Here in Massachusetts, there is an annual safety inspection for all vehicles. One test done is to test the parking brake. On a vehicle with a manual transmission, the procedure is to apply the parking brake, shift into 1st gear and slowly let out the clutch. The vehicle passes this test if the engine bogs down and the vehicle does not move. I can never pass the test and have to argue that there is no way the brakes will hold.
After doing some calculations I can see why the brakes will not stop the truck. The ISB Cummins has an electronically controlled idle speed of about 800 RPM and will apply fuel to maintain this RPM. The torque at idle is almost 300 ft. lbs. First gear ratio is 5. 61 and my final drive is 3. 55. Multiplying the 300 ft. lbs. by 5. 61 and by 3. 55 gives me 5,974 ft. lbs. of torque at the rear wheels. I am not surprised the truck moves.
Can anyone help me out with a solution? I am thinking of sneaking the shift lever into 5th gear but someone must know a way around this crazy problem.
After doing some calculations I can see why the brakes will not stop the truck. The ISB Cummins has an electronically controlled idle speed of about 800 RPM and will apply fuel to maintain this RPM. The torque at idle is almost 300 ft. lbs. First gear ratio is 5. 61 and my final drive is 3. 55. Multiplying the 300 ft. lbs. by 5. 61 and by 3. 55 gives me 5,974 ft. lbs. of torque at the rear wheels. I am not surprised the truck moves.
Can anyone help me out with a solution? I am thinking of sneaking the shift lever into 5th gear but someone must know a way around this crazy problem.