This has prob been asked before, but can you guys elaborate for a noob? 🙂

Not necessarily. Tyre width is also dictated by chainline and frame clearance. There are Boost frames now that still won’t accept anything larger than a 2.4″ tyre.

So is 650b+ the same as boost?

No. 650B+ is a tyre/rim width. The two are often linked as you MAY need Boost if you want to fit wider tyres and rims – say anything larger than 2.8″.

Boost also creates a stiffer wheel. Some say this is a good ting for 29ers

Thanks, because I’ve bought a bike with boost, so its just a wheel strength thing then.

Could be.

I guess that, from a manufacturers pov, it’s easier to have one axle size that takes both wide and narrow.

What bike?

http://blog.artscyclery.com/science-behind-the-magic/wider-and-stiffer-but-necessary-boost-148-explained/

has some useful info, there’s no point in me re-typing anything out 😀

The new Trance 2, it’s my first foray outside of anything with Carrera on it lol.