Some new "Bling" for my old truck "pictues"

**danteross77** · 10-07-2006, 06:58 PM

Well got some new bling for my old truck on Wedensday, what do you guys think?

Also had a question, a friend at work said that the larger 20" rims and tires would make my speedometer less accurate, making it were I am going faster than my speedo says. Not that I am into racing it or anything, but the cops are real jerks around here and I want to be careful going through speed zones. My question is;
Is there any truth to this statement or is he just jealous?

**VABCH350X** · 10-07-2006, 07:27 PM

Originally Posted by danteross77

Well got some new bling for my old truck on Wedensday, what do you guys think?

Also had a question, a friend at work said that the larger 20" rims and tires would make my speedometer less accurate, making it were I am going faster than my speedo says. Not that I am into racing it or anything, but the cops are real jerks around here and I want to be careful going through speed zones. My question is;
Is there any truth to this statement or is he just jealous?

If the tire is taller than what was previously on it, it will indeed register a slower speed than actual. If the tire is close to the old size it may or may not be worth worrying about. If it is, take it down to your friendly locak transmission/speedo shop and have it calibrated. Shouldn't be too pricey.

Paul

**Dave223** · 10-07-2006, 08:24 PM

i once had a Toy 4x4 with 35s, it was 3 miles off at 60mph...I had a Ford 4x4 with 38s, it was 7 mph off at 60mph....i think it takes quite a bit of change to make a small difference. If Im not mistaken, you can get the speedo recalibrated on the Chevy's.

**ATC crazy** · 10-08-2006, 10:59 PM

As long as the overall tire diameter is close to stock, then your speedometer shouldnt be off by more than 1mph, if at all.

I have 33's on my F150, and the speedo is off by 7 mph at 60mph (Im doing 67mph when the speedo reads 60mph)

And you can get any vehicle re-calibrated. Older vehicles use a plastic gear in the transmission ($3), and the newer vehicles can be calibrated with a hand-held tuner or programmer.

**Banage** · 10-09-2006, 02:58 PM

on my car, I went from 14" to 15". when my speedo said 30mph it was 35. and when it said 70mph it was really 80mps

**atctim** · 10-09-2006, 03:26 PM

Originally Posted by Dave223

i once had a Toy 4x4 with 35s, it was 3 miles off at 60mph...I had a Ford 4x4 with 38s, it was 7 mph off at 60mph....i think it takes quite a bit of change to make a small difference. If Im not mistaken, you can get the speedo recalibrated on the Chevy's.

Here is a quick easy way (not 100% accurate, but close).

measure the old tire height - say it is a 31X10.50X15. 31 inches tall = 97.4 inches circumfrance. now, take the new tire height - say 35 inches tall. 35 inch tires are 110 inches in circumfrance.

Now before you would travel 97 inces per 1 tire rotation, now you are traveling more than 1 foot farther per tire rotation. 97.4 inches is 88.5 percent of 110 inches - thus approx 12 % difference. I apply this to speed. If your speedo says you are going 60 MPH - add 12% to it. You are actually traveling about 67.2 MPH.

Just something else about larger tires on vehicles - it not only messes up the MPH guage, but also the Miles guage. So if you put big tires (say the same as listed above) when brand new and drove it until the odometer said 100,000 miles, it would in reality have 112,000 miles on it.

Food for thought!

**3bogger** · 10-10-2006, 12:16 AM

http://www.4lo.com/4LoCalc.htm

theres some calculators that will help you out.

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Some new "Bling" for my old truck "pictues"