Cruise Control ? - RV-Dreams Community Forum

Sassy · RV-Dreams Community Member

Cruise Control ?

igotjam · RV-Dreams Family Member

I use cruise control almost all the time when I'm NOT towing my trailer. I NEVER use cruise when towing. I have no good reason for doing it that way...it's just what I do. I can't answer if it's a good idea to use it or not.

Jim01 · RV-Dreams Family Member

Sassy,

First of all, there are no stupid questions on this forum.

From my experience, if you have an automatic transmission, you can use the cruise control when towing as long as it doesn't make your transmission downshift a lot. Usually on flat roads there is not a problem, but where it is hilly, the cruise should not be used. Also, you might find that when heading into a strong wind, the transmission will downshift a lot, even on the flat roads.

If you have a standard transmission, I would think you can use the cruise as long as the engine can maintain the set speed.

Hope this helps. smile

Jim

RVDude · RV-Dreams Family Member

Jim has it spot on...

If the transmission keeps up/down shifting due to the road/load conditions (also called "hunting") by all means kick the cruise off and go manual.

Using cruise while towing or not is personal pref. Downhill, depending on your system, you'll have already hit the brake thus tripping it off. Uphill won't matter on or off subject to rule above. I run the Eaton VORAD w/ SmartCruise system and actually leave my cruise engaged both up and down hills as it controls my following distance AND engine braking far more smoothly than any human can.

Using cruise or not is no difference in terms of "strain," you are still moving down the road the same whether you have it on or off!

I know I'll take some heat for this comment, but truthfully and pragmatically, none of our rigs nor any of our measurment methods has anywhere close to the accuracy to discern any difference in mileage either using cruise or not. It'll also be very rig and driver dependent. However, there is ample opinion on this topic one way or the other but no repeatable scientific data.

SO... Drive your cruise whichever way YOU personally feel most comfortable!

IT'S ALL GOOD!

thebearII · RV-Dreams Family Member

I always have used cruise control once I'm out of the city on the wide open highway. Normally I will allow the cruise control to take me up a hill until the truck downshifts the first time and then I take over control for the rest of the hill.

I use cruise control downhill with my new truck because it has an exhaust brake. The cruise control, exhaust brake and transmission all work together to maintain the speed I set. On my old truck on a gentle grade I would use cruise control downhill.

I find the cruise control eliminates one more thing I have to worry about while cruising down the road.

After all I already have to worry about:
- cars cutting us off
- blowing a tire
- the trailer coming loose from the hitch
- am I going too fast or too slow
- how much further to the next gas
- did I lock the trailer door
- did I latch the refrigerator
- did I latch the awnings
- staying inside of the narrow lanes
- where's my next turn
.....and more.

I tend to have a heavy foot and the cruise control helps me to maintain a speed where we get the best fuel mileage. I try to stay around 61 MPH towing the 5th wheel.

Without the cruise control, I've looked down at the speedo and discovered I'm doing 71 MPH, that's not good from a safety standpoint or for fuel mileage.

I tend not to formally pay attention to gas mileage, but it seems that with the cruise control it takes longer for the needle to head towards empty on the gas guage vs. when I have control.

I've seen writeups in the technical sections of the RV magazines during the past years, not once have the technical folks indicated there would be any detriment to using the cruise control on flat and level roads.

They don't recommend using cruise control or overdrive on uphills due to the tendancy for searching between gears when the speed is too slow for a higher gear but too fast for the lower gear so the transmission bounces between the two. It's a sickening feeling when that happens and it's not good for the transmission.

Final Thought-
Besides with the cruise control on, I can take a little nap while the truck does the driving..... just kidding. Reminds me of a story an insurance agent told about the new RV'er that put his motorhome on cruise control and went back to the galley to fix a cup of coffee. He woke up in the hospital wondering what had happened. He told the agent he had put the motorhome on autopilot and next thing he knew he was in the hospital.....

blijil · RV-Dreams Family Member

We have an allison transmission with tow haul and the transmisison brake arrangement. We have found that cruise control works great in tow haul and is easiest on the transmission. If it gets hilly then we turn off the overdrive. If the downhill on a long or steep hill requires the brake then braking sufficient to get the speed in line also will downshift to get the transmission down into the right gear. We hit resume when we are at the bottom or things flatten out enough. Works great in 99% of our situations. Can't really tell any difference on mpg except for speed selected. Cruise is definites easier and safer for us.

Larry and Jacki

-- Edited by blijil at 07:38, 2008-06-18

Luvglass · RV-Dreams Family Member

I use it all the time on the flats and moderate hills, and disengage it for big hills. Whether or not your truck down shifts excessively is more a function of the truck power to your rig weight than anything else. An underpowered truck will down shift a lot, sometimes even on flat roads.

ahoweth · RV-Dreams Family Member

These guys have it right on the money!

There is a very good reason you do not want your automatic transmission to downshift excessively. The great majority of wear in an automatic transmission is during shifting. That is because, during shifting both sets of clutches, the gear you are leaving and the gear you are going into, are slipping. Slipping clutches generate heat and wears the clutch surfaces. While a clutch is locked up it doesn't wear and doesn't produce heat. It really is that simple. There are other sources of heat in the transmission, namely the torque converter, but that is normal and the transmission cooler should take care of it assuming it is adequate for the job. Synthetic fluids and a shift kit will help reduce the slippage during shifting but the best cure is to not allow excessive shifting.

JMO

skidrowe · RV-Dreams Community Member

Except for steep hills, I use cruise control. I cruise on the flatland between 60-65 mph. I have a 4-speed automatic diesel pickup (and 5er) which won't downshift to 3rd gear until below ~50 mph. If I get that slow, I usually take over manually. I added an exhaust brake recently, and I am very pleased!

Doncat · RV-Dreams Family Member

I used my cruise control on the way back from the rally (after all the steep grades). I did forget to disable the cruise once on a hill and my engine revved to about 5000rpms (that woke me up!!!) biggrin

Doncat

Speedhitch · RV-Dreams Family Member

Don has a new alarm....Way to wake up Don. I use cruise as often as I can. This allows me to open my beer bottles clinched between my legs....NOOOOOOO just kidding come on...you know I am not that way....Really I do use cruise even on some hills. I have the 6 speed with tow-haul and I can choose 3rd or 4th gear and that drives my RPM up so I seldom shift even on long grades. I just watch the Speedy o meter and if it laggs I let off and go to manual. You kind a get the feel for it after you use it for a while. To each his own but with my old bum leg it sure is nice to let off on that accelerator and let that truck do the work.

And you right RV Dude you will take some heat...Chicken Head.....LOL

Speedy o Meter