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Discussion Starter #1
I have been going back and forth crunching numbers for weeks here. I am looking for any input or advice that may sway me one way or another. I feel ive done all my homework, but cant hurt to ask one last question.

My dilema.
stock rim size is 18x7, my particular rim is +50mm
I am 99% set on running the Hankook Z214 this season, but I cant get comfortable with picking a size.

it basically comes down to two sizes
245/40/18 or 225/40/18, there is also a 245/35/18 but my concern there is the short sidewall may make mounting an issue.

the 245 should fit, but it will be pinched and I have been told it may only have 85% of its intended contact patch, the 225 will fit, but Im worried that due to the weight of my car, it will get hot fast and may not provide as good grip as the 245.

the specs on the two tires are:
225/40/18 measured on an 8" rim
25" OD, 9.1" SW, 8.4" TW, 831 rpm

245/40/18 measured on an 8.5" rim
25.6" OD, 9.7" SW, 9.1" TW, 811 rpm

Hopefully those who respond have an idea wtf they are talking about, but none the less, I apreciate all comments and suggestions :p I figure I need to get this rubber mounted in 2 or less weeks.
 

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Discussion Starter #3
just got off the phone with a hankoook rep, seems most people are big time against running something "too big" on the rim
as much as I would like a 245/35/18 v710, i think thats gonna pinch too much and would be a real whore to get on the rim.
aprecaite the input, but unfortunately doesnt get me too much closer to a decision :p
 

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Discussion Starter #4
for various reasons, I went with 225's
seems not many if any people are running R comps on this forum, so I wont bother with the details. Perhaps Ill try a 245 in the future, but not today.
 

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Why wouldn't there be as much contact patch with the 245? If you are worried about balooning you can always just air down the tire a little bit.
 

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Too little air pressure is a bad idea for R comps, especially the newer gen nylon carcass tires (Hoosier, Hankook, Kumho V710). They don't use steel in the belts to keep the weight down and rely on higher pressures to keep the tread stable. Too little pressure will deform the tread. This is usually evident by the 'groove of doom' where the tire cords in the tread groove.

We had this problem with the old BFG R1 tires in the 90's. The tires worked great at 20-25 PSI, but would cord in the middle due to too little air.

Cosmic made the right choice for now until he can find a used 245 to try on the rim.

PZ
 

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Discussion Starter #7
thanks for the help paul!
so, looks like im going to pass on the BMW event #1 for SCCA #1 even though its a smaller course, a further commute and fewer people will show up.
hopefully David doesnt show up, I dont need any well prepared BMW's on my first event :p just playin, but if for some reason he didnt show up till event #2, Id find a way to be ok with it. hahaha
Did Matt M give up on his 330i for this season? I seem to remember him talking about a H stock 318?
 

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hey! any word yet on the 245. im picking up my speed3 this weekend and want to know what r comps to run, waht rims did you put them on?
 

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Discussion Starter #9
im running 245/40/18's on 18x8's (street tire class setup)
and 225/40/18's on 18x7's (stock class setup)

there really is not a good option for putting a 245 on a 7" rim
one could possibly try the hoosier A6 in a 245/40 flavor, but getting the bead to seat since its a low profile tire and you will want to make sure your installer can do it/is comfortable doing it before you bring him the task of trying
 

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[quote author=dtoups link=topic=72133.msg1315289#msg1315289 date=1175820369]
One of our local hot shoes is running 245 710s, and kicking butt ...
[/quote]

on a Speed 3? stock size rims?
 

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Discussion Starter #12
[quote author=SoraNezumi link=topic=72133.msg1315347#msg1315347 date=1175821912]
[quote author=dtoups link=topic=72133.msg1315289#msg1315289 date=1175820369]
One of our local hot shoes is running 245 710s, and kicking butt ...
[/quote]

on a Speed 3? stock size rims?
[/quote]

cant be on stock rims. they dont make a 245/40 in the 710, only a 245/35 and no way is that going to bead on a 18x7
I spoke with a guy who is very very good at mounting and autocrosses as much as humanly possible and he said he wouldnt be able to get a 245x35 to bead on a 7" the sidewall is just too short.

If I am wrong, please take a pic, I imagine it will be super pinched to the point of a near impossible fit.
 

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definitely stock rims, definitely 245s -- I assumed 710s but will double check next event. He was trying to persuade me to try a 245 on my 6.5.
 

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[quote author=dtoups link=topic=72133.msg1316795#msg1316795 date=1175886790]
definitely stock rims, definitely 245s -- I assumed 710s but will double check next event. He was trying to persuade me to try a 245 on my 6.5.


[/quote]

Cool! What region are you located in? I'd like to check you local results. Also see if you can get that guy to take some picks of his tires & rims on the car. I'm really interested.
 

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Discussion Starter #15
[quote author=dtoups link=topic=72133.msg1316795#msg1316795 date=1175886790]
definitely stock rims, definitely 245s -- I assumed 710s but will double check next event. He was trying to persuade me to try a 245 on my 6.5.


[/quote]

I could see a 245 A6 fitting a 7" rim, but since the 710's only offer 245/35, I just dont see it happening. If the guy fit a 710 on there.. ill eat my shorts and bow to whomever got them beaded. :)

I was afriad to try a 245 R comp till I knew my 245 streets would fit (which they do)
now maybe Ill have to burn thorough my kooks and get some hoosiers with a tad extra bite (width)

definatley grab a pic for us if you can, would love to see it
 

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Discussion Starter #17
There is a guy who put a 245 Z214 on an 18x7 so it stands to reason that a 245 A6 would fit with less problems since its got a considerably softer sidewall.
a 710 would probably fit as well if it came in a 245/40 and not just a 245/35
anyway, aprecaite the follow up, we are learning more about the car each day thanks to everyone that adds to the picture
 

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Discussion Starter #18
just to update the thread
we have confirmation that a 245/40/18 will fit on the stock MS3 rim (18x7) thanks to Joe from wheelstore running them on the front.
I have run 245's in the rear that are bigger than most R compound 245/40's so I think its a safe bet that we can fit 245's on all corners
as far as what flavors will fit...
A6's, A3S05's(older predecessor of the A6) and Z214's and unfortunately those are the only sizes of R comp autox tires there are, maybe avon will have something some day, but for now... we will take what we can get :D
 

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Thats good to hear! I've got some 245's on the way myself. 8)

If I cant get them done at the place I usually go to I might have to take a trip back to Rochester and see if the place that put the 275's on my stock 7" wide mustang 15s is still around. 8) (that was about 15 years ago though)
 
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