This has Cannondale written all over it. Tall guy, big guy.

I’d find any Cannondale frame he takes a liking to, the ST Tourers that I like came in big size jumps. I use a 23, I’d suggest a 25 for your son, if he likes the SR Sports frames, they’re more varied, I think (but not sure) they were sized in 2cm increments.

They have vertical drop outs, which is good, because no wheel slip, and is bad, because chain tension. You can find eccentric hubs, and more expensive, eccentric bottom brackets. That will get your the chain tensioning adjustability you need.

I have a couple Cannonballs, love how they don’t flex. After they were welded the whole frame was heat treated as a piece, a true monocoque frame build. The strongest frames were made between ‘85 and about ‘91/92, way overbuilt.