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[Hujan]

I absolutely love the OEM ZCP wheels, especially with Michelin PSS in 255/35-19 and 275/35-19. That said, I was not a huge fan of having to run spacers (15 mm front; 10 mm rear) to get them to sit fairly flush. (Among other things, I did not want to add another task to my track prep.) I'd also love to save some weight if possible.

I've been considering getting a set of HRE P40SC monobloc wheels. My original thought was to do something like 19 x 9.5" et 22 and 19 x 10.5" et 27, and run Michelin PSS in 275/30-19 and 295/35-19. Of course, this would mean running slightly heavier, more expensive tires with a slightly shorter sidewall than I was running on the ZCPs. I also wonder how much the 275 would numb the steering relative to my old 255 setup.

Then it hit me: Could I do the P40SCs in 9" front and 10" rear like the ZCP wheels, but with more aggressive offsets? Something like 19 x 9" et 15 front and 19 x 10" et 15 rear? (This would be virtually identical to the effective offset that I was running with my ZCP wheels and 15/10 mm spacers.)

The advantages would be lighter overall wheels and tires, slightly less expensive tires, taller sidewalls, and the same steering precision as I had with the ZCPs. Basically, I would end up with lighter, stronger, and flush versions of the ZCPs but without the need for spacers.

Am I nuts for considering this?

[FogCityM3]

I run zcp size wheels on stock zip tire sizes with no rub, 19x9 ET 20 and 19x10 ET25. On the fronts, not sure if you could push it much farther than ET20, rears may have a bit more room. If you can the lower offset in the front, it is like running spacers and helps dial out some of the understeer, you can definitely feel 10mm. Will probably move to 255/35 and 275/35 tire combo as my rims seem to run a tad wider than ZCP and probably can get away with it with PSSs as seem to run narrow.

[Hujan]

Originally Posted by FogCityM3

I run zcp size wheels on stock zip tire sizes with no rub, 19x9 ET 20 and 19x10 ET25. On the fronts, not sure if you could push it much farther than ET20, rears may have a bit more room. If you can the lower offset in the front, it is like running spacers and helps dial out some of the understeer, you can definitely feel 10mm. Will probably move to 255/35 and 275/35 tire combo as my rims seem to run a tad wider than ZCP and probably can get away with it with PSSs as seem to run narrow.

Thanks, FC.

I should have mentioned in my OP that I was running 15 mm spacers on the front and 10 mm on the rear with my ZCPs, no rubbing. My question was less of a, "Would it work?" and more of a "Would it be crazy to buy a set of HREs in ZCP sizes (but not offsets)?" I edited the OP to eliminate the confusion. That's my bad.

[FogCityM3]

Got it and good to know it doesn't rub with those size spacers.

Doesn't sound crazy at all if you feel it improves performance/feel (which I think it does from my own increasing offsets while reducing unsprung weight) and much better to have the spacer effectively "built" into the wheel for weight and less vibration potential. It sounds like you're implying that maybe you should instead run wider wheels instead of ZCP sizes. Another member pointed out this handy contact patch calculator where you can input different parameters for wheels/tires to get the optimal theoretical contact patch size. Playing around with it, I found that oftentimes what you think adds contact area actually doesn't. Pretty interesting and may help narrow down your answer.

http://bndtechsource.ucoz.com/index/...alculator/0-20

Originally Posted by Hujan

Thanks, FC.

I should have mentioned in my OP that I was running 15 mm spacers on the front and 10 mm on the rear with my ZCPs, no rubbing. My question was less of a, "Would it work?" and more of a "Would it be crazy to buy a set of HREs in ZCP sizes (but not offsets)?" I edited the OP to eliminate the confusion. That's my bad.

[Denk]

My last couple of HRE sets were zcp sizes, et20. Just slightly more aggressive without going full bulldog. I liked the setup, looked and felt great with stock size tires.

I love the ZCP's too, I'm just running stock right now. HRE's aren't gnawing at me...at the moment.

Go for it, get those puppies made to your liking.

[W///]

Originally Posted by Hujan

I absolutely love the OEM ZCP wheels, especially with Michelin PSS in 255/35-19 and 275/35-19. That said, I was not a huge fan of having to run spacers (15 mm front; 10 mm rear) to get them to sit fairly flush. (Among other things, I did not want to add another task to my track prep.) I'd also love to save some weight if possible.

I've been considering getting a set of HRE P40SC monobloc wheels. My original thought was to do something like 19 x 9.5" et 22 and 19 x 10.5" et 27, and run Michelin PSS in 275/30-19 and 295/35-19. Of course, this would mean running slightly heavier, more expensive tires with a slightly shorter sidewall than I was running on the ZCPs. I also wonder how much the 275 would numb the steering relative to my old 255 setup.

