Confused About Progressive Shifting

Ok, (Double-Clutching) Normally, you upshift at approx 1500 RPM's and as your RPM's fall to 1100, you slide it into the next gear, right!?

Clutch Neutral Clutch (*) Gear ....(*)place shifter at the "Door" of the next gear and it should slide in smoothly as RPMS fall to 1100. (somewhere between the 1500-1100 drop) Makes for a nice smooth, seamless shift (like butter, right!?

However, with Progressive Shifting, it's my understanding that you shift at approx. 1200 rpm.... so therefore you would be in the lower threshold of the 1500 - 1100 range? Real close to 1100

Won't that make it a "rougher" shift and harder on the transmission?

The only way I see it working, I think, is to, maybe, not use the clutch?.. because you have to be really super quick. But Double Clutching takes a little longer and would cause your rpms to fall more,,,,,,, so won't you likely to be shifting rougher? Or is Progressive shifting done without "double-clutching?

My truck shifts much more smoothly at 1200rpm. You can do it double clutch or float the gear. You learn to do it when your getting your CDL in that higher range because that gives you more time to get the shift done, but once you have the hang of shifting, progressive shifting will probably start to come naturally because you are going to want to shift faster anyway

As new drivers people get fixated on tach numbers. But then you need to get used to the different motor speeds. As long as you keep around 400 RPMs apart you'll be good.

I've never heard of "Progressive Shifting". Back in the age of stick shift cars, young guys (that would be me) would talk about power shifting and speed shifting. For power, you shift in the lower range and speed comes in the upper range. As we matured in our driving, we just shifted when we needed to. My point is, shift when you need to. Also, remember diesels have a narrow range of power, so you only get about 500 RPMs and need to shift 8 times instead of 3 or 4 as a gasoline engine can do.

The timing is the same between double clutch and floating, and that's fractions of a second. In both methods you're waiting for the tranny gears to change speed.

Ok, here's the deal on progressive shifting. The lower gears don't have as much of a jump between them as the higher gears do. Let me give you an example of what that does.

Say for instance you start out in 2nd gear. You rev it up to 1200 rpms, pop it out of gear, and quickly into 3rd probably at around 1000-1100 RPMs. The tach doesn't drop much from the time you leave 2nd (1200) and when you start in 3rd (1000-1100).

Now do the same thing but in 8th gear. You rev it up to 1200 rpms, pop it out of gear, and oooooh noooooo..........you can't go up to 9th unless you let the rpms drop way too low, like probably to around 700-800 rpms. So in order to stay in the proper rpm range you'll have to rev it up to about 1500 rpms in 8th so that the rpms are around 1100 when you pop it into 9th.

What happened? Well because there is a much smaller jump from 2nd to 3rd than there is from 8th to 9th the rpms won't have to drop as much in between gears. So really the goal is to start out at around 1100 rpms for each gear because that's near the bottom of the power band for these engines. In order to do that you have to let the rpms get progressively higher before shifting as you get higher in the gear range.

So to make up numbers for example, you might shift something like:

2nd gear - rev to 1200
3rd gear - rev to 1225
4th gear - rev to 1250
5th gear - rev to 1300
6th gear - rev to 1350
7th gear - rev to 1425
8th gear - rev to 1475
9th gear - rev to 1550

So you're spinning the engine a little faster before shifting as you go up through the gears. The exact numbers you'll use will vary from truck to truck because there is such a variety of engine/tranny/rear gear combinations but the concept will be the same.

Thanks for that Info, Brett. That helped me a lot. No longer am I "confused" in this regard, at least..LOL...

Also, Just want to say, Thank You, for this website. I'm always seeing you posting well informed replies, and not just a couple sentences here and there. You're always going into great detail very frequently in your responses. That is so cool. I know a lot of people here also do the same thing. There's a lot of great people here and some come and go thru the years. I know you created this site over 8 years ago, but to continue to maintain your enthusiasm for it is remarkable in my opinion. Sure you could just do basic website maintenance and allow moderators and members to sort of set the tone, etc. and be a hands-off type, but you "roll your sleeves up" and are right there each and every day. If you took a day off from here, no one would know it.

I decided to choose only 1 Trucking Forum to join and I chose this one. I made the right choice, that's for sure.

Anyway, Thank You. Much Appreciated. -mike (a.k.a....Ruminator)

Thanks Ruminator! I really enjoy helping people out and so do the awesome moderators here. I'm always amazed at the time they take to help everyone out.