Here are the new pics of my car

 

...

 

..

 

looks real nice.. what suspension setup are you running?

 

.......

 

im running sprint/konis

 

me too.. i love that drop..

what are those 17's?

 

18's

 

Where are the centercaps?

 

i know..paul forgot to ship them....he's supposed to be airmailing them too me.....hopefully soon

 

18's? what size tires are you running?

 

225/40ZR18

 

thats your problem.. your speedo is way off.. and i notice that your tires look too big..

http://forums.off-topic.net/attachme...postid=1037737

i am running 235/40 or 245/45

check this site out..

http://www.miata.net/garage/tirecalc.html


and

https://maxima.org/maxfaqs/sub_tires...#TiresWheels_2

 

my speedo isn't off...that is the correct size for 18's on the max////

 

ok if you say so

 

get center caps ASAP

 

then what is the correct tire size???????

 

FYI:

with 225/40

your speedo is .8 seconds fast every 1 mph

with 235/40

your speedo is .3 seconds slow every 1 mph


http://www.miata.net/garage/tirecalc.html

stock tire being 215/55 for the SE ..

but hey.. what do i know

 

I can't say for sure if the error starts over 60 mph or over 100 mph

h

 

i am running 225/40/18's and my speedo is not off either, its a good tire size for 7.5 inch rims.

 

i don't understand....when i took the stock 16's off and rolled them up to the 18's they were the same size.....

how do i fix the speedo.....

 

my son.. its not something you will notice driving.. the only way you can tell is by a radar gun (ie. The cop tells you that you are doing a speed differnt from what your speedo indicates) its not really a big deal right now.. i would just advise you to get the correct size next time... and that is how you fix the speedo problem..

i noticed because i looked at how thick your tires were compared to mine.. the correct tire size or closest to it is 235/40-18

 

i thought the middle # was how thick they were!
aren't you running like a 2--/45/17

 

nope..i am running 235/40-18

when i said thick i meant the size of the tire wall

 

that's what i meant....the middle number=sidewall width...and the first # is the actual width of the tire itself....

225=how wide tire is
40=sidewall width

cuz a 19" rim uses a 35 series tire...which is more of a low profile tire than the 40 series

 

huh? what?

anyway.. 235/40-18 is the right size

 

what does the 1st number stand for?
and the second?

 

If he's running tires too small for the Max, why would his tires look thicker than yours? He has 225/40/18, you have 235/40/18. Your tires are bigger than his, so why do you say his look thicker?

 

i thought 235 was the side wall tire and rim and 40 was the width

 

i think you have it backwards.....

that's what i was trying to say.....

 

yeah you have it backwards. 235 is the part of the tire that rolls on the ground, 40 is the sidewall height.

 

....I am running 225/40/18's and my speedo is as close as its gonna get. Radar tested, officer approved.

 

anyway, I'm glad I did lots of reasearch before choosing my tire size

This is a great link I remembered using when I first bought the tires:

http://www.geocities.com/jgadlage/tirecalc.html

 

wether i have it backwards or not you are still running the wrong tire size

 

well if its .8 over 60 mph.. if you are doing 70 mph .. thats 10 * .8 so thats 78 mph you are actually doing when your car says you are doing 70 mph..

if its over .8 over 100 mph.. it won't matter too much because most people don't drive that fast.. but then.. it would be 108 mph when indicated doing 100 mph and so on...

 

Sprint, his tires are smaller than yours so how could his speedo be reading low and yours isn't? You are running 235/40/18 tires which are bigger than the 225/40/18 tires he's running. His speedo would read high, not low. Your speedo will read low.

 

yeah i know..

mine is .3 secs slow.. his is .8 secs fast..

according to the miata calculator

 

Guys, the second number is not a constant measurement, it's an aspect ratio. Check out this page on tirerack for a full explination.

http://www.tirerack.com/tires/tiretech/size.htm

A 235/45 tire is going to have more sidewall than a 215/45 tire.....

 

kewl... looks good

 

If I remember when Paul had the rims on his car (I saw them in person), those rims are 8.5" wide. That is why his tires look huge. A guy at the same meet, had the same size tire on a 18"x7.5" (or even a 18"x7") and Paul's tires (now pawn's) looked fatter. Honestly, I think the tire size shoudl be 235/40/18 for your car. I think Paul's car had the 15" SE rims before hand and that's why he might have went to 225/40.