Originally Posted by DirtJack
The rear mount of the guide has an offset which should be flipped for rear sprockets bigger than 45. Just loosen the rear bolt and press out the offset nut on the rear and flip it 180 degrees.
Beat me too it
It was done before I bought the bike with 73 miles on the clock
It still rides great on the pavement. Slightly buzzier than the stock gearing, but I can still sit at 65+ all day and still feel my fingers after 150 miles. Where this gearing really shines is on tight trails - where my 520 really stood out, I can now ride my 690 with loads of confidence. I also have the Leo handlebar switch, which really enables this gearing to suit my riding style perfectly.
I rode some nasty single track last weekend on the 690, and was able to ride the same trail on my 250 smoker for comparison. I gotta say the I enjoyed both bikes for different reasons - but found them both very capable. The only hinderance I had was the weight of the 690 over the 250. Both bikes were great tractors