How to recoginize cromoly or hi-ten frames from their welds ?

[Sakamoto]

Hi,

I want to buy a used bike but I have no way of knowing if the frame is cromoly or hi-ten.

I have these pics, are the welding here a good indication ? What do you think the bike are made of ?

http://i.imgur.com/NYfrT5A.jpg

http://i.imgur.com/4rYwBx0.jpg

Thanks.

 

[danfoz]

A picture of the rear dropouts would be better. Cro-mo frames often have forged dropouts, hi-tensile frames often have stamped dropouts. It's no guarantee but may get you a step closer in your investigation.

 

[alfeng]

Do you happen to know the seatpost size?

Without offering a guarantee to the following ...

If the seatpost size is 27.2, 27.0, or 26.8, then it is probably CroMo ...

There are OTHER sizes which were used with CroMo frames, so a different size than the fore mentioned is not a disqualifier ...

Some 'early' 90s Treks made with True Temper steel tubing were theoretically spec'd to use 26.6 seatposts (a 26.8 seatpost seemed to work as-well-or-better in those frames) .

Some Hi-Tensile frames may now use 27.2 seatposts!?!

IMO, beyond the cosmetics & weight, the oddball seatpost size of many Hi-Tensile frames is the greatest inconvenience of a Hi-Tensile frame because the weight difference will generally not be that great ...

And so, the geometry of the frame AND fit (for you!) should possibly be your greater concern.

FWIW. CroMoly frames will typically have a decal-or-sticker on the frame indicating the type of tubing was used to fabricate the frame ...

When the "decal" is absent, then you can probably presume that it was made with Hi-Tensile steel tubing ...

SOME older frames did have "decals" indicating Hi-Tensile steel (e.g., some old Raleighs)!