Buzzkill53120

It was suggested as far back as July to use oversized bearings, and yet you still want to kludge it with shims and/or duct tape?

Iride01 

Why oversized bearings? Why do anything other than replace the entire bottom bracket? Am I missing something? If this is a shell for press in BB's then what's different that you wouldn't replace? I've no experience with press in BB's so if there is another consideration let me know.

BB's are very inexpensive unless you want ceramic.

I guess if you know well the phrase "if they don't find you handsome, they should at least find you handy" might explain some. (Talking mindset... not country).

Psimet2001 

I sense and agree with your frustration. The fact that this thread is sticking around is kind of annoying as well because I never felt the need to actually read every post and detail. I am afraid if I do I will simply create a pile of responses to old posts. I feel like those responses will become increasingly emphatic and near desperate in my appeals for some common sense.

As for the oversized - that BB standard is used by Trek. Trek has just done a horrible job of manufacturing their BB shells on their frames to the point that use will compress an distort their layup to the point that it can no longer retain a press in bearing designed for it. Instead of just recalling the piles and piles of frames they came up with having the standard bearing made slightly larger so that it would press in to those blown out shells the same way a regular bearing would into a normal shell. In other words it was a "better" solution for Trek to just make a new bearing that works in their frames once they're actually used than it was to fix the BB cup layup or design issue. Also they have now started to move to T47 BB's (threaded) as a more permanent solution for frames in the future.

Iride01 

Thanks for the details. That helps me understand much more.

Then I'd tell the OP to get a sledge hammer and charge a dollar a blow to others to use it on the bike. Then use that money to help with getting a new bike.

danallen

I feel sorry for you.

I removed the mangled inner race and generally cleaned up the bearing cup built into the frame. I put new bearings on both side of the bottom bracket.

The side where the bearing was blown out is a little loose and not 100% round. To the best of my knowledge, oversize bearings are available for purchase by people who are not running bike shops. However, there might be ways of working with a non-round bearing seat in the frame which are held exclusively within bike shops for all I know. You must never never reveal that information if it exists and is known to you.

I can envision this situation resulting in the frame being a total loss. There is a benefit of incurring this risk. The benefit is personal, and not relevant to everyone. It's like that quote about riding a bicycle being the best way to see a country. Riding and seeing an area is only part of it. Taking care of the bike with my own hands contributes to a transcendent, spiritual experience with the bicycle.

The ultimate cost of this repair might exceed the cost of leaving the bike in a shop where it would be repaired. The likelihood of that is less than 100%.

Your customers must respect you. One of the things I most highly value when I go into a bike shop, or any business, is being insulted. It would be selfish of me to consume more insults than I absolutely need.

To conserve the insults for others who need ridicule, I never return to businesses of any kind where insults are available free or at a small cost. I cannot remember when I last found one of those precious places that verbally kick my nads, but the way I explained it at the time was something like, "I would not bring my bike to your shop if it was the last shop on Earth." That is is an exaggeration, but, on the other hand, there are other bike shops as well.

Please don't worry, that business consultation was free of charge.

znomit

I don’t think the feelings are mutual.

danallen

Hi, I really appreciate the way you laid out the road on this. That is really helpful.

Shoot, I just re-read the measurements you mentioned regarding interference. I just checked the thickness of my duct tape. This is not regular thickness, it is a little thinner. Depending how hard I squeeze the calipers, it measures from .12mm-.16mm. When the duct tape was wrapped all the way around the bearing, it would the bearing would not go in without pushing the tape off. With no tape on the bearing, it was easy to slide into the frame, and would move slightly up and down with pressure from fingers. I just grabbed the cranks and applied torque perpendicular to the torque of peddling (i.e., I applied torque to in and out with respect to the line made by the direction of bicycle travel when riding). There is a very small but non-zero amount of play. I removed the crank arm and found the tape is gone.

The problem with the bearings is there was no seal, they had no lube, and I kept riding. Then the bearing died. I have been guessing the damage to the frame was caused by the bearings blowing up, might have happened in matter of seconds. When the bearing died, I had almost no understanding of how the bottom bracket goes to together on this bike. I had read about it, and seen the dry bearing, but I really did not grasp it in a detailed enough way to know what was going on. When I discovered the dry bearing (timeline below) the fit was still good. All the damage came after that.

The aspect of this I am most concerned about is the bearing seat in the frame on the left side is not perfectly round. When the regular bearing goes in, there is no interference at all.

Sequence of events.

1. I bought a bike on ebay about two years ago.
2. A few months ago, the crank was not turning as freely as I thought it should. I thought the problem was dirt between the crank and bottom bracket. I removed the crank arm. This led to a first for me. It was the first time I saw the a bearing cartridge in a bottom bracket. I could see the bearing was dry and dirty. I could feel some grit when turning the bearing. I figured that bearing needed replacement.
3. A few weeks later, the bearing blew out while I was on a ride. When I got home, I took the crank arm off and saw the demolished scene. I posted pictures of that.
4. I got a new set of bearings. One the right side, the bearing fits tightly. On the left side, it is slightly loose, where the bearing moves up and down and very small amount. It does not move from side to side (toward the front or back of the bike). I was am unable to recall which geometry theorems to apply, but with some research, i was able to determine that the movement of the bearing in its seat within the frame being on one axis only, the seat must be in a shape that is not 100% round.

danallen

The next time I am born, I will be sure to have preordered all the knowledge needed for everything I want to try. In this life I am stuck being r3tar-ded . Beats your situation.

danallen

I don't understand what you mean. When you say replace the whole bottom bracket, I envision you are talking about something that looks something like one of these. These are bottom brackets


Are you suggesting I replace my bottom bracket with a replacement that is like one of these items in the picture above, except one that fits my bike?




I am assuming you don't mean that, because here is a picture of replacement bb90:

You understood all that, right? And you understand these bearings are installed into the frame? And that my frame is damaged in the spot where one of these bearings goes into the frame? And this is different than how the bottom brackets in the first picture go together, because in the first picture, the bearings go into a bottom bracket shell, but bb90 bottom bracket does not have a shell, it is built into the bike? So one of the things people do to deal with this type of BB is use oversized bearings in cases, like mine, where the frame is damaged in the spot where the bearings go?

And I have been using this thread to learn how this type of bb goes together?

OK, and I just reread your post. I think you were making an assumption that a bb90 has a shell that bearings go into. The shell is built into the frame. That "shell" can be damaged. You cannot install a new one any more than you can install a new set tube. It is built into the frame and the frame can be totalled if the bb is damaged.

danallen

I would have thought your superiority would include a temperament that protects you from being frustrated by the failures of lesser beings.

danallen

How was I to know right off the bat that oversized bearings are not a kludge. I have been experimenting. You have a problem with that?

rubiksoval

This thread and the OP's continued responses is bizarre to the point where it's not even really interesting anymore.

I'd say good luck, OP, but clearly you're more concerned about creating internet drama than working on an actual productive solution.

cb400bill

Thread is circling the toilet bowl. Time to flush.

Thread closed.