I just bought a Cateye Adventure mainly for the altimeter. After it was installed, it showed an altimeter reading of 220 feet even though it should have read 345 feet (my house elevation). I corrected it. Next day I took it to the mountains above 5,000 feet, and it still showed a reading of 345 feet. Shouldn't the altimeter showed an altitude of 5,000 feet? When I started to ride, it correctly showed an increase in altitude from the 345 foot mark. At the end of my 1,000-foot climb ride, I corrected the Cateye to 5,000 feet. When I returned home, it still showed an altitude of 5,000 feet.
I took it back to the store, and they exchanged it. But the new unit did not show any change in elevation from the store to my house, which there is a difference of at least 200 feet or more.