Hello Gurus:

Please view the videos in the links below and let me know:

1. What are the possible reasons for the play in my bottom bracket?
2. What do I need to purchase to replace anything inside the bottom bracket and restore it to proper working condition?

I have a crank puller and other tools to open the bottom bracket, but I'm not sure what parts I need from inside.

Video Link 1
https://drive.google.com/file/d/1cxS...usp=drive_link
Video Link 2
https://drive.google.com/file/d/1jFT...usp=drive_link

Thank you for your time and help. 🙏

First off, your fixed cup is no longer fully seated. My bet is that you need to fully replace the whole bottom bracket. I will presume that the spindle has probably been damaged and that the bearing balls are also beyond repair. A new cartridge bottom bracket with the correct length spindle is the obvious choice for replacement

Presuming your cups & spindle are OK, it'll take ELEVEN 1/4" balls/side for a total of 22.
I don't think you'll be that lucky since it's obviously been ran too loose for too long.

The spindle should have a "code" on it like 3-P, 3-S or similar.
Scroll down a bit to see this chart to pic a symmetrical equivalent BB.
https://sheldonbrown.com/bbsize.html

I noticed that. The bike was bought used, and it came to me like that. I thought the cup might be cross-threaded as well.

As a quick temporary fix, I'm considering removing the fixed cup, screwing it back in, and seeing how it goes. For a permanent solution, I want to replace the entire bottom bracket.


Do you have any recommendations for a bottom bracket that would fit, if and when I am getting a new bottom bracket? It's a 1990 Schwinn World Sport, FYI.

I think it has a pair of cage bearings, with 9 balls in one and a total of 18 balls overall.

At this point, the horse has already left the barn so there is little reason to do anything other than a permanent solution. You may have to chase the threads of the bottom bracket if the cup is cross threaded. It’s not a difficult job but it is also not one you can probably do at home without a significant amount of expenditure for a bottom bracket threading tool. In other words, you’ll need a bike shop or a bike co-op.

Buy a cartridge bearing unit with the same length of spindle as this bottom bracket has. No need to rebuild this one or get a loose bearing bottom bracket.

If your LBS is out then a cartridge UN300 from Shimano is under $20 from
https://www.performancebike.com/shim...all%20webpages
Just pull your present one out measure the length of the axle and order the closest UN300.

I paid $65 for it used and rode more than 10,000 miles on it. Ha ha.

It rides like a champ, and could go on a 100-mile ride as we speak, despite its current BB condition. I've also recently bought an almost never ridden 1990 Miyata 414 in an excellent condition, but 1990 Schwinn World Sport blows Miyata out of the water. It's my favorite bike. It gives me a solid feel in my hands, and keeps running, running, and running. I call it the Toyota Corolla of bikes.

Thank you. I will check it out.

jump to 7:15 or so.. cup and spindle, in a decent lugged CroMo frame... for reference.

there is a small chance that the cups and spindle are ok.. a close inspection of the bearing contact surfaces will tell you if you need a new BB assy or not
and i too recommend the UN300 BB assy... i just ordered two for the shop.. one for a repair job, and one for stock.

caged bearings cost between 3 and seven dollars, shipped, eack... i just paid 16.84, each, shipped, for two 73 wide x 118mm long UN300s.(fits a fairly Modern triple in an MTB, in my case.. yours will be a 68mm x (TBD) size.)
they require a different tool for install/removal, compared to the cup/spindle setup your world sport originally came with .

the crankset, not the bike determine what length spindle is needed. That bike undoubtedly uses a 68mm English threaded BB

It may have caged bearings although how would you know if you haven't had it apart?
We TYPICALLY replace caged bearings containing fewer balls with 11 LOOSE bearing balls per side. The new grease holds them in place for assembly and 11 spreads the load more evenly.
As loose as things look, if it has cages, they're probably trashed.

Don't spend your money on a cartridge BB yet.

I would be willing to bet that that bottom bracket shell has damaged threads.

As you are replacing bottom brackets anyway, the best solution is to

1. Get everything apart, including the fixed cup (backwards thread!). That one might come out easily, but if not and you don't have the tool either go to a bike shop or take a high tensile bolt with corresponding nut and tighten inside the fixed cup. With enough swearing and tightening from both sides, the fixed cup will come out.
2. Clean everything and confirm the thread on the BB shell is damaged.
3. Don't mess around if the thread is damaged. At best you will be retightening it all the time. You need to go to a framebuilder, and get the shell faced to accept one of these :
   

If you have to make a guess, what would be the length of the spindle in this bike's BB?

Also, what specific tool would I need to install/uninstall Shimano UN300?

I didn't realize that I could use 11 loose ball bearings instead of 9 caged-ball bearings. Wonder if I use loose bearings instead of caged bearings, would they wear out or damage the cups, when I open them the next time?

You can make a crude thread chaser from a sacrificial bottom bracket cup by grinding chip channels through the threads in the cup:

If you're lucky, this will work. But if the threads are too badly damaged, you'll need to use a threadless cartridge or ream and tap the shell with fresh Italian threads (this is a job for a bike shop). If the shell is already Italian thread, then the threadless cartridge is the way to go.

