Forum Discussion
158 Replies
- 4x4ord, I know for sure that my truck does not apply the service brakes and I don't think Ron's truck does either but we'll see what his reply is. I know that for my truck it is rare that I need to use the service brakes towing my fiver in the steep mountain grades in BC as long as I'm in the right gear, which is usually 3rd in my G56 manual transmission. This is 1 gear lower than I climb tough grades in. I leave my exhaust brake on the FULL setting all the time, and don't use the variable setting.
Cummins12V98 wrote:
To have zero brake applications they need to be running at the speed they want to maintain then set cruise to say 5mph less but also lock the trans in the same gear you would have climbed that grade in. This will vary based on the grade and load. This takes a human to dial this in.
I easily maintained 30-35mph locked in 2nd gear on a several mile 14% grade at 33k combined simply by moving the cruise speed up or down with my thumb.
For the Cummins closer to 3k will give the best downhill braking.
Cool brakes along any big downhill grade = GOLDEN.
After appling a bit of physics to what you're experiencing I come away thinking your Ram must work similar to my Ford on cruise.... it applies the wheel brakes. Holding 33k on a 14% grade in second gear with 4.10 final gear ratio means about 1000 lbft at the crankshaft. If your engine is revving around 3000 rpm it would be producing about 575 reverse hp. The back pressure on your exhaust brake would need to be somewhere around 180 psi. So I think your truck must be automatically applying the service brakes.Bionic Man wrote:
Cummins12V98 wrote:
To have zero brake applications they need to be running at the speed they want to maintain then set cruise to say 5mph less but also lock the trans in the same gear you would have climbed that grade in. This will vary based on the grade and load. This takes a human to dial this in.
I easily maintained 30-35mph locked in 2nd gear on a several mile 14% grade at 33k combined simply by moving the cruise speed up or down with my thumb.
For the Cummins closer to 3k will give the best downhill braking.
Cool brakes along any big downhill grade = GOLDEN.
Does your truck have adaptive cruise control? Because if it does (and most of the new high trim trucks have it), the brakes will be applied automatically if you are using cruise.
I don't get the brake application part of the test. I guess they have to do something to measure, but it isn't unnerving to apply brakes going down a grade.
No adaptive. Just my input.Bionic Man wrote:
Cummins12V98 wrote:
To have zero brake applications they need to be running at the speed they want to maintain then set cruise to say 5mph less but also lock the trans in the same gear you would have climbed that grade in. This will vary based on the grade and load. This takes a human to dial this in.
I easily maintained 30-35mph locked in 2nd gear on a several mile 14% grade at 33k combined simply by moving the cruise speed up or down with my thumb.
For the Cummins closer to 3k will give the best downhill braking.
Cool brakes along any big downhill grade = GOLDEN.
Does your truck have adaptive cruise control? Because if it does (and most of the new high trim trucks have it), the brakes will be applied automatically if you are using cruise.
I don't get the brake application part of the test. I guess they have to do something to measure, but it isn't unnerving to apply brakes going down a grade.
I don’t believe that adaptive cruise was available on Ram until about 2018.
Well I think the brake application is just a measurement of how well or poorly the Exhaust brake Slows the decent speed.
On Edit: seems you can’t use the correct term r3tards as it isn’t politically correct even used correctly.Cummins12V98 wrote:
To have zero brake applications they need to be running at the speed they want to maintain then set cruise to say 5mph less but also lock the trans in the same gear you would have climbed that grade in. This will vary based on the grade and load. This takes a human to dial this in.
I easily maintained 30-35mph locked in 2nd gear on a several mile 14% grade at 33k combined simply by moving the cruise speed up or down with my thumb.
For the Cummins closer to 3k will give the best downhill braking.
Cool brakes along any big downhill grade = GOLDEN.
Does your truck have adaptive cruise control? Because if it does (and most of the new high trim trucks have it), the brakes will be applied automatically if you are using cruise.
I don't get the brake application part of the test. I guess they have to do something to measure, but it isn't unnerving to apply brakes going down a grade.- Human intervention is still important, example is when I see a grade ahead while using cruise control I drop a gear seamlessly instead of letting it drop a couple mph and then playing catchup.
Besides it gives you something to do when towing. - combined weight of 22,920 lbs towing we don't have an exhaust brake but the allison does the job for us. 30K noway. Happy for the guys that have it for safe towing the bigger loads.
chevman Cummins12V98 wrote:
To have zero brake applications they need to be running at the speed they want to maintain then set cruise to say 5mph less but also lock the trans in the same gear you would have climbed that grade in. This will vary based on the grade and load. This takes a human to dial this in.
I easily maintained 30-35mph locked in 2nd gear on a several mile 14% grade at 33k combined simply by moving the cruise speed up or down with my thumb.
For the Cummins closer to 3k will give the best downhill braking.
Cool brakes along any big downhill grade = GOLDEN.
Although I am not towing the weight you are , I have never had to lock in a gear, it does it automatically when I set cruise on the descent . Mine will hold the setting on the cruise within 5 mph over. If it takes shifting down it does it. If I want to come off a grade at say 45, I set it for 40, and that is where it stays at 45. It seems we are arriving at the same , with doing it a different way.- To have zero brake applications they need to be running at the speed they want to maintain then set cruise to say 5mph less but also lock the trans in the same gear you would have climbed that grade in. This will vary based on the grade and load. This takes a human to dial this in.
I easily maintained 30-35mph locked in 2nd gear on a several mile 14% grade at 33k combined simply by moving the cruise speed up or down with my thumb.
For the Cummins closer to 3k will give the best downhill braking.
Cool brakes along any big downhill grade = GOLDEN. - ^^^ With 30k in tow the trucks needed multiple brake applications at 35 mph. You can imagine what would have happened at 50 mph.
