Motobecane chain issue

At the advice from some posts in this forum, I replaced the drive chain of my Motobecane 50V with a 420 chain, as the 418 chain is difficult to find. The chain fits on the rear sprocket without issue, but it does not fit the front sprocket behind the pulley. Is there something I can do to fix this? Is there an aftermarket sprocket that is made for a 420 chain? I didn't find a post from someone who had this same issue. Any advice would be appreciated!

Re: Motobecane chain issue

You want a 415 chain.

Re: Motobecane chain issue

On the drive side? I was going off the below:,3968229,3935990,3963713

I saw some people running 420. Does it require modification? I can try 415 though, I just can't return the 420 as I used a chain breaker.

Thanks for the advice! I can just pick up 415 if it meshes with the teeth of the front sprocket

Re: Motobecane chain issue

The two chains are very similar , but , the 415 is 1/16" narrower than the 420 . Also , the 420 has higher tensile and a slightly bigger pin .

Re: Motobecane chain issue

Thanks all! Ordering a 415. Surprised to see people running 420. It has to require notification or something. Someone mentioned grinding down a tooth on the front sprocket, but oh well.

Re: Motobecane chain issue

Here's something to think about.

Bigger chain means more rotating mass and weight. That costs you horse power to the back wheel with an already meager 2 hp @ the crank.

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