20寸的ROLF呢，原厂是有的。型号为APEX SL 406和451规格皆有。
Low on weight and high on style, the Apex SL has climbed quickly to the top of the list for 20” folding bike or recumbent wheels. 吀栀攀 Apex SL is available for Shimano 9/10, Campagnolo or Capreo style cassettes and like all Rolf Prima wheels, they are hand built in Eugene, Oregon.
The Apex SL is designed with the rigors of everyday use and commuting in mind. Well sealed hubs, tough rims and a quality hand build combined with a wheel set weight of 1250gms make the Apex SL a great upgrade for any bike.
Wheel size: 20" 406c / 451c
Weight: 1250gm set
Spoke count: bladed 20F/20R
Rim: 24mm 406c / 451c with CNC brake track, alloy clincher
Hubset: Custom Rolf Prima hub set w/ 3-pawl freehub mechanism
Freehub: Forged aluminum - Shimano or Capreo style
Category: Road Race, Climbing, Fitness, Training
Featured technology: Paired spokes, Differential Flange Diameter, Dish Reducing design, Self Aligning Nipple
Upgrades available: Prima Plus and Hero
US Retail: $699
前轮都是一样的。没有什么变化。
这是小鹿飞轮版本的后轮。
国外网络的图片，截自01，小鹿飞轮版本的轮组是作为BF PR super PRO的标准轮组的。
来个侧面看看。
这是shimano 飞轮标准的后轮组。
另外，ROLF还为BF公司特制了一款后轮组，与White Industries合作生产了一个WI塔基的版本。WI的钛塔基和结构当然要强力很多啦。价格当然也贵了很多。重量比其它版本轻50g。
所以。rolf星芒20寸有5种（406的S规格与小鹿规格，451的S规格、小鹿规格与BF特制规格），我倒是觉得星芒的406可以用在AM上，风格与AM挺搭配的。
