I actually did two VO2 max tests, One on the bike and one on the run this year. I am a decently experienced runner and have just started cycling less than a year ago. My scores were wildly different.

69 on the run
56-ish on the bike

I am interested in testing again next year with a lot more miles in the saddle. I always find the tests to be helpful on how to focus training for the next 6-12 months.