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Post by brianbutler on Nov 13, 2020 12:54:58 GMT
I recently acquired a 1975 Motobecane Grand Touring for parts and maybe refurbishment. It has a gas pipe 1020 frame, unlike the later Vitus butted frames. The main problem with the frame is that it has a Swiss BB (i.e. French thread dimensions but left-threaded on the drive side). The drive side flats were damaged, probably from a previous attempt to remove the cup the wrong way. I made it much worse with various tools on the flats. As an exercise, I will try the internal bolt/lockwasher/nut kludge that I have disparaged here several times.
If I get it out, I have the problem of finding a Swiss BB replacement. I am NOT spending $200 on a Phil Wood because it is not a great frame. I am thinking of using an English threaded Sunlite sealed BB and plumbers tape to snug up the threads. The dry fit is actually pretty good. I am interested in critiques of this idea as well as other suggestions.
One alternative would be to reuse the existing BB but rework the flats to a narrower size. I would have to take it to a machine shop for milling, however.
Brian
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Post by oldroadietehachapi on Nov 13, 2020 15:57:08 GMT
I recently acquired a 1975 Motobecane Grand Touring for parts and maybe refurbishment. It has a gas pipe 1020 frame, unlike the later Vitus butted frames. The main problem with the frame is that it has a Swiss BB (i.e. French thread dimensions but left-threaded on the drive side). The drive side flats were damaged, probably from a previous attempt to remove the cup the wrong way. I made it much worse with various tools on the flats. As an exercise, I will try the internal bolt/lockwasher/nut kludge that I have disparaged here several times.
If I get it out, I have the problem of finding a Swiss BB replacement. I am NOT spending $200 on a Phil Wood because it is not a great frame. I am thinking of using an English threaded Sunlite sealed BB and plumbers tape to snug up the threads. The dry fit is actually pretty good. I am interested in critiques of this idea as well as other suggestions.
One alternative would be to reuse the existing BB but rework the flats to a narrower size. I would have to take it to a machine shop for milling, however.
Brian
I think I have some Swiss BB cups about; shall I look for them? |
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Post by brianbutler on Nov 13, 2020 16:03:07 GMT
Not yet, but thank you. I have had problems before with cups that did not match the spindle. I may even have some Swiss cups in my Box o' Stuff. Unfortunately they are probably not labeled as such so I will have to test.
Also, this is just an exercise because I doubt I will use the frame for a build.
Brian |
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Post by wheelson on Nov 15, 2020 11:42:20 GMT
Not yet, but thank you. I have had problems before with cups that did not match the spindle. I may even have some Swiss cups in my Box o' Stuff. Unfortunately they are probably not labeled as such so I will have to test.
Also, this is just an exercise because I doubt I will use the frame for a build.
Brian Now you have me wondering if my 1962 Motobecane Cyclotouriste bb is Swiss threaded. This frameset was purchased on eBay, and the bike was intended as a city bike for the German market. It has a built in wheel lock on the left seat stay. I’ll get some photos up as I start to restore it during the winter shutdown. Sympathetic restoration since it has some pretty neat box lining on the paint that I really don’t want to lose by repainting. Best, John “wheelson” |
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Post by oldroadietehachapi on Nov 15, 2020 15:41:14 GMT
I have a Swiss made Super Mondia frame and was surprised to find it having French BB threading instead of Swiss. I have two Motobecanes, both French thread.
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Post by brianbutler on Nov 15, 2020 22:12:05 GMT
A few years ago I reconditioned a Motobecane Nomade for someone. I believe it had French threading. A few months ago I disassembled a 1977 Motobecane Grand Touring that I am restoring. It has a Swiss threaded Vitus frame. I knew it was Swiss when I took it apart, although I don't know how I knew it. I think maybe I tried unthreading left and felt it tighten, so I went right and it came out. The current Motobecane is a 1975 Grand Touring with a 1020 steel frame. I assume it is Swiss threaded based on the other one, but that could be a mistake. It is a couple of years older and a different tube set, so maybe I have been trying the wrong way. The cup flats are pretty well destroyed at this point but I am keeping the frame so I can figure out how to remove the cup. Aside from the 1020 steel, the frame is in great condition with a nice red paint job.
