Are these real cycling socks or just a novelty pair?

They are a printed novelty sock with a downhill biking theme. Nothing indicates padded soles, arch compression or sweat-wicking fabric, so treat them as casual wear rather than performance gear.

Will they work inside tight mountain bike shoes?

Crew-height socks like these generally sit above the shoe collar. Without stated cushioning or a defined fit, thin riding shoes may feel snug, so check the fit before relying on them for long rides.

Are they good as a gift for a mountain biker?

Yes, if the rider likes retro downhill graphics. The design is the point; a rider who wants padded, technical socks will get more use from a dedicated cycling pair.

How should I wash them?

No care instructions are given. Wash printed socks inside out in cold water and air dry to keep the graphic from fading or cracking.

Do they come in different sizes?

Sizing details are not specified here. Check the size options on the page before ordering, since a printed sock that fits loosely will slide in a riding shoe.