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Discussion Starter · #1 ·
I want to buy a new freewheel and have no idea if I am supposed to be getting a 3/32" or 1/8"?

The bike is an IRO Mark V. I emailed them this morning but haven't heard back yet.

I checked their website and it doesn't mention the size of the chains, chain rings or freewheels. It does say the cogs are 3/32", but I just want a different size freewheel for now.

One would think a 1/8" is a bit more durable so I'd prefer to get that, but I don't want to get it and find the chain and chain ring are 3/32".

If I measure these myself, how do I measure them? Those are pretty precise measurements to use a ruler and eyeball it.
 

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Discussion Starter · #3 ·
Dave Hickey said:
If your chain is 3/32", you need a 3/32" freewheel....If your chain is 1/8" you can use either 3/32 or 1/8' freewheel
Is it going to say somewhere on the chain what size it is? If I measure it myself, what am I measuring? The gap of the area that the teeth would fit into (the inside part of the chain)? Or the entire width of the chain - including the metal?

I do have calipers I can use to measure.

Sorry, I learn something new about bikes everytime I have to replace a part.
 

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what do you have?

Do you have any chains or cogs that you know the size of? You could compare.

If you have a 1/8" cog or chainring, a 3/32" chain will not wrap around it, but will sit up on the teeth.

Sometimes a chainring will have the size stamped on the back somewhere. Same for cogs.

You could measure your existing cog/freewheel, the width of the teeth.

Some websites incorrectly identify this spec as "pitch." This is not pitch. Almost everything is 1/2" pitch, the distance between adjacent teeth or links of a chain.
 

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Discussion Starter · #5 ·
Errrr. No response from IRO yet. Is it stupid to worry about this? Sounds like a 3/32" will work all around so there is no risk in getting that size.

I tried measuring last night, no luck. I can't tell. I have some links from my old geared bike that is likely 3/32" and it appears to be the same size as the chain on the IRO, but the difference is so small I really can't tell.

If the rest of my components are 1/8", is there any advantage to sticking with that? Or should I just get 3/32" and not worry about everything being 1/8" or 3/32"..
 

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Nickel II said:
Errrr. No response from IRO yet. Is it stupid to worry about this? Sounds like a 3/32" will work all around so there is no risk in getting that size.

I tried measuring last night, no luck. I can't tell. I have some links from my old geared bike that is likely 3/32" and it appears to be the same size as the chain on the IRO, but the difference is so small I really can't tell.

If the rest of my components are 1/8", is there any advantage to sticking with that? Or should I just get 3/32" and not worry about everything being 1/8" or 3/32"..
If you compared a geared chain to the chain on your IRO and they look the same, it's 3/32.

The difference between a 1/8" and 3/32" is obvious when compared side by side
 
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