Fixing a flat tire on an ebike can be a bit of a pain, especially if the flat tire is in a hub motor wheel. The best method is to try and avoid flat tires to begin with, but if you’ve already found yourself stuck with a flat tire, here’s how to fix it.
We’ll assume the flat tire is in the hub motor wheel. If it’s not, follow the same steps but you can ignore all the stuff about the motor/wire/etc and just focus on the wheel.
Start by turning the ebike off and flipping it over so it rests on the handlebars and seat. I also like to take the battery out first to make the ebike lighter and ensure the ebike doesn’t accidentally switch on while I’m working on it. Also, consider laying down a blanket first to keep from scratching your seat, rack, handlebars, etc. Don’t forget to flip down any mirrors or other handlebar accessories that could interfere with the bars resting squarely on the ground.
If you have rim brakes, open them so they don’t get in the way of the tire or rim. If you have disc brakes, they’re fine the way they are.
Loosen the axle nuts on either side of the hub motor until the hub motor’s axles are free to wiggle up and out of the dropouts. You may need to remove a torque arm, if you have one mounted on your motor and it interferes with removing the axles from the dropouts.
If your hub motor has a connector close to the motor, disconnect it so that you can pull the wheel all the way out and separate it from the bike. This will make the rest of the job much easier.
Make sure you remember to cut any cable ties that holding the motor wire to the frame so you don’t accidentally stress the wire by pulling it while it’s still attached.
If your motor wire doesn’t have any in-line connector, the rest of the steps will be a bit more difficult. It is still quite doable, but you’ll have to perform each step while the motor is still wired to the bike. Just start by taking the tire off the rim on the side opposite the wire, usually the non-chain side. Next, pull the inner tube out of the tire, including the valve stem from the rim.
Get your new tube ready with a little bit of air in it, but don’t inflate it enough to start stretching like a balloon. Just give it a little bit of air to make it less like a wet noodle and easier to handle.
With your new tube within reach, use one hand to lift up the wheel so the axles clear the drop outs and use the other hand to pull the old tube out (or you could just cut it out to make this step simpler). Now, while the wheel is still up in the air and axles are clear of the dropouts, grab the new tube and squeeze it between the axle and the frame with enough room to clear so that it won’t get pinched when you let the motor down. Now slowly lower the motor back into the dropouts. If the axle flats don’t quite align, use a 10mm or adjustable wrench to rock the axle back and forth a bit until it slides down into the dropouts.
Now work the new tube into the tire, inserting the new valve stem through the rim. Reseat the tire bead in the rim and slowly inflate the tire to the proper PSI, checking that the bead is seating evenly all around the wheel on both sides.
If your motor wire had an in-line connector, you can disconnect the hub motor wheel entirely and do all of these steps either on the ground or work bench, which will make it easier and more comfortable.
Assuming everything looks good, meaning your wheel aligns nicely and the tire is properly seated, close the axle nuts and your brakes. If everything went back just as you had it, your brakes should still be aligned just how they were before you started. If your brakes are now rubbing, check to make sure the axle is seated all the way down on both sides.
Once you’ve got everything closed and set perfectly, flip the bike back over and you’re ready to get back out on the road! And if you want to try to avoid getting a flat tire next time, check out my article on tips to never get a flat tire again!
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