Good day

The photos and the cm height information in the photos do not correspond to reality as the saddle cannot be fully lowered with the supplied seat post. This has now also been confirmed directly by EarlyRider.
The seat post for the Hellion 20 inch bike is also suitable in terms of material and thickness, it is simply a good 10 cm shorter and can therefore be fully recessed. Early Rider has already sent me the seat post of the 20 inch bike free of charge - it fits perfectly.

Greetings and thanks for your answers.

We had the same "problem". I also wanted to shorten the tube or mount a different saddle because I was worried that the change from the 20" would not work so well. But our son coped really well and was riding safely after a few days. The leg length was just right.

Yes, that's how it is with us too. It's normal and it fits from a crotch length of 60 cm. Nevertheless, I shortened it to have more fun on trails. But I would also have expected it to go down further ex works, as it is advertised as a full trail bike.