daiSho

hey again all... ok, slight hitch here in my quest for a replacement Manaray Sport MS-6 Hyper rim... i found a source (thx to Black99 for the hookup!) that can get me the rear wheel i need, but he wants to know what the offset needs to be, and says he can get them w/ offsets from +15 to +44 for the 18 x 9.5 size.

the problem is, my remaining rear wheel has the offset marking rubbed away, and i want to make sure to get the right one! the shop where my car is at tried to measure the remaining wheel, and they say it is a +17 offset, does anyone know if this sounds right for an FD? i bought these rims from the Tirerack many years ago, and after calling them they cannot help me, they claim not to know what offsets they sent me way back then.

if anyone knows what would have been proper for this wheel on an FD, i'd be very appreciative... really don't want to experiment here w/ such an expensive wheel! thx all..

black99

No problem for the hookup but +17 sounds way off. Did the shop measure the backspacing/offset in inches and then convert it to mm? Maybe they converted it wrong?

daiSho

hey Black99... hmm, ok, thats why i wanted to check w/ you guys... i am not sure how he tried to measure them, if i bring the remaining rear rim to a wheel shop should htey be able to measure the offset easily? this was a guy at a goodyear store, surprised he could mess it up so badly... what would sound proper for a rim like this?

black99

Proper to me would be the +44 or somewhere around there. I'd definately recommend taking it to a wheel specialty place(maybe a wheel place that sells and installs rims on imports) and having them measure. Or which might be safer to find something online about how to measure offsets and try measuring it yourself. All you'd need is a straight edge and a ruler.


Hopefully Rishie, SleepR1, dclin etc will check in on this. They could tell you for sure if there's anyway they could be +17, but it's my gut instinct that he wasn't sure about the inches-mm equation or something else went wrong.

dclin

iTrader: (4)

Hey diasho, we can meet up and we can measure it. Get me a list of the available offset numbers, and we can figure it out (I figure even as careful as we might try to measure it, we'll be off by a mm or two. No big deal, if the gaps between available offsets is significant, we can easily figure out which one it is). I agree with black99, the most suitable offset for 18X9.5 (assuming the gap btwn offsets is typical) is +44. It's more then likely no more numerically smaller then +38ish.

I remember your car (and wheels) at Marc's, though it was up in the air hehe. PM me and I'll reply with my number. What side of town are you on?

Ltr!

dclin

iTrader: (4)

BTW, remember the 3 piece SSR decolte with custom Gunmetal powder coated centers on Andy's car? Those were the ones I sold to him (originally Adam Saruwatari's).

Those were 18X9.5 +43 in the rear. We can use that as a ref, if Andy does not mind. His engine's blown and at the shop, right? Still need to give him back his taillamps I p/u from him last year hehe.

daiSho

ok guys, my Manaray quandary seems to be getting worse and worse... today dclin came out to check out the remaining wheels and measure them for offset, and while examining them we find that the 18 x 9.5 rim does in fact retain the factory offset marking (very faded but clearly legible) and it is marked as +53 ! when dclin does his magic to measure out the rim, he comes up w/ +35/+36 (and i could tell he knew what he was doing to!). unfortunately, the front rims are totally lacking offset markings, and i am going to have to replace one of them as well it looks like... this set of rims was purchased from the tirerack, but they have been distinctly unhelpful in providing the offset of the rims they sold me, they claim not to keep those sort of records. to top it off, i don't think contacting Manaray directly in Nagano would solve this problem, as i've been told that the tirerack won't necessarily use the provided application/offsets from manufacturers, and go w/ their own idea of whats right.

does anyone think that maybe these rims were 'mis-marked' at the factory, and the numbers are inverted (e.g. 3 5 = 5 3)? these rims are expensive to replace so i am hesitant to order the replacements blindly... don't suppose anyone here has a hookup at Tirerack that might be able to convince them to dig through their records to fid out what offset they recommended and provided for this rim and my application? thx for all the help all (thx a bunch for coming out today too, dclin... i know looking at my battered FD must have stung!)..

Nathan Kwok

I don't think you can fit 18.9.5" wheels up front without narrow springs, no matter what the offset. You would need to use tires that are really too small for the rim, like 255s max. With 2.5" springs you'll probably want something around 63mm offset in the front to avoid rubbing. 44mm upfront will probably be too little, but you could try running 44mm with 255 tires and roll the fender a bit and that may work. I think the ideal setup would be something like 18"x9.5" all around, 63mm offset, 2.5" coilovers, and 275/35 tires all around, if you're talking about 18"x9.5" wheels all around.

dclin

iTrader: (4)

daisho, you should have prepared me before I saw your car - I was in pain, just looking at it! Need to post pics.

