Phew the shop found it was the whole shebang, my adjusting the brake wire had the effect of making the caliper stick on closing and ruined the caliper, front brake pads shot, brake cable and housing needed to be replaced. Rad said wear and tear so not covered under warranty, but the shop discounted parts and labor so $100 to repair. Given the excessive wear (they also recommended rear pads be replaced) I expect moving forward I should replace the brake pads every 3 months.

The front Tektro Aries manual brake on my RadExpand stopped working at the top of a hill, thankfully the motor inhibitor & rear brake was enough to bring me to a stop before I over-ran into the intersection at the bottom. The bike is 4 months old and I've put about 400 miles on the odo. I had earlier adjusted the caliper bolt to tighten the cable as it began to stretch, but now I wonder if the pads wore out (this is my first bike with disk brakes). I am unsure if the clicking sound is a problem with the brake cable sticking in the housing. After chatting with Rad I'm going to take it in to the shop I bought it from for repair as they're a Rad-authorized dealer so can work with them to authorize any warranty claim for parts & labor. Hoping the repair process is straightforward.

Sorry my mistake, I meant for the handlebar post like this https://www.aliexpress.us/item/3256805699623230.html?spm=a2g0o.order_list.order_list_main.73.16c1180227fcRO&gatewayAdapt=glo2usa4itemAdapt

Has anyone fitted a suspension stem to the handlebar post they can recommend?