barをpsiに換算するには？
barの値に14.5038を掛けます。欧州の自動車メーカーは指定空気圧をbarで印字し、英米の整備用ゲージはpsiで表示しますが、単位が変わるだけで目盛りの原点は変わりません。
psi = bar × 14.5038bar = psi ÷ 14.5038
この二つの単位が使われる場所
バールは 10 万パスカルで、海面での大気圧に近いことが普及の理由です。欧州ではタイヤと潜水の単位になっています。 重量ポンド毎平方インチは米国でタイヤの空気圧や産業用圧力計を表し、1 気圧は 14.7 psi と読まれます。
空気圧のbarとpsiの対応
| 1 bar | 14.5 psi |
| 1.5 bar | 21.8 psi |
| 2 bar | 29.0 psi |
| 2.2 bar | 31.9 psi |
| 2.5 bar | 36.3 psi |
| 3 bar | 43.5 psi |
| 3.5 bar | 50.8 psi |
| 4 bar | 58.0 psi |
| 6 bar | 87.0 psi |
| 8 bar | 116.0 psi |
| 10 bar | 145.0 psi |
すべての値を表示
- 1 bar = 14.5 psi
- 2 bar = 29.01 psi
- 3 bar = 43.51 psi
- 4 bar = 58.02 psi
- 5 bar = 72.52 psi
- 6 bar = 87.02 psi
- 7 bar = 101.53 psi
- 8 bar = 116.03 psi
- 9 bar = 130.53 psi
- 10 bar = 145.04 psi
- 11 bar = 159.54 psi
- 12 bar = 174.05 psi
- 13 bar = 188.55 psi
- 14 bar = 203.05 psi
- 15 bar = 217.56 psi
- 16 bar = 232.06 psi
- 17 bar = 246.56 psi
- 18 bar = 261.07 psi
- 19 bar = 275.57 psi
- 20 bar = 290.08 psi
- 21 bar = 304.58 psi
- 22 bar = 319.08 psi
- 23 bar = 333.59 psi
- 24 bar = 348.09 psi
- 25 bar = 362.59 psi
- 26 bar = 377.1 psi
- 27 bar = 391.6 psi
- 28 bar = 406.11 psi
- 29 bar = 420.61 psi
- 30 bar = 435.11 psi
- 31 bar = 449.62 psi
- 32 bar = 464.12 psi
- 33 bar = 478.62 psi
- 34 bar = 493.13 psi
- 35 bar = 507.63 psi
- 36 bar = 522.14 psi
- 37 bar = 536.64 psi
- 38 bar = 551.14 psi
- 39 bar = 565.65 psi
- 40 bar = 580.15 psi
- 41 bar = 594.65 psi
- 42 bar = 609.16 psi
- 43 bar = 623.66 psi
- 44 bar = 638.17 psi
- 45 bar = 652.67 psi
- 46 bar = 667.17 psi
- 47 bar = 681.68 psi
- 48 bar = 696.18 psi
- 49 bar = 710.68 psi
- 50 bar = 725.19 psi
- 51 bar = 739.69 psi
- 52 bar = 754.2 psi
- 53 bar = 768.7 psi
- 54 bar = 783.2 psi
- 55 bar = 797.71 psi
- 56 bar = 812.21 psi
- 57 bar = 826.72 psi
- 58 bar = 841.22 psi
- 59 bar = 855.72 psi
- 60 bar = 870.23 psi
- 61 bar = 884.73 psi
- 62 bar = 899.23 psi
- 63 bar = 913.74 psi
- 64 bar = 928.24 psi
- 65 bar = 942.75 psi
- 66 bar = 957.25 psi
- 67 bar = 971.75 psi
- 68 bar = 986.26 psi
- 69 bar = 1,000.76 psi
- 70 bar = 1,015.26 psi
- 71 bar = 1,029.77 psi
- 72 bar = 1,044.27 psi
- 73 bar = 1,058.78 psi
- 74 bar = 1,073.28 psi
- 75 bar = 1,087.78 psi
- 76 bar = 1,102.29 psi
- 77 bar = 1,116.79 psi
