My two main commuter bikes, the Main Commuter and the Winter Beater which doubles as a summer backup, are mountain bikes. I have been thinking lately that I might like to try the more upright riding position. Among the several option on the table for reworking my bike "stable" are some that would involve converting the Winter Beater to have a more upright riding position.

Someone has suggested that the mountain bike geometry is better for winter riding because the bent-over position allows for more force on the pedals, and the more even distribution of weight makes better handling. Has anyone found this to be true? My own riding is rather limited, just six miles to and from work, so I don't have a lot of personal experience with different bicycles and extreme conditions.

Thank you.