Firewire, 2025

Firewire Boss Up 2025

1981mm long · 6'6"

511mm wide

73mm thick

39.5litres

See similar boards

Open in Studio See it on firewiresurfboards.com

Sizes & Numbers

Listed by the brand, read off a photo, or worked out

In one line

A narrower tail than most. A rounded pin tail, a medium nose and gently curved rails.

derived · against the 146 other surf boards in the atlas, read off the outlines.

As listed by Firewire

Firewire Boss Up 2025: every size as listed by Firewire
size	length	width	thickness	weight	price
39.5 L	6'6" · 1981 mm	511 mm	73 mm	–	US$914
40.8 L	6'8" · 2032 mm	514 mm	73 mm	–	US$960
43 L	6'10" · 2083 mm	518 mm	75 mm	–	US$980
44.3 L	7'0" · 2134 mm	519 mm	75 mm	–	US$1,000
46.4 L	7'2" · 2184 mm	521 mm	76 mm	–	US$1,010
48.4 L	7'4" · 2235 mm	519 mm	78 mm	–	US$1,040
51.1 L	7'6" · 2286 mm	524 mm	79 mm	–	US$1,060

Prices as the Firewire store showed them on 2026-10-27, in its currency · the cheapest version first, every version on hover

Every size side by side, tails on one line, one scale

Which Boss Up Size for Your Weight?

The Firewire Boss Up 2025 size each rider would pick, by weight and level

Your weight

kg≈ 165 lb

Your level

75 kg · getting there · look for 33.8–41.3 L

The Boss Up 39.5 L

2 sizes fall in your range; the 39.5 L is nearest its middle.

Other boards for you

A rule of thumb (0.45 to 0.55 L per kg you weigh), not Firewire’s chart

Every weight and level

Firewire Boss Up 2025: the size for a rider of 60 to 105 kg, by level
level	60 kg	75 kg	90 kg	105 kg
First sessions0.6 to 0.9 L per kg you weigh	44.3 L	51.1 L	51.1 L · small	too small
Getting there0.45 to 0.55 L per kg you weigh	too big	39.5 L	44.3 L	51.1 L
Confident0.38 to 0.45 L per kg you weigh	too big	too big	39.5 L	43 L
Expert0.33 to 0.38 L per kg you weigh	too big	too big	too big	39.5 L

Rules of thumb, not Firewire’s chart · “small” and “big”: the nearest size, just outside the range · How the sizes are worked out · Find your board

Next to your board?

Lay the Firewire Boss Up 39.5 L over up to four others, at one scale.

Compare with…

Generations

After it · 2026

The 2026 39.5 L is the same length and width as the 2025 39.5 L. Open the 2026

listed length and width

2025 39.5 L 2026 39.5 L

The Firewire Boss Up over time

Shape & Rocker

From above, then from the side, true scale · the chosen size solid, the others dashed

Read off the 39.5 L outline · derived

51 %wide point, 1015 mm from the tail

3.75length over width

391mm wide 12″ from the tail

8,316cm² of planform

Read off the 40.8 L outline · derived

51 %wide point, 1041 mm from the tail

3.95length over width

376mm wide 12″ from the tail

8,294cm² of planform

Read off the 43 L outline · derived

51 %wide point, 1067 mm from the tail

4.02length over width

375mm wide 12″ from the tail

8,552cm² of planform

Read off the 44.3 L outline · derived

51 %wide point, 1093 mm from the tail

4.11length over width

372mm wide 12″ from the tail

8,788cm² of planform

Read off the 46.4 L outline · derived

51 %wide point, 1119 mm from the tail

4.20length over width

369mm wide 12″ from the tail

9,025cm² of planform

Read off the 48.4 L outline · derived

51 %wide point, 1145 mm from the tail

4.31length over width

365mm wide 12″ from the tail

9,206cm² of planform

Read off the 51.1 L outline · derived

51 %wide point, 1171 mm from the tail

4.36length over width

365mm wide 12″ from the tail

9,503cm² of planform

Rocker of the 39.5 L · measured

81 mmtail rocker, at the tip

41 mm12″ from the tail

52 mm12″ from the nose

124 mmnose rocker, at the tip

347 mmflat to within 3 mm, from 42 % to 60 % of the length

50 %of the length to the lowest point, from the tail

87 mmat its thickest, 50 % from the tail · on the photo; Firewire lists 73 mm

21 mmlonger along the bottom curve than flat

Lay this rocker over other boards

Rocker of the 40.8 L · scaled from the 39.5 L measured

83 mmtail rocker, at the tip

43 mm12″ from the tail

55 mm12″ from the nose

127 mmnose rocker, at the tip

351 mmflat to within 3 mm, from 42 % to 59 % of the length

50 %of the length to the lowest point, from the tail

87 mmat its thickest, 50 % from the tail

22 mmlonger along the bottom curve than flat

Lay this rocker over other boards

Rocker of the 43 L · scaled from the 39.5 L measured

85 mmtail rocker, at the tip

45 mm12″ from the tail

57 mm12″ from the nose

131 mmnose rocker, at the tip

355 mmflat to within 3 mm, from 42 % to 59 % of the length

50 %of the length to the lowest point, from the tail

89 mmat its thickest, 50 % from the tail

22 mmlonger along the bottom curve than flat

Lay this rocker over other boards

Rocker of the 44.3 L · scaled from the 39.5 L measured

87 mmtail rocker, at the tip

47 mm12″ from the tail

60 mm12″ from the nose

134 mmnose rocker, at the tip

358 mmflat to within 3 mm, from 42 % to 59 % of the length

50 %of the length to the lowest point, from the tail

89 mmat its thickest, 50 % from the tail

23 mmlonger along the bottom curve than flat

Lay this rocker over other boards

Rocker of the 46.4 L · scaled from the 39.5 L measured

89 mmtail rocker, at the tip

49 mm12″ from the tail

62 mm12″ from the nose

137 mmnose rocker, at the tip

362 mmflat to within 3 mm, from 42 % to 59 % of the length

50 %of the length to the lowest point, from the tail

91 mmat its thickest, 50 % from the tail

23 mmlonger along the bottom curve than flat

Lay this rocker over other boards

Rocker of the 48.4 L · scaled from the 39.5 L measured

91 mmtail rocker, at the tip

51 mm12″ from the tail

65 mm12″ from the nose

141 mmnose rocker, at the tip

366 mmflat to within 3 mm, from 43 % to 59 % of the length

50 %of the length to the lowest point, from the tail

93 mmat its thickest, 50 % from the tail

24 mmlonger along the bottom curve than flat

Lay this rocker over other boards

Rocker of the 51.1 L · scaled from the 39.5 L measured

93 mmtail rocker, at the tip

53 mm12″ from the tail

67 mm12″ from the nose

144 mmnose rocker, at the tip

369 mmflat to within 3 mm, from 43 % to 59 % of the length

50 %of the length to the lowest point, from the tail

95 mmat its thickest, 50 % from the tail

25 mmlonger along the bottom curve than flat

Lay this rocker over other boards

True proportions · dots at 10 mm and 12″ in from each tip · bracket: flat to within 3 mm · Measured on Firewire's photo of the 39.5 L. Tail end set by Firewire's photo convention, not checked by a person.