So I have max clearance on gravel bike is 46mm. Since the transition of 26" to 29" wheels we have been told larger wheels roll faster than smaller wheels( now they are going to 32" ). However this seens to assume we have similar tires. But what is the actual/postulated difference.2.2 RK on 650b wheel and compare to likey 700c 48/44( can fit larger tire on front) gravel thundero HD( want some bite so understand faster tires) for something like unbound 100. Both test well at brr.
I don’t think you’ll notice a difference. Just run whatcha brung and smash.
At the moment I believe wheel size doesn’t matter. Tire construction, however, matters big time.
Joe
The thing is that the radius-as-measured of both will be very similar. That was the whole idea behind bikes like the original Open UP and 3T Exploro, which gave riders the option of using 700c wheels for narrower tires and 650b wheels for wider MTB tires.
For instance, in the link the RAM of 2.1–2.2" 650b tires is 343–351 mm, which is very close to 35–42 mm gravel tires (348–354 mm). Since the radii-as-measured of both are very similar, it means that the bike’s geometry will be very similar, i. e. you get essentially the same handling characteristics either way.
I thought and still think this is a great idea, but the market has spoken and the new Open UP offers more clearance for 700c wheels.
Yeah. That was part of the rationale behind the (now defunct) + mtbs. 3" tires on 650b wheels have about the same OD as 2.4" on 700c wheels.
RK 650b doesn’t come in the Black Chilli fast rolling compound…I believe.
The RK ProTection did come with the blackchilli in a 27.5x2.2… but it’s seems to be hard to come by now and you get a 404 on the conti website 
That’s a consequence of 650b dying, unfortunately. 
Not at all
Not at all. The Dubnital (and other Conti tyres) are available in 27.5. Perhaps the OP can choose a Dub??
Yes i already have the RK’s on my 27.5 and run well. Just wondering if I was given anything up since the move to bigger wheels( i didnt think i was but wanted to float it out there). I agree on the radius thing but its interesting this full switch to biggest 700 possible with all these bikes.
I stand corrected.
I would like 700’s on mine though, rather than 650’s…but I can’t fit the big ones either.