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J

JHJams

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I am sourcing a crank and bottom bracket that will work on my goodyear highway patrol bike circa 1950's. I removed the original set-up and tried my bmx bikes 3-piece crank but the bearing cups wont fit into the bottom bracket. They are just barely too large in diameter. I want to use my 3-piece cranks but what do I need for them to work?

I also may consider using a new 1-piece but I'm not too sure what to buy considering my 3-piece crank set would not fit and they are from an american bb bmx bike. It's all very confusing all of a sudden and any info/help would be greatly appreciated!

Thanks.

IMG_1898.jpg
 
You say that they're slightly too large to fit - are you expecting them to slide in, or are they too large to have a normal press fit? Because they should be slightly larger than the inside diameter of the bottom bracket shell, and they require some form of press to install. I was under the impression that all older American bikes used the same diameter bottom bracket shell, regardless of which bearing/tread combination it had.

Are you looked at using a bottom bracket adapter like Truvativ sells? Presses into the bottom bracket shell and has 3 bolts to retain it. It allows you to install a standard square-tapered bottom bracket into an older bike. If it does turn out to be slightly too large to press fit, then there's enough material on it to have it turned down some.

http://tinyurl.com/7gzqm7s
 
The shell that holds the bearings are slightly over sized. Too much for it to just be pressed in.. not snug fit but def too large for it to fit.
 
What are the actual dimensions? A snug fit is not a press fit; a press fit requires an interference condition. Where I work, I regularly see bearings that have upwards of 0.005-0.006" interference pressed on. So, what are the actual dimensions of the shell ID and the bearing cup OD? Are we talking thousandths of an inch oversize or a lot more than that?
 
I've got a digital caliper and I'll get a measurement of the bb shell and the 3-piece bearing cups and let you know asap. Thanks thus far for all the help.
 
JHJams said:
I've got a digital caliper and I'll get a measurement of the bb shell and the 3-piece bearing cups and let you know asap. Thanks thus far for all the help.
Click to expand...

This is exactly why I have digital calipers that stay in my bike workshop... :mrgreen:
 
Ok, I just took a second look and that bearing cup would not be able to fit pressed or hammered in. The diameter is just way larger than the bb on the old goodyear. I'll still get measurement's soon of the bb on both my goodyear and modern bmx bike and the 3-piece crank set cups.
 
Here is a measurement of the bb shell on my goodyear highway patrol. I hope this helps you guys help me find the proper crankset.

IMG_1908.jpg
 
I could not hold the cup in the caliper and take a pic. The outside of the cup where it would normally slide into the bottom bracket shell measures 2.027 so I doubt it is going to fit at all.

IMG_1910.jpg
 
Apparently something simple I overlooked about 35 times! I did not realize there were cups in the shell. It had rust and other caked up gunk built up covering the seams and could not see that it was a separate piece. It actually appeared to be all seamless.. either way they are out and I popped in the 3-piece crank w/ease. Now I'm off to find a chain and it's riding.
 
Your picture above looks like they are in, but there is no flange showing. Easy to overlook, probably never over look that again.
 
Yeah, I took a flat head to it scrapped some of the gunk and was like WHAAAAT!!!! So I punched them out and installed the 3-piece. I'm running a 39t sprocket from my bmx bike, profile cranks and sealed bearings so I can not wait to get this chain on already.
 
I'm getting ready to do this swap on the Hawthorne I'm building. viewtopic.php?f=21&t=53236

What do I need to look for, look out for, avoid, be sure of, etc., while doing this? Is there anything about a Hawthorne that won't allow a swap? I want to spread the pedals & arms apart about an extra 1/2 inch. Is a 3pc swap the best way to achieve this or is there a better way.
 
From what I encountered.. I removed everything plus the cups, installed the cups and cranks from my bmx bike. (profile racing cranks) I added a spacer in the spindle before installing the crank arms to make sure it cleared enough from the frame.
 

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