Hi guys,
—edit – best link of details on bike I can find:
https://www.cycling2000.co.uk/bikes/road-bikes/claud-butler-radical-gravel-bike-in-greygreen__5236
please note I have 0 experience with this, I am 5'9 and never considered 650b rims so please don't call me stupid if this isn'how this works, or even has anything to do with height
My partner just got a 2nd hand gravel/CX bike (claud butler radical 2022). Decent thing, needs some upgrades but good otherwise. My question is that she occasionally struggles with the size of bikes – the frame fits fine, but just getting her leg over the bike etc. So I'm just asking if 650b rims might help her, and generally make it easier to ride. She's 5'3, and rides a 48 (or 49 can't remember). It just seems maybe that a 650b rim maybe would make the bike a little more relaxed in general?
Is this resonable?
Do I need to have a 650b spesific frame bike to do this?
Anybody with pros/cons on this, or their own experiences would be appreciated – considering a set of Hunts for her birthday/xmas.
Thanks all, stay healthy!
by Boring-Big8874
5 Comments
Just to add. Have read an article or two. I get its primarily for clearance reasons 650bs are around. But this is related more to physical size (and comfort I guess)
I’m riding 650b and the frame is few cm lower (for the same tire size) which could help for a lower top tube.
In the same way, my pedals are hitting the rocks more often.
650b will lower the BB, saddle, and top tube 19mm relative to the ground for the same tire size. It can definitely make sense for smaller riders, as can shorter cranks.
As long as your frame is disc brake and as long as you match the axle and hub specifications, you are free to switch to 650b and it is pretty easy. Just make sure you understand if you have 100/142 TA vs 100/135 QR vs 100/141 QR axles, and whether you have centerlock or 6 bolt discs (probably centerlock) and if your freehub is HG or XD or XDR.
Dropping to 650b will definitely make the bike easier to get on and off. In mountain biking smaller riders sometimes downsize to 650b to make bikes easier to handle, but I don’t suspect she’ll notice a huge difference in handling unless she’s riding technical, low-speed gravel.
In terms of compatibility, so long as the hub spacing and axle width of the 650b wheelset match your existing wheelset, you’ll be fine. If you want to swap rotors and the cassette, you’ll need to make sure the rotor standards (centrebolt or 6-bolt) are the same, and that the freehub is also the same.
I know, frames for small people suck. Not because they have to, but because they aren’t designed from the ground up for smaller people (they share similar components over all frame sizes, like the wheel size crank length, etc.).
That being said, ‘fixing’ a poorly designed frame with smaller wheels isn’t the best idea. Yes you will get everything lower to the ground but in doing that you also diminish the ground clearance making pedaling through corners or riding over roots and stuff more difficult. Something that might help is when you (simultaneously) install shorter cranks, because you can then lower the saddle height.
There are frames however designed for small people that natively have 650B wheels and shorter cranks, maybe look out for those.
Other than that: stretching helps 😉