Originally Posted by
seedsbelize
I installed my second set of press fit headset races. The bottom one went right in, but the top took some effort. It didn't want to go in straight, and it didn't want to go in all the way. My question is this. If that cup was somehow too big for the head tube, would I have the strength to bulge the head tube by trying to force it in? I was using a home made headset press.
You may have been installing 30.2 mm headset cups into a frame whose head tube is sized for 30.0 mm (JIS) headset cups. Sometimes they'll go in without TOO much of a fight. If I remember correctly, Sheldon Brown's page even says it's OK to put 'em in despite the mismatch. But it's been my experience that they can put of a heck of a fight, and I wouldn't be surprised if people have damaged headsets and frames trying to make 'em fit.
I learned about the 30.2/30.0 sizing difference when installing a headset on my daughter's Fuji SJ-10. Those cups were a #$%& to get in and get straight. Luckily, I don't seem to have permanently damaged anything. Here's hoping that new headset lasts longer than I do.