Chris Chicago

thanks for everyone's help

I got the old bb out. lockring was the most difficult, woulndt budge. so i sprayed it with pb blaster, sprayed a bunch down the seat tube as well. waited a few days and struggled a bit but got it off with channel lock pliers. fixed cup actually came off easy with my cheapo adjustable wrench. spindle and cups are pitted. leaning towards a cartridge for replacement.

Road Fan

Good job! Now measure as has been told. What brand of crankset is it?

Plus, this might be a shortcut: Are there any markings on your dead spindle? Give 'em up, if there are. You can usually (Edit: change that to "sometimes") directly cross-reference a cartridge BB from Japanese spindle markings.

Chris Chicago

it's a sugino. tgt i think. spindle says 3u iirc.

Road Fan

From Sutherland's, for the 3U BB spindles the length is 124.5 mm and the SER (Shell to End Right) is 32.5 mm, for 68 mm shell width. The SER is interesting because it is the distance from the right face of the BB shell to the right end of the spindle. In Shimano cartridge BBs there isn't an exact match. The lengths of the closest cartridge BBs is 122.5 (SER 28 mm) for the Shimano NL length, and 127.5 mm length (30.5 mm SER) for the EL length.

So your original spindle may place the crank 2 mm farther away from the center than the widest EL Cartridge BB. You can try that and see if it works. If you measure the chainline and think it's too far offset to teh center, think the crank to chainstay clearance is too small, or have shifting issues on the smaller cogs, perhaps try spacing the EL cartridge BB to the right with a 2 mm spacer. Using the 127.5 mm EL BB you'll have a wider Q factor than the spindle, by 3 mm.

I can't say these fitting discrepancies will cause you any problems or discomfort. They are differences, and some would think they are significant. YMMV.

But double-check if it says "3U."

If you can find a JIS 68 mm BB length 124.5, it's worth a try.

onespeedbiker

The crank is a TGT (or Triple GT). The BB spindle has a Japanese code for the length; you can find the below chart at https://sheldonbrown.com/bbsize.html

Chris Chicago

Wow Roadfan, thanks for walking through all that for me. I was trying to get it all straight in my head last night using the chart one speed biker posted above but pulled the trigger on a 127.5-68 before I had it sorted out as well as I do now after reading your post. The thing that threw me off a little on that chart was the symmetrical equivalent being 133. i took that to mean i should find a 133 spindle cartridge which of course does not exist.

hopefully the one i ordered will work out. i suspect i'm not too sensitive to the old quack factor. we shall see

Bill Kapaun

That's the way I would have went.

You can get a Sugino 3-S from
loosescrews.com
which would basically get you in the same place as the 127.5 cartridge. (3mm short on the DS)
By the time you pay for new cups (if you can find them), you're up into the price of a cartridge anyway.

Road Fan

Chris, that should work well for you, possibly with some shimming.

Bill Kapaun suggests a Sugino 3S, and that would be a good choice to try if you can also buy a new set of cups - you said they were pitted, too. They're not too dear on loosescrews, if I recall. And cup/cone BBs will not need replacement if you overhaul them once a year or so. Clean insides and clean grease is the key. I've seen a wide range of spindles on the Niagara site, and if you can find a 3u, you'll have a direct replacement. They are a bit crudely made, and will need to wear in and then be re-adjusted. At that point the BB should remain stable for a very long time, with servicing.

Glad to help! The handbooks aren't hard to use, but it can take a while to stare at them and understand what they are saying.

Bill Kapaun

Loosescrews seemed to be out of the cups, else I would have suggested them.

I think the cartridge is the simplest way to go, instead of paying shipping from 2 different places IF one can find the cups.

Possibly, the 127.5 cartridge has a bit of offset?? which would help.
Wish there was a chart showing actual offsets for cartridge BB's, since apparently, some aren't symmetrical.

Road Fan

The Sutherland's charts allow you to calculate it. I recall the 127.5 being symmetrical.

Edit: This is wrong, see the next post! It's good to do the math rather than just guess, I guess.

Road Fan

Ok, self-correction! I went back to Sutherland's and did the math. The EL width, 127.5 on a 68 mm shell, is not symmetrical, contradicting my previous post. To start, the SER (again, Shell to End Right) is 30.5 mm. Subtract that from 127.5, getting 97 mm, which accounts for the shell width and the left end width SEL, Shell to End Left. (A symmetrical BB has SER = SEL.) Subtract 68 mm for the shell from 97, which gives you 29 mm left over, which must be the SEL. So the drive-side stub is 30.5 mm from the BB shell, and the non-drive side is 29.0 mm from left edge of shell to the end of the spindle. If possible, cranksets chosen to use with this BB should be designed to center up with this assymmetry.

So, Bill, the 127.5 EL cartridge BB has a 2.5 mm offset, longer on the drive side. And the paragraph above shows how you can figure it out if you ever need to.

FWIW, I looked at the 3S, which seems to have been nut0type only. It has SER of 29.5, 1 mm shy of the 127.5 EL cartridge. As well, the length is 124.5, 3 mm shy of the EL cartridge. So the non-drive end will be 27.0 mm, 2 mm shy.

Biggest issue with the 3S is the nut v. bolt design: nut designs are said to be less reliable than bolted, and a different extractor might be needed, than the old standard Campy. Other than that, one should be mindful of the chainstay clearances on both sides of the bike, due to the narrower spindle length.