Looking for concaved rims
Originally Posted by x838nwy
Theoretically, it is best to keep the same offset and so increasing the width is the way to go, but for most people who don't want to mess about with their fenders, there's very limited room for increasing the width of the wheel.
I dunno why this is even being discussed - err, theorized. We were talking about Import-style wheels - mainly with high offests (greater than 25mm). These rims gain the greatest appearance when the width of the wheel is increased - not the offset.
Let me break it down. Offset is in mm.. width in inches. My rim is 1.5inches wider than stock - or 37mm. Greater than any offset difference.
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guys, i think you missed my point.
What I'm saying is that BOTH offset and width effect the concaveness of the wheel. And yes, for a given offset a wider wheel will 'go in' further, but if you want to keep the width stock (as to keep the tyres, or are restricted by the fenders etc) then you can achieve the effect by changing the offset.
It's likely that 10" wheels will do not fit your car, but a narrower one with low offset might.
No, there is nothing deep and meaningful in this, but it if you keep the offset the same then the centre of the contact patch will remain in the same position as stock = as Mitsu designed it. Now, in theory (or ideally or however else you may choose to put it) this is the 'best' for geometry etc.
I'm not saying your're wrong, just adding to what you said. please read the post again. I believe that it is clear.
p.s. If your wheels are 1.5" wider than stock and you're running stock offset, it will be (1.5/2)*25.4 = 19.05mm 'deeper' than stock. Mine are 1/2" wider but with +30 so I'm 14.35mm 'deeper'. Assuming the same wheel hub thickness. So, very close without using as wide a wheel.
What I'm saying is that BOTH offset and width effect the concaveness of the wheel. And yes, for a given offset a wider wheel will 'go in' further, but if you want to keep the width stock (as to keep the tyres, or are restricted by the fenders etc) then you can achieve the effect by changing the offset.
It's likely that 10" wheels will do not fit your car, but a narrower one with low offset might.
No, there is nothing deep and meaningful in this, but it if you keep the offset the same then the centre of the contact patch will remain in the same position as stock = as Mitsu designed it. Now, in theory (or ideally or however else you may choose to put it) this is the 'best' for geometry etc.
I'm not saying your're wrong, just adding to what you said. please read the post again. I believe that it is clear.
p.s. If your wheels are 1.5" wider than stock and you're running stock offset, it will be (1.5/2)*25.4 = 19.05mm 'deeper' than stock. Mine are 1/2" wider but with +30 so I'm 14.35mm 'deeper'. Assuming the same wheel hub thickness. So, very close without using as wide a wheel.
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Originally Posted by bonestockevo8
Theoretically what you said is true; but cannot be applied to our vehicles because all 8" and under (width) wheels that I have seen for our vehicles come in a minimum offset of +25 or +30.
I think the reason we're seeing +2x and +3x are is simply that these are the more popular sizes(?) and most Japanese cars seem to go somewhere between those two numbers. Another effect is that not many aftermarket wheels out there are 8" and under so what's available is limited. However if you go for 8.5-9.5 then there's a lot more to choose from.
See below for the sizes and offsets the TE37 come in. For 17x9, it goes from +-0 to +40.
http://www.rayswheels.co.jp/cgi-bin/cgi2/sizeGuide.cgi?modelName=TE37
Anyway, there's only a certain range of sizes that can fit our cars, so to get the look you want will usually need to be a compromise...
mmm.... why would you say width dictates the concavity of the wheel when most wheels aren't concave unless you ahve an aggressive offset? there are ce28s that are 17x9 +35 that look almost flush. yet if you get 17x9 in +22 they're concave like crazy.... same with the te37.
i'll give it to you that a 10" wheel is more likely to be concave than a 9" one but that's most likely due to the fact that in order to run it on the specified car you're requiring a certain offset.
look within any wheel series... the wider it is doesn't necessarily mean the more concave it is... however lower offset almost always means that... unless it's a lip wheel.
i think the fn01rc is the only exception to what i said... the 9.5 is much more concave than the 9 given the same offset...
in any case it depends on both numbers... and even more so it depends on the "style" of the wheel.
the problem with these comparisons is what i already said... you need a certain offset to run a certain width, very seldom do you see the case of the fn01rc wehre the 9.5 adn the 9 come in teh same offset. it's ususally the wider it is the more it's pushed out.
