Quote Originally Posted by JuStCrUzIn
im a class A driver meaning i have a CDL and as far as the double clutch thing, you do not need to use the clutch to shift from gear to gear only on take off, can you imagine what your leg would feel like if you double clutch all day in a twelve speed... for a noob to driving trucks you might need to double clutch in a commercial transmission when you push in the clutch it actually stops the trans from spinning its called a clutch brake for the people who have not yet learned the sweet spot of the trans to shift without a clutch, the only time a driver might use the clutch to shift gears is when they are overloaded with weight but even then double clutching is not needed. they teach you that in truck driving school that you need to double clutch but i do not know anyone who does it in my line of work in a commercial vehicle it is a waste of time and actually slows you down.
Agree about the slowing you down bit. And mostly unneccessary, though when you do have to clutch in a commercial truck (Some large day-driver Diesels with only a 6-speed box as well as stuff like Manual 550's and such) you do have to double clutch to keep the tranny from locking up because of the clutch brake. These diesels have a much bigger range between gears than the 10+ gears that full-size rigs have. Full size rigs have sometimes as small as 400rpm difference between gears, whereas something like a manual diesel UPS style truck could have only a 5 speed box and 2000rpms between gears, with a transmission that still doesn't use synchros because they're just one more thing to break on a heavy-duty transmission. Still, double-clutching in a racecar is ridiculous...when you get into Touring Car where the cars are still based off of street cars, most are switched to Sequential transmissions and the driver barely clutches through the whole race.