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-   -   French BB Velo Sq Taper + SunRace 9spd Crankset (https://www.bikeforums.net/showthread.php?t=1196787)

loubikes 03-28-20 11:02 AM

French BB Velo Sq Taper + SunRace 9spd Crankset
 
I'm upgrading a Motobecane's drive-train and I don't know too much about bike mechanics beyond the basics (yes, glutton for punishment and financial woes).

I'm cold-setting and upgrading to 9 speed.

Here's my question:

Do you foresee any problems or missed-considerations in my decision to use these two components? The crankset requires a spindle length of 103, which is the length I will purchase from Velo Orange.Thanks!

dsbrantjr 03-28-20 01:13 PM

You might want to check with SunRace to ensure that the crankset taper is JIS to match the bottom bracket; it probably is but I did not see that specified and I am a belt-and-suspenders kind of guy..SunRace

bikemig 03-28-20 01:23 PM

Also the bottom bracket might be swiss threaded, not French, in which case the BB you are buying will not work. In a French BB, both sides are right hand threaded; in Swiss, the fixed cup is left hand threaded.

https://bikeretrogrouch.blogspot.com...m-bracket.html

Many Motobecanes do have swiss threaded BBs. They are also harder to find but not impossible. IRD sells cups for swiss threaded BBs and that may be the least expensive option.

https://www.interlocracing.com/shop/...bottom+bracket

You will want to post this question along with pics of the bike in the C&V forum. They may be able to help you sort out whether your BB is French or Swiss.

loubikes 03-28-20 01:38 PM

Great, I'll definitely do that, thanks!

loubikes 03-28-20 01:42 PM

Thanks bikemig, I actually have the BB off now ... EXCEPT for the fixed cup. I have now broken two 1/2 bolts trying to remove it using Sheldon Brown's suggested method for BB removal. Really wondering if it's Swiss but I can feel the threads from the other side and I'm 99.9% certain they are right-hand threads. I'm only second guessing what seems obvious because it's just not budging. I soaked it in PB blaster for a week and then broke the 2nd 1/2 bolt.

Going to take it to a bike shop to see if they can remove it I guess.

JohnDThompson 03-29-20 08:39 AM


Originally Posted by loubikes (Post 21388169)
Thanks bikemig, I actually have the BB off now ... EXCEPT for the fixed cup. I have now broken two 1/2 bolts trying to remove it using Sheldon Brown's suggested method for BB removal. Really wondering if it's Swiss but I can feel the threads from the other side and I'm 99.9% certain they are right-hand threads.

Are there any markings on the fixed cup face? If you're lucky, they will explicitly give the thread spec: "35 x 1" for French; "35 x 1 P1 S1" for Swiss. But older components may have more arcane markings:

http://www.os2.dhs.org/~john/bb-cup-markings.jpg
Source: Sutherland's 4th Edition


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