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if one really want to get technical, there should be a sticker on your door jam that has the oem recommended tire size that the whole car was engineered for. they even tell you how much air pressure you need to put in. through millions of dollars of development this was the best compromise the manufacture the engineers came up with all factors considered. so why are so many seeking to alter it? isnt doing so ignoring the engineers advice? if you change the mechanics or deviate from the stock tire wheel size then you are ignoring the engineers advice. :-)

i dont think the pics of the wheels you posted look great but thats only my opinion. for me thats a DM stance or a woo-tang crowd and it wasnt what i was trying to convey. they surely arent the oem size of tires ive listed as an example right?

from my experience in which ive designed wheels for at a major oem. working with the tire and wheel engineers im aware of some of the factors for recommended sizing. there are real limitation is liability or warranty that has nothing to do with safety or performance according to the engineers. depending on the tire having a slightly wider wheel beyond recommended spec to have real world attributes other than appearance like tire response and sharper turn in according to the engineers. remember i said slightly wider within reason.

im in agreement you with effects of excess weight and the rolling diameter gearing alteration. not much have been here mention that the taller tires really compromise the front end geometry when lowering back to stock height and beyond. yes you can feel it.

RUF has 28 lbs boat anchors for wheels on the yellow bird but they were also on their SC and 3.2 cars pushing 230 and 250hp. i find these inexcusable but folks love them.

The 930 or m491 are full of compromises when it comes to wheels by using modified front hub, giant rear spacer and long studs in the rear just to fill up the flare fenders instead of bespoke offset wheels like the rsr. let not mention the additional problems it causes with the excessive scrub radius. but everything is a compromise you take the good with the bad.

yes due diligence... i dont think my mattress is liable to catch fire easier when i cut off the tag or is it?

thank you for the lively debate
Old 02-12-2018, 10:12 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #41 (permalink)
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Quote:
Originally Posted by tributeventures View Post
Wow, what a surprise. Are they still making the Zuff's? Thanks for posting Jeff.
Yes, still producing.
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Old 02-13-2018, 05:42 PM
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Originally Posted by webbarmory View Post
I have an 87 Cab M491 ( Looking for a G50 Coupe M491 myself ) . I picked up some BBS RS rims as a spare set; being 3 piece I'm going to get some new halves from Jae Lee ( Mirage International) and have them sized for 17'.

After doing a lot of research on the board and talking to a few local PCA members. I'm planning to go 8x17-fronts/w 225/45-17 , 10x17 - Rears/w 255/40R17 . 3-5k miles per year on windy country roads and no track use. The offset is the only part I have not reviewed yet.

I did not add much to the conversation but I am considering similar sizing as you originally mentioned.
Now this I would love to see!
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Old 03-10-2018, 07:48 AM
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FYI
To fit em, I am running 3 deg neg camber and rolled fenders with the 225/45/17 up front - no scrubbing at all.

I am also using 225/40/17 (R888) on the rear on 9" rims did not have to go with 10" .
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Old 03-10-2018, 09:55 AM
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Quote:
Originally Posted by betterair View Post
FYI
To fit em, I am running 3 deg neg camber and rolled fenders with the 225/45/17 up front - no scrubbing at all.

I am also using 225/40/17 (R888) on the rear on 9" rims did not have to go with 10" .
Do you mean 255/40-17 on the rear? I am running those sizes on my 3.2 Carrera and did the same tweaks to fit the fronts without rubbing. They look great!

Scrub radius is not the same as rubbing on the fender lips or inner fender. Scrub radius is the distance from the kingpin axis and the center of the tire tread. I think a longer distance because of spacers or big offset is going to have a negative effect on handling and steering effort.

P.S. For autocross I run 225/545-15 and 245/40-15 on OEM 7x8 Fuchs. Light weight, smaller diameter (under 23" instead of 24.8") combine to make the car much quicker but they look kinda stupid when viewed from the side.
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Last edited by msterling; 03-10-2018 at 12:10 PM..
Old 03-10-2018, 12:04 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #45 (permalink)
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Wow, wow, wow! Lively debate to be certain. Overwhelmingly so.

My original purpose for inquiring about 17s stemmed from concerns regarding stock 16" 930 / M491 tire sizes becoming no longer available. As such, I wanted to be 100% sure that if I was going to spend the $$$ on a set of 17" Fikse Fuchs that the sizes and offsets would work for my purposes. More aggressive than 7s & 9s stock, but with ZERO fitment issues. This being said, 17s are not my preference for G Body 911s. 18s even less so. In the interim, I opted to stick with 16s as long as at least one tire that meets my needs remains available. I'm a 16 guy as long as it's an option.

I went with 8x16 944 Fuchs up front and stock 9x16 Fuchs in the rear shod with 225/50-16 and 245/45-16 P Zero Trofeo R N0 spec tires. SPECTACULAR grip on the 100 mile dawn patrol runs up to Julian, CA and back. Treadwear rating sucks, but life's too short to drive high mileage tires.

All of that being said, I'd like to express my gratitude to everyone that chimed in here. I very much appreciate your time, consideration and input. I intend to build an M491 / M470 "Club Sport," if the right donor car ever comes around, and I'll revisit the information on this thread as I decide on wheels & tires for that.

Quote:
Originally Posted by megerian View Post
Frank - since your signature says you are looking for an M491 coupe, and this post is talking about wheels for an M491 coupe, does that mean you've found the stablemate for your cabrio?
Yes, I did (and I also came pretty close to acquiring an '88 M491 targa too). After four years of searching daily, I found it in Orange County, less than an hour from my home. To say that I am "enraptured," would be the understatement of the year.







See #PTSgeminiM491 here https://www.instagram.com/explore/tags/ptsgeminim491/ for more pics.

I am totally loving it. It is also an M470 car and I am leaning towards re-deleting the rear wing that sprouted at some point in the past thirty-one years. I'm kicking around a 3.4 liter twin plug build, or perhaps a 3.6 swap (either of which would end up in an M491 / M470 "Club Sport" build if that ever happens for me).

Quote:
Originally Posted by webbarmory View Post
I have an 87 Cab M491 ( Looking for a G50 Coupe M491 myself ) . I picked up some BBS RS rims as a spare set; being 3 piece I'm going to get some new halves from Jae Lee ( Mirage International) and have them sized for 17'.

After doing a lot of research on the board and talking to a few local PCA members. I'm planning to go 8x17-fronts/w 225/45-17 , 10x17 - Rears/w 255/40R17 . 3-5k miles per year on windy country roads and no track use. The offset is the only part I have not reviewed yet.

I did not add much to the conversation but I am considering similar sizing as you originally mentioned.
Please report back with what you end up going with. I'll have to "upgrade" to 17s at some point.

Appropriately enough, this is forum post number 491 for me!

Best,
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1987 911 M491 Coupe
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Old 10-10-2018, 04:07 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #46 (permalink)
 
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