- 78 bar = 1,131.29 psi
- 79 bar = 1,145.8 psi
- 80 bar = 1,160.3 psi
- 81 bar = 1,174.81 psi
- 82 bar = 1,189.31 psi
- 83 bar = 1,203.81 psi
- 84 bar = 1,218.32 psi
- 85 bar = 1,232.82 psi
- 86 bar = 1,247.32 psi
- 87 bar = 1,261.83 psi
- 88 bar = 1,276.33 psi
- 89 bar = 1,290.84 psi
- 90 bar = 1,305.34 psi
- 91 bar = 1,319.84 psi
- 92 bar = 1,334.35 psi
- 93 bar = 1,348.85 psi
- 94 bar = 1,363.35 psi
- 95 bar = 1,377.86 psi
- 96 bar = 1,392.36 psi
- 97 bar = 1,406.87 psi
- 98 bar = 1,421.37 psi
- 99 bar = 1,435.87 psi
- 100 bar = 1,450.38 psi
- 101 bar = 1,464.88 psi
- 102 bar = 1,479.38 psi
- 103 bar = 1,493.89 psi
- 104 bar = 1,508.39 psi
- 105 bar = 1,522.9 psi
- 106 bar = 1,537.4 psi
- 107 bar = 1,551.9 psi
- 108 bar = 1,566.41 psi
- 109 bar = 1,580.91 psi
- 110 bar = 1,595.42 psi
- 111 bar = 1,609.92 psi
- 112 bar = 1,624.42 psi
- 113 bar = 1,638.93 psi
- 114 bar = 1,653.43 psi
- 115 bar = 1,667.93 psi
- 116 bar = 1,682.44 psi
- 117 bar = 1,696.94 psi
- 118 bar = 1,711.45 psi
- 119 bar = 1,725.95 psi
- 120 bar = 1,740.45 psi
- 121 bar = 1,754.96 psi
- 122 bar = 1,769.46 psi
- 123 bar = 1,783.96 psi
- 124 bar = 1,798.47 psi
- 125 bar = 1,812.97 psi
- 126 bar = 1,827.48 psi
- 127 bar = 1,841.98 psi
- 128 bar = 1,856.48 psi
- 129 bar = 1,870.99 psi
- 130 bar = 1,885.49 psi
- 131 bar = 1,899.99 psi
- 132 bar = 1,914.5 psi
- 133 bar = 1,929 psi
- 134 bar = 1,943.51 psi
- 135 bar = 1,958.01 psi
- 136 bar = 1,972.51 psi
- 137 bar = 1,987.02 psi
- 138 bar = 2,001.52 psi
- 139 bar = 2,016.02 psi
- 140 bar = 2,030.53 psi
- 141 bar = 2,045.03 psi
- 142 bar = 2,059.54 psi
- 143 bar = 2,074.04 psi
- 144 bar = 2,088.54 psi
- 145 bar = 2,103.05 psi
- 146 bar = 2,117.55 psi
- 147 bar = 2,132.05 psi
- 148 bar = 2,146.56 psi
- 149 bar = 2,161.06 psi
- 150 bar = 2,175.57 psi
- 151 bar = 2,190.07 psi
- 152 bar = 2,204.57 psi
- 153 bar = 2,219.08 psi
- 154 bar = 2,233.58 psi
- 155 bar = 2,248.08 psi
- 156 bar = 2,262.59 psi
- 157 bar = 2,277.09 psi
- 158 bar = 2,291.6 psi
- 159 bar = 2,306.1 psi
- 160 bar = 2,320.6 psi
- 161 bar = 2,335.11 psi
- 162 bar = 2,349.61 psi
- 163 bar = 2,364.12 psi
- 164 bar = 2,378.62 psi
- 165 bar = 2,393.12 psi
- 166 bar = 2,407.63 psi
- 167 bar = 2,422.13 psi
- 168 bar = 2,436.63 psi