Why not just take the crank off and measure it?

The idea this bike rides like a champ in that state…

i can't venture a guess since i have no way of knowing what crankset is on the bike.
i always measure BB spindle lengths., like choddo just suggested.

road crank doubles can be anywhere from 103 to 113mm... a triple sprocket type? anywhere from 113 to 123 or so...
and if the bike is currently a Single front sprocket setup... 103 to 123 is a good window..
the RSX crankset i installed on a crazy-light Marin BMX i built up has an old school Shimano RSX C3 crankset, with a 127mm spindle length....

remove the crankset and measure from the outer end of the taper on one side(square part to the other outer end of the taper.

and for the record... putting loose balls in a bottom bracket is typically a frustrating grease slathered sweat fest for most folks... use the caged bearings to avoid panic attacks, loud outbursts that scare pets, and tossing wrenches through coffee tables... or, it might just fall together easily.... too easily... spooky easily.... [insert evil laugh track here]

Can you explain how that would even make sense?

Enough of your trolling.

If that's the only issue, then I can put up with the frustration of a grease-slathered sweat fest for once, and I am all set for another 2 to 3 years. Also, if I am that impatient and unstable, I wouldn't have ridden this bike over 10,000 miles, and wouldn't be riding the bike for around 500 to 1,000 miles a month. Rest assured.

By the way, I have 1/4" new loose ball bearings (as well as 3/16" ones and several other sizes) in my stock. Just need to find time to work on the bike. The cage ones, I need to buy at an LBS, or order online.

Not even an Ashtabula crank approaches that level without gross incompetence

This particular Corolla has really bad rod knock and an oil change would have been good 20,000 miles ago. Hopefully running it with a loose fixed cup hasn't damaged the frame.

work at a Co-Op for a while... you will be enlightened.
schrader valve use baffles some people...

the "wrench thru the coffee table" happened when i had the shift mech. not mesh up correctly for the third time in a row in a XR250R transmission... they are not fun, and it was such a problem that honda redesigned the shift mech. for the next year. It happened in1990 or so.
re-installing it again required tearing apart the trans. again, included using all new gaskets..
i used a rubber band to hold the shaft in place for the fourth time, and marked the shaft and case to indicate "correct" positioning, then cut it just before pulling the case halves together onto the bearings involved.... it worked.
Ashtabule crank installs are easy.... with caged bearings.
touching a spindle to a ring of greased bearings typically drags at least one of the bearings out of it's position, and possibly into the middle of the BB...

i always use caged bearings when they are what was originally installed, except in wheel hubs.
the minimal, marginal "advantage" of a extra ball or two is not worth the trouble possible, including having bearings scatter everywhere, including into the frame tubes, during future services.
There is also a high probability of someone installing one too many bearing balls (especially in a headset)... this leads to other problems, eh?
i always set out the correct count before i stick them into the grease.

and then... there are the few people that convinced themselves that larger bearings mean better bearings, or the ones that were told by their "buddy that rides all the time" that "grease slows you down, so don't use any"... I've actually heard that. i sold the kid a nice used front wheel, with fresh grease in the hub... and with the jam nuts properly snugged up, onto un-pitted cones...
sigh.

i drive an aging Corolla... when i bought it, the engine was smoking under hard acceleration... the previous owner had been pouring "No Smoke" additive into it regularly..
some basic research led me to a known problem with the oil return holes in the lower piston ring land plugging up due to lack of timely oil changes...
the No Smoke plugged the few still unplugged holes up.

in-car tear down... slipped the pistons out.. yep, all return holes plugged... there was over two inches of No Smoke Goop coating the oil pan.. it had nearly plugged up the oil pickup screen too... new bearings, new rings, light hone of cylinders, port/match/cc the head, up the comp. ratio half a point, replace valve guides,.. and drilled oil return holes out to the '95 piston spec... 130k later, no trouble. It reaches redline at least once during every run into the big city... the 10w30 oil is changed every 3k miles.

That’s because we have all been taught to avoid removal of the fixed cup from the frame because they are difficult to remove. If the cup is removed, putting loose bearings in is much easier. There is a better way!

find a better teacher.

the only time i don't remove the fixed cup is when it has completely oxidized itself to the frame.
i find the rusted-in-place NDS cups with only pin spanner holes tougher to remove.
i have a socket and spring loaded retainer for the old DS "Two Flats" cups.

Wrong. SAE 5W- 30 is the suggested viscosity for Corolla. 10W-30 is not.

you forgot to think about what year my Corolla is... and the wear present in a 360K engine, creating extra cam, main, and rod bearing clearances that calls for a slightly higher cold weight, and that the corolla 4afe and 7afe engine is prone to a "knocking rod" sound as it first fires up... and that's what the "general" suggested oil weight noted on the oil fill cap is, but not the only weight suggested in the service manuals, etc.
The 10w30 ends the startup rattle.
i'll keep using the 10w30 oil, and Wix/NAPA filters, but thank you for your concern.