Tube thickness

  • Discuss Tube thickness in the BMX Bike Tech forum in area BMX-Forum Community; Hi I'm building a BMX at the moment, and I cant find anywhere the thickness of the tubing in the frame. If you know how thick tubing in bmx frames has... ...
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D1ver

New Member
Tube thickness post #1
Hi
I'm building a BMX at the moment, and I cant find anywhere the thickness of the tubing in the frame. If you know how thick tubing in bmx frames has to be could you please post it up. I'm using 4130 cro mo tubing for the bike so it should be pretty strong.

Your assistance it appreciated
Thanks
 
AustinK

AustinK

Well-Known Member
Tube thickness post #2
Most modern frames are butted so the thickness is going to vary within one tube.
 
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D1ver

New Member
Tube thickness post #3
OK thanks, the tubing I will be using will be a constant thickness so, I guess I'll just have to make it thick enough to strong constantly through the frame.
 
AustinK

AustinK

Well-Known Member
Tube thickness post #4
if i were you i would try and contact a company like solid, fbm, standard, or S&M and ask them if they could give you some tips on making a frame and what tubing to use.
 
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D1ver

New Member
Tube thickness post #5
ok good idea, thanks for the advice, i might do that, :)
 
CodyPrince

CodyPrince

New Member
Tube thickness post #6
it can range from 1.3 to 8mm usually thinner in places were strength is not needed, eg underneaththe top tube may be .9mm and the tom can be 1.1mm
 
johnuk

johnuk

New Member
Tube thickness post #7
It's usually between 1 and 2 mm, with the butted parts being 2 to 3mm.

It depends entirely on the type of tube you use, how good you are at welding, how the metal is treated for stress relief, annealing, hardening and lots of other stuff.

As the others have said, the bike industry usually uses 4130 and it's double butted - so the tube wall gets thicker at the ends and thinner in the middle - you can't buy that tubing off the shelf.

I'd probably go for 2mm or so to be sure it doesn't snap.
 
J

jawn

Guest
Tube thickness post #8
2mm is .079", way over kill.
 
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D1ver

New Member
Tube thickness post #10
Hi, Thanks for all the help, I gave Soild an email. They suggested between 1 and 1.3 mm is thick enough.

On a different area, has anyone got any advice about the right geometry for the frame, angles and lengths etc.
Any extra advice would be appreciated, Thanks
 
CodyPrince

CodyPrince

New Member
Tube thickness post #11
you owe people rep dude
 
A

abdrider

Active Member
Tube thickness post #12
maybe, a 20.5 top tube
13.75 backend slammed,
71 seat tube
75 headtube
and a 11.8 bottom bracket

its really just personal preferance
but thats what i would have
 
kkmk

kkmk

New Member
Tube thickness post #13
he asked for thickness, not specs...
 
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D1ver

New Member
Tube thickness post #14
Sorry kkmk I did ask for geometry specs at the bottom of the last page, but no worries. Thanks for those abdrider, and thanks everyone else for posing your information has been very helpful. :D
Its possible to work out the other tubing lengths from the top tube length, back end and angles isn't it?
 
kkmk

kkmk

New Member
Tube thickness post #15
ah you did too. My bad.

And yeah, you could work out lengths once you have the main ones.
 
mad082

mad082

New Member
Tube thickness post #16
personally i would speak to a frame builder about the tube sizes. they are going to be able to give you better advice than most of the bike companies as the bike companies don't usually have too much to do with the building process. that is all done in the factory then they just get sent a demo model to look at.

also it is usually only high end bikes that have butted tubing. most bmx completes (but not all) will be single gauge tubing.

a mate of mine built a bike at school once. made it out of fencing rail and made up a set of alloy triple clamp forks. weighed heaps but was pretty cool. that was about 10 years ago now.
 

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