Felt aluminum frame bottom bracket woes

[FrankNBrew]

I picked up a new Felt 1909 a couple weeks back and decided to upgrade to a 3 piece crank with sealed bottom bracket. After driving in the bearing cups with a dead blow hammer the axle was very difficult to install. I had to use the dead blow, and whack the axle quite a bit. After installing the cranks I noticed they didn't spin very well. In fact, they were terrible. So I took everything apart and realized the right side of the bottom bracket on the frame is not totally round. I'm not sure of I should try something to fix the bottom brakcet on the frame, or grind off a bit from the bearing cups so it doesn't collapse as I drive it in. Any thoughts on the best way to deal with this?

Is it normal for the axle to slide right in with the bearings in hand, but be tight and require pounding once installed in the frame? I'm wondering if I shoudl use a cylinder hone to open up the bottom bracket a bit, but I would hate to ruin the frame.

 

[user 26234]

Is it normal for the axle to slide right in with the bearings in hand, but be tight and require pounding once installed in the frame?

In my experience of that style bb - which is from bmx bikes - yes, annoyingly normal.

I had a few frames that needed 'fettling' in order for the cups to install properly. Being bmx frames they were steel so could take a bit of a pounding, either to reshape the shell or to just get the cups in and run the bb in the hope it eased up with use.

I think the alloy cups were seen as a way to allow for sloppy tolerances, which is possibly why that style bb is pretty common in low end bikes.

I'd suspect the r/h side of the bb shell has maybe just taken a bump with no cup/bearings fitted and is now a bit egg shaped? Tap it out from inside the shell or squeeze the shell in the opposite direction if you know what I mean? It's probably not mishapen by enough that you're gonna have to do any massive reshaping of the alloy?

 

[FrankNBrew]

I ended up using a cylinder hone. I would hone for about 2 minutes, clean the bore and pound the bearings in. It took about a total of 15 minutes honing to get the bottom bracket pretty close to perfectly round, and for the bearing housings to go in with what felt like the right amount of effort, and for the cranks to turn properly.

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[OneHorsePower]

well played! nice ride!

 

[LukeTheJoker]

I ended up using a cylinder hone. I would hone for about 2 minutes, clean the bore and pound the bearings in. It took about a total of 15 minutes honing to get the bottom bracket pretty close to perfectly round, and for the bearing housings to go in with what felt like the right amount of effort, and for the cranks to turn properly.

Sent from my iPhone using Tapatalk

Nice work!