Removing French BB fixed cup
 

More on my Moto Grand Record project. I'm down to the BB. Removed the retainer ring & adjustable cup just fine. I thought the Park HCW-4 wrench would work on the drive side, but it is about 2 mm small. (The tool is marked 36mm, the fixed cup flats measure about 38). The BB I believe is a Stronglight. I am 99.9% certain it would be RH threads both sides based on vintage, model, etc. But I don't like the purchase that a large adjustable wrench gives on the narrow fixed cup flats, and I have no doubt it has never been out, so it will be tight. Is there a specialized tool I am not aware of that would fit? Any recommended hacks? This is the last part before I can get the frame to the powder coater.

I just found an old thread about this very problem from 2008. And unfortunately there was no definitive answer! Yikes. The most promising solution suggested for removal was clamping the flats in a vise. I don't know about that. I'll wait to see if anyone has anything interesting.

:popcorn

This usually gets a discussion going with the debate about who's method is the best one.

Seems odd to me as I have never had a fixed cup that was not standard size, I have several wrenches but my go to is my Sugino that I have had for 45 years, it never fails me.

I have a foolproof process that never fails or damages any tools, parts, frames or flesh, period.

It requires a couple of things that are very common aside from a proper wrench.

The direction in the pics is off depending on direction you're going but with this it doesn't matter, if you're going the wrong way it will "crack" loose then you reverse direction and spin it off, easy, peasy. ;)


https://cimg0.ibsrv.net/gimg/bikefor...4cd57d0dab.jpg
https://cimg3.ibsrv.net/gimg/bikefor...32ccf93f22.jpg
https://cimg4.ibsrv.net/gimg/bikefor...915aac66cf.jpg
https://cimg6.ibsrv.net/gimg/bikefor...0a4b956917.jpg

And here I thought that the proper method was just to ride the bike and wait for it to unscrew itself. I believe this is known informally as the @Andy_K method.

One of the oldest tools in my toolbox is one of those 36mm Park wrenches that I had to take a file to so that it would fit on a slightly oversized fixed cup, probably Stronglight. An alternative to not having that wrench is to use a bench vise to hold the flats and turn the frame, but you do need to figure out threading. Sutherlands has a chart on that:

https://cimg6.ibsrv.net/gimg/bikefor...a960da047f.png

I just use the large bolt, washers and nut with two wrenches as found buried on this page from Sheldon Brown. This is the method that worked for me on my Gitane TdF and on a very stuck Jeunet 630 BB.

yeah I just stumbled on that same article and it looks like a pretty brilliant solution if needed. Going to try the vice first.

Most vises that have lived a vise life will splay and not have good "purchase" with something clamped at the very top and will pinch it out under load. You can mitigate some of that by putting a spacer at the bottom of the jaws to keep them parallel.

When it pinches out, the vise will likely have the last word by dinging or scratching the frame.

The bolt and washer method works well for the most part, make sure it is centered and that the washers don't get into the bearing track if you plan on using it again, they can also slip and gouge it as well.

I've seen this butcher some fairly valuable and hard to find cups. ;)

Thanks good points. Not worried about scratching the frame, as it is a beater and getting it powder coated was half the motivation for this project. I don't want to ruin the cup. The races appear good looking in from the non drive side, and the surface chrome isn't bad either (especially compared to the bike!). Maybe I should consider leaving well enough alone and have the powder coat shop mask it off?

Do try to identify (rings, knurling, text; see Sutherland's above) the thread of the fixed cup before starting with heavy-duty tools -- Motobécanes were sold using both French (right-hand thread) and Swiss (left-hand) and maybe even English, though that might be Peugeot. Definitely both French and Swiss. If you've removed spindle and left cup, and cleaned the BB reasonably, you may be able to identify threading with a bright light. Photo might help too.

And if using the bench vise, double-check the direction you're turning before really leaning into it.

