Is a 4 inch backspacing enough for a 13x8 wheel on a CRX or do I need a 5 inch. I am asking because I can get a real good deal on some 13x8's with a 4 inch and would like to by them if I can make them work. My plan is to run the 215 50 13 V710's on them next year. Any advice or experience would be appreciated.

 

I'll try to measure my 13x8's for you.

 

They can work, but it's not the optimal setup. Here's a photo of 13x9's with 4" backspacing on my CRX. Keep in mind that these are a full 1" wider than the wheels you're looking at, but they will still stick out quite a bit. I didn't have any problems with the wheels rubbing the fenders or liners though.



-Brian Meyer

 

what size tire do you run on that 13x9? No rubbing on the inside? And no spacers?

 

Those wheels have Kumho 235/45's on them. They're an old set of tires that I keep around for running sites with really abrasive surfaces. No rubbing on the inside. This car has the '90 Si front brake calipers so I have to use a .3" thick spacer for the wheel to clear the caliper bracket.

I don't recommend this setup, but it can work. I got these wheels and tires on a deal just to use for junk sites.

-Brian Meyer

 

I run 225-45-13 Hoosiers on 13x8 with 5" BS. My unscientific measurements tell me these cars can probably handle at least 5.5" BS and maybe even 5.75". Ideally you'd want to get a 13x9 with 6" BS and use spacers as necessary to adjust.

Something to think about: a car with 4" backspacing will be 4 inches wider then one with 6" backspacing given same width wheels. We're talking wider than a Camaro here. Also a 13x8 or 13x9 with 4"bs will have negative offset possibly causing funky handling characteristics, accelerated hub/bearings wear, steering kickback etc.

When dealing with really wide wheels on an autox car, you should really tuck them in as far inboard as possible as a general rule.

 

thanks for all of the advice I think I will just go ahead and get the right wheels. Are the diamond racing wheels the best bang for the buck or is there anything out there that is a little lighter but wont break the bank?

 

FWIW - I ran 13x8 wheels with a 5" backspace. They were diamond wheels also. I think they are a great value. I found nothing lighter that did not drive the price up by at least $100 per wheel.

A note about the diamonds...if you run 88-89 brakes up front, you are fine as is. However, if you run 90-91 brakes up front you will need a 3/16" spacer (diamond sells them) to keep from rubbing the caliper slightly.

HTH

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RexRacer19 &raquo;</TD></TR><TR><TD CLASS="quote">

A note about the diamonds...if you run 88-89 brakes up front, you are fine as is. However, if you run 90-91 brakes up front you will need a 3/16" spacer (diamond sells them) to keep from rubbing the caliper slightly.

HTH</TD></TR></TABLE>

FWIW, I run the 13x8 5" Diamonds on my 91 and did not have any brake clearance issues. One important thing to note about the Diamonds is that the wheel hub face is larger then the typical Honda hub. This may cause the hub to "dig" into the wheel and eventually cause a wheel failure. I think this has actually happened to someone on here. The solution for this is to run an oversize universal type spacer. Now i dont think this is really a problem for autox use, as i have been running these wheels for auto-x only for 2 years now, inspect the wheels after each use and did not notice any unusual wear/damage on the wheels. But something to keep in mind if you plan on road-racing or hpde these wheels.

Another small problem i noticed when using Diamonds, and only with the 225-45 Hoosiers, is that they seem to have trouble holding air and allways leak a little. Say after 2-3 weeks between events, they'd go down from 40-45psi down to 15-20. No big deal since i just fill them up and they're good for the event but just a little annoying. I think it may have to do with the super-stiff sidewalls on the Hoosiers not flexing and seating properly on the wheel as i didnt have this problem with the 205 Hankooks (marshmallow sidewalls by comparison) on the same wheel.

 

I'm actually running Jeff's wheels currently on an '89 DSP Integra. I'm running the 3/16" spacer Jeff mentioned up front, in order to clear my brakes. Running with this setup for almost a year now, with no adverse effects.

