kmulder

I am in the process of refreshing our RT2 tandem this winter and I am having trouble knowing what bottom bracket standard it uses. The stock bottom brackets are FSA Mega Exo BB-7000/TD.

The exact component is available on Amazon for $56 (https://www.amazon.com/dp/B017YY4JLU) but I'm interested in exploring other options for replacement if this is a standard size I could get from a different brand. For example, most Shimano Ultegra BBs are ~$30, so quite a bit cheaper.

Any ideas what size standard this is? Thank you!

Alcanbrad

This is a very common size. Look for an English thread 68/73mm that supports a 24mm spindle. There are many 68mm offerings, but if your bike requires 73 you need that make sure yours will support 73. The differences are made up with washers so unless you know for sure, look for one that supports 68/73.

Shimano has a few options with smaller diameter bearings and requires an adapter tool to use a standard bottom bracket tool (the new BB usually includes the adapter), anyway, I would stay away from these as the bearings use smaller balls and the radial loads you get from pedaling will destroy those bearings much quicker than the larger size. There is nothing more annoying than the constant click click click on an otherwise silent bike.

kmulder

Thank you, Alcanbrad, for the very thorough and informative response! Very helpful!