Cro-mo frame???

The place for fixies and other rides without gears

Cro-mo frame???

Postby pembo6 » Fri Dec 07, 2012 1:42 pm

Is there a way to tell if my old Japanese made frame is steel or cro-mo?

I assumed it was steel but it seems to be rusting different from my other steel frames and it seems lighter.

I only recently found out there was a difference between the 2.

Its an old japanese Gordonson frame. may from the 70's or 80's?

Thanks
pembo6
 
Posts: 23
Joined: Sun Sep 16, 2012 2:35 am

by BNA » Fri Dec 07, 2012 1:46 pm

BNA
 

Re: Cro-mo frame???

Postby BRLVR.v2 » Fri Dec 07, 2012 1:46 pm

BRLVR.v2
 
Posts: 725
Joined: Sat Jul 09, 2011 8:33 pm

Re: Cro-mo frame???

Postby Mulger bill » Fri Dec 07, 2012 10:17 pm

But what are gaspipes made of?
...whatever the road rules, self-preservation is the absolute priority for a cyclist when mixing it with motorised traffic.
London Boy 29/12/2011
User avatar
Mulger bill
Super Mod
Super Mod
 
Posts: 25800
Joined: Sun Sep 24, 2006 2:41 pm
Location: Sunbury Vic

Re: Cro-mo frame???

Postby Nobody » Fri Dec 07, 2012 10:42 pm

1020 "high tensile" usually.
Nobody
 
Posts: 6640
Joined: Thu Sep 18, 2008 12:10 pm
Location: Sydney

Re: Cro-mo frame???

Postby Mulger bill » Fri Dec 07, 2012 11:01 pm

Nobody wrote:1020 "high tensile" usually.

'Zackly, some steels are realer than others :wink:
...whatever the road rules, self-preservation is the absolute priority for a cyclist when mixing it with motorised traffic.
London Boy 29/12/2011
User avatar
Mulger bill
Super Mod
Super Mod
 
Posts: 25800
Joined: Sun Sep 24, 2006 2:41 pm
Location: Sunbury Vic

Re: Cro-mo frame???

Postby pembo6 » Mon Dec 10, 2012 7:53 pm

Let me rephrase my questions then.......

Is it possible to confirm if a frame is 4130 chromoly or 1020 steel ? I cannot find anything stamped into the frame other than "made in Japan".
pembo6
 
Posts: 23
Joined: Sun Sep 16, 2012 2:35 am

Re: Cro-mo frame???

Postby barefoot » Mon Dec 10, 2012 8:42 pm

pembo6 wrote:Let me rephrase my questions then.......

Is it possible to confirm if a frame is 4130 chromoly or 1020 steel ? I cannot find anything stamped into the frame other than "made in Japan".


Seatpost size can be an indication.

Steel seat tubes all have the same outside diameter. If the material is better quality (ie better than gas pipe), and strong enough to allow it, the wall thickness is reduced - so a bigger seatpost is required.

Gaspipe frames usually have 1" (25.4 mm) seatposts. If the post is bigger than that, you've got a thinner wall tube which is indicative of CrMo. 27.2 mm is a typical seatpost in a good CrMo frame.

tim
User avatar
barefoot
 
Posts: 988
Joined: Tue Jan 29, 2008 10:05 am
Location: Ballarat

Re: Cro-mo frame???

Postby find_bruce » Mon Dec 10, 2012 8:44 pm

pembo6 wrote:Let me rephrase my questions then.......

Is it possible to confirm if a frame is 4130 chromoly or 1020 steel ? I cannot find anything stamped into the frame other than "made in Japan".

If you have a bare frame the easiest weigh is weight - the whole point about 1020 is that it's cheap but soft so they used a lot of it.

Anywhere around 2kg for the frame is most likely cromo- could be some other exotic alloy but that's not a bad thing. Fork should be 1kg or less.
Image
User avatar
find_bruce
 
Posts: 3733
Joined: Mon May 09, 2011 8:42 pm
Location: Sydney

Re: Cro-mo frame???

Postby HLC » Mon Dec 10, 2012 11:29 pm

If its a Japanese made gordonson, it is most likely an old gas pipe shitter.

Without doing some metallurgical tests, you'll never know what your frame is made out of... Other than 'steel'. Sad but true.
User avatar
HLC
 
Posts: 646
Joined: Sun Mar 04, 2012 10:23 pm
Location: Sydney.


Return to Fixed Gear/ Single Speed

Who is online

Users browsing this forum: Exabot [Bot]



Popular Bike Shops
Torpedo 7 Torpedo7 AU
Ground Effect Ground Effect NZ
Chain Reaction Cycles CRC UK
Wiggle Wiggle UK
Ebay Ebay AU

“Bicycles BNA Twitter
“Bicycles BNA Facebook
“Google+ BNA Google+
“Bicycles BNA Newsletter

> FREE BNA Stickers
> BNA Cycling Kit