- 169 bar = 2,451.14 psi
- 170 bar = 2,465.64 psi
- 171 bar = 2,480.15 psi
- 172 bar = 2,494.65 psi
- 173 bar = 2,509.15 psi
- 174 bar = 2,523.66 psi
- 175 bar = 2,538.16 psi
- 176 bar = 2,552.66 psi
- 177 bar = 2,567.17 psi
- 178 bar = 2,581.67 psi
- 179 bar = 2,596.18 psi
- 180 bar = 2,610.68 psi
- 181 bar = 2,625.18 psi
- 182 bar = 2,639.69 psi
- 183 bar = 2,654.19 psi
- 184 bar = 2,668.69 psi
- 185 bar = 2,683.2 psi
- 186 bar = 2,697.7 psi
- 187 bar = 2,712.21 psi
- 188 bar = 2,726.71 psi
- 189 bar = 2,741.21 psi
- 190 bar = 2,755.72 psi
- 191 bar = 2,770.22 psi
- 192 bar = 2,784.72 psi
- 193 bar = 2,799.23 psi
- 194 bar = 2,813.73 psi
- 195 bar = 2,828.24 psi
- 196 bar = 2,842.74 psi
- 197 bar = 2,857.24 psi
- 198 bar = 2,871.75 psi
- 199 bar = 2,886.25 psi
- 200 bar = 2,900.75 psi
- 205 bar = 2,973.27 psi
- 210 bar = 3,045.79 psi
- 215 bar = 3,118.31 psi
- 220 bar = 3,190.83 psi
- 225 bar = 3,263.35 psi
- 230 bar = 3,335.87 psi
- 235 bar = 3,408.39 psi
- 240 bar = 3,480.91 psi
- 245 bar = 3,553.42 psi
- 250 bar = 3,625.94 psi
- 255 bar = 3,698.46 psi
- 260 bar = 3,770.98 psi
- 265 bar = 3,843.5 psi
- 270 bar = 3,916.02 psi
- 275 bar = 3,988.54 psi
- 280 bar = 4,061.06 psi
- 285 bar = 4,133.58 psi
- 290 bar = 4,206.09 psi
- 295 bar = 4,278.61 psi
- 300 bar = 4,351.13 psi
- 305 bar = 4,423.65 psi
- 310 bar = 4,496.17 psi
- 315 bar = 4,568.69 psi
- 320 bar = 4,641.21 psi
- 325 bar = 4,713.73 psi
- 330 bar = 4,786.25 psi
- 335 bar = 4,858.76 psi
- 340 bar = 4,931.28 psi
- 345 bar = 5,003.8 psi
- 350 bar = 5,076.32 psi
- 355 bar = 5,148.84 psi
- 360 bar = 5,221.36 psi
- 365 bar = 5,293.88 psi
- 370 bar = 5,366.4 psi
- 375 bar = 5,438.92 psi
- 380 bar = 5,511.43 psi
- 385 bar = 5,583.95 psi
- 390 bar = 5,656.47 psi
- 395 bar = 5,728.99 psi
- 400 bar = 5,801.51 psi
- 405 bar = 5,874.03 psi
- 410 bar = 5,946.55 psi
- 415 bar = 6,019.07 psi
- 420 bar = 6,091.58 psi
- 425 bar = 6,164.1 psi
- 430 bar = 6,236.62 psi
- 435 bar = 6,309.14 psi
- 440 bar = 6,381.66 psi
- 445 bar = 6,454.18 psi
- 450 bar = 6,526.7 psi
- 455 bar = 6,599.22 psi
- 460 bar = 6,671.74 psi
- 465 bar = 6,744.25 psi
- 470 bar = 6,816.77 psi
- 475 bar = 6,889.29 psi
- 480 bar = 6,961.81 psi
- 485 bar = 7,034.33 psi
