Wading through the big 650b+ compatibility thread has given me some mixed answers on this. I’m looking to go 650b+ on a Transition Smuggler and would quite like to use some Stand Flow EX rims with a 25.5mm internal width.

Is that wide enough to get the full plus tyre benefits I enjoy on my Trek Stache 29+ (50mm rims), yay or nay?

No.

25mm is barely up to scratch for “normal” width tyres.

Of course they’ll fit and you’ll be able to ride with them but you won’t be getting the “full plus tyre benefits “.

Someone best tell Richie Rude that 25mm rims are barely up to scratch 😉

25mm is barely up to scratch for “normal” width tyres.

Good one 😉

For anything up to Schwalbe 2.35 a 22mm rim is generally ok.

I’d agree though, you want 27mm at the very least to run a proper 2.5 tyre without making it all floppy.

Consensus seems to be 35mm minimum for decent support.

That’s what I’ve gone for, picking wheels up from LBS today, after literally months of dithering on the issue.

https://nsmb.com/articles/do-plus-tires-need-plus-rims/

Ok, wide rims it is. Thanks.

That isn’t what the NSMB article I linked above said!