Tonight, I'll again will bump over some rough roads - on my Specialized comp road bike - I will check out slack when in other gear then usual. Bigger front/bigger cassette wheel; gosh I don't know what number of teeth... I usually try to maintain a straight chain and use the middle front ring and the second/third tiniest back "wheel". I can use the biggest front wheel; but usually this brings the leg motion more down than I want. I like to ride with a cadense of 80+. Well anyway, appreciate any reaction. It's getting colder again over here in Holland; so I have to keep a high cadense to stay warm!