hughesl

OK, I know this has been covered, but I am still a little unclear.
My understanding is if I get 13" rims I want 5" backspacing.
Available tire size from Kuhmo 710 looks like 215/50/R13.
Hoosier looks like 225/45/R13 for the A6.

First off which is the better option Hoosier or Kuhmo?
Any opinions would be helpfull.
Are there other size options that I am missing?
Which width wheel would fit best with these tires, 8", 9"?
Is the backspacing of 5" a correct assumption?

Thanks in advance for the help.

rsca_crx

yes, you want 5in backspacing. you might need a thin spacer in the front to get the caliper to clear the back face of the wheel, depending on the wheel and pad thickness. i did with keizers and diamonds.

of the DOT-r's, i've only run the hoosiers. everyone else i used to run with in csp on 13's uses them too, fwiw. they fit well on 13x8's, and i don't think you are going to gain anything on them going to a 9in rim. hoosier recommends a 7-8.5in width. the only case i can see for a wider wheel than 8in is if you want to run a wider tire on them (like a true slick for a mod class) later on.

make sure you bring a friend when you get ready to mount them too.

hughesl

Thanks for the info.
I thought the 9" sounded a little wide.
My understanding is that SM2 still requires DOT legal tires.
Is that a correct assumption?
Unfortunately I do not have the rule book so I just can't look it up.

Thanks again

rsca_crx

yup. rule book is available for download here:

http://www.scca.org/Solo/Index...70&~=

jsi

Actually, you'd want to run at least 13x9" wide in the front if running V710s and i'd go to 13x10 with Hoosiers. The 225 Hoosiers are huuuge compared to 215 V710s. I have both sitting in my garage and everytime i look at them i'm astounded how wide the Hoosiers are. Almost a full inch wider per tire.

For SM, assuming you want to stay with 13s, i say you should run the taller 225-50-13 Hoosier A6 on 13x10 with 5 3/4" backspacing in front. Run 215-50-13 in the back on 13x8 with 5" backspacing.

If going with Diamond wheels, go with 6" backspacing and use a 1/4 spacer.

rsca_crx

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jsi &raquo;</TD></TR><TR><TD CLASS="quote">Actually, you'd want to run at least 13x9" wide in the front if running V710s and i'd go to 13x10 with Hoosiers. The 225 Hoosiers are huuuge compared to 215 V710s. I have both sitting in my garage and everytime i look at them i'm astounded how wide the Hoosiers are. Almost a full inch wider per tire.

For SM, assuming you want to stay with 13s, i say you should run the taller 225-50-13 Hoosier A6 on 13x10 with 5 3/4" backspacing in front. Run 215-50-13 in the back on 13x8 with 5" backspacing.

If going with Diamond wheels, go with 6" backspacing and use a 1/4 spacer.
</TD></TR></TABLE>

are you talking about dot-r's?

i'm not saying your wrong, and the last set of 225/45/13 hoosiers i bought were 04s, but they sit square on the 8in rim. 2in more and they would look straight out of vwvortex. i'm looking at them right now in my garage as well.

nm that hoosier clearly recommends a 7 - 8.5in rim width, and that the measured tread and section widths are 8.5in and 9.3in, respectively. link:
https://www.hoosiertire.com/rrtire.htm\

hopefully i'm wrong, as i'd love to go faster

jsi

I'm very familiar with Hoosier specs. But those specs are on a 7.5" for the 225-45 and 7" for the 225-50, both of which pinch the tire. The 225-50 is a slightly "beefier" tire in height and in width also. Anyways, either of those would love more than 8". Most CSP guys run them on 13x8.5" or 13x9". If I was staying in SM, i would definetely try the 13x10 with 225-50 A6, with Diamonds it would not be an expensive experiment. But i'm converting the car to EP as i'm writing this, so will be running slicks and a different set of issues come up...

If you wanna play safe, go with 13x9s and you can safely run at least 5 3/4 backspacing in front and tuck those suckas in. With Diamonds, that would still mean 6" BS and 1/4 spacer.

rsca_crx

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jsi &raquo;</TD></TR><TR><TD CLASS="quote">I'm very familiar with Hoosier specs. But those specs are on a 7.5" for the 225-45 and 7" for the 225-50, both of which pinch the tire.</TD></TR></TABLE>

my reference to the hoosier spec sheet wasn't so much for the measured tire widths, it was to show what size rims they recommend running their tires on.

RineRacing

I would really be surprised to see a 225 fit on a 10" wheel. A friend of mine was running 225/45/13 Hoosier A3S03 a while ago on a 9" wheel and he was having trouble keeping a seal on the tire. I understand the newer Hoosiers are wider than the older ones in the same size, but still I don't think you could safely run them on a 10" wheel.

