for the locals, I drive an azure pearl 05 tC on 280 between san jose and san francisco daily
for others, it's just some highway with lots of hills
people drive crazy there and I swear there are more chps(cali hw patrol) than anywhere else

speed limit is 65, but if u drive 80 on fast lane, u'll get tailed, honked, flashed and fingered...

Anyways, seems CHP's comfortable with 85mph but not 90...
so I 'v been driving at 85 with cruise control on for months

I recently heard from my friend, that cruise control is really bad for the car in hills.
It got me kinda scared, so I want to find out why so and whether it applies to my case.

I know tC has some sort of uphill technology, not sure what it is or how it works. But in my case, on cruise control at 85, my RPMs dont change driving up hills, it stays a tiny little bit higher than 3000. Some part of the highway is pretty steep, yet RPM does NOT change at all. I'm not sure it's because it's not steep enough or it's because of that uphill technology.


Anyways, does any one know in my case, whether or not cruise control will hurt my car ? Even if the damage is minor, but since I drive 45 miles each way everyday, it might add up.

any input is appreciated

people also say leaving A/C on driving uphills is not good either. I wonder if that applies to my case as well, since my RPMs don't change whatsoever even driving steepest part of 280

 

Open up any manual to a car where cruise control is equipped and you'll read the same thing: Don't engage cruise control when driving on hilly or mountanous roads.
Its basically common knowledge. The most damage done is probably going to be to the cruise control module itself not the car due to it constantly reengaging and disengaging.

Personally I've never heard anything bad about using A/C while driving up steep roads. I have to believe that that's bogus.

 

LOL cruise control all the way up I5 from SD to SF in a rental is fun! Red line that **** for a good 5 miles in some stretches of uphills.

 

The tC's manual does not mention any possible damage to the vehicle as a result of using cruise control on hills. It states that vehicle speed may increase or decrease on grades when using cruise control and that these changes may be greater on steeper hills. It suggests that it would be better not to use cruise control on steep hills because of these speed variations. It does not explicitly say that you can't use it.

 

If your rpm's aren't changing then how bad can it be? I mean freeways are engineered roads don't forget...I'm sure there's laws on max grades just like on how sharp a turn can be.

 

I drive the same stretch of 280 all the time. I don't think any of the hills are steep enough to make a real difference in your RPMs. It's easy to maintain a constant speed on 280.

You're right about the fast lane at 80 mph though. So YOU'RE the one driving slow in the fast lane! GET OUT OF MY WAY! :-P

 

Not sure about the cruise control question... but the whole thing about the A/C is more for bigger vehicles that struggle to make it up big hills. All it does is keep the engine temperature down when you turn off the A/C because the engine doesnt have to work as hard but thats it as far as i know.

 

so u r the crazy box driver who gets pulled over every other day
lol

 

As there are no throttle cables, and the cruise is managed by the computer just as the right pedal is, I don't see how there could be any risks. I use cruise all the time-- probably more than I should-- hills and valleys included.

 

how i miss the insane "flow of traffic" laws that far exceed the posted speed limit of california...

since the tC is drive by wire, there is no real damage that could occour. every thing is controlled by the ECU. one reason people say dont use CC on hills is because if the hill becomes to steep the car may not be able to maintain speed. most newer cars dont have this problem.

and the issue with the AC... not rinning AC will keep your engine a tad bit cooler as it doesnt have to work as hard. back in the day, cars would over heat going up hill. you see it sometims on the grapevine in so cal.

 

I also wanted to point out that the reason your RPMs never change despite the hill is because if engine is powerful enough to keep your car moving at that speed up the hill (which it seems like it is), there won't be any gear changing (I assume you're in an auto so there is even the option for that) and if the gears don't change, RPMs are directly linked to speed, regardless of grade. So 80 up a hill and 80 down a hill have the same RPMs regardless.

My advice is to set your cruise control and then watch the car... if the RPMs and speed start to dip, you're probably pushing it a bit hard. If not, you should be safe. As for the A/C, it just adds to the load. If you've got enough power in reserve, it shouldn't matter.

 

First of all, I don't drive a box.

Secondly, I've never been pulled over. I think as long as you're not swerving in and out of traffic and don't call attention to yourself, you're fine on 280 going 80, 85, 90. Cops don't even think twice about it.

Come to think of it, last time I was driving that stretch of 280, I had my cruise control set at 75 mph (BTW the RPMs never varied much up or downhill) and I was driving in the slow lane. I was one of the slowest ones on the road that day. 280 is nuts! Keep up or get out of the way! So much for 65mph speed limit.

Hey, anyone else see that blue lambo speeding 100+ MPH on that same stretch of 280? Seen him 3 times already!