Trying to get a little more info on this - can someone tell me if the bolt takes a 3mm or 4mm hexallen key? Don't want it if it's 3mm, likelihood of it stripping seems higher. Thanks.
I find that this compressor/expander plug opens more fine tuning/adjustment possibilities when setting up a headset. This is the only kind of top cap assy. I use on my racing bikes. in my opinion, this kind of part makes the star-nut design obsolete.