Nice rest day today which I felt I needed and which has allowed me to catch up on a number of other matters, including getting my Trek serviced ready for the spring, yes, it's now spring! :-)
I've been giving quite a bit of thought in the run up to my Tour de France ride to the weighty issue of body weight with The Alps and The Pyrenees in mind. I decided to do a bit of arithmetic to see just how hard I really need to work to shed a few remaining pounds given that I am not racing anybody and that realistically at the age of 51 I am unlikely to be getting a phone call form any of the pro team directors any time soon ;-)
I decided to take The Tourmalet as a representative climb to do some sums on, just to see what a change of a few kg would in reality make to my experience, given that time really doesn't matter.
Assuming a bike weight of 18lbs if a rider has a body weight of 80kg he or she will climb the 4606' of The Tourmalet in about 83 minutes with an average power output of 240W. If the same rider were to lose 5kg in weight and ride the same bike he or she would ascend the mighty Tourmalet in about 79.65 minutes.
So, lose 5kg of body weight and save say 5 minutes on the climb of The Tourmalet. Now, that 5 minutes matters one heck of a lot if you don't want to lose the Tour de France on that single climb but in a non competitive event when I may well want to stop to take some photos how much would that 5 minutes really matter? To be honest I don't think it matters a great deal.
Now, I don't want anyone thinking that body weight doesn't matter because it does, especially in competition but it does need to be taken in the context of the event one is entering or the challenge on has set oneself. In overall terms being 5kg lighter will make the climbing that little bit quicker, but it won't make it easier because one will always tend to ride to one's ability, you just go up a little quicker if you are lighter. On balance I think for many riders it is important to remain a sensible body weight, to eat well and to remain healthy rather than to try to meet some fantasy body weight.
If we look at a typical (but long by most UK standards) UK climb rather than a Pyreneen giant, lets say the climb of Hartside in the Cumberland Challenge which rises approximately 1500' in total. Our 80kg rider will take about 25.88 minutes to make the climb and our 75kg rider will take about 27.3 minutes, so the lighter rider gains about 1.5 minutes. Only you can decide whether that time gain is worth it for all the hunger and self sacrifice involved but if you aren't actually overweight it's well worth looking at the actual facts and weighing up (pun intended) the actual gains which might be made. My rule of thumb is that Jo Average needs to be able to lose about 7kg to feel or notice much of a difference and if he is already a normal weight he may well lose power in losing that kind of body weight.