Okay.... got my new Quamen G9 in the mail the other day, and started assembly. Clean out the bottom bracket really well and took it to a shop and had them carefully chase the threads to clean out what looked like excessive paint in the shell. The chasing tool went in all the way without any problems. DESPITE ALL THAT, I and other mechanics cannot get the brand new euro cups to thread into the shell, and even though no force was used to try getting them in, it looks like the b.b. shell may have screwed up the threads on the bearing cups. On the drive side, the threads would catch, but once you tried screwing the cup in, it would go in a bit then pop out (and I know we aren't turning the cups the wrong direction!). The left side isn't catching at all and I'm not about to force it.
Please don't tell me I have to go through some warranty b.s. just because the shell was threaded all retarded or something. Would love some feedback from other riders and even Quamen folks about this before I start making phone calls. In the meantime, please stop using euro b.b.'s on frames, BMX companies. Thanks, and f*ck... pfft.

Right-side bearing goes on the left side, left-side bearing goes on the right side. They flipped the BB shell. This way it's highly unlikely that the Euro cups unthread themselves while pedaling.

Source: Former owner of a Delta 2, 3, and 4.

If not, you're f*cked!

I don't think quamen does any "in-house" painting(I may be wrong).  But either way the painter who has been painting these frames should know that there are special gromets, and plugs you can purchase to eliminate these types of issues.  They are not too high in price , and are made of a compound that can be put into gun watching machines for easy clean-up.

I spent hours getting the bearings to thread into my Cyphr due to the same issue I think. What got it to go, finally, was working the threads on the bearings and the bb with a Scotch Brite pad and cleaning the snot out of it until it worked. good luck dude, hope it's not f'd.

So if the thread chaser went in no prob.....how is it the BB isnt going in?  When I was threading mine in I kept moving it slightly crooked until I finally got it squared straight in and pow....spun all the way by hand to the last couple threads.

Those threads are very fine and it's easy to skip the first thread or not align the cups right. Be cautious and take your time. Wrap it with a rag and turn by hand, so you don't hurt yourself and possibly scratch your frame or BB.

They are still using Euro BBs? Seriously?

I'd almost take american over Euro. They break stupid easy, strip out stupid easy, and lock up stupid easy. They're the worst bottom brackets you can use on any frame ever.

With mids and spanish bb's around, not sure why the euro hasn't been phased out of existence yet..

mid is the best.f*ck euro

its not just powder coat, many times its the welder, like the threads need to be redone after the welding, just like a mid, or spanish should be remachined.

i think its mid that should be phased out.. spanish should be the bmx standard to simplify things.  euro though, has the world standard on all the other bikes.  if it was refined in bmx (theres those outboard ones) it can work very well.  its a matter of bmxer's understanding threading direction, instead of the simple caveman hammer.

i miss american "mega" bottom brackets, where i can use some .. "free" 1 peice crank i took off a ten speed in a trash pile.