http://www.specialized.co.uk/us/en/bikes/archive/2005/hotrockgirlsbikes/05hotrock206-speedgirls

Why would a magnet stick to a 2005 Hotrock frame? The specs say it is Aluminium???

Some sort of metallic paint? To be honest, given the weight of those things, it’s probably aluminium tubing filled with hi-ten steel.

The paint is metallic so possibly…any one able to confirm??

Where are you putting the magnet?
Welds, gussets, bottle cage bolts, headset races, probably the BB threads will all be steel. May have a steel seatpost too so it’s sticking to that rather than the alu frame.

it won’t be the paint.

It is more likely something like a steel seat post etc.

Welds and gussets will be steel? Eh?

How do you weld aluminium with steel?

remind me not to buy a frame that Crazy Legs has made 🙂

Did you ‘steel’ it?!? Haw haw!!!! 😉

You obviously have an Aluminum magnet instead of a steel one! 😉

Is it aluminium or aluminium alloy? Some alloys are magnetic.

Does it stick every where with a good solid thunk? Or just a few special places

It won’t, It’s sticking to some iron/steel nearby. Or the bike is just sticky – sap etc?

Pfffft! ampthill said “special place”, chortle!

too late for an edit

🙄

Do you check all your frames for magnetism?

[video]http://www.youtube.com/watch?v=P66fUkXqpYQ[/video]

We have one. I think the seat post is steel and goes through most of the seat tube. (It’s in the car or I’d check.)

Maybe she’s oiled it with ferrofluid?
[video]http://www.youtube.com/watch?v=eDnrFgd7yfo[/video]

nick1962 – Member
Do you check all your frames for magnetism?

I guess I might if I was going to buy a 2nd hand bike and suspected it wasn’t what the stickers said

though more likely the seat post is the answer

You can see if it’s Ally by looking at the welds anyway.

Can you? What’s the difference?

I just had a look at mine and the welds on the steel bikes look smaller. Is that what you mean?

Sit down and watch it for a couple of decades or so. If it’s steel you might notice some rust appear.

Haha!

Yep, that’s what I mean.

IDK if it’s to do with the wall thickness or what but usually Aluminium Alloy frames have welds something like 5-8mm wide, and Steel ones 3 or 4 wide.

Nope sold it and buyer is complaining. I have an identical one and a magnet does stick, I have a couple of other hotrocks and it doesn’t stick at all to them. Very odd…

well a quick google says 2003 models were steel – pic shows a straight top tube – think the ali models had a formed top tube to give stand over though they recently switched back to straight

Is it aluminium or aluminium alloy? Some alloys are magnetic.

I don’t think very much is made from pure aluminium, all bikes frames will be an aluminium alloy.

No aluminium alloys I know of are magnetic – they’d have to have a lot of iron in them. Even stainless steel isn’t very magnetic.

I’d guess either it’s not the frame you thought it was, or it’s steel rivnuts. Get her to send you a picture of the magnet sticking.