No Calibration Needed!

[deserth3]

Here's another way to do it.

Keep a constant speed between mile markers. Measure the time in seconds. divide this number into 3600 and the result will be your average speed between those two mile markers.

i.e. 3600/60 sec.=60 mph
3600/65 sec.= 55.38 mph
3600/55 sec.=65.45 mph

[WVHummer]

I purchased 37x13.5x17 Toyo's earlier this year for my vehicle. The Toyo's are actually 37.1" in diam. compared to my bfg, which were 34.5. I did the math and here is what I came up with.

---------Toyo's------- BFG's
diam.----37.1"---------34.5"
circum.--116.553"-----108.835"--------(63360 in = 1 mile)
rev/mi.--543.615-------584.58

584.58/543.615=1.075
So, the Toyos travel 0.075 mile greater than the BFGs do in 1 mile.
So, when my speedometer says I am traveling at 60 mph, I am really going 64.5 mph.
@40 = 43.00 mph
@50 = 53.75 mph
@60 = 64.50 mph
@70 = 75.25 mph
@80 = 86.00 mph

Also, for every 13.33 miles, I am traveling 14.33 miles
1 mile saved every 13 1/3 miles.

[The Green Lantern]

Originally Posted by WVHummer

1 mile saved every 13 1/3 miles.

[RubHer Yellow Ducky]

Originally Posted by WVHummer

I purchased 37x13.5x17 Toyo's earlier this year for my vehicle. The Toyo's are actually 37.1" in diam. compared to my bfg, which were 34.5. I did the math and here is what I came up with.

---------Toyo's------- BFG's
diam.----37.1"---------34.5"
circum.--116.553"-----108.835"--------(63360 in = 1 mile)
rev/mi.--543.615-------584.58

584.58/543.615=1.075
So, the Toyos travel 0.075 mile greater than the BFGs do in 1 mile.
So, when my speedometer says I am traveling at 60 mph, I am really going 64.5 mph.
@40 = 43.00 mph
@50 = 53.75 mph
@60 = 64.50 mph
@70 = 75.25 mph
@80 = 86.00 mph

Also, for every 13.33 miles, I am traveling 14.33 miles
1 mile saved every 13 1/3 miles.

ROOKIE,

Did you check the dates on this thread ( da !!! ) April 06 was the last entry before yours