Going with 45 or 50 series really depends on your gearing. If you find yourself banging the limit in 2nd all the time I would go 50, but it you're not on the limiter at least once per run, I would go 45.

rsca_crx

the final drive alterations are easy to do with any of the online calculators, depending on if you want to change tires or final gears. i did the calculations to see how funky the crx with a k20 and 225/45/13's would be, if anyone wants it.

hughesl

wow..now I am more confused.
First I should probably give a little more info.
-I have a b16 with CTR pistons and cams. (just for power ref.)
-S1 tranny
-Quaife LSD
Those are probably the more important of the mods.
I am not sure if that will help with the sizing or not.
I am looking at the diamonds (because they are cheap)
Is there a backspacing that will not require a spacer for the front?
I have not ruled out Panasport, but I am not sure the $amount yet (still looking)

Could you explain the theory for running larger tires up front than in the rear.
Currently the car is fairly easy to rotate (205-50-R15 Kuhmo 710 on all corners)
I know some guys run wider tires in the front, but I still debate that it is better.
I already run less tire pressure in the rear to get equal tire contact. The rear is much lighter than the front so even with equal tire width the traction will be reduced. I know you want as much traction on the front as possible, but do you get better results by reducing the rear traction? I am sure many of you have more experiance with this than I do.

hughesl

Bump for the holiday.
Looking to get a little more info.

Grr Wolfe

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hughesl &raquo;</TD></TR><TR><TD CLASS="quote">Could you explain the theory for running larger tires up front than in the rear.
Currently the car is fairly easy to rotate (205-50-R15 Kuhmo 710 on all corners)
I know some guys run wider tires in the front, but I still debate that it is better.
I already run less tire pressure in the rear to get equal tire contact. The rear is much lighter than the front so even with equal tire width the traction will be reduced. I know you want as much traction on the front as possible, but do you get better results by reducing the rear traction? I am sure many of you have more experiance with this than I do. </TD></TR></TABLE>

This is what I know from road racing. Hope it helps for auto-x

Tire temps and wear: The front tires are doing the turning, most of the braking AND the acceleration so they're prone to wear faster and overheat, especially so in the case of the CRX as the shorter wheelbase causes more weight transfer during acel. and decel.. Wider tires offer more rubber for wear and heat absorbsion.

FYI If your talking about wider tires on the same size rim it likely won't give you more contact patch without sacrificing sidewall strength (contact patch shape will improve but sidewall angle will worsen). If it's on a wider rim you'll gain some sidewall stiffness so you can drop some psi.

For neutral handling in a fwd you need more slip in the rear for cornering (and especially while also accelerating!!) so decreasing your front slip instead of increasing your rear makes more sense as you end up with more overall traction. Increasing your front contact patch is a good step, it'll also increase your braking capacity .

Hope this helps.


Modified by Grr Wolfe at 6:45 AM 7/3/2006

Gearz

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hughesl &raquo;</TD></TR><TR><TD CLASS="quote">Is there a backspacing that will not require a spacer for the front? </TD></TR></TABLE>

The spacer is needed to clear the brake caliper unless the face of the wheel where it meets the hub is 5.4" diameter or less (Keizer's and Diamond's are not). See this thread for pictures of Si brake calipers versus HF:
https://honda-tech.com/zerothread?id=1524348

Besides that, you'll need at most 5" backspacing or the inner wheel will rub the knuckle. 4" Backspacing will push the wheels out considerably.


<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hughesl &raquo;</TD></TR><TR><TD CLASS="quote">Could you explain the theory for running larger tires up front than in the rear.</TD></TR></TABLE>

I think you have the basic idea, use smaller tires in back to help kill grip and balance the handling. It's not really needed on a CRX since you can get neutral handling by using a stiff rear swaybar and equal sized tires front and rear. In roadracing where the turns are much longer and more steady state you may want different tires front to rear by I think same size front and rear with pressure differences works best in autox.

Since you have plenty of torque you should consider going with a 15" wheel. If you run a 225/45-13 Hoosier on a 9" wheel you'll be into 3rd gear a lot. I'd recommend the 50 series tire or a 15" wheel so you can stay in 2nd longer.

You asked about the differences between the Kumho and Hoosier. The Kumho's are great and less expensive but they seem to loose grip way before they run out of tread. I rotate mine front to back each event and after about 40-50 runs they're have considerably less grip than when they were new. The Hoosier A6's appear to have just as much grip as the Kumho's when new if not a little more. The tread on them actually wears off faster than the Kumho's but they seem to keep the grip better. I don't know if they will cord before the Kumho's "cycle out" - time will tell. I think the fast times on the new surface at HPT will be set with Hoosiers this year.

-Brian Meyer

hughesl

Thanks for the input.
Basically I understand the thinking behind running a smaller width in the rear.
If I stay with one brand it looks like that is not really an option anymore.
Tire rack is showing 215-50-R13 as the only 13" 710
They are showing two options for the hoosier 225-45-R15 and 225-50-R15.
I am leening toward the hoosiers (for the extra width)
Anyone have experiance running the 45 series compared to the 50 series?
I want to make sure I don't have clearance issues.
I also don't want to hang in 3rd during the autocross.
Looks like people are running 8, 8.5, and 9" wide.
One comment for the 9 was there was some difficulty keeping the bead.
I talked with the Panasport rep today. He said 8.5 would be best.
Any other comments on this subject?
Thanks

Jaker

I ran both Hoosier A3S03/A3S04 225/45-15 and Kumho V710 225/50-15 on my EF hatch with 15x8.5 Kodiaks. They will not fit without some heavy massage of the fenders. I went at it with a 2 lb mini sledge, and it worked great for me for 3 seasons. No rubbing!

