You borrow a floor pump, push the head onto the valve and hear air escaping. Before tightening everything harder, check whether the head is configured for the valve on your wheel. The wrong fit can turn a routine inflation into a damaged valve.
A slender Presta valve has a small threaded tip; a Schrader valve resembles the wider type commonly found on cars. Other designs also exist. Trek’s pump range identifies compatibility as a product feature, so read the actual pump instructions rather than relying on its appearance.
Prepare both sides of the connection
Support the bicycle securely. Remove the valve cap and follow the valve’s instructions; a Presta tip normally needs to be loosened before inflation. Then set the pump head or appropriate adapter as its maker directs. Some heads adjust automatically, while others require a different opening or internal arrangement.
Keep the connector straight and avoid levering a narrow valve sideways. If the seal will not form, stop and recheck the setup. Extra force is not a substitute for compatibility.
Choose pressure from the whole wheel setup
Check the tyre and rim guidance, including any lower limit imposed by a component. Do not treat the maximum number printed on a tyre as a universal target. Rider load, tyre size and the system’s requirements matter; ask a qualified bicycle shop when uncertain.
Use a suitable gauge and make changes gradually. After disconnecting, inspect the valve and replace the cap as appropriate. If pressure falls quickly, investigate the cause instead of repeatedly adding air and assuming the pump is at fault.
A useful note for a shared household pump is simply which valve types it supports and how its head changes between them. Keep the maker’s instructions nearby. The next rider should be able to make the correct connection without experimenting on the wheel.