The Compact Bike Travel Case Built for Real Travel Avoid oversized bulk. Protect your bike with confidence. Designed for cyclists who fly often and want a simpler way to travel with their bike. Fits road, gravel, and mountain bikes while staying compact enough to avoid many airline overweight and oversized baggage fees. One size now. The B2 is built to our old B2-MTB dimensions — and that size works best for road, gravel, and mountain bikes. Backed by a lifetime guarantee.