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Post by oldroadietehachapi on Nov 15, 2020 22:44:01 GMT
I take it the cups are still in and you don't know if it is left hand or right hand thread; I hate that.
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Post by brianbutler on Nov 15, 2020 23:25:59 GMT
Both cups from the Vitus frame are out and in good condition, the right cup being left-threaded. The left cup is out of the 1020 frame and is good. The right cup is stuck with damaged flats and I'm not sure which way it is threaded but the left cups are identical (Sakae 35xP1, which I believe are French thread dimensions, Japanese manufacture notwithstanding) and the bikes are the same make and model, two years apart. I am working on the assumption that the 1020 right cup is also left threaded, i.e. Swiss. If I can get it out without much more damage, I might be able to file the flats down to a smaller dimension and re-use the cup.
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Post by oldroadietehachapi on Nov 16, 2020 1:06:36 GMT
Probably the same. Motobecane frames were sometimes not consistent in specification. Can you see the threads from the side with the cup removed? If so, you might be able to tell if left or right thread. If you (or anyone else) are interested in Motobecane projects, I have an extra 1978 Team Champion frameset I most likely will never get to. I bought it for the fork, so it comes with Columbus replacement. All French thread. Sell, trade?  Motobecane TC 1978 frame by Jim_Gude, on Flickr |
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Post by brianbutler on Nov 19, 2020 15:23:43 GMT
The offending drive side cup has been removed. It turns out to be French threaded, not Swiss. The final bout involved the internal bolt/washer method with plenty of Kano Kroil and a long breaker bar turned clockwise because I thought it was Swiss (i.e. left threaded). The assumption was based on the facts that the bike is the same make and model, but two years apart, as another one that WAS left-threaded, and the markings on the left cups were identical.
After pushing on the cup to the point where it was deforming a Grade 8 bolt, I gave up and decided to remove the bolt/washer assembly which was now also stuck. Using the breaker bar in reverse (left) this time, the entire cup/bolt started to rotate and I was able to remove it.
The flats on the cup are damaged but the inside looks OK. I will clean it and keep it with the rest of the BB, properly labeled FRENCH. Ironically I probably will not use the frame because it is quite heavy (1020 steel), but I will keep it hanging around for a while as well.
NOTE: Thanks to OldRoadie for the suggestion to look at the drive side threads through the left side of the BB. I tried that but could not confidently determine the thread direction visually given what was exposed. I am interested in any further suggestions on this technique because would be useful any time a French bike (and more particularly Motobecane) is involved.
Brian
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Post by oldroadietehachapi on Nov 20, 2020 0:57:17 GMT
Hi Brian! I have an automotive digital inspection camera (bore scope), which helps a great deal. They now have inexpensive versions that attach to your cell phone for about 12 bucks. You can also use a 90 degree pick to feel about and maybe discern right or left thread. You put a mark on the shaft (aligned with the BB shell) and see what happens when you follow the thread.
All The Best
Jim
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Post by brianbutler on Nov 20, 2020 3:33:40 GMT
Thanks Jim. My main problem with following the threads was that the portion exposed was discontinuous due to the holes cut for tubes entering the BB. But perhaps with better lighting and/or the inspection camera you mentioned I could have figured it out.
Finally, the cup was ruined using the bolt clamp technique. The hard Grade 8 hardware under heavy torque forged a pattern on the inside of the cup and squeezed the area around the hole into a smaller diameter. RJ strikes again. I should really stop listening to that guy.
Fortunately it is a French BB, which is much easier to find than a Swiss BB in case I ever need one, but most of the components on this bike are already destined for other projects, so I would be left with only a clunky frame without a bottom bracket - yard art I guess.
Brian
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Post by oldroadietehachapi on Nov 20, 2020 5:21:44 GMT
Someone made this bike bunny with an old frame.
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