Well, truth to tell he's no longer a boy, and his riding is in a whole different area to my audaxing. Essentially he's a swimmer who has taken up Triathlon. In his local (Scottish central belt) events he is regularly in top 5 out of the water, despite a rather ancient wetsuit. He's working on his running but it's never going to be really great. His worst leg (in terms of split position) is the bike where he's down around 20th or 30th position. That's still not bad, especially as he's regularly beating guys with pointy hats & multi-thousand pound machines, and he's on a second hand Carrera aluminium 'road bike' that cost about £120 on fleabay about 7 years ago, has rack & mudguard mounts..... But realistically - he's not going to improve a great deal without a dedicated TT bike. I'm pointing him at things like second hand PX Stealth which often come up for sale within his budget, and he's wondering how much time he might save with a machine like that over a 20km course. (usually slightly rolling where he is) Obviously no simple answer to that one - but I'm wondering if anyone has an idea of the watts that might be gained with a half-decent aero bike, over a very low-rent roadbike ?