I ride a Felt Broam 30, 2020. The bike came with 700 rims. After my first long distance bikepacking event a few weeks ago (BT700XL, 1100 km, 90% gravel, singletrack and ATV trails), I realize I was get very tired from the small amount of cushioning from the tires and hit my rims many time and broke a spoke from impact. I have been thinking of getting a better wheel set. Do I go 650b or 700. So I got thinking and realize that if I can fit 47mm on a 700 rim (bike is spec for 700 x 45mm max), I would be able to stay with 700 rims and there would no need for 650b. For more plush riding I am looking at getting a set of the Teravail Cannonball 700 x 47mm tires. I got thinking and will there be a difference between riding 650b x 47mm or 700 x 47mm. It seems to me that the cross section of the tire would be the same. The advantage of 650b would be that I could ride a 27.5 x 2.0 or 2.1 tire if needed. Any input would be greatly appreciated.
The 700c will have more rollover so it will be more comfortable and maintain speed easier. The downside compared to 650b (if you consider it a downside) is that it makes the handling less responsive but more stable, you may also get toe overlap issues. My wife’s bike has 650b x 47 Cannonballs, they are not true 47s. On a 26mm ID rim they only measure 46. On a narrower rim they would probably be 45 or less.
I should of also mention. Someone near by has a set of new never used PraxisWorks AL24 wheels set 27.5 for 400$ CA (about 280$USD) hubs internal have DT Swiss 350 components. 3 prawls ratchet. rims are 24mm internal. I thought it could be a option to try to get a set of wheels of this size to play around.
I would suggest that you find Rene Herse Cycles on the web and read thru Jan's blog. He's a bit biased because he sells tires (and dang good ones too!) but there's a wealth of information about tire sizes and pressure on there.
I’d suggest going with the 650B as a second set of wheels. I think you’ll have more tire selection at and above 47c. If there is a lot of climbing in your riding, the smaller diameter wheels may also feel like a plus as the hours tick by on those long events. That’s my two cents. I own a set of both and am happy about it.
If you want plush then try Schwalbe Thunderburt and/or G-One Speed. I love the Thunderburt as a front tire and G-One on the back. I'm light at 180 lbs bike/rider, but I run them at 20 psi. That would necessitate a 27.5/650b set but if you have space for 2.1 they are great.
I have both 650B and 700C wheels, nearly identical tires in each diameter, and bikes that can use either size.
The handling feel is different. The 650B is generally more agile, lively feeling, which I prefer most of the time. I need more input to maneuver the 700C. Little noticeable difference in rollover, or “cush” with the same width tire.
I tend to pick the narrower 700C setup for smoother unpaved rides and wider 650B for the rougher ones. On pavement 650Bx38 or 42 slicks are my go-to, and I will use these on gravel.
