1981 Miyata 310 Bottom Bracket - what length??
 

The old bottom bracket looked waaaay too wide - like 1cm at least. I have a 103mm bb which fits the non drive side perfectly but the drive side needs more length - there 's a deeper recess for the bb spindle than on more modern cranks.

the crank says miyata as well.

anyway, i'd be impressed if anyone could dig up this bit of knowledge.

Even though the crankset may be pantographed Miyata, the back of it may have the manufacturer's ID. Once you figure that out, look here.

Sheldon Brown's Bottom Bracket Size Database

Maybe this would help, http://4.bp.blogspot.com/_whtVpXkKwl...600/img013.jpg

Catalog says should be SR crankset.

looks like its an SR SI-5DRG-AH

amazingly i found this - http://equusbicycle.com/bike/sakae/c...log18_%206.pdf

fwiw - i installed a 122mm bb and everything looks good so far. i'll report back with any updates.