Would v-brakes with the normal v-brake long pads (as opposed to shorter brake pads) on road rims exhibit any problematic behavior going downhill at speeds of 50 mph? I am concerned that the longer brake pad may be more susceptible to shudder and/or grabbiness than shorter pads.
The bike in question is a Surly Cross Check which is set up with brake posts for cantilever or v-brake. Caliper is not an option.
The brakes I have ready to put on are Deore XT br-t780 (with long brake pads) , front and back.
Other v-brakes with shorter pads are available, e.g., Shimano BR-M422. (But these M422 are much lower quality than the T780 - and the question is about long vs short pads, not quality of the brakes they come with).
The cable travel in the lever is not an issue as I have the problem solver travel device ready.