Solid Aluminum Handlebars vs. Hollow?

[Moto Fugazzi]

I'm looking to put longer clip-on handles on my V11S, and I normally just buy them pre-made or buy a broomstick handlebar and cut it to length.

Then I remembered there's a speedy metals 10 minutes from me, and they have 7/8" diameter metals in either tube or solid form. Not to say I'm going this route, but was wondering the pros and cons of solid aluminum bars vs. the aluminum tubing with .120 (3mm) wall thickness, or any other material.

Since I'm not a metallurgist, comments would be appreciated.
Ken

[NCAmother]

Thats a pretty interesting question,  both are strong and I wonder if the hollow pipes are better if you crash

[oldbike54]

 Solid aluminum bars will absorb some vibration and bend more easily than tubular bars . Lots of off road MC's run solid aluminum bars because they can be whacked back into shape after a crash . Not sure if that is relevant on a street bike .

 Dusty

[lucky phil]

If I was going for the tube i'd be inclined to go with the .120" wall. What effect either will have on vibration esp the r/h bar is anyones guess and only trial and error will give the answer.
V11's aren't renowned for their smoothness though so a comparison would be interesting.
Ciao

[canuguzzi]

With solid bars you're stuck as far as vibration control is concerned unless you attack the mounting system. With tube bars you can experiment with a variety of solutions, filling them with lead bbs, bar snake, lead strings, internal weights  etc., there are quite a few options if vibes are bothersome.

If $ isn't a critical concern, why not try both and just use what works best?  If you do go with solid you can also substitute other tubing even if the material is heavier.

You can also hit up bicycle shops, try some in titanium or the experimental aluminum tube stuff. Bicycle shops round here use it in their custom and high end models. Pricey but then that is part of cu$tom.

[rocker59]

On the relatively short length of the clip-ons, strength of either solid or tube isn't going to be a concern.

As mentioned, you will only know how each material performs on your bike by trying.

The solid will be heavier and may affect steering feel a little.  It may damp some of the vibrations which can be annoying on a V11 Sport/LeMans, but it may let some other frequencies through that you didn't feel before.

I do know from the experience of changing from thin wall aluminum to thick wall aluminum on my Quota, that small changes to the bars can make a felt difference.

I'd buy some of each and try them out.  Changing out bars on a V11 Sport is pretty quick and painless.

[Rough Edge racing]

Solid aluminum bars will absorb some vibration and bend more easily than tubular bars . Lots of off road MC's run solid aluminum bars because they can be whacked back into shape after a crash . Not sure if that is relevant on a street bike .

 Dusty

 I'm no dirt bike expert but it seems they are mostly tapered diameter aluminum tubing...Bending a solid piece of 7/8 aluminum back into shape sounds difficult based on my experience working with metals..

[Triple Jim]

Solid aluminum bars will absorb some vibration and bend more easily than tubular bars .

It's true that for the same weight, a tube is stiffer (harder to bend) than a solid bar, but for the same diameter a solid bar is stiffer than a tube (harder to bend.  The section modulus for a 1/8" wall 7/8" tube is 0.0486, and for a 7/8" solid bar it's 0.0657, so the bar is about 35 percent stiffer.  It's also a little more than twice as heavy, so the small increase in stiffness comes at a high cost in weight.

[oldbike54]

 Wasn't referring to the effort it takes to bend a solid bar vs a tubular bar , more that a solid bar can be bent W/O breaking .

 Dusty

[Huzo]

Wouldn't go too far with bending aluminium bars after a stack. Aluminium develops fatigue cracks more readily than steel and you wouldn't want it to break off in service, heating it won't help it's ductility either

[twhitaker]

FWIW, the 7/8" bars on my V11 LeMans have the end turned down to 22mm where they fit into the clamps.

[pikipiki]

It's true that for the same weight, a tube is stiffer (harder to bend) than a solid bar, but for the same diameter a solid bar is stiffer than a tube (harder to bend.  The section modulus for a 1/8" wall 7/8" tube is 0.0486, and for a 7/8" solid bar it's 0.0657, so the bar is about 35 percent stiffer.  It's also a little more than twice as heavy, so the small increase in stiffness comes at a high cost in weight.

I'll just copy direct from wikipedia. Its slightly more complicated if the bar is not also T6 , looks like its plain 6016. Same chemical composition different process to make it = big difference in tensile strength -

6061   Edit
Annealed 6061 (6061-O temper) has maximum tensile strength no more than 18,000 psi (125 MPa), and maximum yield strength no more than 8,000 psi (55 MPa). The material has elongation (stretch before ultimate failure) of 25�30%.

6061-T4   Edit
T4 temper 6061 has an ultimate tensile strength of at least 30,000 psi (207 MPa) and yield strength of at least 16,000 psi (110 MPa). It has elongation of 16%.

6061-T6   Edit
T6 temper 6061 has an ultimate tensile strength of at least 42,000 psi (300 MPa) and yield strength of at least 35,000 psi (241 MPa). More typical values are 45,000 psi (310 MPa) and 40,000 psi (275 MPa), respectively.[4] In thicknesses of 0.250�inch (6.35�mm) or less, it has elongation of 8% or more; in thicker sections, it has elongation of 10%. T651 temper has similar mechanical properties. The typical value for thermal conductivity for 6061-T6 at 77�F is around 152 W/m K. A material data sheet [5] defines the fatigue limit under cyclic load as 14,000 psi (100 MPa) for 500,000,000 completely reversed cycles using a standard RR Moore test machine and specimen. Note that aluminum does not exhibit a well defined "knee" on its S-n graph, so there is some debate as to how many cycles equates to "infinite life". Also note the actual value of fatigue limit for an application can be dramatically affected by the conventional de-rating factors of loading, gradient, and surface finish.

[Triple Jim]

I'll just copy direct from wikipedia. Its slightly more complicated if the bar is not also T6 , looks like its plain 6016. Same chemical composition different process to make it = big difference in tensile strength -

I should have posted "assuming the same alloy and temper."  Pure aluminum has an even lower tensile strength than 6061-T0, if you're trying to find the softest aluminum around.