I am trying to upgrade my early 80's Schwinn Continental's cranks. (and bottom bracket of course)

I got the Truvative American to Euro bottom bracket adapter, but I can't get it to work. As this photo hopefully illustrates, two out of three of the screw holes are partially blocked by an inner steel band. Unless I'm missing something? I've searched this forum and found a lot of posts suggesting that the adapter will work with Schwinns of that era, but perhaps mine is special?



Some helpful folks on a local bike forum suggested cutting through the inner band with a Dremel, and that will be my next step I guess, but I thought I'd post the question here also, given that the larger audience may include someone who's encountered this exact situation before and may have an alternative suggestion.

Following the advice in a couple of other threads here about not using the adapter screws to pull the two sides together, I cobbled together a DIY press with a huge bolt, a nut and some washers, but there is no point in pressing in the adapter if I can't screw the thing together.

Thanks in advance for any suggestions or advice.

You have few options...

1. Dremel or file channels for the scews.
2. 'Glue' the adpaters in place. Try green Loctite or a little JB weld. If you go with JB weld I'd only use it in a few spots, maybe a few dabs every 90 degrees.

I am not sure. I need to see what the BB looks like. that had an Ashtabula crank yes? I have seen pics of adapters on here that use what look like regular Asht. type cups bearings and cones, it just has a square taper spindle. is this something like that?

yes, this is an one piece (ashtabula) crank. The only solution is to get a hammer and pound those things out...

but that frame itself is about 12 pounds.

it must be a labor of love.

Yes, you need to remove the Ashtabula bearing cups before installing the TruVative adapter.

OH thanks Scooper now I see how this works, something like an ecentric adapert right? all he need to do is grind enough off those flanges for the screws, providing there is enough depth between the edge and the flange for the cups

The old Ashtabula bearing cups are pressed into the BB shell on both sides of the Continental frame's BB shell and need to be punched out of the BB shell with a drift punch and hammer before installing the adapter. The TruVative adapter then replaces the old bearing cups. The adapter is concentric, not eccentric.

Wow. That looks different then any Schwinn one piece BB shell I've ever seen. Mine have all had a clear shot through the BB shell. I've converted two Super Sports, a Continental, a Twinn Sport (with 2 BBs), and knocked the cups out of a few Varsities and Collegiates and never seen that ridge. Weird!

By any chance was this a Shimano front freewheel Schwinn?

I think the cups are out. the flanges are just odd

Here's an Ashtabula crank bearing cup removed from the red Super Sport BB shell when I installed the TruVative adapter. I could be mistaken, but I think the cups are still in the OP's BB shell.

I don't see any cups in the OP's pic, unless they are invisible.

Uh, that big metal thingie that appears to be pressed into the BB shell?

There isn't much else it could be. Just don't ask me why nearly a quarter of the race is cut away, 'cause I don't have a clue.

You'll note though that that metal sleeve goes all the way from one side of the BB to the other. There's no way that is part of a cup. It's just a sleeve reinforcing the BB, Columbia use a similar form of reinforcement.

Well, I wish the OP would check in. When I pulled the cups off the Super Sport, there was just the inside of the shell. I wouldn't expect Continental to be different. The OP took the photo looking directly at the BB shell, and to me it looks like the cup on the near side, the cup on the far side, and one piece of the TruVative adapter on the outside of the far side cup. I think I see the ends of the down tube and chainstay inside the shell, so if there's a sleeve, wouldn't those tube ends be covered up by the sleeve?

Here's the Super Sport BB shell without the cups (no sleeve).

the tubes pass through the sleeve, which means there's no way to remove it (so it wouldn't possibly be part of the cup).

Regardless of whether or not the cups would have been removed, the bolts for the adapter are not going to clear the sleeve.

Gosh, don't you wish the OP would come back and answer some questions?



I agree with Mos6502, there's a flange in there most of us are not used to seeing. Made me wonder about the bike, even if it was really a Schwinn, so after doing a little internet snooping, I came up with this picture of the entire bike.

I believe this solves the mystery. It's a super size Continental! Possibly the 26" or even the 28" model. It probably needed a very rigid BB shell to take the extra leverage caused by the long seat and down tubes.



Interestingly, the decals appear to be consistent with the '83-'85 style, but the Continental is not included in those catalogs. Here's the page from the '82 catalog, listing the frame sizes.

Wow! This is exactly the kind of response I was hoping to get - clarification that that inner sleeve (I've been calling it a band) was not usually found in the Schwinn bottom brackets of that era. I figured it must be an anomaly since all the other postings about using the Truvative suggest that installing it was a fairly straightforward operation.

The guy from whom I bought the bike said it was "early eighties" but he didn't know for sure. When I got the bike three years ago I looked up the serial number and since then I've been saying it was an '82 - but the decals (long gone by now) definitely don't look like the images from the 1982 catalog. I don't have the serial number with me. I'll look again next time I get home. (I'm forced to ride my sweet unmolested early 80's Trek 500 while the Schwinn is in quaqmire status.)

I most definitely punched out the cups in case anyone is still wondering. Here they are:



So we've established that the sleeve is unusual, and that the adapter screws won't clear the sleeve.

I should clarify that the sleeve does only wraps abound about 2/3 of the inner surface. There is room in its gap for one of the screws.

As MiamiJim did here, some helpful folks on a local bike forum suggested cutting some channels in the sleeve for the screws. That was going to be my next step. But in light of Pastor Bob's theory:
It probably needed a very rigid BB shell to take the extra leverage caused by the long seat and down tubes.

I wonder if digging out a couple of paths is a good idea - stability wise?

And yes, I realize that the bike is heavy and that all this effort and expense is rather silly but I'm enjoying the process and learning a lot on the way. I commute on the thing year 'round in Chicago and it serves my purposes wonderfully without being a very attractive target for theft.

I'm super grateful for everyone's help here!

I've never seen that inner band before. I agree that it looks like the tubes pass through it almost as if the bottom bracket is not electroforged...

Since those screws only keep the adaptor from rotating, I'd wash down the area with mineral spirits to get any oil out of there and JB weld the adaptor in.

Hmm... the adapter is going to require some pressing or hammering to get all the way in. I have no experience with JB weld (despite maintaining an Airhead BMW for many years). Does it take a while to set up? That is, if I use it will I still have time to press in the adapters?

In general I'm a bit leery of using anything glue-like be it green locktite or JB Weld or whatver on a bike, but I'm grateful for the suggestion and at this point I'm certainly not ruling anything out.

The tubes and chainstays do open into the BB shell through the inner band.

I stand corrected.

At this point, I think I'd use a Dremel tool with a grinding tip or maybe a hacksaw to create grooves in the sleeve just deep enough to provide clearance for the adapter bolts.

Good thinking.

I think that if I were facing this issue I would get a brand new rattail file and create two clearance grooves for the adapter mounting bolts. It looks like the grooves could be cut across the chainstays and downtube and that would speed up the process.

Does anyone know from experience how prone these are to rotate if they're just pressed in? I would think a proper press fit should be sufficient to prevent the cups rotating with respect to each other.

I'm liking this idea a LOT. Thanks. Using a Dremel with a cutting tip would be kind of nerve-wracking in that I'd be worried about keeping the line straight. A file, like a hacksaw should result in a straight line once I get it started. I was leaning toward hacksaw, but that would require at least two cuts, which drives up the possibility for human error somewhat. Perhaps a hacksaw just to cut a small guide groove for the file?

I'll have to take a look a the guts of the BB shell again tonight, but my instinct is to stay away from the chainstays and tubes even if it means more work.