How to decide which size is correct?
Is it based on wheel size 406 vs 451?

Excellent gear, guys! I used tern trolley rank, and there was a little problem with transportation, cause hidden bike after you was too wide when you pull it. This gear solve this problem!

This rack is great and has made my bike much easier to transport on my commute to work using public transportation. If you are considering buying this rack, buy it - you won’t regret it. A few notes to tern on areas of improvement; the directions for installing this rack were a mess - ikea directions are more descriptive. Also, the caster wheels work almost too well. I have to hold the bike on the train or it will roll around. Perhaps consider adding a locking mechanism to the wheels to keep it from rolling?