Undersized tires!!
#1
Undersized tires!!
I finally found out why when I am going 65 according to my speedometer, which is the speed limit, everyone is flying by me... I have undersized tires!
This is really pissing me off. I took my GPS around town this evening and when my speedo reports 40 MPH I am really going 36 MPH. I did not have a chance to get up to 65 but I bet that speed is really fast compared to what I am traveling.
I am supposed to be running 235/75 R17s and I have 245/65 R17s. According to the conversion done on some other web page, the stock size is 30.9 inches, and the size I am running is 29.8. A full inch smaller.
Will undersized tires cause any adverse effects on my Truck? They don't have much tread left on them so by next spring I'll be getting new ones anyway, for now I need to figure out at what speeds I am going on the dash to what they really are on the street.
Thanks!
This is really pissing me off. I took my GPS around town this evening and when my speedo reports 40 MPH I am really going 36 MPH. I did not have a chance to get up to 65 but I bet that speed is really fast compared to what I am traveling.
I am supposed to be running 235/75 R17s and I have 245/65 R17s. According to the conversion done on some other web page, the stock size is 30.9 inches, and the size I am running is 29.8. A full inch smaller.
Will undersized tires cause any adverse effects on my Truck? They don't have much tread left on them so by next spring I'll be getting new ones anyway, for now I need to figure out at what speeds I am going on the dash to what they really are on the street.
Thanks!
#4
Better Gas Mileage yeah, I am also logging a bunch of false miles on the odometer...so I need to alter my signature line because I am not really getting 15.5 MPG either.
That is good to know that nothing serious can happen. I thought when I bought it they looked smaller than normal but I didn't think anything of it.
That is good to know that nothing serious can happen. I thought when I bought it they looked smaller than normal but I didn't think anything of it.
#5
#6
#7
A 1" difference in tire size will cause about a 3%, not a 10%. Your speedo was off from the factory (no surprise). The dealer should be able to reflash the computer to correct, or better yet, get yourself a programmer - you can improve your mileage (I gained 2 mpg with SuperChips) and get more power.
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#8
#9
I was just thinking about the percentages and how off it would be, so thanks for clarifying that. I went to Ford a while back and they want $75 to program the speedo and I said I think I'll wait.
I had a superchips micro tuner on my 2001 and I loved it, I may look into getting another one for this truck. Also on the 2001, the GPS and the Speedometer were only 1 MPH off over the entire range of speeds 5-95 MPH. I tested it!
95 was hard to sustain with out worry of getting pulled over so that didn't last long, but it read accurately. I'll start looking for programmers and see what the money flow states as to purchasing.
I had a superchips micro tuner on my 2001 and I loved it, I may look into getting another one for this truck. Also on the 2001, the GPS and the Speedometer were only 1 MPH off over the entire range of speeds 5-95 MPH. I tested it!
95 was hard to sustain with out worry of getting pulled over so that didn't last long, but it read accurately. I'll start looking for programmers and see what the money flow states as to purchasing.