Then it hit me: Could I do the P40SCs in 9" front and 10" rear like the ZCP wheels, but with more aggressive offsets? Something like 19 x 9" et 15 front and 19 x 10" et 15 rear? (This would be virtually identical to the effective offset that I was running with my ZCP wheels and 15/10 mm spacers.)

The advantages would be lighter overall wheels and tires, slightly less expensive tires, taller sidewalls, and the same steering precision as I had with the ZCPs. Basically, I would end up with lighter, stronger, and flush versions of the ZCPs but without the need for spacers.

Am I nuts for considering this?

What you are forgetting is that the HRE's are lighter than the relatively heavy ZCP's, which are the heaviest OEM wheels available on the E9x M3.

I'm running 9.5" front (22) and 11" rear (27) if I'm not mistaken, and with bigger tires, they still weigh roughly the same as OEM setup. I went from OEM sized PSS to 295 rears and the amount of traction increase is awesome. Looking to go 275 up front eventually.

So keep that in mind. Personally, I'm a sucker for a nice aggressive setup

[Hujan]

Originally Posted by FogCityM3

Doesn't sound crazy at all if you feel it improves performance/feel (which I think it does from my own increasing offsets while reducing unsprung weight) and much better to have the spacer effectively "built" into the wheel for weight and less vibration potential. It sounds like you're implying that maybe you should instead run wider wheels instead of ZCP sizes. Another member pointed out this handy contact patch calculator where you can input different parameters for wheels/tires to get the optimal theoretical contact patch size. Playing around with it, I found that oftentimes what you think adds contact area actually doesn't. Pretty interesting and may help narrow down your answer.

http://bndtechsource.ucoz.com/index/...alculator/0-20

Thanks for the link, FC. I will check that out. You are correct that I am worried I might be missing out on something by paying for custom wheels but not going with something wider than the OEM ZCP wheels. Would be interesting to know if I'm really getting a significant increase in mechanical grip with the wider setup.

Originally Posted by Denk

My last couple of HRE sets were zcp sizes, et20. Just slightly more aggressive without going full bulldog. I liked the setup, looked and felt great with stock size tires.

I love the ZCP's too, I'm just running stock right now. HRE's aren't gnawing at me...at the moment.

Go for it, get those puppies made to your liking.

Thanks, Denk! I didn't realize you did that. I thought I was the only one crazy enough to even think of it. I appreciate the encouragement.

Originally Posted by W///

What you are forgetting is that the HRE's are lighter than the relatively heavy ZCP's, which are the heaviest OEM wheels available on the E9x M3.

I'm running 9.5" front (22) and 11" rear (27) if I'm not mistaken, and with bigger tires, they still weigh roughly the same as OEM setup. I went from OEM sized PSS to 295 rears and the amount of traction increase is awesome. Looking to go 275 up front eventually.

So keep that in mind. Personally, I'm a sucker for a nice aggressive setup

Thanks for the comments. I am taking into account that the ZCPs are heavier and significantly so. That is actually where my hesitation to go wider comes from: Why spend $$$ on lighter wheels, only to give up most of the weight savings with heavier, stiffer tires?

I didn't mention it in my OP, but my goal is to shed as much weight from the car as possible without sacrificing too much (or any) in the way of comfort and performance. Lighter exhaust, brakes, wheels, maybe a battery, seats, etc.

[W///]

Originally Posted by Hujan

Thanks for the link, FC. I will check that out. You are correct that I am worried I might be missing out on something by paying for custom wheels but not going with something wider than the OEM ZCP wheels. Would be interesting to know if I'm really getting a significant increase in mechanical grip with the wider setup.



Thanks, Denk! I didn't realize you did that. I thought I was the only one crazy enough to even think of it. I appreciate the encouragement.



Thanks for the comments. I am taking into account that the ZCPs are heavier and significantly so. That is actually where my hesitation to go wider comes from: Why spend $$$ on lighter wheels, only to give up most of the weight savings with heavier, stiffer tires?

I didn't mention it in my OP, but my goal is to shed as much weight from the car as possible without sacrificing too much (or any) in the way of comfort and performance. Lighter exhaust, brakes, wheels, maybe a battery, seats, etc.

Because you gain that much more traction. IMHO, I'd rather gain that traction, than lose a couple of lbs per corner that you might not even feel. When I went from 220M to ZCP's, it's not like I could feel the weight difference to be honest (although this was 2 years ago, so I could be wrong).

