# Will a 265/35/18 Kumho fit all the way around on a 330i?



## Andy (Jul 16, 2003)

*265 Kumho fit all the way around on a 330i? (UPDATE : Yes they will!!)*

I want to run my numbers and calculations by you guys just to have another set of eyes look at this. Please tell me what you think.

My Goal :
I want to run a set of 265/35/18 Kumhos all the way around (for autocross only) and I want to see if they will fit without rubbing.

Current Settings :
I have a set of OEM M72 wheels that I plan to mount these tires on.
Front : 8" x 18" with a +47 mm offset plus a 6 mm wheel spacer (1/4")
Rear : 8.5" x 18" with a +50 mm offset plus a 6 mm wheel spacer (1/4")

(* I understand that this is outside of the mfg's recommended wheel width range for this tire.)

Scenario #1 (difference based on width in mm 255 vs 265):
FRONT : 265 - 225 = 40 / 2 = 20 mm = 3/4" wider on each side
REAR : 265 - 255 = 10 / 2 = 5 mm = 1/8" wider on each side

CURRENT INSIDE FRONT GAP : 5/8" + 6 mm spacer (1/4" spacer) = 7/8" clearance
CURRENT INSIDE REAR GAP : 1/2" + 6 mm spacer (1/4" spacer) = 3/4" clearance

FINAL INSIDE FRONT GAP : 7/8" - 3/4" = *1/8" clearance*
FINAL INSIDE REAR GAP : 3/4" - 1/8" = *5/8" clearance*

Scenario #2 (difference based on mfg's section widths):
STOCK FRONT WIDTH : 9.1"
STOCK REAR WIDTH : 9.8"

KUMHO FRONT WIDTH : 10.7"
KUMHO REAR WIDTH : 10.7"

FRONT : 10.7 - 9.1 = 1.6 / 2 = 0.8" wider on each side
REAR : 10.7 - 9.8 = 0.9 / 2 = 0.45" wider on each side

CURRENT INSIDE FRONT GAP : 5/8" + 6 mm spacer (1/4" spacer) = 7/8" clearance
CURRENT INSIDE REAR GAP : 1/2" + 6 mm spacer (1/4" spacer) = 3/4" clearance

FINAL INSIDE FRONT GAP : 0.875" - 0.8" = *1/16" clearance*
FINAL INSIDE REAR GAP : 0.75" - 0.45" = *5/16" clearance*

The photos below show the factory measurements for the outside of the tire to the fender (with no wheel spacers). I loaded the suspension as far as it would go by jacking up the other side of the car. Photo #3 shows the car pretty much under max suspension load in an actual race situation.

Based on this information, it would appear that a set of 265/35/18 Kumhos would fit all the way around. However I would really like your input on this as well as to what you think.

*UPDATE : They do fit... see post #8 for pics and a review.*

Thanks,
Andy


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## AF (Dec 21, 2001)

Andy . . . isn't this overkill for a 330 ?

I would think the best autocross combo if you* have* to go 18's would be 225/40/18's all around or 235/40/18 all around

Someone might want to correct me if I am wrong but going with the combo you have proposed seems to big & wide and the 330 seems to underpowered to really need it.

Plus I would think adding spacers especially for Autocross reasons which already tends to put stress on the suspension, I would think the stress points being changed by the spacers would affect the handling as well as possible damage . . .

I am no expert so I am sure someone else who is much more experienced then myself can chime in and I might be totally wrong :dunno:


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## Andy (Jul 16, 2003)

AF330i said:


> Andy . . . isn't this overkill for a 330 ?
> 
> I would think the best autocross combo if you* have* to go 18's would be 225/40/18's all around or 235/40/18 all around
> 
> ...


AF, thanks for the reply.

I've been doing a lot of research on several different forums and also speaking with some of the local autocrossers in my region and this is what I discovered...

For optimal grip and handling, you want to get the widest tire that will fit up under the car without rubbing. This will allow you to carry more speed through the corners.

