The internal hose routings like in your photos will be a smaller stainless tube brazed in so there's no access for water or mud to actually get inside the frame tube, it would just get into the hose routing tube which as I say, will most likely be stainless.
The internal hose routings like in your photos will be a smaller stainless tube brazed in so there's no access for water or mud to actually get inside the frame tube, it would just get into the hose routing tube which as I say, will most likely be stainless.