eloist2

First off, I searched!

My buddy just got a 70's Motobecane road bike.
The crankset is in bad shape from what he tells me.

He ordered an Ultegra crankset to install on it, but when he took it to the LBS to get installed he discovered that his BB is french threading, cottered taper.

He wants to swap it out for a square taper so he can use his new Ultegra crank.

I have done a bit of research for him on sheldon brown and i see that Phil Wood makes a conversion BB for 115 bucks.

Is there a cheaper option?

Also, is there anything else I should tell him?
He lives in illinois, and I am in Nashville, so I am advising him over the phone.


thanks in advance guys!

Iowegian

Try here:

https://www.velo-orange.com/grcrufrthbob.html

Staggerwing

^^^^^Solution nailed on first response. VO is great to deal with too, and has many interesting bits.

vinfix

Maybe re-tap the threads on the BB? Or try Harris Cyclery? Unless this is a high end Motobecane it doesn't seem worth putting new Ultegra parts on. I had a Mirage basket case, I just re-packed the BB, but it was a little newer, early 80's, Swiss thread, cotterless

eloist2

Thanks guys!

I will point him towards the velo orange BB.

As for putting the Ultegra crank on the bike...he got a great deal on it. 80 bucks brand new!

wrk101

Ultegra crank does not use square taper, and has not for many years. My 2003 is octalink, newer ones have the external bearings, hollowtech II.

bleukahuna

I have an early Ultegra square taper on my PX-10 and a113mm Velo Orange BB

cudak888 

Hold on here. Provided this is a square taper crankset, has anyone bothered to check the bearing cup raceways to see if they're pitted or not?

If the cups are OK, only the spindle will need to be replaced.

-Kurt

bluenote157

i did this conversion to square tapered a couple of years ago on an old mercier? or was it a peugeot?? Anyway, if the cups are good, you can just get a spindle. I recall I needed to get a japanese spindle that had the lips of the spindle farther out (if that makes senes..??) so that when you install the cups, the bearings wont end up falling to the bottom of your bb.

abarth

I recently solved my Moto Grand Record French BB problem. I used the cups from a late 60's UO8 cottered crank with a Japanese square tapered spindle. It fitted perfect. With new bearings and grease, it spins flawlessly. YMMV.

top506

With a Moto be sure that the BB is French and not Swiss before you act.
Top

Grand Bois

Good advice!

Poguemahone

+2. Trusting a shop with French repairs can be... er... dubious. In many shops, they might as well be looking at a flying saucer when you bring in a Frenchie.

Many Motos were Swiss thread-- the fixed cup, though with the same thread pitch and diameter as French, is reverse threaded. The VO fix will not work on Swiss thread bike.

eloist2

thanks for the concerns.

here's an update:

my buddy is actually on his way down from Chicago right now with the bike.
I went to my LBS, they specialize in restoring vintage bikes.

They advised just swapping out the spindle as well, and I think this will be the most cost effective option.

As for the tapers on the Ultegra crank, it is a standard JIS square taper.
I am sure of it. My buddy sent me a pic.

So it looks like we'll just be swapping the spindle and repacking the BB.

I'll post some pics once we get going on it.


Thanks again for your help guys!