Chen You-ben (陳有本; 1780~1858), also of the 14th Chen generation, is credited with starting another Chen training tradition. This system also based on two routines is known as “Small Frame” (xiao jia; 小架). Small Frame system of training eventually lead to the formation of two other styles of Tai chi chuan that show strong Chen family influences, Zhaobao jia (趙堡架) and Hulei jia (Thunder style; 忽雷架). However they are not considered a part of the Chen family lineage.
By all accounts Chen Youbeng is most famous for promoting both a large frame version and a new version (known as New Style), which emphasized the value of the smallest of movements. His top student was Chen Qingping, who became extremely famous for promoting two small frame styles. His top non-family student was Wu Yuxiang who created the Wu Yuxiang style which is also sometimes referred to the Hao style.
However, at this time, an enormous shift in popularity amongst versions of the Chen Style took place, spearheaded by Chen Changxing. As mentioned previously, Chen Changxing is noted as the one who organized the multiple sets into two sets known as Yi Lu and Er Lu (or, First and Second Routines). His style is characterized as two sets of “big frame” Taijiquan. He taught the first non-family student his Taijiquan for a combined 18 years. That student, Yang Luchan (A.K.A. Yang Fu Kwei), would develop his own style of Taijiquan: Yang Style Taijiquan. Chen Changxing was known for his de-emphasis of outward power. Instead he focused on the power of softness and developing a strong center of gravity by maintaining a more upright posture. There's no question that these two principles are consistent with the Traditional Yang Style Taijiquan we see today.
Chen Changxing's style has also been handed down as the Lao Jia, or Old Frame. Now, whether this “old” frame is what Chen Fake and Chen Zhaokwei taught in Beijing or whether a more elaborate version remains to be verified. However, if Yang Style did develop from Changxing's version, then it would very likely have to be a more efficient version of the style. Regardless, Changxing is also credited with internalizing Heng and Hah which was a more internal version of a Ki Ai. Changxing saw huge value in developing internal power by making the sounds within his mind and vibrating them through the body, rather than aspirating them. Changxing was an outstanding internal martial artist, and both developed and preserved the efficiency and internal tenets of the style.http://www.chiflow.com/html/Taijiquan_Chen.htm
[8 & 9] CHEN YOUHENG & CHEN YOUBEN
Chen Youheng, called Deji, passed the county-level civil service examinations in the first year of the reign of Emperor Daoguang . He was obsessed with Taiji Boxing, but drowned in Dongting Lake in the prime of his life.
His younger brother, Youben, called Daosheng, passed the county-level civil service examinations at the age of thirty-six. He reached the deepest level of the Taiji boxing art for his generation. He had an unassuming demeanor, always acting inferior to the other person. At that time, all the best Taiji Boxing exponents had learned from him.
Chen You-Ben is known as the creator of “Small Frame” which is a similar work to Chen Chang-Xing's amalgamation into Yi Lu and Er Lu; Small frame players call Chen Chang-Xing's work “Large Frame”.
(Jarek Szymanski writes, http://www.taiji-bg.com/articles/taijiquan/t35.htm)
Transmission of Small Frame of Chen style Taijiquan (brief):