Motobecane Help

pinksuedebike said:

I have inherited a Motobecane Super Mirage, date unknown [I am not a biker, I can't say anything more than mid-80's] and a piece on it is broken. It is the plastic cross-bit that holds up the lower part of the rear chain

the white piece in this photo. I'm sorry I don't know the names for parts of my bike, I hope I've explained it enough.

For a while, this broken bit was not a problem other than the fact that the chain would occasionally jump. I use the bike as transportation around a small college town, and it was only when I moved the gear shift that I had crippling problems: the upper joint of the rear chain mechanism stopped threading properly, causing the lower joint to bend in and lock in the spokes. So it is time for me to finally get that replacement part.

My problem is, I do not know where to find it. First of all, Motobecane, as I understand it, is no longer a bike company, and secondly, I don't even know the name of the part that I am looking for. All I can describe it as is "a small plastic bar with the words "Sachs Huret" on it". I searched that and looked around the SRAM website, but had a lot of difficultly knowing what I was looking at/for.

Can anyone help me?

It looks like you just need a new derailleur (although I can't see where it's broken in your photo) - that's the mechanism that moves the chain around when you shift. Pretty much any rear derailleur at a bike store will work but you'll probably need a new chain too. It's not a hard job to do but since you obviously don't have any experience at all you'd better let the bike shop do it. Won't be expensive.

I have a Motobecane Grand Touring that I bought new in 1980. I totaled my rear derailer twice and replaced it twice. I usually do my own repairs, but the second derailer was rubbing the gears. I brought it to my local bike shop where I bought the derailer and they were able to get it to work correctly. Don't remember what they did.

I remember the kid working on it had fun. Usually just got to set up bikes, fix flats, normal stuff. This was something different.

-- John