[DavidPJ]

So I drove our Terrain for 750+ miles and the cruise control set exactly as it should with the little thumbwheel. Some of the time I would just hold the wheel in the up position to increase speed and release it when I hit my desired cruise speed. Sometimes I would step it up or down in 1 mph increments. Most of the time I had it set for 70 mph. However, at one point I couldn't set the speed to 70 mph. The display would go from 69 to 71. I further increased the speed by stepping up at 1 mph increments with the thumbwheel and found another speed was missing. I think it was 74 mph.

I tried all sorts of ways to set 70 mph without success. Maybe an hour later I tried again and the 70 mph setting was once again available.

Any ideas what could be going on?

 

[mdh4psu]

I have the same experience with my Terrain. All that comes to mind is that there is some sort of error in the rounding logic in determining the speed of the cruise control versus the speed of the vehicle--just an idea.

 

[tnmats]

I have the same experience with my Terrain. All that comes to mind is that there is some sort of error in the rounding logic in determining the speed of the cruise control versus the speed of the vehicle--just an idea.

I've observed the identical thing in my Equinox and it looks like rounding error. The simple fix is just to disengage the cruise system and then just pick the new speed you want.

 

[GMCdriver]

I have never seen this happen but I drive with the vehicle set in metric so it always goes up or down 1 Km/h at a time rather then 1 mile at a time.
It stands to reason that the programing is written in the metric system and the MPH display is simply converted & displayed out of that programing, in that case it could be very likely that a rounding error could be occuring after every so many clicks of the wheel.

 

[Old Lar]

I wouldn't be that anal about 1 mph with cruise. When I have my car on cruise, it will vary 1-2 mph just going up and down hills and even on a straight away.

 

[GARYD]

Have to agree with Old Lar.
Of all the times I've used cruise, I've never noticed anything out of the ordinary. I always set my speed 5 mph above the limit. 55,60,65 or 70

 

[Seveniron]

My cruise in the Terrain acts exactly the same way. Sometimes it increases or decreases by one and sometimes by two. Mine is in KM as well. If I really insisted upon a certain speed, I would set it manually if I could not get it set while the cruise was already engaged.

 

[NoobNox]

Have to agree with Old Lar.
Of all the times I've used cruise, I've never noticed anything out of the ordinary. I always set my speed 5 mph above the limit. 55,60,65 or 70

5mph above the limit is too risky for me. Having friends/family that are police officers of one type or the other..I know that 5mph over is pretty much the upper limit of tolerance....and as already mentioned, you can easily exceed this by 1-2mph going down a hill with cruise on. 5mph over may not be enough to grab the attention of most cops, but 6-7mph (combined with an improperly calibrated radar gun) can easily alert a traffic cop that isn't having much luck nabbing anyone really going fast. Just play it smart and realize that some rural police departments have no tolerance at all for above the posted limit and you'll be fine....I haven't had a ticket in nearly 20 years.

For me it goes like this:

70mph limit- cruise set on 72
65mph limit- cruise set on 68
55mph limit- cruise set on 58
50mph limit- crusie set on 53
45 and below- no cruise and try to not vary by more than 1-2 mph

Also, I've never had an issue with the cruise on my Nox...it has always worked perfectly for 1mph increments.

 

[RNOX]

On the highways I don't use eco mode. Maybe that could be causing the flucuation?

 

[GARYD]

5 over is nothing here in the Chicago area, 10 over is usuall the low side. I could easily do 15 to 20 with absolutely no fear...on the highways I'm talking about. Depending on the type road, 5 over is the norm on suburban roads. Even then, I'm usually passed up.

 

[RIT333]

5 over is nothing here in the Chicago area, 10 over is usuall the low side. I could easily do 15 to 20 with absolutely no fear...on the highways I'm talking about. Depending on the type road, 5 over is the norm on suburban roads. Even then, I'm usually passed up.

I've dailed in 10 over the speed limit in both city and highway, and haven't gotten a ticket in 35 years. Last speeding ticket was becausde my car didn't have cruise, and I was 20 mph over - whoops ! Got it reduced to parking on the highway !

No cops on this forum, right ?

 

[GARYD]

OK BUDDY, PULL IT OVER! ;D

I'm with you RITT333.

The last ticket I goy was going 27 in a 25 mph residential street(at least that's what I thought the limit was). The residentila streets in the area around my office alternate from 20 on one street and the next street it's 25 and so on and so on. I was on the 20mph street when I got the ticket. I told the cop the speed limit is 25....he said that's on the next street over. I say why the difference. He said the streets that are 25mph have sidewalks and the streets that are 20mph don't have sidewalks. Politicians...you gotta love 'em.

 

[kuppyr]

I noticed this issue once on my Terrain, I don't remember the exact speed but it was probably in the 80 mph range not 70 lol
I just reset it to the speed I wanted and it started working correctly again.

 

[Old Lar]

5 over is nothing here in the Chicago area, 10 over is usuall the low side. I could easily do 15 to 20 with absolutely no fear...on the highways I'm talking about. Depending on the type road, 5 over is the norm on suburban roads. Even then, I'm usually passed up.

The last time I was driving through Chicago on I-90 posted 55 mph and driving at 80 mph, I couldn't keep up with the traffic. I avoid that highway if going up through Chicago.

 

[RNOX]

In NJ a few years back when they raised the speed limit to some roads to 65 the troopers were writinh tickets for 67 in a 65 zone. Also in NJ if you get a ticket in a 65 zone (Any moving violation I believe) the fines are doubled.

I got a ticket for 60 in a 40 zone. I was going downhill to a 55 zone. I plead not guilty and the park police let me plea to a parking ticket. Still cost me $130. About 1/2 what the fine would be

 

[GARYD]

WOW, talk about anal cops. A good reason not to go to NJ. Most speedometers have a good 2 to 3% error and ALL motorcycle speedometers do.
I'm sure there are a couple cops out there that are the same, but the large majority will give you at least a 5mph leeway.