I was watching the new frames on sale and this 700c one just came up for 28 bucks shipped. It says it's chromoly but just plain steel would be a bargain also. I ordered it right away. Is there a way to verify metal is chromoly vs steel?
28 dollar cromoly frame?
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Explain please
Place one or two drops of concentrated nitric acid (full strength) on a metal surface that has been cleaned by grinding or filing. Observe the resulting reaction (if any) for about two minutes. Then, add three or four drops of water, one drop at a time, and continue observation. If there is no reaction at all, the test material may be one of the stainless steels. A reaction producing brown colored liquid indicates plain carbon steel. A brown to black color indicates gray cast iron or one of the alloy steels containing chromium, moly, or vanadium. Nickel steel will form a brown to greenish black liquid. Tungsten steel will form a brown colored liquid with a yellow sediment
You’re testing how much chromium is in the material
The tubes on carbon steel bikes are gas pipe construction. A very old metal industry method for making tubing from sheet metal. Invented in the 1800s, initially used for distributing gas to houses, so the name stuck. Cheap to do and able to make miles of it every day. Used for countless metal pipes like plumbing, electrical conduit, fence posts, furniture, etc. There is a seam weld on the inside running the length of the tubing. Use a flashlight and look in where you can. Also gas pipe tubing isn't exactly round. It rather depends on the individual production line that made them. The more rollers they used to change the flat strips to round, the more round the final product. You can use some decent calipers to measure the diameter and rotate the calipers around the tube and you will see the measurement change. Most frame builders will have to ream out the top end of the seat tube for the seat post. Same for a seamed steerer for the stem. Most straight seat posts are gas pipe. It's not unusual for them to vary by a 1.00 mm in diameter. Steel handlebars are usually seam welded too. Some gas pipe tubes, stays, fork blades are so out of round you can see or feel the seams.
most cro-mo is drawn. the old school high end brands like Reynolds, Columbus, Tange, Ishawata were made from solid steel alloy rod, heated until mushy, punched through and drawn through dies and sized on butted mandrels. They are pretty round. A caliper turned around them won't change. Reynolds did make a seam welded cromo straight gauge tube set one time. model 500 or 501 tubing. That was a rare exception.
Many mid range bicycle frames are a mix of cro-mo and carbon steel. I've seen some labled "cro-mo seat tube". Yeah, just 1 part of the frame. Many were cro-mo main tubes only like the Raleigh Super Course. Many high end bikes were cromo tubes, stays and forks but still had seamed head tubes made of regular steel.
Weigh the frame. Yes, cro-mo steel weighs the same as low carbon steels per cubic unit. But cro-mo is so much stronger builders can use thinner wall thickness tubing and get a lighter frame that is still much stronger.
Measure the wall thickness. 1mm is typical for cromo. 1/8" was used on the Schwinn EF frames.
most cro-mo is drawn. the old school high end brands like Reynolds, Columbus, Tange, Ishawata were made from solid steel alloy rod, heated until mushy, punched through and drawn through dies and sized on butted mandrels. They are pretty round. A caliper turned around them won't change. Reynolds did make a seam welded cromo straight gauge tube set one time. model 500 or 501 tubing. That was a rare exception.
Many mid range bicycle frames are a mix of cro-mo and carbon steel. I've seen some labled "cro-mo seat tube". Yeah, just 1 part of the frame. Many were cro-mo main tubes only like the Raleigh Super Course. Many high end bikes were cromo tubes, stays and forks but still had seamed head tubes made of regular steel.
Weigh the frame. Yes, cro-mo steel weighs the same as low carbon steels per cubic unit. But cro-mo is so much stronger builders can use thinner wall thickness tubing and get a lighter frame that is still much stronger.
Measure the wall thickness. 1mm is typical for cromo. 1/8" was used on the Schwinn EF frames.
Good info!
They had one more, in purple and fork included for 6 bucks more so I ordered it too.
I can check to see when the delivery happens, so I can send the wife out to get her hair or nails done or something.
I've only worked with standard headsets, so this will be something new to me.
They had one more, in purple and fork included for 6 bucks more so I ordered it too.
I can check to see when the delivery happens, so I can send the wife out to get her hair or nails done or something.
I've only worked with standard headsets, so this will be something new to me.
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Try and dimple the chain stays for a wider tire with a tool like this one on the bottom.
The delivery came while the wife was out spending money! So it will be stored away until the purple one shows up. The frame looks as good as the ad picture. The welds look good.
The inner diameter of the headtube is 35mm. I'll have to write that down and also measure the fork tube to make sure I get the right headset. The fork should arrive in a day or two. I'll look up the name to see if there are any reviews on these frames.
The inner diameter of the headtube is 35mm. I'll have to write that down and also measure the fork tube to make sure I get the right headset. The fork should arrive in a day or two. I'll look up the name to see if there are any reviews on these frames.
That’s a score for $28. I want one.
MattiThundrrr
Rattus All Terrainus
Tange made a seam welded chromoly as well. Their Infinity tubeset was made this way, and they were also able to double butt it. It allowed them to customize the butting without adding complexity or cost.
