Bottom Bracket Maintenance

[buickmike]

Seems like the answer. However the diameter. Of the bottom bracket would vary between different manufacturer s. Tell us more

 

[Cooper S.]

Huh I’m going to have to try those out on some of my schwinns

 

[Krakatoa]

In my experience each maker either uses a crank supplier or has in house forging capabilities. From make to make and geographically there are differences in what is considered oem in terms of crank type, bearing cup type, tpi's, and the type of race used, hardware stack etc.. Best way to learn is to take apart and reassemble known og bikes of different makes and years to familliarize yourself with what is typical.

 

[Krakatoa]

Shelby early has fine and later switches to a course thread.

A lot of nos races pairs of all types were sold recently from memory lane, and hopefully will hit the market again here on the CABE.

Most times nos races have a number stamp plus R or L. That number will correspond to an application chart by that mfg, WALD for instance. Other times they are unmarked and you will have to know by experience or measurement.

The difficulty is knowing what you have if A they are loose or B may be incorrectly swapped out non original type for your application.

 

[SKPC]

Does anyone have a trick on how to re-surface worn crank arm cones in the shop?

 

[fordmike65]

Does anyone have a trick on how to re-surface worn crank arm cones in the shop?

Just replace them. I believe they are surface hardened, so attempting to resurface them will not yield lasting results.

 

[buickmike]

Does anyone have a trick on how to re-surface worn crank arm cones in the shop?

Maybe if you had access to a valve grinder you could cut the cone - provided it was the older style. Straight 45° as opposed to radius or modern cones. The only generic bmx style bb was a black set I bought at LBS. This set had a flare to the cup right at the point where the seating flange started Thus increasing the O.D. enough to catch and seat itself in bore.