Originally Posted by
chagzuki
I don't think there's any appreciable flex in the m bars, the flex comes from the ancient stem design where you have a 1 inch tube exiting the steerer at the point of maximum stress. I did a lot of experimentation on this and realized there's very little that can be done to reduce flex except using a configuration that involves lowering the handlebars. Incidently, most riser bars are for downhill use and are heavy and the S stem is around 80g heavier than the M stem, so over all the configuration is heavier.
I beg to differ on this one. As Fietsbob mentions there is a reason someone sells a clamp to stiffen up the M bar. There is no way that the small internal diameter aluminum bar on the Brompton doesn't have flex compared to my Tioga. I do agree there is flex in the stem but that is what you can expect within the confines of the design. As for the weight difference, have you picked up your Brompton lately? They aren't light weight to begin with so 80 grams heavier is nothing. If I was concerned about weight I wouldn't have bought the Brooks saddle, or the fenders, or the 3 speed or the Brompton tires. In fact if I was so concerned with weight, I wouldn't have bought a Brompton in the first place.