tire sizing - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

Tuck&Poke · 11-20-2001, 03:04 PM

ok look let me give you a sample 215/40zr 18 ok now my friend says that the 215 is the width of the tire. but that doesnt make sense becasue that 215 is in millimeters which means his tires are 2.15cm wide (uh....no) but it does make sense if its the profile of the tire.  now also how does the aspect ratio work.  i know its a ratio of the profile and the width but do you divide the 215 by the width of the tires in inches or cm or is it totally diffienrent

Tuck&Poke · 11-20-2001, 03:08 PM

oh yea and the 215 can be cm (2m wide doesnt sound right either) and it cant be inches.

BlankFlip · 11-20-2001, 03:21 PM

well, 215 mm is about 8.46 inches. n 215 mm is 21.5 cm not 2.15 cm, big difference there.

Tuck&Poke · 11-20-2001, 05:49 PM

oh shit.....oops guess hes right then.  i was divinding by 100 and i didnt even notice...#### dislexia

S13Grl · 11-20-2001, 08:37 PM

WeST taught me this tonight, I'd also never been sure about it:

"215/40/18 "

215 is the width of the tire
40 is the 40% of the width (or height of the tire)
18 is the rim size

Thank you, WeST!

*LanceS13* · 11-21-2001, 01:19 AM

good...some people besides me know what it means now <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/wink.gif" border="0" valign="absmiddle" alt=';)'>
I was getting tired of explaining it myself <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/smile.gif" border="0" valign="absmiddle" alt=':)'>

konkman · 11-21-2001, 02:14 AM

One thing that pisses me off with tire and rim sizing.  the measure the rim width in inches, but they measure tire width in millimetres.  Being Canadian and not knowing standard measurements that well, it sucks.

S13Grl · 11-21-2001, 07:07 AM

Hey, I agree  with you there. I'm European, and I've been here for five years and still haven't learned the conversions because, well... I really don't want to... When  I get told a distance in feet, if it's large, I just think of my height (5'3") and if it's smaller, I think of my rims (15"-17") (I hope you're not laughing).

So, yeah... the mix in the tire size doesn't make sense.

BlankFlip · 11-21-2001, 02:45 PM

i just remember that 205 is basically 8". n if u add 10 to it, which would be 215, u add about half an inch, so 205- is approx. 8" n 215 is approx. 8.5". so w/ 195, u just subtract .5", so 195 is about 7.5". i know it's NOT EXACT so no need to say the #'s r off by a lot cuz i know i can figure it out exactly, but this is just how i remember it basically when i don't want to do exact math or don't have a calculator handy. a lot of ppl don't seem to get what the different tire sizes mean, so it's cool that ppl can learn about it now.

11-21-2001, 05:34 PM

OOOOOOOOOOOO... thanks s13grl.  they should just measure the profile in mm too.  theres no point in that aspect ratio.  who the crap invented that??

MattS14 · 11-22-2001, 11:05 AM

S13Grl: I thought that the 40 in 215/40/18 the 40 represented 40% of the 215mm and that made up the side wall?

my240likenoother · 11-22-2001, 08:25 PM

can you fit a 40 tire on a 18" rim without doing modes to the supention???

11-20-2001, 03:04 PM	#1
Tuck&Poke Zilvia FREAK! Join Date: Aug 2001 Location: MIA Age: 38 Posts: 1,046 Trader Rating: (0) Feedback Score: 0 reviews	ok look let me give you a sample 215/40zr 18 ok now my friend says that the 215 is the width of the tire. but that doesnt make sense becasue that 215 is in millimeters which means his tires are 2.15cm wide (uh....no) but it does make sense if its the profile of the tire.  now also how does the aspect ratio work.  i know its a ratio of the profile and the width but do you divide the 215 by the width of the tires in inches or cm or is it totally diffienrent

11-20-2001, 03:08 PM	#2
Tuck&Poke Zilvia FREAK! Join Date: Aug 2001 Location: MIA Age: 38 Posts: 1,046 Trader Rating: (0) Feedback Score: 0 reviews	oh yea and the 215 can be cm (2m wide doesnt sound right either) and it cant be inches.

