To Use Cruise Control on Not to Use Cruise Control That is the Question

[sirtate]

Originally Posted by Mark 7

I use cruise nearly all of the time in my leisure and professional life. Semi tractor says I use cruise 97% of miles driven. Ice, it's off, but that's about it.



In my '14 Ram it cruise gets pretty stupid when I am towing 13,000 # 5'er. Forces downshift and way more throttle then needed on the slightest grade, so I turn it off then.



Side note... I seldom use tow-haul mode. If it's an easy pull, nothing wrong with as much OD as I can use. I watch the transmission temp gauge and if it stays cool, I run it normally. I don't need the modified shift points as I drive with a very light foot and don't care if it takes me an extra 15 seconds to get up to speed. This may change if I am merging on to a higher speed roadway.



Another unsolicited fuel saving tip for these high diesel fuel prices for those driving them... SLOW DOWN! I drive 56 MPH in my work truck (Volvo VNL with a 13L engine set at 425 HP and 10 speed iShift). I pull a 53' van, and yes... I do drive on 75 MPH posted speed interstates. In 20 years doing this I have had nobody rear end me, though I am sure I have upset a few people. I average 7.9 MPG and have always been the top driver in "fuel efficiency" in our fleet of 60+ trucks. Only one other driver even close... and our fleet is governed at 65 MPH in any case.



Many of you are retired and should not have to be in a hurry to get anywhere! Slow down, enjoy the scenery, and save money!

I drive BigTruck too...
And never exceed 65mph when towing my TT.

It's better for fuel economy, and braking...
The amount of energy that has to be converted to heat in your brakes quadruples for every double in speed.
(As much heat is produced in your brakes slowing from 70-50 than from 50 to a stop)

I too drive a 65mph governed truck in 75mph zones... (At 62mph)

Studies have shown that rear end collisions don't increase with that Delta-V.

Wet roads aren't slippery when you have proper tires. (Not bald)
I use CC as often as I can... Even in the rain.
I am always ready to tap it off, and coast while approaching uncertain traffic or road conditions, and will resume it's use ASAP.

[CamperLifer]

Originally Posted by sirtate

I drive BigTruck too...
And never exceed 65mph when towing my TT.

It's better for fuel economy, and braking...
The amount of energy that has to be converted to heat in your brakes quadruples for every double in speed.
(As much heat is produced in your brakes slowing from 70-50 than from 50 to a stop)

I too drive a 65mph governed truck in 75mph zones... (At 62mph)

Studies have shown that rear end collisions don't increase with that Delta-V.

Wet roads aren't slippery when you have proper tires. (Not bald)
I use CC as often as I can... Even in the rain.
I am always ready to tap it off, and coast while approaching uncertain traffic or road conditions, and will resume it's use ASAP.

You seem like a man with common sense. Be careful here. Lots lack it and will redicule you for it.

[CamperLifer]

Originally Posted by KPMullen

Don't assume we all have late-model rigs or tow vehicles with all the latest bells and whistles. When you assume... well, you know. That said, even with the newest adaptive CC, forward collision warning, brake assist, etc. drivers often rely on safety systems and features too much getting themselves in trouble. Wet roads can be enough to result in hydroplaning especially with worn tires. Considering the varying levels of experience driving vehicles of the size and type we're dealing with on this forum it's still a best practice to disengage CC in inclement weather of any kind.

I think you probably rely on systems and features too much and thus think all others also do. Most of us have enough sense to replace tires too worn for highway use. We cannot help what others' experience with the vehicles they drive are. Cruise control is fine on a wet road.

[CamperLifer]

Originally Posted by Bill Nourse

Says right in the 2022 Chev 2500/3500 HD owner's manual not to use cruise on slick roads. Wet roads without snow or ice can be slick. Hydroplaning is always an issue with wet roads.


Right out of the 2022 Manual:
"Cruise control can be dangerous where
you cannot drive safely at a steady
speed. Do not use cruise control on
winding roads or in heavy traffic.
Cruise control can be dangerous on
slippery roads. On such roads, fast
changes in tire traction can cause
excessive wheel slip, and you could lose
control. Do not use cruise control on
slippery roads."

A slippery road and a wet road can be 2 different things. A slippery road might be wet but a wet road isn't necessarily slippery with good tires.

[ShelbyM]

Slippery when wet....

[Sv Todd]

Originally Posted by jergle

I'll use cruise control while towing if I'm on a relatively flat stretch without much traffic. I don't try to use it with hills. As far as the regular gas vs. premium, if your vehicle doesn't require it (mine doesn't), I don't think you would see any benefit from premium gas.

I bougth a Diablo tuner and had custom tunes made for my 2500HD gasser for both regular and premium. Then I towed with both and didn't observe a big enough perfomance or fuel economy difference to justify the expense of the premium fuel. I was even okay with a wash on cost if it meant I could get 20-30 miles more from a tank while towing but never saw a big enough difference to justify the premium.

