I have 235/15 on the ranger, while the manufacturer calls for 225/15. So in order to know how fast I am actually going, does this mean I divide 235/225=1.044444, and then multiply 1.04444 by the speedometer to get the actual speed?
2007-04-20 06:18:41 · 7 answers · asked by Anonymous in Cars & Transportation ➔ Maintenance & Repairs
Your skipping a bit of information here. The Ranger OE tire size is P225/70R15 100S (yes, it is important to include the ENTIRE description). 235/15 means nothing - most of the description is missing. I assume you mean P235/75R15 105S but you could mean P235/70R15 102S. We just don't know.
A P225/70R15 100S tire has a diameter of 27.4 inches and should rotate around 765 times per mile. A P235/75R15 105S has a diameter of 28.7 inches and should rotate around 725 times per mile. A P235/70R15 102s will be right about in the middle of those figures.
The 225 and 235 represent the width of the tire. You don't divide those by anything to get a speedometer correction.
Assuming the speedo was accurate with the original tires the formula for determining the correction is:
Actual MPH = new tire diameter/old tire diameter x indicated mph
2007-04-20 08:49:57 · answer #1 · answered by Naughtums 7 · 0⤊ 0⤋
None of these numbnuts know what they're talking about. A 235/75R15 is taller that a 225/75R15. The 75 is the height of the tire expressed a a percentage of the width. So, if it's wider, it's that much taller. That said, just get a gps and check the speedometer. You don't know for sure how accurate it was before. The difference should be about 3mph at 70.
2007-04-20 18:01:15 · answer #2 · answered by Nomadd 7 · 0⤊ 1⤋
To check your speed, drive 60 on the freeway and clock the average time between mile marker posts. This will help you devise a better multiplier or MPH calculation.
2007-04-20 13:25:33 · answer #3 · answered by Anonymous · 0⤊ 1⤋
Depends on the tires aspect ratio. You only gave the tire widths so there isnt enough info to tell. It probably will be close enough to not matter though.
2007-04-20 13:29:32 · answer #4 · answered by Anonymous · 0⤊ 1⤋
that is nothing of the sort your speed has not changed cuz all you did is went to a wider tire not taller or shorter
2007-04-20 13:22:54 · answer #5 · answered by bowhunter6778 2 · 2⤊ 1⤋
you just made the tire widers not taller so the speed on your speedo is correct
2007-04-20 13:44:24 · answer #6 · answered by Anonymous · 1⤊ 1⤋
wide /// tall
2007-04-20 13:24:27 · answer #7 · answered by Anonymous · 0⤊ 1⤋