First drive impressions - 17x9 ET70 Cup II fronts / 18x10 ET47 Cup II replica rears
05-03-2010, 09:46 AM
#16
Supercharged
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You must post a price when listing your car for sale...
Oh wiataminute... I now see it's not actually for sale. I thought with all those pics it was a for sale ad.
j/k
Looks great!
Oh wiataminute... I now see it's not actually for sale. I thought with all those pics it was a for sale ad.
j/k
Looks great!
05-03-2010, 09:56 AM
#17
Dude.............................what's this I spy? Even Kohler has those replaced, you are falling behind.
05-03-2010, 09:57 AM
#18
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Would love to get my hands on a pair of 18x10 or 18 x 11 Cup IIs - then I could sell my spare pair of 18x8.5 Cup IIs
05-03-2010, 02:24 PM
#22
Rennlist Member
The car looks nice [super photos] and although a little strange, the different sizes will work- however I would have used a 285 or 295x30 section and have a lower rolling radius? If you have the GT rear spacers fitted you should have no problems with tire clearance. On my S4 I had 285x30's with a 60mm offset and no problems at all- not even close. On my current GTS I had to remove the stock 38mm spacer and fit a 24mm one to clear the fender by a reasonable margin.
I suspect you will quickly find that the rear end cannot keep up with the front and it will probably give you are a car that is tail happy- no problem if you can handle that. Stiffening the front end up if you have an adjustable bar or front links will help reduce this if you experience this.
Re-check your alignment and set the toe to min spec- you will find this sharpens turn in with out making the car too twitchy.
I suspect you will quickly find that the rear end cannot keep up with the front and it will probably give you are a car that is tail happy- no problem if you can handle that. Stiffening the front end up if you have an adjustable bar or front links will help reduce this if you experience this.
Re-check your alignment and set the toe to min spec- you will find this sharpens turn in with out making the car too twitchy.
05-03-2010, 02:40 PM
#23
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If Mille Miglia made them (past tense) then they still know how to make them. It's just a matter of convincing them to turn the faucet back on, though that might be a tough sell for 5-10 sets (though I'd seriously consider a set in the dimensions Dan proposes....)
05-03-2010, 09:35 PM
#25
Rennlist Member
Thread Starter
First of all, thanks everyone for your kind words and comments. This setup has been in the works for over 7 months now, with several unforeseen delays and setbacks. It's certainly been a labor of love, and I'm very happy that you guys seem to like it as much as I do. With that said, let me respond to some of your comments and questions:
Rick, I'll have to crawl under it and measure, something I certainly plan to do in short order. I'll post the results as soon as I get them. As I recall, it was about 150mm in front before the change, and that's probably what I'll be shooting for again.
EDIT:
LF 150MM RF 152MM
LR 168MM RR 166MM
Looks like a have a little fine tuning to do. Will probably raise the rear a few MM and leave the front alone, while trying to even it all out.
Actually, Mille Miglia made them. I'm told by the folks at Tire Rack the Cup II replica was discontinued ~ 2003. Since then, I believe the company has gone out of business. If someone knows differently, please let me know. It would have been far easier and cheaper to buy them new if they were still available. And yep, they're a little on the heavy side.
We are certainly in agreement, and it's funny you mentioned having some new ones commissioned as I had thought about that myself. I have a couple of machine shop customers who have 5 axis machines, one of them does parts fab work primarily for the aerospace industry (think 737 and the new 787 Dreamliner), the other does giant valves for oil refineries and pipelines. The thought of taking one of my rims to one of them and having it scanned and programmed for reproduction has certainly crossed my mind. The most pressing need would be turning the 18x8.5 ET52 fronts into something with an ET that would work for our 928s. After that, we could work on widening the 10" rears.
If I were to do so, I'd also have them make it out of a stronger alloy. As you know, these particular replica wheels have a reputation for being heavy, soft, and prone to both bending and cracking. Mine were all of the above, and had to have extensive welding and straightening work before being sent to the painter. It was certainly time-consuming and in no way inexpensive, but I wanted those 18x10's. I know you understand.
I used the size calculator at: http://www.rimsntires.com/specs.jsp
It suggests my front setup is .1" taller than my D90 setup. No big deal. Out back, there is a larger difference with the stock 245/45/16 being 24.6" tall (77.4" circumference) vs. the new 265/35/18 with a height of 25.3" (79.5" circumference). It was this difference that I was trying to minimize while retaining the trim, tucked-in look of the tire on the rim. A 275/30 would have been very close, but alas, not available in the Dunlop I chose to go with. Furthermore, this would have resulted in a shorter sidewall, making the rim even more vulnerable to bending/cracking. In summary, the 265/35 appeared to me to be the best compromise of availability, diameter, and appearance I was aiming for.
See my comments above. I still have my pair of 18x8.5 Cup II replicas as well. Tried selling them, can't seem to even give them away. As such, I may just keep them and pursue using them as a model should I go the machine-shop route.
Appreciate your insight, Fred. As I mentioned, I haven't really pushed the car so I don't have any impression of its handling at the limits.
My 90GT has no spacers, unlike the 89GT and later GTS. I'm sure I could get away with more tire, as I can easily slide my fingers between the rear tire and the outer fender well.
