Two Spoke Forums banner

1 - 12 of 12 Posts

·
Registered
Joined
·
33 Posts
Discussion Starter · #1 ·
I just thought the idea of having a square shaped frame instead of the usual rounded one would be kind of cool but can the rectangular / square shape withstand as much force as having a circular shape of pipes?

Does anyone have a bike like this?
 

·
Premium Member
Joined
·
12,350 Posts
That would allow it to flex on the vertical plane, which would be ok. But it would also flex on the horizontal plane, which is very bad.

The custom XC bike that my ex wife just sold for peanuts had a rear triangle constructed of rectangular tubing. Because the tubing was taller than it was wide, it had lots of lateral stiffness. But you need to get into long travel, DH style bikes to see any real benefit.
 

·
FreerideLife
Joined
·
77 Posts
Its been done and it works just fine.

UFO bmx frames back when used square tubing. Redman bikes (one of the TOP custom bike makers in bmx, next to staats) used a monocoque square tube and down tube design.

Its been proven to work well, but rather pointless because a round tube bike will be generally easier to build, and generally like said stiffer in parts.

Many, MANY mtb companies use square tubing for rear triangles. Square tubing in the rear actually is better in many cases than round (but like industry said, its a bigger travel thing for the square). Just the front triangle suffers from square. IE generally breaking at the head tube like ufo's did. Redman used that notorious monocoque that got them famous that allowed more welding surface area to avoid those head tube cracks.
 

·
Slowin it up.
Joined
·
4,299 Posts
I don't see why it wouldn't work. If you measured your angles properly and payed consideration to your welds you ought to be alright.
 

·
FreerideLife
Joined
·
77 Posts




and last but not least, one of the best race bmx frames ever made bar none. The frame that got redman so high up on the custom bike podium.


 

·
Registered
Joined
·
453 Posts
I am an apprentice frame builder located in Sussex, England. Square tubing does work well. It is homely, however. Round tubing is easier to make and makes for an eye pleasing structure. Some of the earliest carbon efforts were of square construction.

In the shop, above my bean, is a handmade carbon frame of box construction. It was easy to form and worked well. It did not require a mold to build. Today, all, or most carbon frames are molded with fair edges.
 

·
Bent Newbie - old rider
Joined
·
144 Posts
Cycle Genius uses a square top tube for their recumbent frames.

I think Sun Bicycles also has some partial square tube frames.
 

·
Registered
Joined
·
352 Posts
Cycle Genius uses a square top tube for their recumbent frames.

I think Sun Bicycles also has some partial square tube frames.
So does Zox. The original RANS Rocket was also built with Square tubes. For a given width, a square tube will be stiffer but heavier. That's because the measurement diagonally across the tube will be further. Square tubes will simplify aligning the tube cuts.
 

·
Chris
Joined
·
1 Posts
Help

I have a squre tube bike from the late 70's. I bought it when I was 8 or so
I still to this day do not know what kind of bike it is. Can anyone
help?
 
1 - 12 of 12 Posts
Top