i'll give it to you that a 10" wheel is more likely to be concave than a 9" one but that's most likely due to the fact that in order to run it on the specified car you're requiring a certain offset.
look within any wheel series... the wider it is doesn't necessarily mean the more concave it is... however lower offset almost always means that... unless it's a lip wheel.
i think the fn01rc is the only exception to what i said... the 9.5 is much more concave than the 9 given the same offset...
in any case it depends on both numbers... and even more so it depends on the "style" of the wheel.
the problem with these comparisons is what i already said... you need a certain offset to run a certain width, very seldom do you see the case of the fn01rc wehre the 9.5 adn the 9 come in teh same offset. it's ususally the wider it is the more it's pushed out.
Last edited by trinydex; Jan 30, 2006 at 12:20 AM.
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I think what wheel manufacturers do is get a particular design and make a number of of molds to cast/forge the wheels.
One way of doing it is to decide on the range of offset and hole pcd they want and try to get one casting mold to make all of them. So if you choose to make anything up to 120mm pcd and all the way from +12 to +55 offset then you're going to just about cover every car out there. However, to do it with one mold, you're going to end up with a pretty hefty piece of casting, a lot of which you're going to machine out anyway. You're going to end up with more costly production and not exactly minimum wieght for a lot of sizes. Specially when you have obsessive people on evom putting your wheels on scales.
So what they do (I guess) is divide the offset range into several parts and have one mold for each. Say one for +55 to +38, one for +35 to +12 and so on. Now it's clear that if this is what they do then the 35-12 mold can be more concave than the other one cos it doesn't need the centre to come all the way out, just to be machined back again. So in this particular case, a +38 and +35 wheels will be quite different, while the +55 and +38 may look pretty much the same.
A good example is the GC05 ( http://www.prodrive-japan.com/products/gc_05f/size.html ) the thing that stands out are the 18x8.5 wheels. Offsets 23 and 32 come with face F2 while offsets 34/39/44 come with F1 face. F2 is more concave than F1. To see faces, click on the 3rd row under the work 'line up' and hover.
Obviously the width still has an effect, but as trinydex pointed out the change in offset can have a very pronounced effect, specially if you go over the 'step' the manufacturer chose. And yes, there is the 'style' of the wheel, which probably turns out to have more affect than the geometry...
One way of doing it is to decide on the range of offset and hole pcd they want and try to get one casting mold to make all of them. So if you choose to make anything up to 120mm pcd and all the way from +12 to +55 offset then you're going to just about cover every car out there. However, to do it with one mold, you're going to end up with a pretty hefty piece of casting, a lot of which you're going to machine out anyway. You're going to end up with more costly production and not exactly minimum wieght for a lot of sizes. Specially when you have obsessive people on evom putting your wheels on scales.
So what they do (I guess) is divide the offset range into several parts and have one mold for each. Say one for +55 to +38, one for +35 to +12 and so on. Now it's clear that if this is what they do then the 35-12 mold can be more concave than the other one cos it doesn't need the centre to come all the way out, just to be machined back again. So in this particular case, a +38 and +35 wheels will be quite different, while the +55 and +38 may look pretty much the same.
A good example is the GC05 ( http://www.prodrive-japan.com/products/gc_05f/size.html ) the thing that stands out are the 18x8.5 wheels. Offsets 23 and 32 come with face F2 while offsets 34/39/44 come with F1 face. F2 is more concave than F1. To see faces, click on the 3rd row under the work 'line up' and hover.
Obviously the width still has an effect, but as trinydex pointed out the change in offset can have a very pronounced effect, specially if you go over the 'step' the manufacturer chose. And yes, there is the 'style' of the wheel, which probably turns out to have more affect than the geometry...
Originally Posted by x838nwy
I would not say that it is entirely true that the width of the rim solely determines how concave it is. The offset, as we know, is the distance the mating surface (to the rotor) from the acutal centre plane of the wheel.
Example:
So, if you have a 10.5" wide wheel and you're running +38mm offset (about 1 1/2" offset) then the mating surface is 5.25-1.5 = 3.75" inward of the rim's outer edge. Let's say the hub on your wheel is 2" then the face on which the nuts sit is only 3.75-2 = 1.75" inwards of the outer rim.
Now if we do the same for a 8.5" wheel you end up with 0.75" inwards from the outer rim. So less, but basically less by the difference in width divided by two.