11-20-2001, 03:21 PM	#3
BlankFlip Nissanaholic! Join Date: Oct 2001 Location: The Future Posts: 1,627 Trader Rating: (0) Feedback Score: 0 reviews	well, 215 mm is about 8.46 inches. n 215 mm is 21.5 cm not 2.15 cm, big difference there.

11-20-2001, 05:49 PM	#4
Tuck&Poke Zilvia FREAK! Join Date: Aug 2001 Location: MIA Age: 38 Posts: 1,046 Trader Rating: (0) Feedback Score: 0 reviews	oh shit.....oops guess hes right then.  i was divinding by 100 and i didnt even notice...#### dislexia

11-20-2001, 08:37 PM	#5
S13Grl Married to the Mob Join Date: Dec 2000 Age: 44 Posts: 3,670 Trader Rating: (0) Feedback Score: 0 reviews	WeST taught me this tonight, I'd also never been sure about it: "215/40/18 " 215 is the width of the tire 40 is the 40% of the width (or height of the tire) 18 is the rim size Thank you, WeST!

11-21-2001, 01:19 AM	#6
LanceS13 AutoX Junkie Join Date: Jun 2001 Location: MS Age: 43 Posts: 2,044 Trader Rating: (0) Feedback Score: 0 reviews	good...some people besides me know what it means now <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/wink.gif" border="0" valign="absmiddle" alt=';)'> I was getting tired of explaining it myself <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/smile.gif" border="0" valign="absmiddle" alt=':)'>

11-21-2001, 02:14 AM	#7
konkman Zilvia Junkie Join Date: Aug 2001 Posts: 534 Trader Rating: (0) Feedback Score: 0 reviews	One thing that pisses me off with tire and rim sizing.  the measure the rim width in inches, but they measure tire width in millimetres.  Being Canadian and not knowing standard measurements that well, it sucks.

11-21-2001, 07:07 AM	#8
S13Grl Married to the Mob Join Date: Dec 2000 Age: 44 Posts: 3,670 Trader Rating: (0) Feedback Score: 0 reviews	Hey, I agree  with you there. I'm European, and I've been here for five years and still haven't learned the conversions because, well... I really don't want to... When  I get told a distance in feet, if it's large, I just think of my height (5'3") and if it's smaller, I think of my rims (15"-17") (I hope you're not laughing). So, yeah... the mix in the tire size doesn't make sense.

11-21-2001, 02:45 PM	#9
BlankFlip Nissanaholic! Join Date: Oct 2001 Location: The Future Posts: 1,627 Trader Rating: (0) Feedback Score: 0 reviews	i just remember that 205 is basically 8". n if u add 10 to it, which would be 215, u add about half an inch, so 205- is approx. 8" n 215 is approx. 8.5". so w/ 195, u just subtract .5", so 195 is about 7.5". i know it's NOT EXACT so no need to say the #'s r off by a lot cuz i know i can figure it out exactly, but this is just how i remember it basically when i don't want to do exact math or don't have a calculator handy. a lot of ppl don't seem to get what the different tire sizes mean, so it's cool that ppl can learn about it now.

11-21-2001, 05:34 PM	#10
Guest Posts: n/a	OOOOOOOOOOOO... thanks s13grl.  they should just measure the profile in mm too.  theres no point in that aspect ratio.  who the crap invented that??

11-22-2001, 11:05 AM	#11
MattS14 Leaky Injector Join Date: Nov 2001 Posts: 72 Trader Rating: (0) Feedback Score: 0 reviews	S13Grl: I thought that the 40 in 215/40/18 the 40 represented 40% of the 215mm and that made up the side wall?

11-22-2001, 08:25 PM	#12
my240likenoother Zilvia FREAK! Join Date: Aug 2001 Posts: 1,261 Trader Rating: (0) Feedback Score: 0 reviews	can you fit a 40 tire on a 18" rim without doing modes to the supention???