Titanium BB

[pubrunner]

I recently bought a french made NOS Titanium bottom bracket; indeed, on the box it states . . .

"Axe en Titane"

It weighs (with cups & end bolts) 235g.

However, a magnet sticks to every part; I thought that titanium wasn't magnetic ?

Has someone 'pulled a fast one' ?

 

[Gerry Attrick]

Titanium is regarded as "paramagnetic" and is only very weakly attracted to magnets. If your magnet holds fast, then questions should be asked.

 

[Gerry Attrick]

One thing, it is unlikely the balls in the bearings are titanium, is your magnet attached to them?

 

[pubrunner]

Titanium is regarded as "paramagnetic" and is only very weakly attracted to magnets. If your magnet holds fast, then questions should be asked.

Yes it does !

The bearings are in a case.

 

[pubrunner]

One thing, it is unlikely the balls in the bearings are titanium, is your magnet attached to them?

The magnet attaches to axle, cups - everything !

 

[snailracer]

Drop it in a bucket of concentrated hydrochloric acid. If it dissolves, it's not titanium.

 

[Fattman]

Drop it in a bucket of concentrated hydrochloric acid. If it dissolves, it's not titanium.

Yikes!

Drop it in a jar of water - if it displaces 30cubic cm it's steel, if it displaces 51cubic cm it's titanium. I think that's about right (7.8g/cc steel, 4.5 for Ti.) but always was a bit rubbish at maths.

A quick scoot round the internets suggests Ti often contains iron and so can be a bit more magnetic than expected... And how strong are your magnets? Fridge-magnet or skin-pincher rare earth?

 

[Tynan]

I was always taught that water is displaced my volume rather than material?

what on earth are you suggesting?

 

[Svendo]

I was always taught that water is displaced my volume rather than material?

what on earth are you suggesting?

That's right, but if as in this case we know the weight, we can measure the volume by dispacement, calculate the density and so deduce the material due to the different known densities of steel and titanium.

 

[Tynan]

but the bb must be the same size in steel or titanium surely so it's a simple matter of weight isn't it?

 

[steve52]

erm the density will not effect the displacment,only the volume, so even knowing the weight dosent help? how could it ,im often wrong so do explain please then one of us will lern somthing and if its me all to the good

 

[Tynan]

if a bb is always same size then the saving must be in weight due to lighter/stronger materials so making things out of carbon fibre/titanium/aluminum saves weight

thems my assumptions, if OPs bb weighs a lot less than a steel or whatever bb and does the same job then it's a winner I'd have thought?

this isn't the Archimedes gold crown connundrum I suggest

 

[Fattman]

if a bb is always same size then the saving must be in weight due to lighter/stronger materials so making things out of carbon fibre/titanium/aluminum saves weight

thems my assumptions, if OPs bb weighs a lot less than a steel or whatever bb and does the same job then it's a winner I'd have thought?

this isn't the Archimedes gold crown connundrum I suggest

I was slightly shooting from the hip while dealing with the kids' bath/book/bedtime, so it was with a headache... as Svendo said, you can get its density, which is known for steel & titanium - so you might have a stab at knowing what it actually is made of, and if pubrunner wanted to buy a Ti BB, he wants to get a Ti BB!

Not really a serious proposition anyway as you'll end up with water in it (which might cause trouble if you are trying to argue for recompense) and unless it is solidly one material and there are no air pockets etc. you might consider your findings inconclusive...

So apologies to the OP for going down a not-necessarily-very-helpful route for helping with what might well be a real issue.

 

[dan_bo]

Drag a sharp knife scross it. If it scratches, you've got a pup.

 

[pubrunner]

Drag a sharp knife scross it. If it scratches, you've got a pup.

"Woof"

I've got a pup !