If you don't have mudguards, it becomes much easier to put bikes in a small car.
I have mudguards on all my bikes but never had any issues putting them in my Peugeot 205 with the front wheel removed. Even my Pashley Royal Mail bike goes in.
Ironically, it is harder to put bikes in the Skoda Fabia and now Toyota Yaris that have replaced my 205 despite them being much bigger on the outside but apparently it's called progress.