But if we take our 8.5" wheel and run a +12mm offset (about 1/2"), we get ((8.5/2)-0.5)-2 = 1.75" inwards of the outer rim. Which is the same as the 10.5" wheel.
This is fairly simplistic and the numbers are slightly silly to make them easier on my brain. However, my point is that the numbers work together. Theoretically, it is best to keep the same offset and so increasing the width is the way to go, but for most people who don't want to mess about with their fenders, there's very limited room for increasing the width of the wheel.
If it is purely the concave effect you're after, getting smaller diameter wheels wil help make the effect more promounced, perhaps (making it look like it caves in steeper).
Example:
So, if you have a 10.5" wide wheel and you're running +38mm offset (about 1 1/2" offset) then the mating surface is 5.25-1.5 = 3.75" inward of the rim's outer edge. Let's say the hub on your wheel is 2" then the face on which the nuts sit is only 3.75-2 = 1.75" inwards of the outer rim.
Now if we do the same for a 8.5" wheel you end up with 0.75" inwards from the outer rim. So less, but basically less by the difference in width divided by two.
But if we take our 8.5" wheel and run a +12mm offset (about 1/2"), we get ((8.5/2)-0.5)-2 = 1.75" inwards of the outer rim. Which is the same as the 10.5" wheel.
This is fairly simplistic and the numbers are slightly silly to make them easier on my brain. However, my point is that the numbers work together. Theoretically, it is best to keep the same offset and so increasing the width is the way to go, but for most people who don't want to mess about with their fenders, there's very limited room for increasing the width of the wheel.
If it is purely the concave effect you're after, getting smaller diameter wheels wil help make the effect more promounced, perhaps (making it look like it caves in steeper).
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Originally Posted by bonestockevo8
Very true; unfortunately the 5 months of research the guy did was pretty sloppy! 
One additional point; only certain rims will concave w/ increase in width. my 17x9.5 gtv's look like a 17x8.5 gtv; besides the width of the lip.
One additional point; only certain rims will concave w/ increase in width. my 17x9.5 gtv's look like a 17x8.5 gtv; besides the width of the lip.You can call my research sloppy all you want but I have been working with the guys at mackin
I guess my last post was a little off ... as I have been looking at only 18" and 19" wheels ... no 17s ..
18" is a lot easier to get concave look but you need to go wide. Inorder to get the concave look of all the track cars posted you really need a +15 offset or lower on a 18" or 19" rim.
Some of the other non track cars I dont consider very concave looking except for the guy with the rotas.
Sorry if I came off as rude; I was just joking. Like I said in my PM to you; the GTR face (concave) te-37 can be obtained w/ a +22. If youre going for something like they use in the japan time trials; yes; you'll probably have to go even lower. I'm sure it will spider out even more if you lower the offset.
Like I said in my PM to you; the GTR face (concave) te-37 can be obtained w/ a +22. If youre going for something like they use in the japan time trials; yes; you'll probably have to go even lower. I'm sure it will spider out even more if you lower the offset.
Originally Posted by M3this
You can call my research sloppy all you want but I have been working with the guys at mackin
I guess my last post was a little off ... as I have been looking at only 18" and 19" wheels ... no 17s ..
18" is a lot easier to get concave look but you need to go wide. Inorder to get the concave look of all the track cars posted you really need a +15 offset or lower on a 18" or 19" rim.
Some of the other non track cars I dont consider very concave looking except for the guy with the rotas.
I guess my last post was a little off ... as I have been looking at only 18" and 19" wheels ... no 17s ..
18" is a lot easier to get concave look but you need to go wide. Inorder to get the concave look of all the track cars posted you really need a +15 offset or lower on a 18" or 19" rim.
Some of the other non track cars I dont consider very concave looking except for the guy with the rotas.
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Originally Posted by bonestockevo8
Sorry if I came off as rude; I was just joking. Like I said in my PM to you; the GTR face (concave) te-37 can be obtained w/ a +22. If youre going for something like they use in the japan time trials; yes; you'll probably have to go even lower. I'm sure it will spider out even more if you lower the offset.
Like I said in my PM to you; the GTR face (concave) te-37 can be obtained w/ a +22. If youre going for something like they use in the japan time trials; yes; you'll probably have to go even lower. I'm sure it will spider out even more if you lower the offset.
Originally Posted by jbrown