- 490 bar = 7,106.85 psi
- 495 bar = 7,179.37 psi
- 500 bar = 7,251.89 psi
- 510 bar = 7,396.92 psi
- 520 bar = 7,541.96 psi
- 530 bar = 7,687 psi
- 540 bar = 7,832.04 psi
- 550 bar = 7,977.08 psi
- 560 bar = 8,122.11 psi
- 570 bar = 8,267.15 psi
- 580 bar = 8,412.19 psi
- 590 bar = 8,557.23 psi
- 600 bar = 8,702.26 psi
- 610 bar = 8,847.3 psi
- 620 bar = 8,992.34 psi
- 630 bar = 9,137.38 psi
- 640 bar = 9,282.42 psi
- 650 bar = 9,427.45 psi
- 660 bar = 9,572.49 psi
- 670 bar = 9,717.53 psi
- 680 bar = 9,862.57 psi
- 690 bar = 10,007.6 psi
- 700 bar = 10,152.64 psi
- 710 bar = 10,297.68 psi
- 720 bar = 10,442.72 psi
- 730 bar = 10,587.75 psi
- 740 bar = 10,732.79 psi
- 750 bar = 10,877.83 psi
- 760 bar = 11,022.87 psi
- 770 bar = 11,167.91 psi
- 780 bar = 11,312.94 psi
- 790 bar = 11,457.98 psi
- 800 bar = 11,603.02 psi
- 810 bar = 11,748.06 psi
- 820 bar = 11,893.09 psi
- 830 bar = 12,038.13 psi
- 840 bar = 12,183.17 psi
- 850 bar = 12,328.21 psi
- 860 bar = 12,473.25 psi
- 870 bar = 12,618.28 psi
- 880 bar = 12,763.32 psi
- 890 bar = 12,908.36 psi
- 900 bar = 13,053.4 psi
- 910 bar = 13,198.43 psi
- 920 bar = 13,343.47 psi
- 930 bar = 13,488.51 psi
- 940 bar = 13,633.55 psi
- 950 bar = 13,778.59 psi
- 960 bar = 13,923.62 psi
- 970 bar = 14,068.66 psi
- 980 bar = 14,213.7 psi
- 990 bar = 14,358.74 psi
- 1,000 bar = 14,503.77 psi
- 1,025 bar = 14,866.37 psi
- 1,050 bar = 15,228.96 psi
- 1,075 bar = 15,591.56 psi
- 1,100 bar = 15,954.15 psi
- 1,125 bar = 16,316.75 psi
- 1,150 bar = 16,679.34 psi
- 1,175 bar = 17,041.93 psi
- 1,200 bar = 17,404.53 psi
- 1,225 bar = 17,767.12 psi
- 1,250 bar = 18,129.72 psi
- 1,275 bar = 18,492.31 psi
- 1,300 bar = 18,854.91 psi
- 1,325 bar = 19,217.5 psi
- 1,350 bar = 19,580.09 psi
- 1,375 bar = 19,942.69 psi
- 1,400 bar = 20,305.28 psi
- 1,425 bar = 20,667.88 psi
- 1,450 bar = 21,030.47 psi
- 1,475 bar = 21,393.07 psi
- 1,500 bar = 21,755.66 psi
- 1,525 bar = 22,118.26 psi
- 1,550 bar = 22,480.85 psi
- 1,575 bar = 22,843.44 psi
- 1,600 bar = 23,206.04 psi
- 1,625 bar = 23,568.63 psi
- 1,650 bar = 23,931.23 psi
- 1,675 bar = 24,293.82 psi
- 1,700 bar = 24,656.42 psi
- 1,725 bar = 25,019.01 psi
- 1,750 bar = 25,381.6 psi
- 1,775 bar = 25,744.2 psi
- 1,800 bar = 26,106.79 psi
