One peice crank to square taper.

[Grant]

I am planning on upgrading a Schwinn Continental to a square tapered bottom bracket. I want to know if it fits right in or if you need an adapter. If I need an adapter to convert it, where do I get it?

I want to convert a bike with cranks like this...

To a bike with cranks like this.

This is a successful conversion on a Schwinn Varsity.

 

[Chad T]

The American to Euro bb adapter would do,

Hope to see @Chad T comment here

I use this kind. It allows the use of a modern cartridge bearing bb. My local bike shop has these for $19.

If you just have the square taper cranks then this might be the simpler way to go.

If you have the whole bb from a donor bike the first one might be better. Do some research if you've never messed with 3pc cranks. You need a puller for the arms and on one side the bearing cups will be reverse threaded...I think...been a while since I've had one apart.

 

[RustySprockets]

There are two approaches. The first involves replacing the bearing assembly with one that accommodates a matching square-taper spindle. It gets pressed into the existing shell and installation is pretty straightforward.

The second option is a Truvativ adapter that effectively converts the Schwinn BB shell into a European style. While this may pose more work, it also grants more flexibility.

Chad is right about the bearing cups. The 'drive side' cup is typically left-hand threaded.

 

[HuffnPuff]

I recently converted a bike using the truvativ adaptor. Had a devil of a time getting the adaptor in, probably due to the frame having been powder coated and the adaptor fits a lot deeper than a one piece bearing cup. Once it was fitted the BB screwed in quite easily.

 

[Dr. Tankenstein]

I went with this sealed bearing unit on my strandie build.

Excellent quality and pedals smooth as butter.

https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.com/ulk/itm/322162906143




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[Grant]

I would rather use a cartridge.

 

[MojoK]

I would rather use a cartridge.
View attachment 92788

So if it converts to English threaded, it should also work with external bearing units? That could allow some flexibility with spacing the chain line

 

[Indyjps]

Dr Tankenstein has the plan.
The adapters end up squeaking. Theyre about 30 plus the cost of the bottom bracket, it ends up about the same money but the sealed set up is much less BS.

Nothing wrong with the simple straightforward YST conversion. I assume you dont plan on taking your continental in the mud.

 

[RustySprockets]

So if it converts to English threaded, it should also work with external bearing units? That could allow some flexibility with spacing the chain line

Good question. Most offerings appear to have a significant ridge along the outside that might preclude the use of external cups. The Fenix brand, shown below, is the only one I've found that is smooth. I suspect one would need to account for the few millimeters of additional width when calculating chain line and spindle size.

 

[Chad T]

I went with this sealed bearing unit on my strandie build.

Excellent quality and pedals smooth as butter.

https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.com/ulk/itm/322162906143

ooh I like that setup....makes me want to start sniffing around for some vintage campy cranks. Square taper is nice because you can get just the arms pretty cheap.

Correct me if I'm wrong but isn't @Chad T using an external on his Scrambler?

Yes they fit with the Truvativ adapter. I have them on a collegiate as well.

I think that ridge is in there so the spacing comes out right.

 

[RustySprockets]

I think that ridge is in there so the spacing comes out right.

It is indeed. I'm glad you can confirm those external bearings nestle right in there.

 

[Wildcat]

Even the cheap conversion feels more solid than the one piece cranks:

 

[Duchess]

Used the 3-bolt threaded adaptor on Interrobang and it works really well. Only issue I had with the Sears Spaceliner bottom bracket was the excess metal I had to grind out of the way for the through-bolts—slow going as I couldn't get anything in there but a Dremel and hand files.

 

[DosDiablos]

I went with this sealed bearing unit on my strandie build.

Excellent quality and pedals smooth as butter.

https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.com/ulk/itm/322162906143




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Building my 1st BMX Cruiser and stuck on the "Cranks".

Trying to convert from one-piece to three-piece like most and ran into a problem that you might have had as well, just curious how you handled the width of the BB Spindle? Looks like the one you mention is 127mm .. i used a Cone/Bearing one like the one referenced above @ 128mm.

Anyway, it's pretty wide and sticks out pretty far ... i've seen others mention 128mm is way too wide as well.

So what did you do? .. it just sticks out? Can you explain your thoughts on the width of the one you used .. i'm pretty "new" so maybe i'm missing something.

Thx so much!

 

[Dr. Tankenstein]

My frame is a ‘modern’ mass produced unit so it has (what I believe to be) a standard width BB tube.

Here’s a top view, the chainring side is flush to the clamping ring, the non-drive sticks out a bit (~3/8” or so).

I chose this conversion unit because, with clamping rings, I can adjust the spindle right or left to get the chain line dialed in.
For me and the light cruising I do, the slight left/off center is unnoticeable.
With the chain clearance challenges of stretch cruisers, I’ll definitely use this type of BB setup for my current project.

Also, those sealed bearings are as smooth as butter


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[Grant]

My frame is a ‘modern’ mass produced unit so it has (what I believe to be) a standard width BB tube.

Here’s a top view, the chainring side is flush to the clamping ring, the non-drive sticks out a bit (~3/8” or so).

I chose this conversion unit because, with clamping rings, I can adjust the spindle right or left to get the chain line dialed in.
For me and the light cruising I do, the slight left/off center is unnoticeable.
With the chain clearance challenges of stretch cruisers, I’ll definitely use this type of BB setup for my current project.

Also, those sealed bearings are as smooth as butter


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Crocs!

 

[Dr. Tankenstein]

Yeah, they’re my ‘muddy yard shoes’ and it was raining yesterday..... [emoji16]


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[Grant]

I think this concept would be good for any Varsity TT conversion modernization. Especially with hollowtech!

 

[DosDiablos]

@"Tank" ... So your Shell must be wider than mine? .. sorry, trying to learn.

Here's mine at the moment ... i read someone suggested a 108mm Spindle? ... but i can't find a 108ish threaded Spindle that will work with my Bearing/Cup/Cone Assembly i bought ... i'm open to buying a new one, still just a little confused as to what to get.

Thx for any direction.

 

[MazdaFlyer]

I’ve used several of these old style bottom brackets for the square taper three piece cranks. They always seem to work well. Think they come in three lengths.

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