In regards to wheel spacers... Increased track is a good thing, however like you pointed out, going with too big of a spacer will cause additional stress on the wheel bearings. A lot of guys are running 5 mm and 6 mm spacers to increase their track and to allow for a wider tire. 1/4" is the max spacer you can go with on a stock offset wheel (1/4" = 6.35 mm) in the stock class. The amount of additional stress on the wheel bearings is very minimal (if any) with a spacer this small.

When it comes to an autocross tire, it comes down to Kumho and Hoosier. Kumho has a great tire, that provides plenty of grip, good feedback and will last for an entire season. Hoosier providers better grip then the Kumho, however has very little feedback (before breaking loose) and the tire is good for approx 30 runs (3 months).

With that said, my first choice in tire would be the 265/35/18 Kumho. My second choice would either be the 245/35/18 Hoosier or the 225/40/18 Kumho. 225 just seems like too narrow of a tire.

I too am still somewhat new to all of this, however from the couple months of research that I have been doing, this is what I learned.


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## Pinecone (Apr 3, 2002)

Only thing is, too wide a tire might not get enough heat, therefore actually have less grip than a narrower tire.

Bob Tunnel went back to narrower tires on his E36 M3 at one point because of that reason, IIRC.


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## Andy (Jul 16, 2003)

Pinecone said:


> Only thing is, too wide a tire might not get enough heat, therefore actually have less grip than a narrower tire.
> 
> Bob Tunnel went back to narrower tires on his E36 M3 at one point because of that reason, IIRC.


Now, see that is good information to know, I did not know that. I had yet for someone to tell me that IT IS possible to go too wide. Thank you, Pinecone.

Now, the question is... is the Kumho 265 too wide to produce enough heat for optimal grip? I know that the Hoosiers require a lot of heat before they get nice and sticky, however I've heard that the Kumhos do not require AS MUCH heat for optimal grip. Was Bob Tunnel running Kumhos or Hoosiers?

Can anyone answer this one?

I'm still interested if you guys think that the 265 wide tire will fit up under my car based on the numbers and photos.


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## Andy (Jul 16, 2003)

Pinecone said:


> Andy, look at your own sig picture. That should tell you if the tire moves unp into the wheel well.


Based on Photo #3 it appears that the rear tire just barely tucks up under the fender (but not much). I'm not sure if the suspension if fully compressed in that picture, but it's pretty close as it will get on the autocross course.


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## Andy (Jul 16, 2003)

I went ahead and ordered two of these tires from Gary to do a test fit (one for the front and one for the rear). He said that I should receive them Monday or Tuesday of next week. As soon as I get them mounted, I'll post some pics and let you know how they fit.

Thanks,
Andy


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## Andy (Jul 16, 2003)

265/35/18 KUMHOS WILL FIT ALL THE WAY AROUND AND NO SPACERS NEEDED!!! :banana:

We had some warm weather today so I decided to mount the Kumhos on the car, find an empty parking lot and put them to the test. A couple weeks ago I installed Koni double adjustable shocks & struts (set to near full stiff) and Racing Dynamics' 27 mm front sway bar set to full stiff... so I wanted to test these items out as well.

My first impressions...
- Turn-in was a bit too slow (probably due to the wide tires up front).
- Major understeer.
- The tires seemed to grip really well

I went back home and switched the front sway bar to full soft and then checked the tire pressure. The tire pressure was set to 30 PSI all the way around. I checked the Kumho booklet that came with the tires and they state that the recommended tire pressure should be between 30 to 40 PSI. They stated that lighter cars would work best around 30 PSI and heavier cars work best around 40 PSI. Well the 330i at 3200 lbs is not light, so I adjusted the tire pressure to 40 PSI in the front and 37 in the rear. I figured with the sway bar change and the tire pressure change that, that should help reduce the understeer.

