Seems like 44/32/22 chainrings are standard on modern mountain bikes which equates to about a top speed of 25-30mph. I want to be able go go faster on the road sections of my routes. Is it just a case of changing the outer ring to 46 teeth on my Shimano Deore or is there another way to increase maximum speed?
You could also look at the rear cassette and see if you could replace the smallest cogs you are using with anything smaller, that would have a similiar effect, or look at a combination of the 2, slightly increasing the front chainring size whilst slightly reducing the rear cassettes smallest sprocket.
Perhaps a browse through Sheldon Brownes site may give you a better insight into your gearing options.