Although an uneducated observer may not be able to discern between the violin and the viola, there are many subtle differences between the two instruments. The instruments themselves differ in weight, length, price and playing technique. These same differences apply to the violin and viola bows. While it is possible to use a violin bow for a viola, or visa versa, a careful musician will make sure that he has the appropriate bow for his instrument.
Violin bows are lighter than viola bows. The average weight for a violin bow is around 60 g (56.7gr). For a viola bow, the average weight is 70 g (70.9gr).
Although the violin is smaller and shorter than the viola, the violin bow is generally slightly longer than the viola bow. The standard length for a violin bow is 75 cm (29.5 inches); viola bows average 74 cm (29.1 inches).
The violin bow has a smaller band of horsehair than does the viola bow. Violin maker Hans Johannsson says that as a general rule, a violin bow has 150 hairs on the bow while a viola bow has 175. This varies depending on the specifications of the individual bow.
Because of the differences between violins and violas, the bows require different techniques. A viola bow requires more arm weight and a slightly faster pull to generate the same smoothness of tone as a violin. A viola bow does not respond as quickly; a violist must begin his bow stroke slightly ahead of the beat in order to sound his instrument directly on the the beat.
Because it requires sturdier wood and more hair, a viola bow will be more expensive than a violin bow of the same quality. As of 2010, Shar Music charges £15 for a student-level brazilwood violin bow and £22 for a student-level brazilwood viola bow. For an advanced player, Shar charges £975 for a Pernambuco wood violin bow and £1,365 for a Pernambuco wood viola bow.