break-in (Rad RadWagon 5 manual).
• Shimano puts the bar and stem, derailleur mounts, seat clamp and saddle bolts first when you torque bolts to spec (Shimano).

What you need

• Hex keys and Torx keys
• A torque wrench with the right bits
• An axle nut wrench for a hub motor's axle nuts
• Your owner's manual. Shimano says its components print the torque on the part in newton meters or list it on Shimano's website (Shimano).

Steps

1. Turn the bike off and remove the battery.
2. Stem and handlebar. Check the stem bolts that clamp the steerer and the faceplate bolts that hold the bar. Rad tightens faceplate bolts evenly, a quarter turn at a time in an X pattern (Rad). On the RadWagon 5, Rad lists 10 Nm for the faceplate bolts and 15 Nm for the stem clamp bolts (Rad RadWagon 5 manual). Other stems differ a lot: Park Tool's chart shows stem bolt specs from about 5 Nm to 10 Nm depending on the maker (Park Tool).
3. Brake levers, throttle and display. Rad lists 5 to 7 Nm for its brake lever clamps on the RadWagon 5 and says to tighten the throttle and display clamps securely without overtightening (Rad RadWagon 5 manual).
4. Seatpost and saddle. Check the seat clamp and the saddle rail bolts. Rad lists 10 Nm for both on the RadWagon 5 (Rad RadWagon 5 manual). Park Tool says seatpost clamps need only modest torque and warns against overtightening (Park Tool). See set saddle height.
5. Axle nuts and thru axles. A hub motor's rear axle nuts carry a lot of load. Rad lists 55 to 65 Nm for the RadWagon 5 rear axle nut and 10 to 15 Nm for its front thru axle (Rad RadWagon 5 manual). Park Tool gives 29.4 to 44 Nm as a general range for solid axle nuts (Park Tool), so always use your bike's own number for a motor wheel. Check the torque arm bolt too, which Rad lists at 5 Nm (Rad RadWagon 5 manual).
6. Brake calipers and rotors. Rad lists 6 to 8 Nm for caliper to frame bolts and for T25 rotor bolts on the RadWagon 5 (Rad RadWagon 5 manual). Park Tool's chart shows Shimano and Tektro calipers at 6 to 8 Nm (Park Tool).
7. Cranks and pedals. Rad lists 35 Nm for both the pedals and the crank arm bolts on the RadWagon 5 (Rad RadWagon 5 manual). See replace pedals and check cranks and the bottom bracket.
8. Rack, fenders, kickstand and lights. Rad lists 4 Nm for its fender bolts, 8 Nm for the front headlight and fender mount, and 50 to 60 Nm for the center kickstand on the RadWagon 5 (Rad RadWagon 5 manual). Rack bolts aren't listed there, so check your rack's own instructions.
9. Battery mount. Rad lists 5 Nm for the RadWagon 5 battery bracket bolts (Rad RadWagon 5 manual). Only check the outside mounting bolts. See battery mount.

Common mistakes

• Using someone else's numbers. The Rad figures above are for one model. They show the kind of spread you'll see, not a spec for your bike.
• Overtightening carbon or small bolts. Low numbers like 4 or 5 Nm are easy to pass with a long key.
• Forgetting the bolts you touched. Recheck anything you worked on after a ride or two.

Videos

When to get a pro

• A bolt keeps coming loose, or the threads feel crunchy or strip.
• The axle nut keeps loosening, or the torque arm is bent. See torque arm.
• The headset knocks after you check the stem. See adjust a loose headset.
• More on what to leave to a shop: when to call a pro.

Sources

• RadWagon 5 owner's manual, Rad Power Bikes
• Adjust your bike for comfort and safety, Rad Power Bikes
• Torque Specifications and Concepts, Park Tool
• Spring cleaning and maintenance, Shimano

Stuck after these checks? Find a shop near you.