Chevy Aveo Speedometer

luckins

I have one of those radar signs in my neighborhood that tells you how fast you are going. On my old car, the sign said what was close to what my speedometer said, but on my Aveo, it reads lower, sometimes substantially lower. However, the odometer is spot on correct. I know in older cars the two were related and if the odometer was correct, then the speedometer is correct. Is that still the case?

Also does having an all-white car have any effect on radar or on these signs?

I like to drive the speed limit and I can't tell if I'm going any faster or slower than usual because 99% of the other drivers fly by me anyway. I have found that if I drive the same speeds as always, I arrive at about the same time as the old car, or just a little bit sooner.

timseh

Get on the highway and use a stopwatch. Time yourself from mile marker to mile marker. 60 MPH should be exactly 1 minute. I believe 65 MPH is about 55 seconds. 70 MPH should be 51 seconds or so. 55 MPH should be about 65 seconds. On surface streets, if you can avoid stoplights/signs, 45 MPH should be 80 seconds even. 35 MPH should be 102 seconds (1 min. 42 seconds).

The color of the car has absolutely no bearing on radar... unless you managed to get your hands on some of that cool radar absorbing/deflecting military stealth paint.

wave54

I figured out the first couple of days that the speedometer was off. Comparing to radar signs, the speedo reads 5 mph over in the 50-65 mph range and 3-5 mph over around town at lower speeds. I compensate by allowing a higher reading than what I want to actually be traveling.

Have also checked against mile markers over a considerable distance, and the odometer reads high by 4-5%.

luckins

Thanks for replying.

I will try the stopwatch thing, but I don't like looking at a stopwatch while driving as I live in a very high traffic area. But, I plan to take a long trip out to the desert and there are some places where I might be able to do that. I'll take the numbers you posted with me.

I found some research that says that most speedometers on American cars tend to read as much as 4% higher than the actual speed. But, in my case, it read up to 20% off, though it does seem to be improving. Yesterday, the sign seem to indicate that it was around 10% off. The odometer is perfect, right on the mark, so I'm not worried about mileage.

The car was an ugly duckling on the lot that I got it from. It was driven heavily for the first few years, then dropped off at a dealership, and basically only driven for 20 miles during the last few months. It also rained heavily during that time and there were several problems by the time that I test drove it. But, a lot of them have resolved themselves just by regular driving and a little TLC. Maybe this will be one of those problems that will resolve itself. I just hope that if there is a problem, I can convince the dealer to fix it.

wave54

I don't know why there is such a problem with speedometers reading high. Of the last 4 cars I've driven, 3 had speedometers that were inaccurate.

This isn't exactly a high-tech dilemma. It's probably just a little plastic gear that needs to be the right size, so what's the problem?

luckins

Yeah, I hear that some of them are also just a magnetic connection between the dashboard and the cable to the transmission or wheels, too. But, that's what several studies have said, I don't remember the exact places, but it was several.

I know that my last 2 cars that I've owned had very accurate speedometers, too. In fact, I was "paced" by a motor officer when I had a Ford Granada and when I went 1 mile over the speed limit before he waved me to slow down.

I just noticed, today, that my local freeways don't have mile markers on them. :confuse: I have to go way out of town before I start seeing them.

luckins

I just found out that there is a TSB relating to incorrect speedometers on the year and model that I have. I am taking the car in for a timing belt change in a couple of months, and will bring this up to the dealer. Hopefully, having a TSB number or copy of the TSB will convince them something needs to be done if it's really is inaccurate. I will let everyone know how the road test went when I can do it. It's not a major thing, but I like my speedo to be correct as possible.

wave54

What year is your car and does the TSB include every vehicle in that model year?

luckins

The NHTSA number is 10018606 and seems to cover all models. I have a 2004, but it seems to cover up to 2006. I haven't been able to find out all the details, yet, but I'll dig around. It seems to be a recent TSB. I also get a number 3774, I think, too. The problem is that you have to pay to get the full reports.

wave54

Thanks. Went through the entire list of TSB reports for my model year. Almost all the issues I've had are addressed, but the dealers have been unable or reluctant to fix the problems.

Doesn't matter to me now as its got high mileage and was restyled by a snow plow in December. The inevitable progression from shiny new car to beater.

luckins

Yeah, I think it's going to be a pain convincing them on this one because the car was "certified" after the date that the bulletin came out. And, I guess the fix is to replace the instrument cluster. I wonder how long they would take to do that?

Since I think it's about 10%, I may just drive with the speedometers at about 10% higher unless I know I'm going through a photo enforced zone. I haven't checked it against mile markers. I have checked the odometer against the clock and it reads exactly 1 mile at 1 minute when I drive 60mph and I've already confirmed it's accuracy.

It's possible those speed signs in my neighborhood aren't working right.

wave54

Every time I see one of those portable radar set-ups on the side of the road, I check my speedometer against it. The speedometer is ALWAYS reading high by about 9% -- that has been consistent over years and many thousands of miles.

The TSB states that the readings are 7-9% high, so that's right on the money. I got used to driving at a 5 mph faster speed (by the speedometer) and I've never had a problem.

busiris

My o5 hatchback also showed a faster speed than actual speed, showing about 61-62 mph at actual 55 mph. Like you, I just adjusted my driving habits to include the speed differential...

luckins

I am wondering if the sign is off because when I went walking today, I went past it and all the cars seemed to be going about 10% lower than usual. The speed limit on our street is 35, but most people go around 45 to 50 MPH. But, today, the sign read most of the cars around 37 to 42 even when I could tell the car was really hauling.