bottom bracket bearings
 

I've taken apart my bottom bracket, it is a Sugino GT. When I took it apart I expected to find ball bearings in a bracket, instead what I found was loose ball bearings. I'm not sure if they were placed in there loose or if the bracket had eroded away. I expected to find some grease too, but that was in very short supply.o

After looking at the spindle i'd like to replace that along with new bearings. One of my many issues is I'm not sure what size of spindle to use or how to measure it. Is it over all lenghth?

On the current spindle it says "3rrb", "83-k", and "Cr-Mo". It is square taper.

On the bearing cup/cap for lack of better term is states Sugino 1.27x24T.


It came out of an old MTB, that I want to use for commuting. It has a triple crank.

Any recommendations on what I should replace it with?

thanks

Sheldon shows 113 - 118 mm, nothing seems to measure this. The overall length is 136 mm.

The spindle below has the same appearance as mine without the threads on the end of the spindle.

What exact model is the GT crankset, there is a double and a triple. It may be marked on the inside of the arms, like "TGT" .

I know with a '83 Stumjumper and the Sugino AT triple(straight arms) , a Shimano UN72 in a 127mm was perfect. The original spindle was a 124.5mm.

The 3rrb is supposed to be 136mm, which would be really wide ! The AT arms are straight , as are the GT, so it should work with a 127 too(assuming it's a triple). I've read of others using the 127 with 1-2mm spacers on the driveside. Cranks do not need to be perfectly symmetrical either. The only longer BB's than that are Phil Woods, is it worth it for these cranks ?

Don't buy a Shimano cartridge UN54/55 either, they are not spacer friendly . A Tange LN-3922 would be best.

Here's a partial database of spindles available. It's also show you how.

I see from the photo, that you have a nutted spindle. You can buy another or buy a hollow bolt on spindle with the same dimensions (note: the threaded studs aren't included in the measurement).

If you cannot match your spindle exactly, get the closest you can.

FYI, a D-xxx spindle is hollow, bolt on, and a N-xxx is a nutted like yours.

X-3xxxx means it's for a 68mm wide bottom bracket (like yours) while X-5xxxx is for a 70mm wide.

BTW- you typo'd the cup dimension, which is 1.37" not 1.27.

Why do you want to replace the spindle? I don't see any pitting in your picture. If it's in decent condition, keep using it.

Perhaps this can help you find a replacement, if you need it:

http://www.os2.dhs.org/~john/spindles.jpg

Source: Sutherland's 4th Edition

Take the spindle with you to the oldest bike shop in town and see what they have. You might be very pleasantly surprised by what you find. I've had good luck recently doing that.

You should post a picture of your spindle -- otherwise, people will think this picture is yours. ;)

If there is no pitting on your spindle, I'd keep using it. Ball bearings are 1/4", and you'll want 9 on each side.

9 balls per side if they're in a metal or plastic retainer, 10 or 11 if they're loose.

D'oh, 10 or 11 is what I meant -- just repacked a rear hub and was thinking of that.

11 loose bearings will replace 9 caged bearings, bearing size is 1/4 inch.

FWIW, 11-ball retainers are available:

http://www.os2.dhs.org/~john/11-ball.jpg

Never 10. Always 11.