Bombtrack Hook – 28″ to 27.5″ – customer service says it’s not possible, are they right?

Heyho loveliest Community! 😁

Fairly new to the hobby & proud owner of a Bombtrack Hook Size L (54cm).

After doing quite some shorter trips, I been playing for quite a while now with the thought of transferring my wheelset from the stock 28″ to a 27.5″ to make the bike more capable off-road + more comfy for proper bikepacking adventures.

Well, with my first long trip in Cyprus on the horizon, yesterday I stumbled over a damn good deal on DT Swiss GR1600 in 27.5″ & immediately pulled the trigger.

Being no expert at all in geometry & fairly new into everything off-road biking, I did my research today & stumbled over the fact that the Bombtrack Hook (28″) & Hook EXT (27.5″) actually have slightly different frame geometries. Although I kind of recall in my head, that they both are identical, except for the wheelsets.

I immediately approached the Bombtrack customer service & just received feedback, that the frame won’t fit anything but 42c in both 650b & 700c. Which hurts me to hear, as well as making me sceptical.

It is a god damn pitty, cause I immediately also ordered 5.25″ & 5.1″ Vittoria Mezcals as new tyres… 🥲

Now the question – is customer service right (see link for screenshot)? Are 650B on my frame really completely stupid?
Or are they legally obliged saying it for liabilities sake, cause the frame is not built for this wheelset size?

[Customer service screenshot & Tyre clearance pictures](https://imgur.com/a/nnfM2MU)

Any help & thoughts would be damn greatly appreciated 💚

by oxolotltl