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HarryS

Pedigreed Bulldog
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Posts posted by HarryS

  1. Here's a comparison of the two sizes. You can see the speedometer will be off and you will use more RPMs to get the correct speed. Your truck computer may adjust or maybe it can be programed to the new size. One other consideration is the ride with less sidewall and the new tire not being mounted on the correct width rim. Below came from a google search comparing the two sizes.

    Side by side Overlay

    285/70-17 275/55-17 Difference

    Diameter inches (mm) 32.71 (830.8) 28.91 (734.3) -3.8 (-96.5) -11.6%

    Width inches (mm) 11.22 (285) 10.83 (275) -0.39 (-10) -3.5%

    Circum. inches (mm) 102.76 (2610.04) 90.82 (2306.87) -11.94 (-303.16) -11.6%

    Sidewall Height inches (mm) 7.85 (199.5) 5.95 (151.25) -1.9 (-48.25) -24.2%

    Revolutions per mile (km) 616.6 (383.14) 697.63 (433.49) 81.03 (50.35) 13.1%

    275/55-17 TiresMichelin Latitude Tour HP275/55-R17$229 eachKumho Road Venture APT KL51275/55-R17$155 eachSee All 275/55-17 Tires (7)

    Speedometer Difference

    Speedo Reading Actual Speed

    20 mph (32.19 km/h) 17.68 mph (28.45 km/h)

    25 mph (40.23 km/h) 22.1 mph (35.56 km/h)

    30 mph (48.28 km/h) 26.52 mph (42.67 km/h)

    35 mph (56.33 km/h) 30.93 mph (49.78 km/h)

    40 mph (64.37 km/h) 35.35 mph (56.9 km/h)

    45 mph (72.42 km/h) 39.77 mph (64.01 km/h)

    50 mph (80.47 km/h) 44.19 mph (71.12 km/h)

    55 mph (88.51 km/h) 48.61 mph (78.23 km/h)

    60 mph (96.56 km/h) 53.03 mph (85.34 km/h)

    65 mph (104.61 km/h) 57.45 mph (92.46 km/h)

    Gear Ratio / RPMs for New Tire (@ 65 mph) 2.35 2.73 2.94 3.07 3.21 3.31 3.42 3.55 3.73 3.91 4.11 4.27 4.56 4.88 5.13 5.29 5.38 5.71 6.17 7.17

    1775 2062 2221 2319 2425 2501 2584 2682 2818 2954 3105 3226 3445 3687 3876 3996 4064 4314 4661 5417

    Better Fuel Economy Factory Ratios Increased Power

  2. I'm not sure about the newer trucks either. The wiper motor on my B is a Trico Folberth and it is stuck in the park position. I took the motor off today and using shop air on the inlet valve it will go one direction and stop. If you put the air to the park valve it will travel back and stop. I took the motor apart and there is a mechanism in there that looks like it is supposed to reverse the air flow from the inlet valve to a lower valve. I didn't find any blockage or krud in there or in the valving. It seems the reversing mechanism needs adjusting but I don't see how to do that.

  3. That auction is not far from me. The contractor that owns the trucks and equipment has a yard about 4 miles from my house. He has a fairly large collection of trucks mostly GMC & Chevy pickups and a variety of others. The '61 B Model is pretty nice but has deterioated over the past few years from sitting outside. He used to use it to pull a four car trailer hauling the pickups. I've seen the A Model but didn't look at it close.

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  4. I just got my new straight pipe for the B-model. Some say it might be a bit much but I think it will help it breathe a little better:)

    Will post pics when installed.

    That should relieve any back pressure problems. Can't wait for the pictures.

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