[Sv Todd]

Originally Posted by wrvond

For years (decades) I lived by the maxim that cruise control provided the best fuel mileage. However, I have discovered that I get better mileage leaving it turned off. Not just better, significantly better. I imagine part of the reason is I can anticipate ascents while the cruise control cannot. Knowing a climb is coming up I can gently accelerate before starting up and can then actually coast a bit before the crest is reaches.
When I do use the cruise control, if I forget it's set and the rig starts a steep downhill, my truck can (and has) jumped from sixth gear to second gear to maintain it's speed as if that's not enough simply turning off the cruise won't release it from it's screaming descent. I have to actually accelerate going downhill to force an upshift and get the needle out of the redline.
I've also found that if I set the cruise control a few MPH below my target speed, let the truck achieve that speed then increase the setting one "+" at a time, I can get to the target speed without increasing engine RPMs.

Was going to type something vey similar, but this is exactly what I do.

[Sv Todd]

Originally Posted by CamperLifer

Where is this wet road rule ? Might have been a thang in 1983 or so ...

Vehicle dynamics! When you lift your foot of the throttle, before you brake, there is a weight transfer that occurs. This is the reason front brakes of any vehicle are bigger than the rear brakes.

If you are using cruise control and you need to make an emergency stop you will actually apply the brakes before this weight transfer starts. Because you are already in a traction limited situation due to the rain, aggresive braking before the throttle is closed, thus before the weight transfer begins, increases the likelyhood of locking the front wheels and loosing steering control, even if only momentarily.

Normal calm driving situation it's not a problem. It's only when you need to initiate aggresive panic/emergency braking that it becomes a risk.

[Sv Todd]

Originally Posted by CamperLifer

I think you probably rely on systems and features too much and thus think all others also do. Most of us have enough sense to replace tires too worn for highway use. We cannot help what others' experience with the vehicles they drive are. Cruise control is fine on a wet road.

Except when an emergency situation arises! What if a deer jumps out in the road before you? Do you really want to brake aggresively while the throttle is still open? Do you really want to swerve with the throttle still open,or are you going to brake and swerve at the sametime? It's not usually the best decision to apply two different aggresive inputs at the sametime!

[CamperLifer]

Originally Posted by Sv Todd

Vehicle dynamics! When you lift your foot of the throttle, before you brake, there is a weight transfer that occurs. This is the reason front brakes of any vehicle are bigger than the rear brakes.

If you are using cruise control and you need to make an emergency stop you will actually apply the brakes before this weight transfer starts. Because you are already in a traction limited situation due to the rain, aggresive braking before the throttle is closed, thus before the weight transfer begins, increases the likelyhood of locking the front wheels and loosing steering control, even if only momentarily.

Normal calm driving situation it's not a problem. It's only when you need to initiate aggresive panic/emergency braking that it becomes a risk.

Then don't panic and you will be fine.

[CamperLifer]

Originally Posted by Sv Todd

Except when an emergency situation arises! What if a deer jumps out in the road before you? Do you really want to brake aggresively while the throttle is still open? Do you really want to swerve with the throttle still open,or are you going to brake and swerve at the sametime? It's not usually the best decision to apply two different aggresive inputs at the sametime!

Anyone who swerves or panic brakes to miss an animal on the road values that animals' life more than their own or the passengers'. Not smart.

[mike91eagle]

Originally Posted by CamperLifer

Anyone who swerves or panic brakes to miss an animal on the road values that animals' life more than their own or the passengers'. Not smart.

What's not smart is hitting a deer at any speed with a vehicle. Having been in the collision industry for many years I've seen what the damage is to the vehicle and passengers. Avoid that collision if possible. Break, swerve whatever. I've actually seen where a deer came through the windshield into the passenger compartment.

[mike91eagle]

Originally Posted by Sv Todd

Except when an emergency situation arises! What if a deer jumps out in the road before you? Do you really want to brake aggresively while the throttle is still open? Do you really want to swerve with the throttle still open,or are you going to brake and swerve at the sametime? It's not usually the best decision to apply two different aggresive inputs at the sametime!

Just wondering, how do you get the weight transfer to begin without using the brakes?

And as for the open throttle, doesn't the cruise cancel closing the throttle the instant you touch the brakes?

[Psneeld]

Originally Posted by mike91eagle

What's not smart is hitting a deer at any speed with a vehicle. Having been in the collision industry for many years I've seen what the damage is to the vehicle and passengers. Avoid that collision if possible. Break, swerve whatever. I've actually seen where a deer came through the windshield into the passenger compartment.

My accident investigative skills tell me I have a better chance of surviving without panic handling than with it.

A trained auto racer may be able to panic stop in traffic or swerve and maintain control...not me or I think many others.

I will take significant damage from a deer hit versus a rollover or multiple vehicle pileup. The chances of being injured just from the deer I feel are substantially less. Yes they do occur but till I see some significantly, we'll investigated statistics on this type of accident....the best I would ever try at highway speeds is minimal braking and a tiny swerve like as if avoiding a small pothole which many of us are well acquainted with.

The first couple of safety articles I just googled agree about NEVER swerving. Braking yes, but only to the point of not losing control is what I would add.