sunv

I recently bought a Shimano Dura Ace Cog 16t 3/32" from bikepartsusa.com
This is the cog: https://www.bikepartsusa.com/product_...2&p=01%2D95117

It came in the mail today and I noticed that it seemed a bit thicker than my other cog. And the teeth especially were thicker and lacked any thinning like my other cog. Thinning as in like a knife thins down to the blade. I think what im describing is like ramping.

Also on the back of the cog it says around it: DURA-ACE VIA SHIMANO JAPAN EH 18
I'm wondering what the 18 there means. I'm starting to suspect I received a 1/18" rather than the 3/32" I ordered. I checked the part number on the box and it matches with the correct 3/32 part online, but the cog looks a bit big to me. Can anyone tell me if my cog is 1/18 or 3/32? Is the difference in cogs with different widths extremely noticeable?

baxtefer

does it fit into your 3/32"chain?

freeskihp

if your cog is in-fact 1/8 then if you haven't bought your chain or chainrings yet get 1/8, problem solved

Chrysiptera

You might want to post this in the "Bicycle Mechanics" forum too.. I'd be inclined to agree with baxtefer; if it fits, ride it.

vee_dub

I think u got a 1/8...from ur description. But I am sure u can exchange it and they will bare the postage cost since its their fault for sending thr wrong product.

sunv

wait I thought you could interchange 1/8 and 3/32 in your drivetrain how ever much you liked. the only problem would be the horrid grinding sound it would make while riding because they would mesh right.
So are you saying 1/18 cog teeth wouldn't fit in the links of a 3/32 chain?

But to answer freeskihp's question, yes I have bought a 3/32 rocket ring and 3/32 chain already. So I would like the cog to be 3/32. I will try the cog on the chain later when I get all my parts in.

bonechilling

Check to see if your cog has the NJS stamp. If it does, it's 1/8", if not, then it's 3/32".

sunv

Yes I think I got the wrong cog
Mine looks more like this 1/18" cog:


Than this 3/32" cog which has beleveled teeth:


Yes I guess I might as well shoot the people at bikepartsusa an email saying I need an exchange.
Sucks I wanted to be able to ride by this weekend.

freeskihp

you can put a 1/8 or 1/32 cog and/or chainring under a 1/8 chain

you can not put anything 1/8 under a 3/32 chain

sunv

Ok that is very relieving to hear. Thanks for the clarification freeskihp. Anyways here is a picture of my cog
I'm so dumb I read the 16 stamp as 18. Its easy to get confused when the number is stamped so small. So the 16 just indicates the teeth number. Im still puzzled as why my cog has less beveling on the teeth than other 3/32 cogs.

Here is a picture:

freeskihp

you have the 3/32. If you wanted to make sure though you just need to see if your chain sits flush on the cog

666pack

hold the phone here, a 1/18" drivetrain... as in one eighteenth of an inch?

wow, ultimate.

sunv

lol oops i've been saying 1/18
i meant 1/8, im having major brain diarreha today

Sizzle-Chest

the quickest way to check is see if your 3/32 chain will wrap around the cog

lvleph

Your's

1/8


3/32




Compare the images. You have a 3/32. 1/8 has a bevel below the teeth and 3/32 doesn't.