Would bigger tires help with the odo problem?

rww22 · 01-04-2005, 11:48 AM

I (like many others) have realized that my odometer is off by about 5.5% or so. Now I am definitely not an engineer, and math is not my strong point, but if I were to get tires that were, say 5.5% bigger, would that cancel out the miscalibration? I'm sure it's not that simple, but it would give me an excuse to get bigger tires!

BudmanHemi · 01-04-2005, 11:58 AM

I dont think so. Tire size will effect your speedometer, and it would need to be calibrated according to size, but odometer should remain the same.

Here's a link to how odometers work. Both mechanical, and computerized. I dont see it changing by tire size..

http://auto.howstuffworks.com/odometer.htm

juma · 01-04-2005, 12:06 PM

maybe. first determine if your speedo is off too. measure your time between mile markers on the interstate hiway several different places. drive at a steady 60 mph and see if you cover the distance in 1 minute or more or less seconds. report back by PM on how many seconds it took you to cover the mile with your speedometer reading 60 mph and I will tell you what tire to use if it will fix the error. juma

c_t_smith · 01-04-2005, 12:52 PM

Quote:

Originally Posted by BudmanHemi

I dont think so. Tire size will effect your speedometer, and it would need to be calibrated according to size, but odometer should remain the same.

Here's a link to how odometers work. Both mechanical, and computerized. I dont see it changing by tire size..

http://auto.howstuffworks.com/odometer.htm

Changing the tire size (or the axle gear ratio) absolutely WILL effect the speedo and the odometer.

scr38 · 01-04-2005, 01:23 PM

The odometer is usually reading low. Larger diameter tires will increase the error. The speedometer/odometer is getting it's signal from driveshaft revolutions. A larger tire will move the truck more per wheel revolution, so the error will be greater. A smaller tire (by the same % the odometer is off) will correct the problem, but why worry about it?. As the tires wear they become smaller in diameter and will give a more accurate reading.

juma · 01-04-2005, 03:36 PM

let's say it is reading 5 percent less miles than traveled and you have stock 235/75/17's. Your stockers are 30.9 inches tall. you need 5 percent less in height - .95 x 30.9 = 29.3 inches. so, a 265/60/17 would be just about right. the
Kumho ECSTA STX at tire rack for $94 looks pretty good but there are a couple of others in that size too. juma

the head · 01-04-2005, 04:26 PM

If you have VDC, you'll have to turn it off when you dirve it anywhere.

dman · 01-04-2005, 05:27 PM

Who really cares if the speedo is just a bit off, especially to the low side...this just means you are putting slightly fewer miles on the odometer than you really are...maintaining higher resale value. Plus you will be getting more out of your warranty period (based on miles not years).

Believe it or not Dodge used to have their speedos set a little fast just to cut the amount paid on warranty claims. The odometers were moving quicker than they should be and therefore their vehicles would make it out of warranty quicker. It was a pretty good scam until the industry caught on to their tricks and put an end to it.

dalt1 · 01-04-2005, 07:32 PM

Speedometer in my 05 LE Crew cab is right on compared to my GPS which is supposed to be very accurate. Haven't been able to check the odometer yet.