Alright maybe this is a dumb question but here goes: Why would a RH thread (as on this BB) unscrew itself on the drive side? It screws in clockwise. You pedal forward clockwise. What am I missing? It seems the potential problem would be on the other side: pedal direction counter-clockwise, BB RH threads unscrew counter-clockwise.

Some cups will come loose no matter what direction they go, Murphy's law, The Force, karma, etc. that being said Mark is trying to be funny. ;)

The VAR BB tool has several "jaws" to fit different fixed cup styles, I guess one would fit yours. Maybe a lbs has one, if you don't mind not doing it yourself.

Maybe, many here advocate leaving it in, not me, they always come out, no sense of humor, period.

IMO it is part of a proper service, R+R cup, clean, inspect cup and BB threads, lube and torque to spec so it comes out for the next time. ;)

Spindle says Stronglight 118.
https://cimg1.ibsrv.net/gimg/bikefor...fa09f63783.jpg
Drive side. 8 flats.
https://cimg2.ibsrv.net/gimg/bikefor...5604bdc987.jpg
adjustable cup. 6 flats

Would the marking on the drive side be "one ring", 8 sides?

I've read that it has to do with the bearings spinning counter-clockwise and the bearings are what's squashed up against the inside of the cup.

I’ve seen much different ring markings on Stronglight cups (a very small groove rather than a deep channel as on yours), but it’s likely French threading.

If you look at the axle, bearings, and cup as a planetary gear system it's easy to understand. Picture the drive-side, and focus on the ball at the top of the axle. The top of the axle goes forward as you pedal, it drives the bottom of the ball forward. The top of the ball drives backward, driving the cup against which it bears backward (i.e. anti-clockwise). So a left-hand threaded cup will be driven tighter by normal pedaling, a right unscrews.

That spacer idea will only work if you have a spacer exactly the same size as the cup you're trying to grab - another cup would do, but there is a better way:

You need a large bolt & nut, and two appropriately sized stout washers. One washer goes inside the cup, the bolt goes through that, put the frame in the vice and clamp the flats. The bolt should hang down between the jaws, take the other washer (which is big enough to span the gap at the bottom) under the jaws and put the nut on and tighten it. This way you don't even need to tighten the vice as much - you're not using the clamping force of the vice jaws to hold the frame in place.

I like it, but to be clear: the tightened bolt would be pulling the frame down to the vice, with the flats between the jaws acting like the wrench. The tendency for the flats to be ejected would be countered by the pulling force of the tightened bolt?

I know how it works, I never do it that way, have my own method that works way better for me, see post #2.

Been a mech/tech all my life, fomoco + ASE Senior Master tech for 25 years, 20+years drag racing motorcycles, lots of time spent wrangling and solving problems at work, home, on the road, track and everywhere in between. ;)

In case I muck things up or otherwise cannot continue using the original BB: anyone have any experience with Velo Orange French threaded sealed cartridge? They claim it will work, although their spindle is JIS and my Stronglight crank is ISO. Sheldon Brown offers some advice on making a spindle length adjustment when mixing these standards.

IIRC it is a counter intuitive thing called precession

https://www.sheldonbrown.com/brandt/left.html

I try, really, I do try.

If you really want to laugh, follow my publicist's posts. Now THAT guy is funny. His grammar and spellling are much better than mine to boot.

The first time that I had to deal with a very tight eight-sided fixed cup I wondered why they increased the # of flats, which only serves to increase the local stress where the wrench applies force!, and which increases the tendency for the wrench to slip and round off the corners of the cup.

So I was going to make an eight-sided wrench from 1/8" flat stock.
I also wondered if by chance some standard size of twelve-pointed wrench or socket might just happen to engage the flats/corners really well.
I tried a 1-1/2" socket and got my answer!
I also tried a 1-7/16" size, which would not fit on the cup.

Anyway, this has been my go-to method ever since.

https://cimg8.ibsrv.net/gimg/bikefor...30b609735c.jpg