Danclark

I bought a cheap fixie as my foray into the fg world - have since upgraded to a build of my own. Was taking apart the old bike, and just took out the bb. How bad a condition is this? Is that rust typical? Just asking out of curiosity....

JohnDThompson 

Rust isn't unusual. Are the bearings smooth? If so, ride on.

alcjphil

If the spindle still turns smoothly, the outside condition of the bb cartridge isn't important. If you are er installing it, clean it off as best you can and smear it with a covering of grease to protect it.

HillRider

That rust is superficial and as long as the spindle turns smoothly it is not important. What is more of an issue is how water got into the frame to cause the rust and has it damaged the frame itself. Be sure there is a drain hole in the bottom bracket shell and inspect the frame for internal rust. If the frame is still sound, a thorough Weigel Frame Saver or Amsoil HDMP treatment is a good idea.

Danclark

Thanks, I think that frame will be consigned to the shed for a while, or maybe tidied up and given away. It seems to be in otherwise fine condition. I only paid $50 for the complete bike, so I reckon I did pretty well out of it.

HillRider

As the saying goes; "rust never sleeps". If you ever plan to use that frame you really should be sure the interior is cleaned of rust and sealed.

Danclark

Sounds like a worthy project...

Danclark

So ive checked out the frame and the bb shell hasn't been drilled. I'm guessing that's only the start of the issue? Is this likely to be a headache not worth beginning?

trailangel

I've never had a bike that had an open hole drilled in the bottom bracket, or even came with a hole in the bb from factory.
I guess I now need to get the drill out and drill all my frames. What is the best sized hole?

SparkPlug

I wouldn't be certain about 'start of the issue' or drilling the crank. Perhaps think about hoe the water got in there in the first place. In my mind you have just two possible sources. Through the seat post or through the 'cups'. I'm used to cups but given this is a sealed unit they no longer are and off the top of my head I cannot think of the correct term. I suppose the headset might qualify as a possible.

Looking at your picture the major corrosion is on the threads which kind of implies that is where the water has, over time, got in and then it might have filmed over the centre section of the unit. Check inside your bottom bracket to see how far the corrosion extends. If it is by and large restricted to the threads then that would suggest the ingress has been via the cups.

Given you have the assembly out of the way then there is of course the opportunity to spray some gunk up the tubes. Otherwise as suggested clean up the threads as best you can both on the 'cups' and the bottom bracket. Perhaps one of those green kitchen scourers or wire wool with some Autosol metal polish. Paint some Kurust on the sets of threads and then reinsert the cups with a coating of Autosol and screw them in and out until they are moving freely and then clean the gunk out.

On final reassembly, and others might differ, use Copper Loaded grease to lubricate and prevent subsequent ingress of water. As I suggest it looks very much like that is where the water has got in. Either the original grease went past its live by date or someone forgot to put it in in the first place. Beyond that, and perhaps something else, the only remaining concern might be that having removed the rust the threads might not be as close fitting as they were originally. Again the grease will help in that respect.

HillRider

I've never had a bike that didn't have a drain hole in the bb shell right from the factory. Most newer bikes have two holes, one threaded for the cable guide and the other as a drain hole. I think a 1/8" hole would be adequate if your shell doesn't have one.

I think it's unlikely the water go in through the bb cups. More likely it ran down the seatpost.

trailangel

I have a 2013 Jamis Coda.... no hole.
I better to take it back and have the hole put in it.

Danclark

This is fantastic, thanks. I'm guessing the bike has never been too well maintained, given the price and the dude I bought it off...I'll follow your steps, and see how I go...


this forum is f&@$ing great

Danclark

Wait, if it's the seat post, does that just mean it wasn't regulalry greased? Or are there other steps that need to be taken?

fietsbob

Just take the seat post out and grease it and put it back in, see The dozens of stuck seatpost treads for the Why..

cyccommute 

I'd say just the opposite. I don't know that I've ever owned a bike that had a drain hole in the bottom bracket.

I'd agree. Another source of water could be water bottle cages, however. Especially if the cage braze-ons don't have bolts in them.

Bandrada

I've seen a few bikes with drain holes. I don't think it's common practice though, since it's more likely to introduce water and dirt that drain it. I certainly would not go drilling holes in the bottom bracket, either. If water is being introduced, it's likely through the frame tubes, and with regular use should exit in the same manner. It never hurts to inspect the bottom bracket after a wet ride, BTW. I found that out the hard way just recently.

Bandrada

Mostly this just applies to steel. I do apply a liberal amount of grease to the insertion on some aluminum frames if it's a little stubborn. Otherwise, it's not that necessary.

trailangel

"Hole in the BB" must be an east coast thing, huh?
I was stopping riders on the street yesterday, asking them if they had a hole in their BB,
I almost got a black eye....