Square set up?

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01-23-2011, 11:13 AM

#16

Gary R.

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Sell em and buy the correct wheels ya stubborn mule!

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01-23-2011, 11:21 AM

#17

Streak

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I'm going both directions. I have a wtb on Pelican. It would be great to work with what I have though.

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01-23-2011, 11:28 AM

#18

Gary R.

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Quote:

Originally Posted by Streak

I'm going both directions.

I've heard that about you, not that there is anything wrong with that...

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01-23-2011, 11:45 AM

#19

FredC

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Go check Mark Hupfer's car at Sebring. You should feel better about your tire choices.

Quote:

Originally Posted by Streak

The car: 1986 911 E Stock

The problem: Like a true moron I didn't do enough research and have purchased a set of 7 and 8x15 Fuchs. Only after did I discover that the best tire choice is not available. That being a 275/35. I had been told that a 275 will fit but I'm leery.

So here's the question: Is it crazy to run a square set up? I currently run 225 front and 245 rear on 16's. When I compare the 225 to the 245 the true difference in width is very very small. Hoo 225's are either very wide or the 245's are narrow. My thought is that if I run 225's front and rear I'm giving up minimal contact patch. The other option is to run 205's up front.

Bottom line: Is square a bad idea? Does a 275 really fit a 8x15 Fuch?

Keep the abuse to a minimum please

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01-23-2011, 11:59 AM

#20

Gary R.

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Quote:

Originally Posted by FredC

Go check Mark Hupfer's car at Sebring.

I fully intend on doing that. Streak, i'll send you some pictures... of the tires.

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01-23-2011, 12:27 PM

#21

Carrera51

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It all depends on the work travel schedule. I just need to mount up the tires.

I do like how the car feels on the 16s much better than with the heavy 17s it had on it before. The time sheets will tell if it is truly faster.

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01-23-2011, 12:39 PM

#22

Astroman

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Quote:

Originally Posted by good hands

If you can't fit the lower profile tire what is the sense of running the 15's ?

Because both the 225/45/15 and 225/50/15 have a reduced rolling diameter over any 16" or 17" tire.

Quote:

Originally Posted by FredC

Go check Mark Hupfer's car at Sebring. You should feel better about your tire choices.

I'll make it easy for them: At least at Road America, MH uses 225/45/15s in the front on 8" wheels and 225/50/15s in the rear on 9" wheels.

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01-23-2011, 12:41 PM

#23

Larry Herman

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Quote:

Originally Posted by FredC

Go check Mark Hupfer's car at Sebring. You should feel better about your tire choices.

Good point. He gets that Euro SC around unbelieveable fast on what most feel are undersized tires.

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01-23-2011, 12:44 PM

#24

Gary R.

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Quote:

Originally Posted by Astroman

Because both the 225/45/15 and 225/50/15 have a reduced rolling diameter over any 16" or 17" tire.

I ran some 225/s and 245's on 15's at Limerock from a friend's car at the last DE day '10 and there was virtually no difference in gearing.

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01-23-2011, 12:51 PM

#25

Astroman

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Quote:

Originally Posted by Gary R.

I ran some 225/s and 245's on 15's at Limerock from a friend's car at the last DE day '10 and there was virtually no difference in gearing.

Correct. The 245/50/15 has essentially the same rolling diameter as 16" and 17" tires. I was referring to the two 225 choices.

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01-23-2011, 01:21 PM

#26

Streak

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Quote:

Originally Posted by Gary R.

I've heard that about you, not that there is anything wrong with that...

IGNORING YOU!

Quote:

Originally Posted by Astroman

Because both the 225/45/15 and 225/50/15 have a reduced rolling diameter over any 16" or 17" tire.

I'll make it easy for them: At least at Road America, MH uses 225/45/15s in the front on 8" wheels and 225/50/15s in the rear on 9" wheels.

Seems like that's backwards since the taller tire is in back but who am I to say.

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01-23-2011, 01:33 PM

#27

Gary R.

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Quote:

Originally Posted by Streak

Seems like that's backwards since the taller tire is in back but who am I to say.

Adds to the rake, .0000016 less Cd.

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01-23-2011, 01:42 PM

#28

Streak

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if I use the smallest diameter will I run out of gear at WG or VIR? Long straights there.

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01-23-2011, 01:43 PM

#29

sig_a

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From Hoosier sizing spec sheet:

225 50 15 wheel width range 6" - 8" and tread width of 8.8" (23.8" dia)

225 45 15 wheel width range 7 - 8.5" and tread width of 9" (22.9" dia)

So in Astroman Jack's example mounting 225 50 on 15 x 9" rear must not make any difference in spite of Hoosier specification for maximum wheel width of 8" ???

Hupfer knows what he's doing, obviously.

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01-23-2011, 01:43 PM

#30

Astroman

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Quote:

Originally Posted by Streak

Seems like that's backwards since the taller tire is in back but who am I to say.

I guess, traditionally, our cars came with 205/50/16s in the front and 225/45/16s in the rear. But as far as sidewall/aspect ratios are concerned, the front 225/45/15 and rear 225/50/15 combo is no different than the sometimes used front 225/45/15 and rear 245/50/15 combo. That 245/50/15 is a really tall tire.

Here is another bit of confusing info: Oddly, the 225/45/15 on a 8" wheel is essentially the same width as a 245/40/17 on a 8" wheel. Chris M. and I did a side by side comparison... it was surprising. So, anyone using the 225/45/15 in the front (on an 8", not a 7") is losing nothing to the popular 245/40/17.

Last edited by Astroman; 01-23-2011 at 03:21 PM.

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