Originally Posted by
chagzuki
According to the official website Terns are heavy.
I've found flex to be a major problem with the Brompton and, indeed, it's frustrated me greatly. In a way it's ludicrous as most of the stem is thick steel tubing with zero flex (way stiffer than aluminium varieties) but it attaches to the steerer via a puny 1" wedge insert which totally defeats the purpose of the upper section being so beefy. This is just crap design, but it almost works, i.e. for certain riding styles and particularly for the S model the flex is within tolerable limits. I've managed to improve matters slightly by installing a better headset and inserting the stem all the way down contrary to the advice of the manual. Having it buttressed against the headset nut improves rigidity a little, hopefully it won't cause any problems.
How thick is thick steel tubing? did you measure the walls? I did not but I cut the stem to modify the bike and was suprised how thin the walls are. Before that I expected it to be thick walls it the steerer tube by the way it looked.
If the M flex too much for you but the S is better maybe the main problem is the M bars??