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Just another data point for everyone who's interested.

13x9" Diamond Racing wheels with 5.5" backspacing

Everything fits perfect and there is no rubbing whatsoever.  The tires look perfect on a nine inch wheel, as you can see from the pictures in John's post above.  I would assume that you could stretch them over an 8" wheel without too much trouble, but 9" looks really good.

I'm excited about next weekend.

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Jake
Finger Lakes Region, NY
'91 Sentra SE-R --- Rally Beater
'92 Miata --- CSP

eselred:

Just another data point for everyone who's interested.

13x9" Diamond Racing wheels with 5.5" backspacing

Everything fits perfect and there is no rubbing whatsoever.

 I'd love to know if they'd fit over 1.8 brakes

 Thanks,

 --Bryan 

I'd love to tell you, but I don't know.  I have 1.6 brakes.  If I had to guess, I'd say no.  Maybe I can find a Miata with 1.8 brakes at the autocross on Sunday.  I can't think of one that runs in my local region off the top of my head, but it's possible that one will show up.

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Jake
Finger Lakes Region, NY
'91 Sentra SE-R --- Rally Beater
'92 Miata --- CSP

I was up in Pocatello for their Summerfast event and I tried my wheel/tire setup on a friends '96 Miata.  I only tried the front and they did not fit - they rubbed and would not turn.  I was going to try a spacer, but he only had the stock wheel studs and they were not long enough.

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John
Utah Region, #23 CSP Miata

Bummer. My 13 x 7.5 Lenso VPD's fit fine (+25 offset, I think). I wonder if a 5" backspace or something would work?

Any feedback on just how much faster these are than the previous crop of 13" tires?   These are a lot more money per run than my present v710's, and i am trying to figure out how much additional bang for buck they offer, so I can decide when to switch.

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WTB: CSP Spyder parts. What you got?

anyone find the "perfect" wheel width and offset yet?  :)

I think that the 13"x9" with 5.5" backspacing is perfect, but I haven't done any testing to verify this.  It keeps the car as narrow as possible and I don't see there being much, if any, gain in contact patch from running a wider wheel.  Comparing my wheels to my friend's (he's running a 13"x10" with 5" backspacing), the tires seem to fit equally as well with no pinching on the narrower wheel.

 This is, of course, one local competitor's semi-informed opinion, so take from it what you will.

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Jake
Finger Lakes Region, NY
'91 Sentra SE-R --- Rally Beater
'92 Miata --- CSP

eselred:

I think that the 13"x9" with 5.5" backspacing is perfect, ...

That's what I'm using.  I have 13"x9" with 5.25" backspacing, but I also use a 1/4" spacer on the front to bring it to 5.5".  I don't use a spacer on the rear.  This is on a 1990 Miata.

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John
Utah Region, #23 CSP Miata

thanks guys, that does help.

 

good comparison on the 9" vs the firnds 10"

York:

eselred:

I think that the 13"x9" with 5.5" backspacing is perfect, ...

That's what I'm using.  I have 13"x9" with 5.25" backspacing, but I also use a 1/4" spacer on the front to bring it to 5.5".  I don't use a spacer on the rear.  This is on a 1990 Miata.

 

what wheel is that? (I am thinking about the 13x9" Diamond Racing Mini Stock, mostly because it is inexpensive)

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Alex Narconis

1990 Miata #42 CSP/STS2

York:

eselred:

I think that the 13"x9" with 5.5" backspacing is perfect, ...

That's what I'm using.  I have 13"x9" with 5.25" backspacing, but I also use a 1/4" spacer on the front to bring it to 5.5".  I don't use a spacer on the rear.  This is on a 1990 Miata.

Wouldn't 5.25" spacing with a 1/4" space make that effectively 5" backspace?  You've moved the inside edge of the wheel towards the wheel hub reducing that distance.

Dang!  I didn't think about that.  Let's see - Do you mean I've move the inside edge of the wheel away from the wheel hub?  You know - instead of the wheel sitting on the wheel hub, I've added a 1/4 inch spacer to move it away?  I know that if I just mount the wheel as is, it rubs against the brake caliper.  So, if my wheel had an actual 5" backspace, it would probably fit?  Hmmm?  Now you got me thinking.

Edit: OK, inside edge of the wheel would be the rim?  I was thinking inside edge of the mounting surface.

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John
Utah Region, #23 CSP Miata

Caliper clearance issues are normally intrinsic to the mounting face design and spoke design of the wheel...not necessarily backspacing.  You need a wheel that has spokes that angle up harder off the mounting face or a wheel with a thicker mounting face (which you've created by adding a spacer).  Unfortunately, the only way to know for sure is to test fit them personally...or take careful meaurements and have them custom made.

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"Thanks JT!"
1992 Nissan 240SX
2006 Nissan Xterra OR 4x4

I has anyone run these with any luck on the Lenso 13x7.5's?

I test fit one on a 13x8 Rota RB if anyone cares. Not on a Miata so I can't help there...

 

Debating on getting new wheels (lighter/wider/costlier) for next season or just making due with the 13x8's we have. Will probably start off on the 13x8's and see how it works first.

Van
 

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1986 Trueno GT-S (DSP), 1989 Honda Civic Si (HS)
Autocrossing on the cheap.

oo yes plz update us on how it goes on the ROTA's i have the same setup

Got any pics of a 255 and 225 both on 8" wheels standing next to each other?

The sidewalls don't look pinched much at all.....I'm curious if the overall width is as noticable as with 9" wheels. 

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Jay Storm
96 Impreza L FSP
98 98 Impreza 2.5RS- co-driver DSP
Wives are like SCCA rules...
If she doesn't say you can...you can't

Unfortunately, I've never run the 225 Hoosiers. Always been a Kumho guy but..."if you build it they will come"....

That being said, here's a comparison of the 255 Hoosier vs 215 V710 on the same 13x8 wheel...

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Hoosier is shorter (on the right)...

 

Van

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1986 Trueno GT-S (DSP), 1989 Honda Civic Si (HS)
Autocrossing on the cheap.

Nobody even has a guess for me on how much faster these are than the 225-45-13's.......?   Please?   

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WTB: CSP Spyder parts. What you got?