anyone has picture of :
225/45/15 A6 mounted on 5.5 inch wheel
205/45/16 A6 mounted on 6.5 inch wheel
side by side. I want to know which is actually wider.

Thanks, Jack

 

The 225 tire will have a wider section.

 

Go to tirerack.com. If you go to your tire, there is a Specs section, and that will tell you the actual tread width. That's the number I'd think you'd want.

225/45/15 - tread width = 8.8"

205/45/16 - tread width = 8"

So you're losing almost an inch of contact patch, plus the 16" wheel and tire package would probably be heavier. The 16" tire is 1lb lighter, but I think that would be offset by the weight of the 16" wheel.

Or are you just thinking about asthetics?

 

I'm not a tire expert so forgive the following comment about this quote.

225 wide tire on a 5.5" wheel, I don't think so!! Not if you don't want to seriously limit the life of the tire, that is if you can even get it on without damage to tire or rim. A 8" wide wheel is ideal for a 225 wide tire. Astheticly speaking your side walls would be angled in alot!!

 

First of all, I have already read the specs on tirerack, but, that is based on mounting it on recommended rim width. What I need to know is actual width, when mounted on the oe size wheels...

GOTCURVES, I have posted on Hstock forum for a reason, I am not too concern with the life of the tires, as long as it last about 50 minutes before it cords I am good.
I am currently running the 225 set up on 5.5..also have a 215 kumhos on the 6.5...I am buying couple sets of tires, and wanted to know whether 205 on 6.5 is wider than 225 on 5.5.
reason i dont want to run kumho is because there is no contingency money.

Jack

 

Ok my bad!

I can't imagine that a 225 wide tire on a 5.5" wheel would net positive results, but what do I know I'm not good enough to earn contingency money for tires. Not sure I'd run a tire just because it could be free, more competitive would be what I'd want.

Sorry for the post.

 

The width of the tire shouldn't change enough to be a concern. You may end up with slightly rounded shoulders, but the width would still be greater with the 225's.

 

I reckon that thang must look like a Great Dane puppy! All paws...

And I was debating a 225 on a 7" rim...

Got a picture of the setup you're now running?

 

Believe it or not people are running 225s on 5.5" rims. There were a few cars at Nationals this year competing. I know it is possible to wedge 'em on the rims, but I thought there were rubbing issues with the stock rim offset. I bet you need to run a 1/4" spacer (max allowable for stock) to get it to work.

Anyhow, I know these aren't side-by-side photos you requested, but they may shed a little light on how the different combos compare in the heat of battle.

Note: The black MINI won Nationals on the 205/16" rim set up.

 

Mounted between these two using Hoosier A6 tires
I would predict that tread width would be slightly wider than 8" with the 225/45-15 than slightly less than 8" with the 205/45-16

The reason is the 225/45-15 fits rims 7 to 8.5" with perfect fit for rims 7.5".
Since the 5.5" rim is a full two inches more narrow than perfect the 8.8" tread width will be reduced.

The 205/45-16 tire fits rims 6.5-7.5" wide and perfect for 7" rim so mounted on a 6.5" rim would be slightly less wide than the 8" tread width (mounted on 7" rim).

The estimate is tire section width changes 0.2" for every change of 1/2" of rim width from perfect fit.

So for this example-
225/45-15
Section width 9.8"
Tread width 8.8"
Perfect rim width 7.5"
Actual rim width 5.5"
With difference of 2" a predicted decrease of 0.8" of section width and slight decrease in tread width approaching slightly more than 8".

205/45-16
Section width 8.7"
Tread width 8"
Perfect rim width 7"
Actual rim width 6.5"
With difference of 1/2" a predicted decrease of 0.2" of section width and slight decrease in tread width approaching slightly less than 8".

Different tires may vary from these numbers and even if Hoosier claims these are the number they might not be exact.

Personally I run on tires that fit the rims and given this is for Stock class autocross you can get only so much out of an oversized tire given limited front camber and limited power.

For stock 15" rims I use 205/50-15 with good results on the regional level plus they tend to wear pretty well, cost less and weigh less.

If you don't care about wear then that's fine. The stock 15" rims will weigh less than the stock 16" unless you get Rota Slipstream in 16x6.5 which are 13 lbs each.

 

LOL, the first pic (red car), is my car at national with my co-driver driving.
I am still debating as to what to run, I know national champ is running the 16s, so is many others. But my past experience with the 16s hasnt be all that good. maybe its the stiff sidewall.

 

So if the 15s are wider, why do people run 16s?

 

the 225/15 is pinched on the wheel, so you end up with less actual contact patch, and sloppy turn in. ultimate lateral grip may be higher, but would only matter on a course with sustained sweepers.

the 205/16 (hoosier) or 215/16 (kumho) offer much crisper turn in, Hoosier better than Kumho. both are much more precise in transitions than the 225.

the 16inch tires play to the strength of the MINI