1980 Schwinn to BMX

Feb 28, 2019
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Hey all,

New to the board and looking for some help specific to my 1980 Schwinn Cruiser (CC7-6) to BMX/Klunker build.

I have found catalogs online, but nothing that give me specific sizes/measurements of things like bottom bracket or forks that I can use. I have built up Jeeps before and built my own modern dirt jumpers, but finding info on this older stuff is a bit hard.

Anyone able to point me in right direction?
 
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May 10, 2016
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Welcome.

BB will be a standard one piece, or American.
If you a to convert to three piece square taper, there are conversion BB’s out there, 122mm-130 length.

Seatpost will be 13/16”

Headset will be 1” with 32.5 or 32.7 cups (same thing, different labels) crown race will depend on fork, but 26.4 is most common, the sunlite econo fork is 27.0.

Fork options currently available are the mentioned sunlite (cheap, so not to use off road) SE landing gear, Santa Barbara cruisers, Johnny true torch, genuine bike products, and others.
Vintage forks can be found inexpensively if you keep looking. Although I depend on how high end or whatever ya wanna go.
 
Feb 28, 2019
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So as not to clutter up the build thread, want to keep this parts question thread separate.

Wheels: Front axle is a 3/8", but what about rear? Looking to upgrade wheel set to a modern 26" BMX wheel set, but not sure on that rear axle size and what size rear hub will fit between dropouts.

Sprockets/Gearing: What are some of you running on your builds. I am already converting over to a 3-piece crank set-up, but if possible looking to get a bundle deal on cranks/sprocket.
 
Jul 16, 2019
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Here's a couple of charts of gear ratios.
p4pb15219941.jpg
26CRUISER_GearRatioChart.jpg

*Basically the same charts, just a little bit of extra in one or the other end.
The standard BMX ratio is something like: 2X+2:X ie 32:15 or 34:16 or 36:17 or 32:15 (front sprocket has twice the teeth, plus two more, than the back). However, you have to figure out what you like. I made a doc with all my bikes'gear ranges and tested them out by going for rides in one specific gear. I kinda like these ranges: 38:16, and 48:21, that's for a mountain bike that doesn't have to climb mountains, and I like top end!
 
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Feb 28, 2019
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New rims and tires.

I had a set of Vans Cult gum/blacks ordered out of Denmark and when they didn't show up, I had UPS do a search for them and apparently they were lost in US Customs.

So temporary tires for right now to cruise around until I can find another set, which is apparently not looking good.

Wanting to drop in 3-piece crank and sprocket next. Any brand advice?
IMG_0590.jpeg