This is a hard one....

[ribbert]

Does our resident metallurgist, or anyone at all, have an opinion on the C49?





It's on a recently purchased JT sprocket.

Noel

[fj1289]

C49 appears to be a variety of high carbon steel.   I have no idea what in "particular"* differentiates it from other high carbons steels nor why it would be a good selection for this application.   I'd simply trust JT (or other parent heavy industry) that chose the alloy based on strength, durability, compatibility, and economic value. 








* pun intended - the added "particles" that make up the alloy and create desirable stresses in the crystal structure of the steel being alloyed

[ribbert]

* pun intended - the added "particles" that make up the alloy and create desirable stresses in the crystal structure of the steel being alloyed

Haha, as was my subject heading.

I know what it's meant to indicate, but can you find any reference to it anywhere or is it just a bit of creative marketing from JT. The previous set was C40.

Noel

[Pat Conlon]

The folks at JT mention that they are the only motorcycle sprocket manufacturer that uses C49.
Looks to be an up grade over the earlier C45 sprockets made by JT.
http://www.jtsprockets.com/fileadmin/files/press/The-JT-Sprockets-Difference---Parts-Magazine-Mar-2011.pdf

[ribbert]

The folks at JT mention that they are the only motorcycle sprocket manufacturer that uses C49.

That was my point, I can't find any reference to it on the net other than in JT's own blurb, hence my question for an expert, is it real or is it marketing hyperbole.

[Carson City Paul]

Does our resident metallurgist, or anyone at all, have an opinion on the C49?





It's on a recently purchased JT sprocket.

Noel

If the carbon content has been increased it will heat treat to a harder RC giving it a better wear resistance.
If you go to hard it becomes more brittle and can break under shock.

[Carson City Paul]

Does our resident metallurgist, or anyone at all, have an opinion on the C49?





It's on a recently purchased JT sprocket.

Noel

If the carbon content has been increased it will heat treat to a harder RC giving it a better wear resistance.
If you go to hard it becomes more brittle and can break under shock.

There is carbon steel, high carbon steel and ultra high carbon steel.
I doubt this would fall under the ultra high category, ultra high carbon steel would not be suitable for this application. 

[Millietant]

So, I'm guessing "C45" steel is this

https://www.makeitfrom.com/material-properties/SAE-AISI-1045-S45C-G10450-Carbon-Steel

And "C49" steel is this

https://www.makeitfrom.com/material-properties/SAE-AISI-1049-G10490-Carbon-Steel

Hardness and strength seem higher in 1049 vs 1045, with 1049 potentially having a tiny bit more carbon in it. Lots of info in the tables for comparison.

[Bones]

Just had a look and the new sprocket I bought recently for my GSXR rear wheel is an MTX brand and is also made from C49 carbon steel. I don't normally take any notice of numbers apart from teeth count, as long as it's a steel sprocket and not alloy. Will have to check the old one out of curiosity now.

[fj1289]

From the category of making shit up ...

I'm going to guess it is a .49% carbon alloy - making it in reality a mid carbon steel (but toward the higher end of that range.  It would also be in the range to be suitable for gears and "train tyres" - makes sense to me to use it for sprocket use them.  Good "tooth" strength for gears would translate to sprocket use pretty well - maybe better without a v-type groove to concentrate stresses.  And the long wearing properties that make is suitable for "train tyres" (still think that is a funny term) while not being so hard as to prematurely wear the companion piece (train track in this case — the chain in our case) would also translate well to sprocket use. 

Then again - that could all be a load of crap!   

[Carson City Paul]

Working as a machinist for over 51 years, 4 in tool and die, 4 in gear cutting and the rest as a conventional machinist I have worked with a wide variety of materials.
That being said, it still doesn't make me an expert. I have machined parts from cast iron, brass, bronze, aluminum bronze, tin bronze, all series of stainless steel, air hardened tool steel, oil hardened tool steel, 1018, 1045, 4140, 4340, 8620, titanium and i"m sure I may have left something out.
The majority of my final years working were spent making parts for production and manufacturing equipment. Over the coarse of those years I made changes to the materials that were being used to improve performance and longevity. My experience working in gear cutting and tool and die helped me to better understand the different materials and their uses.

Back to the subject of the C49 sprockets. I too would suspect that the manufacturers probably tested different formulas (C46, C47, C48, C49 and beyond and came to the conclusion that C49 was as far as they could push the envelope without failure.
You might also be interested in knowing the front sprocket is not made from the same material. It is made from SCM420 Chromoly steel alloy. And to the fellow that wouldn't run an alloy sprocket on his bike, I have news for you, you are running alloy sprockets on your bike.

Live Long and ride as long as your able... Cheers!
 

[Sparky84]

and if they don't have a C number on the JT sprocket?

I can see the C49 and C45 on a couple but none on 1

[ribbert]

I can see the C49 and C45 on a couple but none on 1

Geez Alan, do you collect them?

Noel

[Old Rider]

Cleaned and lubed  the chain the yesterday and did a check and I have the c49 The chain and sprockets has  run a little under 20 000 km.

[gumby302ho]

Working as a machinist for over 51 years, 4 in tool and die, 4 in gear cutting and the rest as a conventional machinist I have worked with a wide variety of materials.
That being said, it still doesn't make me an expert. I have machined parts from cast iron, brass, bronze, aluminum bronze, tin bronze, all series of stainless steel, air hardened tool steel, oil hardened tool steel, 1018, 1045, 4140, 4340, 8620, titanium and i"m sure I may have left something out.
The majority of my final years working were spent making parts for production and manufacturing equipment. Over the coarse of those years I made changes to the materials that were being used to improve performance and longevity. My experience working in gear cutting and tool and die helped me to better understand the different materials and their uses.

   You must remember the old IndexingHeads. The number crunching and formula and table sheets to figure it all out. I cant remember any of it anymore but I remember the Tool. You could mount it on a horiontal our universal mill and had the plates with all the tiny holes to follow, one wrong move, ooops. I miss cutting steel. And everything was still imperial. Not saying metric sucks, I use it but imperial is hardwired in my brain.