- 1,825 bar = 26,469.39 psi
- 1,850 bar = 26,831.98 psi
- 1,875 bar = 27,194.58 psi
- 1,900 bar = 27,557.17 psi
- 1,925 bar = 27,919.76 psi
- 1,950 bar = 28,282.36 psi
- 1,975 bar = 28,644.95 psi
- 2,000 bar = 29,007.55 psi
- 2,050 bar = 29,732.74 psi
- 2,100 bar = 30,457.92 psi
- 2,150 bar = 31,183.11 psi
- 2,200 bar = 31,908.3 psi
- 2,250 bar = 32,633.49 psi
- 2,300 bar = 33,358.68 psi
- 2,350 bar = 34,083.87 psi
- 2,400 bar = 34,809.06 psi
- 2,450 bar = 35,534.25 psi
- 2,500 bar = 36,259.43 psi
- 2,550 bar = 36,984.62 psi
- 2,600 bar = 37,709.81 psi
- 2,650 bar = 38,435 psi
- 2,700 bar = 39,160.19 psi
- 2,750 bar = 39,885.38 psi
- 2,800 bar = 40,610.57 psi
- 2,850 bar = 41,335.76 psi
- 2,900 bar = 42,060.94 psi
- 2,950 bar = 42,786.13 psi
- 3,000 bar = 43,511.32 psi
- 3,050 bar = 44,236.51 psi
- 3,100 bar = 44,961.7 psi
- 3,150 bar = 45,686.89 psi
- 3,200 bar = 46,412.08 psi
- 3,250 bar = 47,137.26 psi
- 3,300 bar = 47,862.45 psi
- 3,350 bar = 48,587.64 psi
- 3,400 bar = 49,312.83 psi
- 3,450 bar = 50,038.02 psi
- 3,500 bar = 50,763.21 psi
- 3,550 bar = 51,488.4 psi
- 3,600 bar = 52,213.59 psi
- 3,650 bar = 52,938.77 psi
- 3,700 bar = 53,663.96 psi
- 3,750 bar = 54,389.15 psi
- 3,800 bar = 55,114.34 psi
- 3,850 bar = 55,839.53 psi
- 3,900 bar = 56,564.72 psi
- 3,950 bar = 57,289.91 psi
- 4,000 bar = 58,015.1 psi
- 4,050 bar = 58,740.28 psi
- 4,100 bar = 59,465.47 psi
- 4,150 bar = 60,190.66 psi
- 4,200 bar = 60,915.85 psi
- 4,250 bar = 61,641.04 psi
- 4,300 bar = 62,366.23 psi
- 4,350 bar = 63,091.42 psi
- 4,400 bar = 63,816.6 psi
- 4,450 bar = 64,541.79 psi
- 4,500 bar = 65,266.98 psi
- 4,550 bar = 65,992.17 psi
- 4,600 bar = 66,717.36 psi
- 4,650 bar = 67,442.55 psi
- 4,700 bar = 68,167.74 psi
- 4,750 bar = 68,892.93 psi
- 4,800 bar = 69,618.11 psi
- 4,850 bar = 70,343.3 psi
- 4,900 bar = 71,068.49 psi
- 4,950 bar = 71,793.68 psi
- 5,000 bar = 72,518.87 psi
- 5,100 bar = 73,969.25 psi
- 5,200 bar = 75,419.62 psi
- 5,300 bar = 76,870 psi
- 5,400 bar = 78,320.38 psi
- 5,500 bar = 79,770.76 psi
- 5,600 bar = 81,221.13 psi
- 5,700 bar = 82,671.51 psi
- 5,800 bar = 84,121.89 psi
- 5,900 bar = 85,572.27 psi
- 6,000 bar = 87,022.64 psi
- 6,100 bar = 88,473.02 psi
- 6,200 bar = 89,923.4 psi
