NateG

I have had what I assume is an early to mid eighties Motobecane Mirage for quite a long time, I haven't ridden the bike in about 10 years and I am currently working on refurbishing it as a bike to ride back and forth to work. I have already replaced the tires, cables, chain, inner tubes, front wheel and brake pads. I also have a set of MKS stream pedals for it, I ordered MKS touring pedals but they sent me the wrong ones but I will try these first. The last big thing to replace it looks like is going to be the crank set and bottom bracket, the large chain ring has broken teeth and the bottom bracket shaft is bent and the bearings are shot. I found a couple different sets of vintage Shimano crank sets on ebay for about $40, not original tourney's but I'm not going for original just reliable and inexpensive, but I am not sure what bottom bracket I will need. I know I can measure the length but I am not sure of the thread size and was wondering if anyone would happen to know what I need off hand.

wrk101

Hopefully you are after the Swiss phase. Some of the French bike companies transitioned from French to Swiss to eventually the Brit standard, all during the early to mid 1980s. Google Swiss bb, it will tell you how to identify it. After that era, the bb is all dictated by the crankset.

auchencrow

IF all else fails, you can buy a Velo Orange Grand Crue cartridge bottom bracket which basically plugs in irrespective of the threading.


Welcome to C&V Nate!

NateG

Thanks that helps, I googled it and apparently if it has reverse threads on the left side its Swiss and need to go with the Velo, I take it I would use the threadless version rather then the threaded. Hopefully this will be the last of the worn out parts I find If you don't include the consumable things, tires tubes ect, I think I will only have $170 into the bike, add in the rest of the stuff and its probably going to be about $250 which doesn't seem too bad at all.

NateG

Yay for ebay, I found a seller selling just the drive side crank and chainring set of almost the exact same cranks that are on the bike, the only difference is the small chain ring currently on the bike is 40t and the one I just ordered has a 39t ring. The best part is it was only $15 and looks almost new. Now I just need to sort out the bottom bracket, is it possible to just get the BB shaft and a new set of bearings and just reuse the rest of the parts?

Here's the listing: https://cgi.ebay.com/ws/eBayISAPI.dll...m=120744625016

NateG

I went down to the bike shop to see if they had any new axles kicking around and after about half an hour of looking another guy came over and asked what we were looking for, he went back and pulled out a small box of used axles I was able to find one that was almost exactly the same, the center width is the same but the drive side square end is about 1mm longer so I bought it and some new bearings. Just put it in and it looks like it should work fine. Now I just need to wait for the new crank arm and chain rings to get here and I can finally button this project up and start riding the bike.