Okay, here's something from a cognitive perspective. Please be advised that this is outside of my field of specialisation and it's only one aspect influencing memory.
Memory and Cognitive Schemata
Most people that use the internet often have cognitive schemata about domain names. This means they have expectations about how domain names look and will use that information to aid (memory) performance. As most (commercial) websites use either a dot com or country code TLD (.nl; .co.uk; .de; and so on) or both, domain names using such a familiar TLD are often easier to remember, as it does not require some piece of unfamiliar information.
So "cyclingnews.com" is easier to remember than "cyclingnews.bike", as you have to specifically store the ".bike" piece of information in the latter case, while in the former case you can rely on the "normal domain name"-schema to fill in the usual TLD. While bike is semantically related to both the name "cyclingnews" and the website's content, making successful memory retrieval more likely, I think it's likely that at least some potential visitors would get it wrong if they are a bit fuzzy on the details.
If you're considering a .bike TLD because the .com-equivalent is taken, then I predict that at least some visitors will end up on the wrong website (i.e., the .com website instead of your .bike website).
So, I would recommend to either register the domain name with both TLD (i.e., .bike and .com) or to go for a dot com only domain name.
(In the Open-Source Software community, a lot of websites use "dot org" domain names. With some exceptions, I usually get it wrong the first time by defaulting to "dot com" and end up on some ad site, as ad companies know people make that mistake often.)