If driving a semi what is the purpose of double clutching I know it has to do with the transmission but how is it done and what happens
2006-09-08 17:50:41 · 7 answers · asked by humantouch_fan 1 in Cars & Transportation ➔ Maintenance & Repairs
Push in the clutch and pull the stick to neutral, let out the clutch, push in the clutch and put it into the gear you need. I haven't had to do this since driving the 60's models column shift transmissions to keep from grinding while downshifting. All modern transmissions have synchronizers so there is no need to double clutch. When I drove a semi I just used the clutch when stopping and taking off, the rest of the time, I just slid it into the right gear when my engine RPM's were in the right spot. Some practice will get you there. Shifting on the big rigs is a little different than shifting on a regular car, after a while getting used to your rig, you will know when the right time to shift is, and you will not need the clutch as often. The purpose of double shifting when using a non-synchronized transmission is to allow time for the speed of the spinning gears in the transmission to slow down, and come closer to the same rotational speed and not make the shift so harsh, especially when going to a lower gear.
2006-09-08 18:06:25 · answer #1 · answered by yugie29 6 · 0⤊ 0⤋
The days of double clutching are gone. The reason 25 years ago was the truck motors were small horse. To build enough horse power to move the 80,000 lb load, you had to rev the motor into the top rpm's. The trannys were not fully sycronized so you would build up the rpm's for the movement of the heavy load and to catch the next gear you would press the clutch in, pull out of gear(foot off the accelerator) quickly push again on the clutch and hold while raising the rpm's again and catching the next gear. This method allowed you to move the tractor/trailer faster.
now we have auto's and fully sycronized trannys that the only time you need the clutch is to start and stop. We now float the gears. Great question!
2006-09-09 01:18:00 · answer #2 · answered by ebay junkie 2 · 0⤊ 0⤋
When shifting say from 2nd to 3rd,...push the clutch in (then release) once to take it outta gear (2nd), then push it again to put it back into the next (3rd) Basically, once to release from gear, then again to go back in...DIG? It keeps those BIG torquey motors' RPMS a little softer. Learning where the motors' RPM's like to be shifted at can save you the trouble of Double Clutching, unless you need your left calf a little more muscular. It's a good way to get a tranny to shift when all else fails.
2006-09-09 01:02:38 · answer #3 · answered by mYkuL C 2 · 0⤊ 0⤋
double clutch is pushin in the clutch pullin it out of gear,then pushin in the clutch and placin it in next gear. it is done because the gear box in a semi is unsyncronized unlike you typical automobile. alot of "oldtimers" dont double clutch at all ,they "float" the gears without ever touchin the clutch. they use their ears to sync up the engine speed with the road speed and away they go
2006-09-09 01:22:17 · answer #4 · answered by puros_bran 1 · 0⤊ 0⤋
i think its because the gears aren't synchronized, you have to push in the clutch and shift from first to neutral, then press the clutch again and go to second
2006-09-09 00:57:45 · answer #5 · answered by crazylarry88 4 · 0⤊ 0⤋
one push to get it out and one to get it into the next gear,its done mostly on older crash boxes and helps line up the next gear.
2006-09-09 00:56:24 · answer #6 · answered by frank m 5 · 1⤊ 0⤋
Read these 2 articles:
http://en.wikipedia.org/wiki/Double_clutch
AND
http://www.elecdesign.com/Articles/Index.cfm?AD=1&ArticleID=6137
2006-09-09 00:56:47 · answer #7 · answered by Anonymous · 0⤊ 0⤋