I've been playing with numerous badminton rackets:
- large blade
- long shaft
but are there exact badminton racket specifications regarding length and/or weight?
On the Badminton World Federation (BWF) website, there are a lot of official documents to be found.
You need to go to the second tab (Organisation) on the main site and choose Law & Regulations.
After that you need to click on Laws of Badminton (circled red):
The document, titled: PART II, SECTION 1 A, LAWS OF BADMINTON, elaborates in chapter 4 on the racket specifications:
The racket shall be a frame not exceeding 680 mm in overall length and 230 mm in overall width consisting of the main parts described in Laws 4.1.1 to 4.1.5 as illustrated in Diagram C.
After that, in paragraph 2 of chapter 4, the following is explicitly mentioned about the racket:
4.2 The stringed area:
shall not exceed 280 mm in overall length and 220 mm in overall width. However, the strings may extend into an area which otherwise would be the throat, provided that:
the width of the extended stringed area does not exceed 35 mm; and
the overall length of the stringed area does not then exceed 330 mm
The weight isn't specified, thus out of bounds.
Modern Badminton Rackets are light in weight and usually below 100 grams. The frame of the Racket can be made of steel, aluminum, carbon fiber, ceramic, boron or a combination of some of these.
It shall not exceed 680mm in overall length and 230 mm in overall width.
The weight should not exceed more than 100 grams.
A majority of racket manufacturers use 1U, 2U, 3U, 4U to indicate the weight of the racket, 1U being the heaviest and 4U the lightest. The weight of high quality rackets range from 83 grams to 100 grams.
2U - 90 to 94g
3U - 85 to 89g
4U - 80 to 84g
The racket head may be either oval or square.
Badminton strings are thin, high performing strings in the range of about 0.62 to 0.73 mm thickness. Thicker strings are more durable, but many players prefer the feel of thinner strings. String tension is normally in the range of 80 to 160 N (18 to 36 lbf). Recreational players generally string at lower tensions than professionals, typically between 80 and 110 N (18 and 25 lbf). Professionals string between about 110 and 160 N (25 and 36 lbf). Some string manufacturers measure the thickness of their strings under tension so they are actually thicker then than specified when slack. Ashaway Micropower is actually 0.7mm but Yonex BG-66 is about 0.72mm.
There are two main types of grip: replacement grips and overgrips. Replacement grips are thicker, and are often used to increase the size of the handle. Overgrips are thinner (less than 1 mm), and are often used as the final layer. Many players, however, prefer to use replacement grips as the final layer.
Most racket manufacturers provide four grip sizes. In Japan, they range from G2, G3, G4 to G5 where G2 is the biggest size and G5 is the smallest size. In some countries, the opposite applies. Some brands go by small, medium and big sizes.
Hi-Qua / Tactic G2 - 3.25 inches, Yonex G2 - 4.00 inches
Hi-Qua / Tactic G3 - 3.50 inches, Yonex G3 - 3.75 inches
Hi-Qua / Tactic G4 - 3.75 inches, Yonex G4 - 3.50 inches
Hi-Qua / Tactic G5 - 4.00 inches, Yonex G5 - 3.25 inches
For more info about the terms G and U refer here.