Anyways, back to the topic at hand - that faded print really has me thrown for a loop, though everything that we looked at and what you told me says that the wheel offset should be smaller, inline with the +35/+36 I measured. Maybe some of the guys here can share their ideas.

Offset is simply the difference between the back of the center pad where the wheel mounts to the hub/rotor, and an imaginary line splitting the rim down the middle. Here is a good illustration, hehe:

http://www.tirerack.com/wheels/tech/offset.htm

To measure offset, we simply measure the overall width, divide it in half, and subtract it from the backspacing (distance from the center pad to the inner rim edge.

We did this by laying the wheel face down, and taking a straight edge yard stick laid horizontally across the the wheel edge. Taking a second straight edge, we set it vertically where it measures from the ground up to the horizontal straight edge. This is the overall width. The second measurement is simply measuring the distance from the center pad to the same horizontal straight edge.

Because I was using an aluminum yard stick that had a bit of flex, we needed to make sure the yard stick was turned so that there is no flexing in the direction we are measuring.

Also, because your tire is still mounted, we have to allow that there will be a little room for error (a mm or two), because the rim edge is not 'exposed'. The tire sidewalls over lap the rim edges pretty evenly on both sides, about 3mm - so margin of error should be low.

Also, given that we cannot be sure that the shop floor or the tire sidewall is perfectly flat, we took 4 measurements at different spots, for both the overall width and the back spacing measurements. I noticed about 1/16" variance among the 4 total width measurements, and less then 1/32" diff among the 4 backspacing measurements.

The final measurements I settled on were:

10 9/16th" total width (268.29mm)
and
6 11/16" backspacing (169.86mm)

We can calculate the imaginary center line by dividing the total width measurement in half:

268.29mm / 2 = 134.15mm

Now we take that and minus it from the backspace:

169.86mm - 134.15mm = 35.72mm

Because we know that the centerpad face sits on the outboard side of the imaginary center line, we know that the offset is positive (+).

So, we have a measurement of +36, give or take a mm or two for margin of error, given the crudeness of the measuring situation.

Now, take these ideas into consideration:

1) the Mazdaspeed MS-01 Mag wheel fitment for the FD is 18X9.5 +38 in the rear:

http://rayswheels.co.jp/cgi-bin/cgi/...odelName=01MAG

( http://rayswheels.co.jp/cgi-bin/cgi/...ker=MAZDASPEED )

2) You mentioned that when the shop installed your wheels, they said they had to add a little bit of negative camber to get the wheel to fit.

A smaller numericall offset (+35 vs +45 for example) will push the wheel out (assuming same wheel width/size). In this example, the front/outer face of the +35 wheel would have been pushed 10mm outwards compared to the +45.

*note* one cannot compare offsets of different size/width wheels. ex. an 18X10 +50 will sit very differently then a 18X8 +50.

When you have a wheel that is pushed out (a little bit), you can add a bit of negative camber which would tip the top of the wheel/tire in, so that it tucks into the fender. This of course, is not an ideal solution to fitting wheels/tires, but maybe ok if it's not too far off of factory specs.....

And then we see a faint "53" on the offset label.... talk about messing with a guy's head. I really don't know what to say, other then we should get a hold of the manufacturer to clear this up hehe. If anybody can chime in with ideas, please do so. I'm not going to get any sleep until this is figured out...

Let's meet up again sometime daisho, and stick the good wheel on my car. I remember how my previous wheels sat inside of my fenders, and should easily be able to tell a 17mm diff.....

dclin

iTrader: (4)

We're just talking about rear fitment, his front is 18X8 or 8.5, did not look at them.

18X9.5 +63 might work up front (with the skinnier springs as you mentioned), but in the rear the inner edge will likely contact the trailing arm (not sure even the M2 arms will allow it to fit), and definitely the sway bar linkage. Looking at pretty much all the Japanese wheel manufacturer sites' fitment recommendations, a 18X9.5" rear call for anywhere from +38ish thru +45ish.

From RaysWheels (Volk):


SSR's site (though they recommend only a 18X9 +37 in the rear, which has a same front spacing as a 18X9.5 +43):

http://www.speedstar.co.jp/collectio.../matching.html

275/35/18 is too tall to use in front. That would work out to a theoritical 25.6" overall diameter, whereas stock (225/50/16) is a theoritical 24.9".