I would note, the widest OEM wheel Porsche made for the 928 was the 928 Cup Racer, essentially a 17x9.5 ET68 Cup I wheel. It was used at all four corners. Devek and 928 Specialists used to sell them, and IIRC the suggested setup from the factory contained no tire stagger, or maybe 10-20mm at most.
I'm anxious to see if my setup has removed so much push that it's now prone to oversteer. As you mentioned, a beefier front bar might well be the perfect balancing solution. (I had a Devek bar on my former GT and really liked it) I would also add that I ran my setup thoughts past none other than Kim John Crumb, who probably has about as much 928 setup knowledge as anyone, and he thought I was on the right path. We shall see...
Thanks again everyone!
EDIT:
LF 150MM RF 152MM
LR 168MM RR 166MM
Looks like a have a little fine tuning to do. Will probably raise the rear a few MM and leave the front alone, while trying to even it all out.
Looks fantastic Jarrod. You know, they say imitation is the highest form of flattery, hence my plans to replicate what you have done.
I agree, hard to beat the Cup II's for our cars. They just look right with the rounded details of the spokes.
How expensive would it be to have some wheel shop replicate the Mille Migilia's Cup 11's in the following sizes 9JX18 ET65 and 11JX ET55? Anyone have a guess? How about you guys that own 5 Axis mills. How much to do the design, CNC program, buy the alloy stock and then cut these babies then Powder coat them? What sort of numners of sets would we need in a group buy to get to a reasonable cost?
I agree, hard to beat the Cup II's for our cars. They just look right with the rounded details of the spokes.
How expensive would it be to have some wheel shop replicate the Mille Migilia's Cup 11's in the following sizes 9JX18 ET65 and 11JX ET55? Anyone have a guess? How about you guys that own 5 Axis mills. How much to do the design, CNC program, buy the alloy stock and then cut these babies then Powder coat them? What sort of numners of sets would we need in a group buy to get to a reasonable cost?
If I were to do so, I'd also have them make it out of a stronger alloy. As you know, these particular replica wheels have a reputation for being heavy, soft, and prone to both bending and cracking. Mine were all of the above, and had to have extensive welding and straightening work before being sent to the painter. It was certainly time-consuming and in no way inexpensive, but I wanted those 18x10's. I know you understand.
It suggests my front setup is .1" taller than my D90 setup. No big deal. Out back, there is a larger difference with the stock 245/45/16 being 24.6" tall (77.4" circumference) vs. the new 265/35/18 with a height of 25.3" (79.5" circumference). It was this difference that I was trying to minimize while retaining the trim, tucked-in look of the tire on the rim. A 275/30 would have been very close, but alas, not available in the Dunlop I chose to go with. Furthermore, this would have resulted in a shorter sidewall, making the rim even more vulnerable to bending/cracking. In summary, the 265/35 appeared to me to be the best compromise of availability, diameter, and appearance I was aiming for.
The car looks nice [super photos] and although a little strange, the different sizes will work- however I would have used a 285 or 295x30 section and have a lower rolling radius? If you have the GT rear spacers fitted you should have no problems with tire clearance. On my S4 I had 285x30's with a 60mm offset and no problems at all- not even close. On my current GTS I had to remove the stock 38mm spacer and fit a 24mm one to clear the fender by a reasonable margin.
I suspect you will quickly find that the rear end cannot keep up with the front and it will probably give you are a car that is tail happy- no problem if you can handle that. Stiffening the front end up if you have an adjustable bar or front links will help reduce this if you experience this.
Re-check your alignment and set the toe to min spec- you will find this sharpens turn in with out making the car too twitchy.
I suspect you will quickly find that the rear end cannot keep up with the front and it will probably give you are a car that is tail happy- no problem if you can handle that. Stiffening the front end up if you have an adjustable bar or front links will help reduce this if you experience this.
Re-check your alignment and set the toe to min spec- you will find this sharpens turn in with out making the car too twitchy.
My 90GT has no spacers, unlike the 89GT and later GTS. I'm sure I could get away with more tire, as I can easily slide my fingers between the rear tire and the outer fender well.
I would note, the widest OEM wheel Porsche made for the 928 was the 928 Cup Racer, essentially a 17x9.5 ET68 Cup I wheel. It was used at all four corners. Devek and 928 Specialists used to sell them, and IIRC the suggested setup from the factory contained no tire stagger, or maybe 10-20mm at most.
I'm anxious to see if my setup has removed so much push that it's now prone to oversteer. As you mentioned, a beefier front bar might well be the perfect balancing solution. (I had a Devek bar on my former GT and really liked it) I would also add that I ran my setup thoughts past none other than Kim John Crumb, who probably has about as much 928 setup knowledge as anyone, and he thought I was on the right path. We shall see...
Thanks again everyone!
Last edited by JWise; 05-05-2010 at 12:25 AM.
05-03-2010, 10:18 PM
#26
Race Car
Ditto Afshin's remark. Wow. It's cashmere/5 speed in my minds eye...though black int would be fine too...and I'm acclimating to my goat's auto in my old age....
05-03-2010, 10:19 PM
#27
Race Car
05-03-2010, 11:05 PM
#29
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Thread Starter