I haven't had any problem losing air between events, as John mentioned above. I'm running a 215/50 Yok A032R-S. They may drop 1-2lb. but not the 20 or so mentioned.

 

i also run the diamond 13x8 5 on 91 si calipers and they require a spacer in the front- i use a 5mm h&r. more worn pads might alleviate the need for a spacer, but i have no proof.

are we all talking about the regular centers, not the ff centers diamond offers?

i don't know if they will fit over any larger calipers or rotors. anyone?

edit: dspda3- which model is your integra?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jsi &raquo;</TD></TR><TR><TD CLASS="quote">My unscientific measurements tell me these cars can probably handle at least 5.5" BS and maybe even 5.75". Ideally you'd want to get a 13x9 with 6" BS and use spacers as necessary to adjust.
</TD></TR></TABLE>

I followed that exact mantra when I ordered my Kodiak wheels for my EF. 15x8.5" 5.75" backspace. I then use 1/4" spacers to move the front wheels out enough that the Wilwood Superlite calipers clear the bolt heads on the inside of my 3 piece wheels. I also use 1/4" spacer in the rear to move the tire out from the trailing arm. I'm using 225/50-15 V710s (have also used 225/45-15 S04s).

For a point of reference, with the V710s on the car, the front is 68.75" wide from the outermost point of the tire on the ground to outermost on the other side, and the rear is 68.25".

 

Jaker, thanks for the hard numbers. I guess i was pretty much in the ballpark with my backspacing estimates.

Now all this talk about caliper clearance made me wonder enough that i went to the garage to look for any rubbing/scraping marks on my wheels i may have overlooked. And nope, nothing on the inside of the wheel except brake dust and the usual small scuff marks from mounting/unmounting on the car. These are the std rwd centers. My car is originally a 91 CX (Canadian, basically a US STD but with the D15B2/5-speed). I have no idea if the calipers are different between the Si and other models.

As for the air leakage issue, i really dont know. The stiff sidewall is just a guess. Again i didnt have this problem with the 205-60 Z211 and all 4 of the Hooisers are doing it. FWIW, i have a brand new set of 215-50-13 A032RS (thanks to Yoko Canada!) that will be my rain setup for next season and while much stiffer than the 205-60 Z211s, they are NOWHERE near as stiff as the 225-45 S04 Hoosiers. These things have almost ridiculously thick, beefy sidewalls when compared to other r-tires.

For next year, I was thinking of getting a pair of 13x9s 6"bs for the front and running 215-50-13 V710s but now i'm wondering if these 8.6" section tires will actually sit on a 9" wheel. I guess at the price the Diamonds go for, it's worth a try...

 

I read the conversion formula recently on another message board:

Divide the width of the wheel by two
Then take the known offset and convert to inches
now add the above two answers and this is your backspacing.

I'm assuming you'll want at the same or less backspacing in order to clear the suspension by the inner side of the wheels/ tires.

So let's look at a stock like wheel:

15x6 +50

That would be 6" wide divided by two is 3 inches

and +50 offset (divided by 25.4 to get inches) is 1.9685 inches

So that would be 3 + 1.9685 = 4.9685 in backspacing.


13x9 with 4" of backspacing could be worked backwards to determine offset (X) in inches:

where Z is backspacing, plug in ½ of the width (Y) and subtract that to determine offset (in inches) then convert.

Y/2 + X = Z (backspacing)

X = Z - Y/2

X = (4) - (9)/2

X = -.5"

Now multiply by 25.4 to get mm

-.5 * = -12.7mm offset!


Can somebody check my math here?

And do you always want oem backspacing - regardless of how wide you go with a wheel?

 

This is almost correct and until recently i used to calculate like that too. The only problem is that the outermost part of a wheel is different when calculating backspacing. For backspacing measurement the actual outermost part of the wheel is used. For offset calculations it is the vertical area just inside the lip that is used (same as measuring wheel width).

So basically, you have to substract the tickness of that outter lip from your offset calculations. Varies dedpending on wheel mfg, but usually about 1/2" or ~12.5mm.