The way my car is riding, it's still very comfortable (and I do have Swift springs). I wish I was able to give you a ride to give you a better idea. Well you are in San Diege, maybe there are some members with my kind of a setup that you can meet up with?

[LarThaL]

Originally Posted by Hujan

I absolutely love the OEM ZCP wheels, especially with Michelin PSS in 255/35-19 and 275/35-19. That said, I was not a huge fan of having to run spacers (15 mm front; 10 mm rear) to get them to sit fairly flush. (Among other things, I did not want to add another task to my track prep.) I'd also love to save some weight if possible.

I've been considering getting a set of HRE P40SC monobloc wheels. My original thought was to do something like 19 x 9.5" et 22 and 19 x 10.5" et 27, and run Michelin PSS in 275/30-19 and 295/35-19. Of course, this would mean running slightly heavier, more expensive tires with a slightly shorter sidewall than I was running on the ZCPs. I also wonder how much the 275 would numb the steering relative to my old 255 setup.

Then it hit me: Could I do the P40SCs in 9" front and 10" rear like the ZCP wheels, but with more aggressive offsets? Something like 19 x 9" et 15 front and 19 x 10" et 15 rear? (This would be virtually identical to the effective offset that I was running with my ZCP wheels and 15/10 mm spacers.)

The advantages would be lighter overall wheels and tires, slightly less expensive tires, taller sidewalls, and the same steering precision as I had with the ZCPs. Basically, I would end up with lighter, stronger, and flush versions of the ZCPs but without the need for spacers.

Am I nuts for considering this?

If you have too aggressive an offset with 255 front tires, you will rub. I would go for a set of APEX PS-7 19x9.5 ET22 front and 19x10.5 ET22 rear. You can then run 255/275 and have a nice flush look. The weight of the wheels is nice and so is the price.

[wrecklessfool]

Do a search for the RAC RG63 wheels on this forum. They are 19x9 and 19x10. Same as stock but the offsets are et22 front and rear. They are 8,000 TON forged by the same manufacturer of Ferarri, Neez, and Champion wheels. Extremely high quality and very lightweight. They were produced in very limited numbers for members of this forum a few years back but pop up for sale every once in a while. I have a set and LOVE them. They are wearing 255/35 and 275/35 just like you are looking to run.

[wrecklessfool]

Here is a pic of them on my car.

[wrecklessfool]

And a closeup

[Hujan]

Originally Posted by wrecklessfool

Do a search for the RAC RG63 wheels on this forum. They are 19x9 and 19x10. Same as stock but the offsets are et22 front and rear. They are 8,000 TON forged by the same manufacturer of Ferarri, Neez, and Champion wheels. Extremely high quality and very lightweight. They were produced in very limited numbers for members of this forum a few years back but pop up for sale every once in a while. I have a set and LOVE them. They are wearing 255/35 and 275/35 just like you are looking to run.

Dude, I love the RAC RG63s. If they still made them, I'd buy a set. That was actually what gave me the idea to do HRE P40SC in ZCP sizes. They look great on your car.

[Denk]

Originally Posted by Hujan

Dude, I love the RAC RG63s. If they still made them, I'd buy a set. That was actually what gave me the idea to do HRE P40SC in ZCP sizes. They look great on your car.

The concave on the HRE looks so aggressive, on a scale I haven't seen on another aftermarket mesh wheel.

[Hujan]

Originally Posted by W///

Because you gain that much more traction. IMHO, I'd rather gain that traction, than lose a couple of lbs per corner that you might not even feel. When I went from 220M to ZCP's, it's not like I could feel the weight difference to be honest (although this was 2 years ago, so I could be wrong).

The way my car is riding, it's still very comfortable (and I do have Swift springs). I wish I was able to give you a ride to give you a better idea. Well you are in San Diege, maybe there are some members with my kind of a setup that you can meet up with?

That's a good idea.

I am getting mixed information on the grip benefits. The online calculator linked to above suggests that although a 295/30 Pilot Super Sport on 10.5" wheel has a larger contact patch than a 275/30 PSS on a 10" wheel, the 255/35 PSS on a 9" wheel has a larger contact patch than 275/30 PSS on a 9.5" wheel. If that's true, the grippiest PSS setup would be 255/35 on 9" front with 295/30 on 10.5" rear.

As I think about it more, my biggest hesitation is with the 275/30 and 295/30 setup would be increased harshness from the shorter sidewalls. They are actually shorter than the OEM 245/35 and 265/35 setup. If the ride is noticeably harsher, I'd be willing to give up the increased grip.

Or maybe I should run 18" wheels on the street? Sigh.