I have the single but we are about to purchase a double. The City Mini Double and the B Agile double both fit through standard doorways.
We LOVE our city mini single, but decided to go with the B Agile double because it doesn't have the bar across the bottom between the two back wheels. DH and I both tend to kick the bar on our City Mini (would be my only "complaint" about the stroller, if you can call it a complaint).
Married 08/18/07 BFP 02/15/11 EDD 10/27/11 Born at 35w3d on 09/25/11 BFP 10/13/12 EDD 06/25/13 Born at 37w0d on 06/04/13
I have it and it fits through my narrow doorway just fine! In fact, one of the reasons I got it (besides having the single and loving it) was that I saw a mom at Hobby Lobby fit through the doorway with her double. Neither my husband nor myself have ever had trouble kicking the bar in the back. HTH!
We've never had a problem fitting it through doorways. The only thing you need to watch out for is pinched fingers. Sometimes DS puts his hands out to touch the door as we are going through and he has gotten his fingers pinched once of twice. He learned pretty quickly not to do it.
Re: Baby Jogger City Mini Double
I have the single but we are about to purchase a double. The City Mini Double and the B Agile double both fit through standard doorways.
We LOVE our city mini single, but decided to go with the B Agile double because it doesn't have the bar across the bottom between the two back wheels. DH and I both tend to kick the bar on our City Mini (would be my only "complaint" about the stroller, if you can call it a complaint).
Married 08/18/07
BFP 02/15/11 EDD 10/27/11 Born at 35w3d on 09/25/11
BFP 10/13/12 EDD 06/25/13 Born at 37w0d on 06/04/13
BFP 12/11/15 EDD 08/23/16 Early miscarriage
BFP 02/02/16 EDD 10/16/16

I have the City Mini double (have had it for two years now) and fit through every door. Never an issue!
Here is the stroller in my house, in my standard doorway
Sorry it is sideways.
Emily 8.8.08
Madeline 1.2.11
William 8.5.12