rclodfelter

I'm building a recumbent tadpole trike from parts from other bikes. I have head tubes, tires, axles, etc.... All of the bikes I have have American one piece cranks. I can certainly use those on the new trike but I was wondering if it is possible to convert a cruiser one piece crank to shimano type crank?

Do they make bottom brackets that will fit inside the bottom bracket tube that is common on a cruiser?

-TIA

surreal

https://www.treefortbikes.com/product...FQ6f4AodMHcAiQ

rclodfelter

I visited that site and they say this.

This will convert an American bottom bracket shell to accept English threaded bottom brackets, it will not work with other threaded standards.

Are the Shimano cranks English threaded?

-Thanks

Dannihilator

They are, going to be doing that soon myself.

rclodfelter

All the bottom tubes on all the bikes I have that I would consider to transplant to my tadpole have the same dimensions. They are much larger in diameter than a newer bike I have that has a Shimano setup. Are the conversion kits fairlu standard or do I need to measure the diameter of the bottom tube and then match that up with what ever Shimano crank I need?

Sorry for the noob question but I'm just trying to cut to the chase and not waste a lot of time.
-Thanks

Dannihilator

It will work, the adapter will make the bb shell fit an english threaded bb.

rclodfelter

I was thinking of at least two chain rings . I see on Amazon and other places you can buy the whole Shimano crank with chain rings. Are they universal and fit into the product mentioned at https://www.treefortbikes.com/product...FQ6f4AodMHcAiQ

likebike23

To understand how this works, you need to understand what a bottom bracket is. The bottom bracket is the assembly that has the bearings and spindle (axle) that you will attach your chosen shimano cranks to. Once you choose your crankset, you need to get the appropriate bottom bracket that will work with it. The converter is pressed into the frame's bottom bracket shell and has threads to accept the bottom bracket. You then install the crankset. Make sure that you put the converter in the right way, the threads are reverse threaded on the right (drive) side.

rclodfelter

I understand the mechanics of how they work. I'm just nervous about ordering something that doesn't fit the tube that I have or the crankset/bottom bracket I purchase.

If the American BB/tubes that I have are a standard size and the converter kit mentioned fits all Shimano BB then I'm good.

Dannihilator

They do.

rclodfelter

Thanks all!

surreal

Not to be a pedant, but Shimano does make BBs with Italian thread (70mm wide shell, 36mm ID with 24tpi, neither side is reverse-threaded) and oversized English threaded BB's (1.37" ID with 24tpi, DS is reverse threaded, but for 73mm wide shell.) The vast majority of the Shimano BBs are standard English thread, which is to say 68mm wide shell, 1.37"x24tpi, with a reverse-theaded DS. Just make sure you're buying a 68mm english-threaded BB, and it will fit the adaptor. (Now, to make sure that the BB is right for your crank is a whole different thread...)

If you're going with the newer Hollowtech II outboard BBs, you don't need to worry about the 68mm vs 73mm thing (there are spacers for using a 73mm outboard BB on your 68mm setup). You just want to make sure you don't buy an Italian-threaded BB.

I hope this helps. In summation, please consider the following: OPCs rule.

-rob

fietsbob

this is where your LBS is a comfort zone . you can see things, in person, before you Buy them..

surreal

Really, Bob? Go to your LBS today and ask to see their american-to-euro BB shell adaptors. I bet you a crankset that they won't have 'em in stock. Moreover, most won't order something like that without a deposit.

fietsbob

Our Local takes care of the Customers out here , and the many International Visitors

passing through enjoying the Oregon Coast , and finishing the Transamerica/ Louis and Clark trail.



'Most' would need actual statistical research.. I suspect its just an Opinion ...whatever..

surreal

But do they have the adaptor *in-stock*, Bob?

It's not an opinion, it's an assertion-- a hunch. A hypothesis, if you prefer. Statistical research would provide evidence, but there's no opinion involved here.

I don't feel like I have to conduct any research-- I'm willing to bet that only 1 shop within 20 miles of my home would possibly have such an item in-stock. Even there, I'd be fairly surprised if they did. But my friendly wager didn't have to do with "most" shops, Bob--- I bet you that your LBS doesn't have the adaptor in-stock.

Dannihilator

Some of the suppliers have both the truvativ and the mrp ones in stock.

surreal

Absolutely. The things are readily available on internet retail sites, and from wholesale suppliers for the LBS to order from.. My point was more that the typical LBS is highly unlikely to keep these in-stock at the shop.

wahoonc

Mine does, they average about one conversion a month according to the owner. Funny thing is they don't sell a lot of cruisers, primarily high end road and MTB stuff. If you want commuter/touring stuff you have to order.

Aaron

surreal

In some ways, that's awesome. Not a lot of shops support components for those primitive components.

OTOH, I love me some OPCs, and on the occasions that I do feel the need to "upgrade", I tend to go BMX 3pc with a sealed American BB.