Have just fitted some 20mm bar risers - fantastic increase in comfort and all for a measly £18.50. They are not quite the same shape as the bar clamps which are tapered but they fit well, glad I didn't go for higher as the brake pipe has very little slack now - luckily it doesn't go across the suspension so the length is constant. I have also taken out the little blocks under the seat for better height, can't work out why I didn't do both three years ago when I got the bike.