Machtig
09-20-2004, 01:21 PM
#1
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Machtig
since i saw you guys having a convo about this below, explain something to an en-tire-ly handicapped person such as myself (HA, en-TIRE, i crack myself up). The big number in the 235/40 is the width right? 235 is stock and 240 to 245 is the widest people have gone? and then 40 is the height right? (how much sidewall you gonna have?)
I am thinking about getting some 18X8.5 inch rims but i want to know what that is in tire-talk. i am assuming our stock tires are 8 inchers so it will be a little bit wider (like 240 versus 235?) but that it wont be any higher (because its still an 18 inch wheel). So am i correct in assuming harnessedlucy has only 35 height sidewalls because he has 19 inch rims and wants to retain the overall rim+tire diameter (for speedometer accuracy etc?)
TIA
I am thinking about getting some 18X8.5 inch rims but i want to know what that is in tire-talk. i am assuming our stock tires are 8 inchers so it will be a little bit wider (like 240 versus 235?) but that it wont be any higher (because its still an 18 inch wheel). So am i correct in assuming harnessedlucy has only 35 height sidewalls because he has 19 inch rims and wants to retain the overall rim+tire diameter (for speedometer accuracy etc?)
TIA
any other questions, hit up my gmail account.
09-20-2004, 01:26 PM
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The 40 or 35 # is the ratio or % of the width, not an absolute height # . . .
so 235/40 would have a sidewall height of 94 (.4 x 235) in mm or about 3.7 inches.
09-20-2004, 01:34 PM
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so the width number (225 in dojo's case) is an absolute width (im mm)
but the smaller number is always the ratio of that width (so dojo's sidewall height would be 225*.4 or roughly 3.54 inches tall?)
Thanks for clearing that up guys. Dojo, so are your tires slightly thinner than stock? (width)
Thanks for clearing that up guys. Dojo, so are your tires slightly thinner than stock? (width)
09-20-2004, 01:41 PM
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yes, and yes. (below)
<center><img src="http://pictureposter.audiworld.com/17215/129-2980_img.jpg"></center><p>
so the 3 numbers represent:
example: 225/40/18
225 = width of the tire in MM (in this case 225 MM)
40 = the aspect ratio of width vs size tire (18inches)
18 = the diameter of the tire.
or as best explained on Tirerack.com If you need to hit the wheel tire forum and ask for Eddie, he's awesome, or call sasha @ Edge racing, and is good as well, OR still, call Eric @ SPP and he'll give you the same amount of great info.
I've included a pic of my tire/wheel to demonstrate, it IS a bit thinner than the stock profile of 235/40/18 which is on an 18x8 where as I'm on an 18x 8.5.
hth's
David.
so the 3 numbers represent:
example: 225/40/18
225 = width of the tire in MM (in this case 225 MM)
40 = the aspect ratio of width vs size tire (18inches)
18 = the diameter of the tire.
or as best explained on Tirerack.com If you need to hit the wheel tire forum and ask for Eddie, he's awesome, or call sasha @ Edge racing, and is good as well, OR still, call Eric @ SPP and he'll give you the same amount of great info.
I've included a pic of my tire/wheel to demonstrate, it IS a bit thinner than the stock profile of 235/40/18 which is on an 18x8 where as I'm on an 18x 8.5.
hth's
David.
09-20-2004, 01:58 PM
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gotcha
thanks for all your help. i love your wheels.
LAST question and i swear i am done
"18x8.5" "ET35" "5x112"
the wheels i want are 18x8.5 ET35 5x112 BBS CH and i am trying to figure out if they fit. is the 35 the ratio % of the width we were talking about? and the 5 is the number of lugs? and the 112 is the length in mm? is that all kosher with our cars? (i know the 35 is, but is that "112" the right length?)
really sorry for being such a bum and not looking this stuff up but it makes more sense coming straight from the experts themselves
LAST question and i swear i am done
"18x8.5" "ET35" "5x112"
the wheels i want are 18x8.5 ET35 5x112 BBS CH and i am trying to figure out if they fit. is the 35 the ratio % of the width we were talking about? and the 5 is the number of lugs? and the 112 is the length in mm? is that all kosher with our cars? (i know the 35 is, but is that "112" the right length?)
really sorry for being such a bum and not looking this stuff up but it makes more sense coming straight from the experts themselves
09-20-2004, 02:07 PM
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my et is 32, but 35 should be fine. oh and btw,
no problem and your welcome!
5 = lugs.