- 6,300 bar = 91,373.77 psi
- 6,400 bar = 92,824.15 psi
- 6,500 bar = 94,274.53 psi
- 6,600 bar = 95,724.91 psi
- 6,700 bar = 97,175.28 psi
- 6,800 bar = 98,625.66 psi
- 6,900 bar = 100,076.04 psi
- 7,000 bar = 101,526.42 psi
- 7,100 bar = 102,976.79 psi
- 7,200 bar = 104,427.17 psi
- 7,300 bar = 105,877.55 psi
- 7,400 bar = 107,327.93 psi
- 7,500 bar = 108,778.3 psi
- 7,600 bar = 110,228.68 psi
- 7,700 bar = 111,679.06 psi
- 7,800 bar = 113,129.44 psi
- 7,900 bar = 114,579.81 psi
- 8,000 bar = 116,030.19 psi
- 8,100 bar = 117,480.57 psi
- 8,200 bar = 118,930.94 psi
- 8,300 bar = 120,381.32 psi
- 8,400 bar = 121,831.7 psi
- 8,500 bar = 123,282.08 psi
- 8,600 bar = 124,732.45 psi
- 8,700 bar = 126,182.83 psi
- 8,800 bar = 127,633.21 psi
- 8,900 bar = 129,083.59 psi
- 9,000 bar = 130,533.96 psi
- 9,100 bar = 131,984.34 psi
- 9,200 bar = 133,434.72 psi
- 9,300 bar = 134,885.1 psi
- 9,400 bar = 136,335.47 psi
- 9,500 bar = 137,785.85 psi
- 9,600 bar = 139,236.23 psi
- 9,700 bar = 140,686.61 psi
- 9,800 bar = 142,136.98 psi
- 9,900 bar = 143,587.36 psi
- 10,000 bar = 145,037.74 psi
barはちょうど100,000パスカルです。psiはちょうど6,894.757293パスカルで、重量ポンドが4.4482216152605ニュートン、平方インチが6.4516 cm²と定義されているためです。14.5037738という比は定義から導かれるもので、都合のよい丸めではありません。 算出方法と出典.
よくある質問
タイヤのサイドウォールに51 psiとあるのはなぜ？
それはケーシングが耐えられる上限であって、入れるべき圧力ではないからです。サイドウォールにはMAX. PRESS. 350 kPa (51 PSI)、つまり3.5 barと刻まれ、指定空気圧は運転席ドア開口部のラベルにあり、多くは2.2から2.4 bar、すなわち32から35 psiです。上限まで入れると乗り心地が硬くなり、トレッド中央だけが摩耗し、濡れた路面での制動距離が伸びます。
14.5038と14.696、どちらを使う？
どちらも正しく、答える問いが違います。14.5038は換算係数で、1 barは常に14.5038 psiです。14.696は標準大気圧をpsiで表した値で、101,325パスカルが1.01325 barだからです。後者はゲージ圧を絶対圧に直すための数字であり、barの換算には使いません。
kg目盛りの圧力計は何を指している？
重量キログラム毎平方センチメートル、つまりkgf/cm²で、古い空気圧縮機や日本製の機器ではkgと略されます。98,066.5パスカル、すなわち0.980665 barで14.22 psiです。barとの差は2 %未満なのでタイヤでは実害がありませんが、250 kgf/cm²目盛りの油圧回路は250 barではなく245 barです。
自転車のタイヤは何barが適正？
細いタイヤのロードバイクで6から8 bar、つまり87から116 psi、マウンテンバイクで1.6から2.2 bar、つまり23から32 psiです。同じ自転車でも4倍の開きがあります。適正値は必ず範囲でサイドウォールに書かれており、フロアポンプに両方の目盛りがあるのは、欧州のタイヤがbar表記、米国のタイヤがpsi表記だからです。
ダイビングのタンクは200 barそれとも3000 psi？
国によって両方あり、しかも同じタンクではありません。欧州のスチールタンクは200 bar、すなわち2,901 psiまで充填し、高圧仕様は232 bar、すなわち3,365 psiです。米国の80立方フィートのアルミタンクは3,000 psi、つまり206.8 barまで充填します。片方で切りのよい数字は、もう片方では決して切りがよくありません。