Hoosiers:


Kumhos:

hughesl

This may be of interest, and is related to the post.

Here are the calculated tire heights for various sizes:
1- 215/50/R13 = 21.46" Tall
2- 225/45/R13 = 20.97"
3- 225/50/R13 = 21.85"
4- 225/50/R14 = 22.85"
5- 205/50/R15 = 23.07"
6- 225/45/R15 = 22.97"

hughesl

Man, those 15's really fill up the wheel wells.
I can understand the need to roll the fenders with those.

hughesl

Anyone use the Rota RB 13X8?
good/bad results?

Thanks

parkerfly

I'm researching autox wheels/tires for my 91 CRX.. are people just running really stiff suspension with the larger tires to avoid rubbing?

I'm worried about getting too stiff since the parking lots around here aren't always smooth.

solorexer

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hughesl &raquo;</TD></TR><TR><TD CLASS="quote">
Here are the calculated tire heights for various sizes:
1- 215/50/R13 = 21.46" Tall
2- 225/45/R13 = 20.97"
3- 225/50/R13 = 21.85"
4- 225/50/R14 = 22.85"
5- 205/50/R15 = 23.07"
6- 225/45/R15 = 22.97"
</TD></TR></TABLE>

Speaking from experience using the 225/45s and 225/50s back to back when I ran my car in csp, I really feel that the 225/45 is the only real choice for a good auto-x tire on an 88-91 Honda. The 50 series are almost as tall as a 15" wheel/tire which foces you to lower the stock suspension to the point that the geometry is compromised. You also have to rape the fenderwells to keep the tires from rubbing. 45s put the car at the correct ride height without too much geometry change and do not require fender modification. Their gearing was also far superior with D series power.


Modified by solorexer at 12:46 PM 7/27/2006

hybridmoments

I run the 13x8 Rb's on a 92 civic
225/45/13 Hoosier AS304's

i took them to the "place" (cough: Radial Tire) locally for mounting race tires. it took them about 4 hours to mount them all. not counting the weekend before when i brought them and they couldn't mount them. they had to order some attachment for this mounting machine they rarely use.

they said that the drop center on them is very small, so you have to really stretch the sidewalls of the tire to mount them. and with the hoosiers, the sidewall is incredibly stiff. probably an 1" thick.
they charged me $120 to mount all 4. the owner made me agree that i wouldn't hold them accountable for damaging the rims. they knicked them up quite a bit.

so honestly i'd recommend not using the RB's based on that experience.

88 rex

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hybridmoments &raquo;</TD></TR><TR><TD CLASS="quote">I run the 13x8 Rb's on a 92 civic
225/45/13 Hoosier AS304's

i took them to the "place" (cough: Radial Tire) locally for mounting race tires. it took them about 4 hours to mount them all. not counting the weekend before when i brought them and they couldn't mount them. they had to order some attachment for this mounting machine they rarely use.

they said that the drop center on them is very small, so you have to really stretch the sidewalls of the tire to mount them. and with the hoosiers, the sidewall is incredibly stiff. probably an 1" thick.
they charged me $120 to mount all 4. the owner made me agree that i wouldn't hold them accountable for damaging the rims. they knicked them up quite a bit.

so honestly i'd recommend not using the RB's based on that experience.</TD></TR></TABLE>

Go to a better tire place

hybridmoments

haha
well i went there because they are supposed to be the best place in the area
they shave race tires, sponsor all the WDCR autocrosses.

hughesl

Thanks for the feedback.
Fred, how did you end up doing at the autoX last weekend?
I only got to see your first run and then they had timing light problems so I had to bail with my son.

I think I have settled on the 225X45XR13
It will be interesting to see what the gearing is like.
I am currently running the S1 transmission.
It will probably be fine for a tight course, but likely end up in solid 3rd gear on an open coarse. I don't want to cut my fenders to get tires under the car.
I drive it around town and to work on occasion.

The biggest thing I am currently debating now is the wheel.
Looks like the options are:
1. Panasport $$$$
2. Keizer $$$$
3. Weld $$$$$
4. Compomotive $$$$
5. Rota RB $$
6. Diamond racing $
7. Superlight (England) $$$ http://www.superlite-wheels.com/

I am currently investigating the superlight wheels.
They are in between the Panasport and Diamond in both weight and price.
Only problem, they don't have any sales reps in the US so you have to order from England. I have not been able to locate much info, good or bad on them.
Thanks for the ongoing feedback. I thought this thread was dead.