ok i have a 92 lx, which comes stock with 14 inch steelies. i put on 15 alloys off of a 93 anniversary edition. everything run fine and works. my question is. i know my speedometer is off bc when i drive by one of those radar's that shows you your speed is a couple miles off of what i am going. Does anyone have the exact numbers or formula to calculate how much its off, or how fast i am really going? thanks in advance.

 

haha you won't be off by that much lol, 14" to 15" won't do too much and those radar things aren't exactly the most accurate ever. I think the speedos get off after age.

 

14.8% off....if you're running on just the rims! It depends on your tire size, but like TMM said, radar stations aren't the most accurate, and it's hard to judge exactly on needle gauges. It's not going to be enough to worry about, the tire size is usually adjusted with bigger rims to have roughly the same circumference as the stock tires.

 

ok well obviously im not running on rims alone
but the whole tire n rim is about 1 inch bigger tho. i went from 185/65/R14 to 195/60/R15. i didnt measure exactly but i put them next 2 each other and i looked like about and inch. im not worried about it, im just currious.

 

Those little radar stations are vastly more accurate than our spedometers.

 

bah i dunn phil, I've driven past one at a steady 25 and those things fluctuate like crazy, especially if there's other people around you.

 

That's because they're switching back and forth between different cars. Radar guns are very accurate. I have a lot of friends in the police department, so I know first hand how well their different types of equipment work. I even get to see all the new gadgets before they get distributed to the force.

Fluctuations of 1 mph is very common with those portable radar booths, because they're using a slightly wider beam. If it hits the car just right, 2 mph fluctuations aren't uncommon.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JohnD1079 &raquo;</TD></TR><TR><TD CLASS="quote">i went from 185/65/R14 to 195/60/R15. </TD></TR></TABLE>

http://www.neons.org/tire/

at 65mph you're off by 2mph

 

Some night get on the interstate and put your car on cruise. With a stopwatch, time how long it takes to go, say, 5 miles at that speed. Use the green signs next to the interstate - they are accurate.

Figure out the number of seconds it took you to drive one mile and divide that number into 3600. That's your speed, in miles per hour.

OK, now increase your speed by 5 mph or 10 mph, set the cruise again, and do this again. By this time you'll know how your odometer is reading.

And I highly recommend that people do this, even if they aren't changing rim size. My odometer is off by 4 or 5 mph (reads high) when I am driving at about 75 mph (if my odometer reads 75, I'm doing 71. If it reads 80, I'm doing 75 to 76). And no, Honda odometers are not adjustable (at least in the 6th generation).

 

When I was making a 4 hour return trip home from Dallas, I was bored and calculated my mph using the same method Heat just described. (I was so bored, I repeated it over and over again for hour.) My spedo was off by the same 4-5 mph. (Spedo read faster than I was actually going.) Coicidentally, that's the same difference when comparing my spedo with the portable radar stations.

 

Hmm interesting, I'll have to play with mine, I have a feeling phil you may be right, I never thought my speedo could be off by a whole 5 mph, that may make those stations a bit more correct.

 

Some places (like Europe) there's big penalties for car companies making speedometers that read low. Since there's always gonna be variations in manufacturing, they make them read high just to be really sure that none of them read low. 3% or 4% is pretty typical.

 

xluben, good site. i give u props for that. as for what heat said i will have to try that to see how accurate i am. thanks for all the reponses

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JohnD1079 &raquo;</TD></TR><TR><TD CLASS="quote">
xluben, good site. i give u props for that. as for what heat said i will have to try that to see how accurate i am. thanks for all the reponses</TD></TR></TABLE>

there's a diff. site with the same calculator in a sticky somewhere, but i couldn't find it. that was just the first one that came up in google.

i'll have to try cruise control, road sign method someday. my speedo always seems a couple mph higher than the roadside radar things.

also, i think honda got/is getting sued for having the odometers go up at an increased rate. i think it only applies to 7th gens and other newer hondas, though.