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Ahhh, great and thanks @lockem. Phew...so the new QVs now sit at the same height of the Q4s. Thats interestng. But all good to know! Based on Racer Z's 255's on his Q2 I know they will fit the Q4 and shouldn't be any rubbing issues. The only issue I see is that I'd be putting 255s on an 8.5 wide wheel vs racer z's, which are on 9 inch wide wheels. Maybe this raises the height of the wheel, but the Q4's sit higher than the Q2s. Though I'm lesss concerned considering how @JoeCab got the 255s on his QV tenicinos and I believe without rubbing. Thnaks for clarifying. Ill post pics and create a thread when I get them installed.

Appreciate your comments, contributions to the forum and help with this particuar question. :smile2:
I did not say that the new QVs are the same height as the Q4. From what I gather from a mix of forum posts and my measurements:

Original QV, 4" front and rear.
New QV, 5" front and rear.
2.0T RWD, 5" front, 6" rear. Note that this has worse entry angle than a QV.
Q4 6" front, 6.5" rear.

For best handling the generally accepted practice is to select a rim width that is 0 to 0.5" wider than the planned tread width. This puts lateral tension on the sidewalls of the tire (popularly known as "stretch"), reducing sway and keeping the tread in better contact with the pavement during cornering. The stock 225s (7.8-7.9" tread width for most tires) on 8" rims meet this criteria. 255s (9.0-9.2" tread width for most tires) on 9" rims slightly miss the mark while 255s on 8.5" rims miss the mark by a lot.
 
Interesting. Is that thanks to the retractable splitter?
No, that is because a higher rear means a lower nose.
The original QV and 2.0T RWD had the same entry angle (within a fraction of a degree), but now with the QV raised up, RWD is lower.
 
I did not say that the new QVs are the same height as the Q4. From what I gather from a mix of forum posts and my measurements:

Original QV, 4" front and rear.
New QV, 5" front and rear.
2.0T RWD, 5" front, 6" rear. Note that this has worse entry angle than a QV.
Q4 6" front, 6.5" rear.

For best handling the generally accepted practice is to select a rim width that is 0 to 0.5" wider than the planned tread width. This puts lateral tension on the sidewalls of the tire (popularly known as "stretch"), reducing sway and keeping the tread in better contact with the pavement during cornering. The stock 225s (7.8-7.9" tread width for most tires) on 8" rims meet this criteria. 255s (9.0-9.2" tread width for most tires) on 9" rims slightly miss the mark while 255s on 8.5" rims miss the mark by a lot.
Thank you sir! I stand corrected re height. Makes complete sense now. Thanks for the education on the tires and wheels! Guess I got some rethinking to do re tires. So extremely helpful. I had assumed with @JoeCab's setup I'd be okay, but the above gives me just a bit more perspective. Thanks
 
Hi sorry I’m not on this forum much anymore. Maybe once a week for a bit.
The 305’s fit just fine on the Giulia QV without any rubbing. My rears originally rubbed because my negative camber was set way too much! Now that that is fixed there is no rubbing it all and the car puts all the power down now so burnouts are not so crazy anymore and 0-60 time is really fast now!!
I have lowering springs on but I’m sure with the stock springs would be the same and no rubbing.

So this is my recommendation for maximum sizes without any rubbing.
Ft 255/35/19 rear 26" tall (+.2")
Rear 305/30/19 26.3" tall (+.5")

I have lowering springs on front and rear. For stock springs on the front you might be able to go to 265 width but I would not do it as there’s a wiring harness that could get rubbed.

I’m real happy with the sizes I have now and I’m also really happy with the Michelin PS4s.

I have almost completed what I feel is an amazing front brake cooling mod that will be available for sale in a few weeks and I have a thread on it. Consists of a new backing plate with a 3 inch diameter hole in it, ducting and a 3-D printer made air scoop that attaches on the control arm that scoops air into the pressurized system.

I’m surprised no one seems to be much interested in it as the car really needs brake cooling BADLY if you track it!. Also can make your brake pads and rotors last 50% longer!
Are you worried about understeer because the rear is technically 20mm wider while the front is only 10mm ?
 
Hi sorry I’m not on this forum much anymore. Maybe once a week for a bit.
The 305’s fit just fine on the Giulia QV without any rubbing. My rears originally rubbed because my negative camber was set way too much! Now that that is fixed there is no rubbing it all and the car puts all the power down now so burnouts are not so crazy anymore and 0-60 time is really fast now!!
I have lowering springs on but I’m sure with the stock springs would be the same and no rubbing.

