Please choose the correct ending to complete the given sentence: Cars & Other Vehicles: [header] How to fix a bike tire [title] Use an upright bike stand to elevate the wheel while you work. [step] Alternatively, you can lay the bike on its left side-that is, with the bike chain and rear derailleur facing up. If necessary, you can turn the bike upside down to work on it, but you may damage the handlebars or seat this way.

Ending1: [substeps] If you are not able to stand up on the bike, find a sturdy, elevated location to work. You can safely work the bike into a fixed position without help from friends or family. Ending2: [title] Remove the rear derailleur (with the tire chain) to remove it. [step] The front derailleur is now removed. Ending3: [title] Loosen the nuts on the wheel axle with a wrench. [step] Use silicone spray or even cooking spray if the nuts refuse to loosen with a wrench or ratchet alone. Ending4: [title] Attach one end of the bike chain to the lower half of the wheel. [step] Cross the other end of the chain over the wheel, and tighten it or else the bike will not work properly.

Answer format: ending1/ending2/ending3/ending4