112 mm = distance between each bolt (pretty sure)
then there is a thread pitch and count that factors into the bevel or ball seat on the lug itself.
hth's.
5 = lugs.
112 mm = distance between each bolt (pretty sure)
then there is a thread pitch and count that factors into the bevel or ball seat on the lug itself.
hth's.
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09-20-2004, 02:11 PM
#8
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Re: gotcha
18x8.5 - 18" wheel diameter, 8.5" width
et35 - 35mm offset (distance between wheel centerline and hub mounting surface), smaller offset pushes the wheel out
5x112 - 5 bolts, 112mm diameter bolt circle
Yes, these whells will fit just fine.
et35 - 35mm offset (distance between wheel centerline and hub mounting surface), smaller offset pushes the wheel out
5x112 - 5 bolts, 112mm diameter bolt circle
Yes, these whells will fit just fine.
09-20-2004, 02:16 PM
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Your actually not that far off...
<b>235 / 40 / 18</b>
You are correct, the 235 represents the width, from one edge of the tire, up the sidewall, across the width of the tire, as well as the other side of the sidewall.
The 40 represents the aspect ratio. And it does have something to do with the height of the tire. The 40 represents 40% of the tire width (235). So, a 45 series tire would have 45% of the width. You can imagine what a 205/70 tire would look like. Super tall sidewall and narrow width.
The 18 represents the size of the rim. In our case, 18".
It's interesting to note, that a plus size increase in wheels does not necessarily mean that your going to need a wider tire in terms of 235 vs 245. Actually, you drop the aspect ratio.
So, stock, we are 235/40/18.
Going to 19", I have 235/35/19 tires.
The diameter went up 1", and the aspect ratio has gone down, yielding a tire that is both wider in tread and shorter in sidewall. Going with anything lower than a 30 series tire is asking for trouble because you'll bend a rim. And if anything, you'll want to use a 30 tire in the rear, but would want to increase the size of the tire (the 235 #) as much as possible. Because, a 265/40 tire is going to have a lot more sidewall than a 235/40 tire. (Same percentage of sidewall but with a much larger tire, so larger sidewall)
Rolling diameter is something to keep in mind when you are thinking about tires and plus sizing. It's best to use the <a href="http://www.miata.net/garage/tirecalc.html">wheel calculator</a> in order to find out what the rolling diameters are for different tires.
That's how I found that a 235/35/19 tire has the same rolling diameter as the 235/40/18 tire.
Hope that helps! ;-)
You are correct, the 235 represents the width, from one edge of the tire, up the sidewall, across the width of the tire, as well as the other side of the sidewall.
The 40 represents the aspect ratio. And it does have something to do with the height of the tire. The 40 represents 40% of the tire width (235). So, a 45 series tire would have 45% of the width. You can imagine what a 205/70 tire would look like. Super tall sidewall and narrow width.
The 18 represents the size of the rim. In our case, 18".
It's interesting to note, that a plus size increase in wheels does not necessarily mean that your going to need a wider tire in terms of 235 vs 245. Actually, you drop the aspect ratio.
So, stock, we are 235/40/18.
Going to 19", I have 235/35/19 tires.
The diameter went up 1", and the aspect ratio has gone down, yielding a tire that is both wider in tread and shorter in sidewall. Going with anything lower than a 30 series tire is asking for trouble because you'll bend a rim. And if anything, you'll want to use a 30 tire in the rear, but would want to increase the size of the tire (the 235 #) as much as possible. Because, a 265/40 tire is going to have a lot more sidewall than a 235/40 tire. (Same percentage of sidewall but with a much larger tire, so larger sidewall)
Rolling diameter is something to keep in mind when you are thinking about tires and plus sizing. It's best to use the <a href="http://www.miata.net/garage/tirecalc.html">wheel calculator</a> in order to find out what the rolling diameters are for different tires.
That's how I found that a 235/35/19 tire has the same rolling diameter as the 235/40/18 tire.
Hope that helps! ;-)
09-20-2004, 03:34 PM
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Remember that the 225 is somewhat a relative number...
Not all tires have the same 'width' as far as their widest parts.
S-03's run really wide. I had 225 S-03's and they were 1.2" wider than the 225 Kumho's I got rid of for them.
Best thing to do is to get close with the rated width, and look on tirerack for exact dimensions (to make sure you wont rub, if you are going wider)
S-03's run really wide. I had 225 S-03's and they were 1.2" wider than the 225 Kumho's I got rid of for them.
Best thing to do is to get close with the rated width, and look on tirerack for exact dimensions (to make sure you wont rub, if you are going wider)