So for a 13x8 5", 5-(8/2) = 1" = 25mm. Now say minus 12.5mm for the lip and you get ~12.5 offset. So your 13x9 4" example would be even worse at negative -25mm!

For reference:

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Black R &raquo;</TD></TR><TR><TD CLASS="quote">

And do you always want oem backspacing - regardless of how wide you go with a wheel?</TD></TR></TABLE>

Not really. You'd want to be closer to the OEM offset as that what would be closer to your OEM scrub radius. But then again, some extra positive scrub radius is prefered in a race application for better feel and feedback. I'd shoot for no less than about 25mm offset though. But then the scrub radius thing can almost be a philosophical debate and driver preference. One thing's for sure, too much one way or the other is not good.

 

Actually, just realized the error in my own calcs. Just substract the extra lip width from your backspacing number. So 5" backspacing would be about 4.6 or 4.7 for the purpose of calculating offset. That lip is very roughly about 8-10mm on my Diamonds. So anyways, in the end it ends up being only about 4-5mm less offset than with the original formula.

 

ok, now I'm even more confused... must... let.... it... marinate.....

Personally, I'm thinking of trying some 15x8 +27 and seeing how that feels. I've heard of at least one crx in japan running 15x10 +0, but according to these calculations that just doesn't seem right.....

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Black R &raquo;</TD></TR><TR><TD CLASS="quote">ok, now I'm even more confused... must... let.... it... marinate.....

Personally, I'm thinking of trying some 15x8 +27 and seeing how that feels. I've heard of at least one crx in japan running 15x10 +0, but according to these calculations that just doesn't seem right..... </TD></TR></TABLE>

for the 15x8 +27 is right on. around 5" is right. that will be coming soon to take advantage of my 224-45-15 avons


Modified by shakedown94 at 1:03 PM 10/24/2005

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jsi &raquo;</TD></TR><TR><TD CLASS="quote">Now all this talk about caliper clearance made me wonder enough that i went to the garage to look for any rubbing/scraping marks on my wheels i may have overlooked. And nope, nothing on the inside of the wheel except brake dust and the usual small scuff marks from mounting/unmounting on the car. These are the std rwd centers. My car is originally a 91 CX (Canadian, basically a US STD but with the D15B2/5-speed). I have no idea if the calipers are different between the Si and other models.</TD></TR></TABLE>
The problem is with CRX brakes, not Civic brakes. The '90-91 CRX Si has different calipers vs. Civic Si/DX, CRX DX, and '88-89 CRX Si.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by rsca_crx &raquo;</TD></TR><TR><TD CLASS="quote">

edit: dspda3- which model is your integra?</TD></TR></TABLE>

'89 RS.

FWIW, a while back I did a test fit on a 13x7, FWD center, 5in. backspace, and they fit fine, no spacer needed, front or rear.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by shakedown94 &raquo;</TD></TR><TR><TD CLASS="quote">

for the 15x8 +27 is right on. around 5" is right. that will be coming soon to take advantage of my 224-45-15 avons


</TD></TR></TABLE>

Cheap bastards at Avon scamming people 1mm of tread...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jsi &raquo;</TD></TR><TR><TD CLASS="quote">

Cheap bastards at Avon scamming people 1mm of tread...
</TD></TR></TABLE>


haha, I caught that too... didn't want to be such a stickler though!

fwiw, I ran my new old setup on the hatch last sunday and it sticks out a good bit:

15x7 +42 with 225/45/15 hoosiers. It looks really mean, but I will need to cut/ flare/ roll the fenders a bit more.....

Is anyone actually trying to keep/ salvage the factory splash guards up in the fenderwells somehow? I can't think of a way to retain them and am not sure it's worth the trouble.....

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Black R &raquo;</TD></TR><TR><TD CLASS="quote">Is anyone actually trying to keep/ salvage the factory splash guards?</TD></TR></TABLE>

GONE

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jsi &raquo;</TD></TR><TR><TD CLASS="quote">

Cheap bastards at Avon scamming people 1mm of tread...
</TD></TR></TABLE>

english bastards