Two different chains, same chain length, different wheelbase!

I bought a replacement chain for my BMX – obviously a 1/8” chain. I cut it down to the same number of links as the chain I was replacing. However, when I installed it, it was so long that to get any chain tension I had to have the axle right at the end of the dropout, almost falling out of the dropout. When I removed one link, the chain was so short that the axle had to be right the way forward in the dropout, and it was almost impossible to get the chain on the chainring & sprocket. With the old chain, the axle was in the centre of the dropout.

While the obvious solution to this is to get a half link chain, that’s not what I’m interested in – what I want to know is how two almost identical chains can give such a huge discrepancy. Any ideas?

1. They are not identical.
   
2. Magic
   

Purchase a bicycle designed for adults.

1. They are not identical.
   
2. Magic
   

1. Counting fail (but dont rule out pixies)
   

Err.... stretch and wear?

Err.... stretch and wear?

No, the new was longer, so shrinkage (but still betting on pixies).

No, the new was longer, so shrinkage (but still betting on pixies).

Considering the date surely Leprechauns are more likely?

It's down to the size of the parts that directly sit on the freewheel and chainring.
If one chain has a slightly smaller diameter of "rollers" the the larger one will pull the wheel in slightly... I gather you are talking about a small amount of difference here?

Fixed

It's down to the size of the parts that directly sit on the freewheel and chainring.
If one chain has a slightly smaller diameter of "rollers" the the larger one will pull the wheel in slightly... I gather you are talking about a small amount of difference here?

Fixed

^swat I said. Pixies, interferring with your rollers.

(would'nt the old chain appear to be longer as the rollers would be worn?)

Fixie pixies

Tooth fairies!

Pahah get it? Tooth.. chainring, chain.... nvm.