Originally Posted by
candan
Well, given the bike I tested today, at least the friction is not normal and makes my rear wheel stop more quickly than the one in the store. I don’t think it’s because of the attachment of wheel, because it turns in balance. Am I wrong?
Was the bike in the store equipped with internal hub too? A wheel with internal hub will stop sooner than one without, but should still execute many turns once it is put in motion.
You have the option of taking the rear wheel off and testing its rotation around the axle in isolation from the rest of the bike. The process of wheel removal is cumbersome on Brompton and there is plenty of room for messing things up, particularly when putting the wheel back on. There are videos that show the process such as
. This should tell you unambigously whether the problem is inside the hub or not.
As you have a store nearby that carries Bromptons, since you went there to check another Brompton, can't you take your bike there for an examination? A mechanic with experience in Bromptons will tell you right away whether there is anything wrong there or not. Room for an error in diagnosis is only there if you go to a mechanic who mostly encounters bikes with internal gears that are complete clunkers and qualifies Brompton as such and decides that the problem is within the tolerance range expected for such bikes. My tendency would be trust the mechanic much more than yourself with the only option for reverse being of the mechanic having limited experience with internal gears.