I'm sure if you're reading this, you've most definitely heard of these trick little pieces... and if not, listen up! If you run Profile or any other style of bmx cranks, and are sick of demolishing the thin little euro bearings on your big wheel shredder (and, even worse if you want to run some new 22mm wombolts or fly cranks!), well, this is the solution! The Fly cups are similar in concept to the newer outboard "x-type" bearing now found on mtb's, but these were released by Fly Bikes a number of years ago for the bmx world (which has since switched to Mid or Spanish bb shell straight up abandoning the euro w/out looking back). They are made up of cnc'ed cups that thread into your euro bb shell, but have a larger outer diameter for larger and much stronger press fit Spanish bearings. Very smooth and TRICK set-up! and I should mention, there were only around a dozen originally brought to North America by Fly bikes... including sponsored set-ups... Anyway, take a gander at some rarity here... This set in the first pictures was a lucky score on some of the originally imported used ones, and right now on my SplinterMX. They are so solid and never creak like my old euro bearings! Just hooked'em up with some new Demolition Medial cranks and a profile spindle too (not pictured). These particular ones are 19mm (but 22mm bearings and spacers can easily be swapped by yourself) the older, fairly beat set I have on the Splinter MX: For those of you who care about chainguide compatibility, the drive side fits PERFECT with a TruVativ Box-guide back-plate, but we'll see how it works with an e.13 LG-1 boomerang... But honestly though, this set-up belongs on a dedicated Street/DJ/park bike, since the mtb big wheel world seems to be taking so frickin' long to convert to the Mid or Spanish press fit bb shell, these are the key to properly using the bmx style cranks, esp. 22mm Fly or Wombolt cranks, but are smooth with any 19mm cranks, as how I am running them. With very limited exceptions, you will be hard pressed (haha...) to find an "mtb" frame that doesn't come with a euro shell (like Nemesis/USB/Tonic/Geekhouse/that's just about all I can think of off the top of my head actually, and absolutely NONE on the full-sus. side of things). It's too bad that Mid and Spanish are taking so long to trickle over from BMX, longer than I expected actually. With the much wider external spacing vs. the reg. euro bb cups I was running, they seem WAY stiffer and no doubt much stouter than those paper thin euro bearings (even worse if I were to run a 22mm spindle on some flys if I ever get around to picking some up...) that I was using. As you can see, they do add just about 10mm (9.7mm avg according to my calipers) to the overall width to each side, which is more than the typical 4mm or so that the euro cup extends, but it isn't bad, and you don't have to use the cone spacers, you can run the crank arm butted straight up to the bearing if you wish. just for comparison, here's a pic of a set-up with the WTP dubwide euro 19mm bearing kit currently on my Eastern26: and here's a quick photo of one of the NOS kits I have... might throw one on the Eastern, but not sure yet... the 19mm would work excellent with the WTP royals and ti spindle I have, but I'd like to possibly pick up some of the new fly cranks, in which case I'd have to pop out the 19mm bearings that are in there for some 22mm... sorry for the above pic qualities and rambling write-up, I'm at work, hahaha..., kind of jumbled but I can add more later... Let's hear what you think!