The muscle structure of an obese person is invisible, and varies massively. One 300 lb man (for example) can have little muscle mass, yet another 300 lb man be hiding a body builder's physique underneath. If one never uses stairs, and another climbs stairs 100 times a day for a living then you have two 300 lb guys, one of whom can pedal far harder than the other.

The variation between 300 lb people is.. massive. So the whole subject is pretty much irrelevant to the O.Ps question, as i see it.

Looks to me as though the question is whether carrying additional weight on the body or the bike is preferable. That reflects the luggage argument (rucksack or pannier) though i think this is different. I've been the same weight for nearly 40yrs, and the same build since i was 10yo, i've never been obese so i don't know the difference between carrying or not, or whether you get used to it, etc. But i can still bet that almost everyone will get on better with a lighter bike. Perhaps though, a few hundred grams will make less of a difference to someone weighing 300 lbs than someone weighing 100 lbs.

It's not irrelevant, it just shows that the original question cannot be answered unless we know where the weight taken off the rider is coming from.


Having ridden when I was obese (I'm normal weight now), I can tell you that pretty much every factor goes against speed--aero, cardio/pulmonary, riding posture, tendencies towards mechanical breakdowns, you name it. Marginal differences in the weight of the bicycle would have been about the last thing I noticed.

I'm 5'10. At the time, I was very lean. I'd say of the different disciplines of bike racing, XC requires the most upper body strength. That's not to say you should bulk up, but don't neglect your upper body (chest, shoulders, and even upper arms). Stay lean and strong. Good luck to you, whatever your goals may be.

Thanks, like I say, I don't race, but I do like to ride fast.

Good luck to you as well.

BTW, great example of the importance of genetics--I'm about an inch shorter than you, but with my frame, if I went down to 148-153 lbs., I would have to have almost no muscle on me at all.

Look at it this way. Your legs dont know if they are hauling 5 pounds of fat or 5 pounds of bike weight up a hill. There was some mention of the only difference would be in wheel weight. Heavier wheels accelerate slower.

Ah! You got me! There is some non-zero but inconsequential increase to rolling resistance (tires and bearings) that will likely occur with a weight increase.