Originally Posted by
Bandera
Indeed.
If the purported low rolling resistance of wide/low volume 650B is indeed a fact testing, much less adoption, by the traditional community of performance cyclists (even if retired) is hindered by any wheelsets suitable for fast paceline use where acceleration rules.
I'll save you the trouble, for absolute speed on the road, 650bx38 or 42 or whatever is going to be slower than a 700x23/25 racing tire.
It's not so noticeable on most group rides where there's differing abilities but at the pointy end it is obvious. I switch between bikes a bit and I've never been able to hang with the paceline on my 650b bike. No problem with my 700c bike.
Wide 650b has a lot of benefits and I think that for most recreational riders it is a more sensible choice than 700x23/25 racing tires. However, if you want to race or emulate racers or just be really really fast, you're not going to be happy with 650b.
I've been running a 650bx42 bike since August 2015 and as soon as I run through the last two tires I have I'm going to sell the wheelset and go back to 700c.
Also, rim brake 650b rims are probably going to be a dead end so I don't really expect to see a lot of development. All-road and modern 650b designs are heavily invested in disc brakes where rims are building on mountain bike development and good carbon rims are already available.
I've posted this before but it's really the best illustration of my switch from 700c to 650b.
