Hi, I have available to me a set of Bravo 3X uppers with Bravo 1 XR lowers for my Bullet 31. I was wondering if this combination is 0K, I haven’t found much information about it. I guess what I want to know is that are the X uppers all the same meaning the lower unit determines if it’s a single or duo(1 vs 3). Thanks!

Yes, all late model Bravo uppers fit all the Bravo lowers. The lower is what makes it a 1, 2 or 3

Best to check the ratios there are 3 possibilities for the upper and 3 for the lower even though the most common lower is 15/19 which would be from a 1.5 XR

I did a spread sheet a while back, I'll post it later.

Thanks for the info guys! What are the advantages or disadvantages if any with the X upper with XR lower combo? Thanks again.

What you’re describing is what mercury marketed as an XZ drive,
there really isn’t any disadvantages to it

The only thing you would need to do is put the XR prop hub in your prop

As mentioned, there are different ratios of uppers and lowers,
I’m going to assume that you are looking for 1.5:1 gearing, if that is the case,
you’ll want the 2:1 upper (27/32 tooth count) with the 15/19 tooth count gears in the lower