i have a really nice frame.  unfortunately, this past winter, I had a bottom bracket cup fail.  in failing, it just went ahead and toasted the threading in the frame at the same time.  tres bon.  you've all heard the joke about the $599 power amplifier that fries itself to save a $1.39 fuse?  same deal.  the frame is a very nice quattro assi.  and other than the fact that I cannot ride it because i cannot put a crank into it, i'm really happy with the frame.  so what to do?  i frankly regarded the issue as hopeless but was unwilling to part with the frame.  others were notably more optimistic.  principally, i offer a compliment to dr. tim barry who was gracious enough to point me to reviews, possible vendors and offer a small amount of email banter about the likelihood of this working.  i still was not entirely convinced.  i sought out the best mechanical advice i could find. 

deep within the bowels of the racing union commend bunker, well below the plaza de la revolucion, and far outside of any sort of deep-bunker-busting-tactical-weaponery range, i put the revolution's finest minds, the brain trust and science team, to work.  we drydocked the frame and a thorough evaluation was conducted using the most advanced methods. 

in order to fix this, we elected to use a yst bb993 68 x 113 threadless. 

we picked it up fairly cheap from bike tools etc.  it's a full 100 grams heavier than an ultegra octalink bottom bracket, so those of you who are allergic to excess grams will get the hives.  but honestly, at this point where my frame hangs inert on the wall, weight is hardly the issue is it?

in this picture, the bottom bracket is actually reversed.  the threading should go on the left side, but it gives you the gestalt.  the basic approach here is that if you have toasted the threads in the bottom bracket shell on the frame, this will still work. the cups have no external threads so they just slide right in.  for those of you who are curious, you do not need to mill out the threads to get the cups to go in.  they do not need to be pushed or clamped or pressed.  the bottom bracket will be held in place by the tension you produce by screwing the two halves together.

installation is a snap.  the two pieces just slide in.  i elected to use a little bit of the green phil wood grease on the internal threads

you can use a standard shimano bb tool to install it. 

two technical notes.  one thing to note is that if you really plan to tension this thing, you might need two bottom bracket tools.  remember that usually, one side of the bottom bracket seats itself into the frame so you only need to tension one side.  with this product, that's not the case.  the cups can spin in the frame under sufficient torque durign installation.  it does nto appear that this would happen during normal operaiton as the spindle spis free int he housing which is in the frame. 

an altogether more subtle issue is one of installation torque.  you work on bikes for a while and you sort of develop a feel for how much torque something requires.  aluminum on aluminum, steel on aluminum, steel on steel, etc.  this one is tricky.  you don't get quite the same feedback you expect.  knowing you want the bottom bracket to be rock solid, a natural inclination is to really torque this thing down, but you're unsure how strong the threads are.

and this leads us to the ineviable mcgyver moment.  the bottom bracket is not designed the way others are.  i have been trying to figure out how to describe this, and i can't think of a really clear way so i'll just go with what i've got.  the borttom bracket has two pieces: the right side shell and spindle with attached cup and the left side cup which threads onto the shell.  here's the catch.  it's not the case that the right side (shell and spindle) is firmly attached to the cup.  they are attached, and they won't come apart, but if you hold the cup, you can actually move the spindle and shell laterally and foreward and backward.  the only way to remove the play in the spindle/shell is to properly tension the cups.

you may ask why this is an issue and why i'm going on and on about it.  after installing the bottom bracket (effortless and easy by the way) i realized that at the maximum level of torque that i was willing to put into the bottom bracket, it did not take the lateral or fore/aft play out of the spindle and shell.  i checked the installation again and everything looked good.  i needed the shells to be bit closer to take the play out of the spindle.  and so here's the rub.  generally, you get a bottom bracket based on the spindle width, but in this particular case, it appears that the product shoudl be ordered based on the dimenensions of the bottom bracket shell of the frame.

i tried the inevitable mcgyver.  i used a dremel to ever so slightly reduce the outer diameter of a 1" spacer for a headset to try to make a spacer to take up the slack (i.e. help fill the space so that the spindle and bb body shell would be isolated and positioned).  this was more of an attempt to see if i could get the thing working than to come up with a long term solution. 

as an aside to people who are inclined to these types of operations, you'll find that dremels and light aluminum spacers are a bad idea.  the things heat up like mad when you are grinding them down and i suspect the material is becoming exceedingly brittle as a result of "heat treatment".  i had two of them crack.  ironicaly, this was helpful.  i ground down the ends, twisted them and used them like a locking washer up inside the cups of the bottom bracket.

it's entirely possible that the bb shell size is a bit too large for my frame and obtaining a smaller size (109.5 or even less) would work.  i have sort of looked into this option.  you can probably tell from my description that this device only works if you can get it tightened just the right amount.  it looks as if one threading revolution is good for about 1 - 1.5mm.  in my frame, I could turn the left side (tensioning) cup 3.5 revolutions.  when i put the thing together ouside the bike, it takes 4.5 - 4.75 revolutions before the thing is tight.  hnce the spacer idea.  another option is to ream the frame and try to reduce the frame bb shell width or bore out part of the frame to allow the wedge shaped cups to enter the frame slightly farther.

I'll continue today with a search for a washer that is the correct size.  my son and I are headed to home depot for chicken wire to use as a base in fabricating a paper mache nascar body shell for one of his (almost) life size cars.  we'll look for a suitable washer and report back later. 

- - - posted by scott