100k for a 9yo is stout.
Having 12 and 8yo girls, I cant imagine doing 100k with them.
My oldest did 38 mi when she was 10 and my younger did that distance earlier this year. The pace and continued encouragement would be draining for them to have completed 100k.

Impressive that your youngest can accomplish that distance.

As for the gravel- its practice. Practice and notice. You guys do it right with calling out what's approaching so she can prepare.


The kenda kontender tire is 507 sized per isla.
https://www.islabikes.com/product/ch...tire-luath-24/

A 23mm tire is absurd for an 8 or 9yo. Just no upside to it unless they are competitive youth triathletes, and even then I would think a 25 or 28mm tire could be just as good overall. That's a super narrow tire to have to keep pumped for such a light body.
Odd that a youth bike company would spec a 23mm tire.


Unfortunately, there arent a lot of 24" tires that are light, supple, and as wide as you want(or that will fit the bike). The 507 size especially.

Circle back to- practice and warning.