Perhaps the chamfered Mavic threadless BB is the one to chase. Maybe period correct?
I've installed one with a fine round file, no Mavic tool.
In fact that Panasonic shell looks slightly bevelled...I betcha.

Note the burrs pushed up at the inner ends of the "splines". This suggests that the BB was pressed in and never intended to be removed or serviced.



The BB shell looks like it's made of cast aluminum Could be soft cast steel but???

Bikes like the Bridgestone Kabuki Submariner had the tubes cast into aluminum "lugs" and BB.



Any guess as to why the original BB was removed???

Maybe some one parted out the frame like the fools on eBay who disassemble cheap steel rim wheels and try to sell the spokes individually! DOH!

verktyg

Hey all, thanks for all your comments. Sorry for the late reply, when I tried to comment yesterday it said I could only post 5 times a day.

For now, I've ordered the suggested treadless YST bottom bracket off of eBay (Made sure it was YST). It'll take a couple weeks until it arrives, but I'll keep you all updated!

verktyg I'm afraid you're right about the original BB being removed, it really does look like it. I'm not sure how many previous owners there were for this frame so it'll be a complete mystery as to why it was removed.

I'll have to chase the Mavic treadless BBs if the YST one is a bust, but at that point I might consider just getting a different frame.

dddd Thanks for pointing out the spindle length. I did indeed order the wrong spindle length for my FC-1050 crank haha. I'll try to get the order cancelled and order the correct one. Do you think 1mm will make a big difference? I'll need a 115mm spindle, but I can only find 116mm on eBay.

edit: I just found the manual for my crank online. it says I'll need 115mm for a 70mm bottom bracket (113 for 68). Does this mean I'll need a 68x113 bottom bracket? Sorry for the dumb question, my brain is absolutely fried and somehow I can't figure it out.

My burley rock and roll tandem had a similar BB shell that I feel was close in dimension to what you have. It was a pair of pressed in cartridge bearings with a separate square taper spindle. The issue there would be finding the replacement spindle, the bearings were a standard size but obviously the spindle wasn't. Was my main reason for getting rid of it.

1mm is not a significant amount, especially when considering the manufacturing tolerances used on bicycles.

For those of us trapped in the non base 10, non-ISO world of fractional portions of a long dead British kings foot, 1mm = 0.0394" or slightly larger than 1/32" of an inch or a bunch of human hairs!

verktyg

verktyg Good to know, thanks for the reply!

I'm still trying to figure out spindle length I need to get.

I'm still trying to wrap my head around this. If I understand correctly, for my FC-1050 crank (spec'd at 68x113 or 70x115), I'll need to order a 68x113 bottom bracket, instead of a 68x115 (or 116 since 115 is not available on eBay), due to the spindle being offset 1mm to the right?

Your only real concern is not getting one too short, so the inner ring interferes witrh the chainstay. A mm or two long will make no real difference.

For consideration of a well-centered chainline between the crankset and freewheel, yes the bb spindle should be 2mm shorter than spec'd for the particular crank.

On a small number of frames, the left arm might possibly interfere with the left chainstay, but I've had that problem just once out of over 100 builds where I was trying for the shortest chainline (for the usual reasons of reduced chain angle and lowest Q-factor).
The chainline issue would be less of a consideration for a rider who prefers to use primarily the small chainring, riding at in-town speeds.

Alright, thanks for the explanation!

I'll order a 68x113 and see where it goes, I'll keep the thread updated.

Thank you to everyone that has commented so far, it's been such a help!

edit: I'll also post pictures when it's done, I'm looking forward to it

That amazed me! Holy smokes, didn’t realize press fit went so far back!

dddd et al....

Reference my post above: https://www.bikeforums.net/newreply....ply&p=22293819

1960's Cancer Stick Ads for 100mm and 101mm long carcinogenic devices:



Somethings to consider... 3mm is less than 1/8"... Measure 3mm or 1/8" and then hold your fingers apart that much and look through the gap!

I threw this Flickr Album together one night 10 years ago when I was building a SS wet weather beater. I was looking for a BB combo using parts that I had on hand. Read my notes below the photos.

https://www.flickr.com/photos/282672...57627678462359

Bottom line: IF IT FITS - IT WORKS!

When crank arms are removed and reinstalled or when they are re-torqued, the aluminum deforms and the arms move further up the BB spindle/axle each time. When installing used arms, there's no telling what their history is. Before mounting them, I slip them onto the spindle to see how far they go on or if they will work at all.



Next I thread in a fixed cup and using caged 1/4" ball bearings I put the spindle into the BB and then slide the drive side crankarm on till it stops. That will give me an idea of how close the inner chainring comes to the chain stay. Bear in mind that when tightened the crankarm will fit on 2mm to 3mm closer.

One of the caveats about buying used cranksets is what condition are the squares in. If they have been wallowed out from running loose or have stretched too far from frequent re-tightening you have a problem.

A simple fix that sometimes works when the cranks fit too far on the spindle is to put a second washer under the crank bolt to take up some space. File or grind the opening of the washer so that it will pass over the end of the spindle.

NEXT: Chain Line.... Precise Chain Line was/is an obsessional British affectation when using stiff 1/8" chains on Fixed, Single Speed or Internal Gear Hubs.

With the advent of flexible 3/32" chains in the late 70's chainline is not that much of in issue if it's close enough - if you can easily shift on and off of all of the rear sprockets. One concern is when the chain is on the small chain ring, making sure that it doesn't rub or drag on the inside of the big ring when you are using the smallest rear sprockets. It's more of an issue with triples.

Common sense and tradition says don't use Big-Big and Small-Small chainring - rear sprocket combos.

Consider 9,10,11 and 12 tooth cassettes and how much a chain has to deflect to cover the full width.

BTW, how wide are the 10, 11 and 12 speed cassettes. After 15 minutes of searching was how wide the chains were???

verktyg

The Edco "Grip" bottom bracket cartridge isn't press-fit. It uses eccentric cups to lock the cartridge in place. I used one for a while but gave up on it when it kept coming loose in cold weather. The aluminum cups shrink more than the steel bottom bracket shell in the cold, and no longer hold securely. It's annoying to have to stop mid-ride to tighten the bottom bracket.

I should have mentioned that I am quite fussy with regard to chainline.
I live in the foothills, and prefer to be able to smoothly use the full range of rear cogs while staying on the big ring as much as possible, so my bias is always for a shortest-possible chainline!
The issue became more of an issue when compact cranks (with their 16t gearing gap) arrived, and the issue is also more of an issue when using DT shift levers.

As I said though, for more of an in-town ride, a longer chainline is less of an issue since the rider will be dropping to the small ring often or may stay there.

Also, some gruppos designed around possible oversized seat tubes and/or triple cranks really have on over-generous chainline, because the component group was firstly designed to work with all the worst-case situations of achieving a robust shift to the small ring. But for bikes with 26.8mm standard steel seat tubes, the chainline usually tends to be greater than it should and needs to be for robust (front) downshifting and smoothest chain movement.

Did the shop tell you why they couldn't cut threads into the shell; that is, do they lack the proper tooling to do the job, or is the inside diameter of the shell unsuitable for standard threaded bottom bracket dimensions?

Depending on the inside diameter measurement, it may be possible for it to be threaded, or perhaps even install a threaded sleeve:


https://www.framebuilding.com/NEWPAR...B%20shells.htm