구어체잖아..... In formal, as a korean, I would rather say "나는 여름에 자전거를 타는 것을 좋아합니다." It's a [안긴문장]. ->나는(S+조사)+ (여름에 자전거를 타다, 또는 그 행동)를(O+조사)+ (V)좋아(어간)+합니다(어미). "여름에 자전거를 타다" also can be verified? as 여름에(부사)+(내가)(S+조사)+자전거를(O+조사)+타다(V) And then It became an some soft of act by removing 다 in 타다 and adding 는 것.
Different interpretation of "것"
V(으)ㄹ•것 = the prospect (expected action) of V-ing
V는•것 = the act (actual action) of V-ing or simply, V-ing
V(으)ㄴ•것 = the fact (complete action) of having V-ed.
"나는 여름에 자전거 탈 것을 좋아합니다." could be interpreted as I like the prospect of riding a bicycle in summer or I like to get to ride(/to be able to ride) a bicycle in summer
"나는 여름에 자전거 타는 것을 좋아합니다.", I like the act of riding a bicycle in summer or simply, I like riding a bicycle in summer
Note: Use bicycles, if speaking generically / a bicycle, if wished to be specific.