What diameter tubing for bmx build?

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thefonz78
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Joined: Mon May 10, 2010 15:35 pm

What diameter tubing for bmx build?

Postby thefonz78 » Thu Oct 28, 2010 18:52 pm

I can not find any info on building a bmx frame. I plan on building frames for road tourers, off road and bmx. I can not find any info on frame thinkness on bmx's. I have the Reynolds tubing catalogue i'm not sure what diameters you would use for a bmx. Any ideas?

Berk Bonebonce
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Postby Berk Bonebonce » Thu Oct 28, 2010 19:30 pm

You sound as if you know what you are doing. I think the first step would be to measure the tubes in a bmx frame.

Reynolds do not show people how to build frames because they are not framebuilders.

And furthermore, Reynolds main tubes are all butted, and you may even find that BMX frames are made with pg tubes.

thefonz78
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Joined: Mon May 10, 2010 15:35 pm

Postby thefonz78 » Thu Oct 28, 2010 20:31 pm

No i no nothing. I've bee doing a bit of reading. I going to build a jig, then have a go at building some frames. Only a bit of fun i like a project. What is pg tubes?

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softlad
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Postby softlad » Thu Oct 28, 2010 20:43 pm

pg - plain gauge. Not sure I'd want to buy one of your frames, to be honest.....

thefonz78
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Postby thefonz78 » Thu Oct 28, 2010 21:00 pm

haha not going for sale just having a bit of fun

Berk Bonebonce
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Postby Berk Bonebonce » Fri Oct 29, 2010 00:22 am

I think a good starting point would be to measure the tubes in an old bmx frame and then cut them up to get an idea of the wall thicknesses. You should also be able to just about tell whether bmx's are built with butted or plain gauge tubes.

keef66
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Postby keef66 » Fri Oct 29, 2010 10:29 am

Get yourself on a framebuilding course and learn how to do it properly

thefonz78
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Joined: Mon May 10, 2010 15:35 pm

Postby thefonz78 » Fri Oct 29, 2010 13:15 pm

Yeah would love to. They all have 2 year waiting list's! Maybe get hold of some frame builders and see if the want a free dog body a few days a week in exchange for lessons. I can not find any builders in South Wales.

keef66
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Postby keef66 » Fri Oct 29, 2010 16:03 pm

Me too. Praps I'll put my name down for a course when I retire.

lae
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Postby lae » Fri Oct 29, 2010 23:52 pm

You're gonna MIG weld 'em right, rather than braze them? For your first practice frames I'd start with cheap mild-steel tubing rather than anything fancy. Rather than paying a fiver a foot for chromoly stuff, it'll be more like a fiver for two metres.

Someone I know has made frames (for a cruiser) using 40mm main tubes and 25mm chainstays. That's about right for a BMX. Wall thickness was 1.6mm - you could go up to 2mm or more, if you wanted more strength, but apparently a metre length of the 1.6mm stuff didn't flex if you stood on it. The downside is that it weighs a ton compared to chromoly, but it's a BMX, it's not supposed to be light!

Once you've mastered the mechanics of framebuilding, then I'd move onto the expensive tubing. No point in spending 30 quid in materials to find out that your frame geometry is wrong!

Sounds like a really interesting project, anyway. Let me know how it does!

Berk Bonebonce
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Postby Berk Bonebonce » Sat Oct 30, 2010 17:30 pm

frinkmakesyouthink wrote:You're gonna MIG weld 'em right, !


Yes, practice with mig welding. But good quality tubes are Tig weldable only.

hounslow
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Joined: Thu Mar 11, 2010 19:04 pm

Postby hounslow » Tue Nov 02, 2010 17:54 pm

check fbmbmx.com, they do custom bmx frames, really nice ones. you may be able to get some advice out of them too.
i would recommend asking on a bmx website, such as bikeguide.org as they are much more knowledgable on the subject, with some having quite a bit of experience on the subject.

ryanarcher
Posts: 2
Joined: Mon Mar 11, 2013 14:03 pm

Re:

Postby ryanarcher » Mon Mar 11, 2013 14:05 pm

keef66 wrote:Get yourself on a framebuilding course and learn how to do it properly



You sir are a virgin

ryanarcher
Posts: 2
Joined: Mon Mar 11, 2013 14:03 pm

Re:

Postby ryanarcher » Mon Mar 11, 2013 14:07 pm

hounslow wrote:check fbmbmx.com, they do custom bmx frames, really nice ones. you may be able to get some advice out of them too.
i would recommend asking on a bmx website, such as bikeguide.org as they are much more knowledgable on the subject, with some having quite a bit of experience on the subject.



for a frame to be half decent it would be preffered to be TIG welded am at college now learning to tig


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