I went back out to the same parking lot and WOW!!! :wow: NIGHT AND DAY DIFFERENCE!! HOLY CRAP!! These tires grip like nothing I have ever driven on in my life. The car now felt very neutral, in fact I was having trouble getting the tires to break loose. I actually had to go find a larger parking lot so I could build up enough speed to get the tires to break free. When pushed REALLY hard (and I mean REALLY HARD) the front end would push (understeer), however that can be expected.

I then went and found a newly constructed road that was just opened up not long ago, it had no traffic on it because the one end of the road had not been finished yet. It was a four lane road (2 lanes on each side) with a turn lane in the middle. I decided to do a slalom test, going in and out of the dotted white lines. I'm in 2nd gear, doing about 30 MPH and I get a good rhythm going... At this point I am absolutely amazed at the grip... the tires aren't even close to letting go. So I slowly start increasing my speed. I'm not sure how fast I got up to, but I eventually decided to stop because I was going so fast that if the tires did let loose, I was afraid I would spin off the road. However, just so you know, the tires were still sticking without a sign of letting go (I just chickened out).

These tires are soooo much fun to drive on!! I'm sure it's a combination of all of my newly installed mods, but the tires have far exceeded my expectations. I am soooo looking forward to the start of autocross season!!


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## Andy (Jul 16, 2003)

A few more pics...


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## Andy (Jul 16, 2003)

Couple more pics per Karl's request...

Front : 1/8" clearance from outside of fender / 1/8" clearance from strut
Rear : 1/2" clearance from outside of fender / 1/16" clearance from inside wheel well


* Note : My car is stock ride height with stiffer shocks and struts. Roughly -1 degrees of camber in the front and roughly - 1.5 degrees of camber in the rear.


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## Kaz (Dec 21, 2001)

Why don't you put 335s all the way around and get this obscession over with?


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## TeamM3 (Dec 24, 2002)

Kaz said:


> Why don't you put 335s all the way around and get this obscession over with?


 :rofl: :angel:


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## The HACK (Dec 19, 2001)

:rofl: You should take your wheels off and see if they're rubbing on the INSIDE.

Looks like they should be rubbing pretty bad too.










If you draw a straight line up from the edge of your tire and the shock in this picture, it looks from this angle that your inside tire is RUBBING against the shock.

Worst yet, you should see rub marks up front against the fender-liner in the wheel-well both front and back, but only on the inside. I wouldn't be surprised to see a nice little spot on the strut with rub marks as well.


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## TeamM3 (Dec 24, 2002)

WOB


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## Andy (Jul 16, 2003)

The HACK said:


> :rofl: You should take your wheels off and see if they're rubbing on the INSIDE.
> 
> Looks like they should be rubbing pretty bad too.
> 
> ...


I think it must be the angle that I took the picture, because I thought the exact same thing after I saw the photo. But trust me, it's not rubbing. I took two pieces of cardboard taped together (about 1/8") and was successfully able to slide the cardboard clear around the inside of the tire around the fender and shock. Take a look at this photo, this is closest point of contact. Here there is about 1/16" between the inside of the fender and the tire.

After several hard drives, I took all the tires off and inspected them and the car for any signs of rubbing and found none.


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## Jon Shafer (Dec 15, 2001)

Bump. Thread reactivated...


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## Karl (Dec 23, 2001)

Woohoo! Now to save all the information and pictures in this thread before Andy decides to delete it again...


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## Andy (Jul 16, 2003)

Jon Shafer said:


> Bump. Thread reactivated...


Thanks Jon.



Karl said:


> Woohoo! Now to save all the information and pictures in this thread before Andy decides to delete it again...


Don't worry it won't happen... I've learned my lesson.


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## TeamM3 (Dec 24, 2002)

Karl said:


> Woohoo! Now to save all the information and pictures in this thread before Andy decides to delete it again...


 

what's to save? They're approx. the same size as the the 255/40-17 kumho's the DS National Champion won on at Nationals with his 330Ci :dunno:

:angel:


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