So this is my recommendation for maximum sizes without any rubbing.
Ft 255/35/19 rear 26" tall (+.2")
Rear 305/30/19 26.3" tall (+.5")

I have lowering springs on front and rear. For stock springs on the front you might be able to go to 265 width but I would not do it as there’s a wiring harness that could get rubbed.

I’m real happy with the sizes I have now and I’m also really happy with the Michelin PS4s.

I have almost completed what I feel is an amazing front brake cooling mod that will be available for sale in a few weeks and I have a thread on it. Consists of a new backing plate with a 3 inch diameter hole in it, ducting and a 3-D printer made air scoop that attaches on the control arm that scoops air into the pressurized system.

I’m surprised no one seems to be much interested in it as the car really needs brake cooling BADLY if you track it!. Also can make your brake pads and rotors last 50% longer!
Are you worried about understeer because the rear is technically 20mm wider while the front is only 10mm ?
It not a lot of difference. People who put spacers on their cars (something I would never do for many reasons) change it a lot more.

The car is balanced so well and handles so well it’s easy to make adjustments in your driving also.

What I noticed with the wider rear tires the most is when tracking I am able to put all my power down coming out of turns especially coming out of turns and up a hill. Before the wider tires often they would just smoke up. Now the rear tires have quite a bit more grip and don’t spin so much.
Very pleased with the set up I have now. Zero problems, better handling, better looking and some curb rash protection now the tires stick out a bit more than the rims.
 
Wheel tire sizes

Joe Cab. Great fit with the new tires. I didn’t realize how right the Oem wheel and tires fit. Oh well doesn’t look like I will be upsizing to 10.5 rears and 9.0 up front. Bummer. But I like your idea of bumping up the width of rubber. Nice full look without major fit concerns.
 
Joe Cab. Great fit with the new tires. I didn’t realize how right the Oem wheel and tires fit. Oh well doesn’t look like I will be upsizing to 10.5 rears and 9.0 up front. Bummer. But I like your idea of bumping up the width of rubber. Nice full look without major fit concerns.
On the QV, I have been running 20x11, 20x9 and having a blast. I'm running 295 FK510's now on the rear, 265's up front.
Only rub is on full lock, only in reverse, and only mild rub on the felt liner 'venting' area. Lowered on Novitec springs. No issues, and tremendous grip/handling/braking difference overall. I am weird and switch things up a lot (my last car had no less than 6 sets of wheels in just 5 years). So, will be selling shortly and going a different direction for the whole car (looks, build, color scheme, etc). My next set will be 20x11 and 20x9 again as well, no brainer on the QV. Not sure 305's are needed, at least in the FK510 rubber, as I'm hooking and cornering just about perfectly at this point even in wet.
 
Would appreciate any details and specs for the 20 x 9 and 20 x 11 wheels that worked well for you. Specifically vendor, wheel brand and model and definitely offset. Thanks.
 
I would imagine a 20x9 with 255/30 should be between a +30 and +35 offset. As for the 11" with a 305/25 I'd estimate a +50. In terms of wheel manufacturers this would be a custom wheel so I'd imagine there could be several multipiece/forged manufacturers who can produce this. If you want a monoblock I know I've ordered BC Forged wheels before and had custom offsets produced. If you want something affordable I have also sourced Forgestar "rotary forged" wheels that are simply flow formed and not technically forged imho. I personally feel that 20" is a bit large of a diameter and very limiting on tire selection for the Giulias. I do believe 19" wheels are the ideal diameter for the QV simply because of the OEM tire diameter and "tire affordability". There are many other domestically manufactured 3 piece wheels options like HRE, ADV.1, CCW, Rotiform, Weld racing, etc.... the list goes on and on for companies who can produce our 5x110 PCD but the prices of wheels skyrocket. There are some Japanese 3 piece companies that might be able to do custom PCD like Work Wheels as well but the trick is finding the right offset relative to caliper clearance and width of the wheels.

Below would be your more affordable options to manufacturers.
https://www.bcforged-na.com/
https://www.forgestar.com/wheels/

I'm running some Aspira AV-5 Forged wheels in 19x9 and 10 on my Giulia. I know of some other members running 255/35 and 295/30 on this setup as well.
 

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Thank you for your recommendations. Very much appreciated. 20-inch is not my main focus which tend to be heavier overall. Wheel width, weight, and tire footprint are my priorities. I think the Alfa QV can benefit from more tire width and contact patch. I'm guilty of believing you can never have too much tire/wheel width as long as they fit within the fenders and there are no interference issues. The front seems to be the most limiting. I'm not opposed to custom fitting and will measure the stock wheel fit, available clearance/interference and offset adjustments. I do appreciate others experience and will certainly follow up on your recommendations. Regards.
 
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