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2017 Infiniti Q60 Red Sport
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I thought the spacing was fixed and they move together.
The strut does not move in the rear. Why do you think OP added spacers.
 

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Discussion Starter #402 (Edited)
I would be careful driving like that. I am guessing you have 5mm from the wheel to the strut. When the wheel goes in compression or bottoms out when going up a steep incline, the wheel will rub the strut.

I have a Q60 with 20x12+40 with -2 camber in the rear. It is about 12mm away from the strut. Under full compression going up a very steep incline, the wheel rubs against the strut and you can imagine metal to metal contact is no bueno. I estimate that the wheel should at least be 15mm away from strut for clearance.
Thank you for your concern. But, I’d estimate that the inner barrel of my 18x11 +56mm wheel with a 5mm spacer (essentially +51mm offset) is 13-14mm away from the OEM strut body while my car is parked (under my car’s own load at the rears, not under full compression). I did not observe the wheel’s inner barrel rubbing the OEM strut body when I went for a test drive that included speed bumps at 5 mph, flat but bumpy roads at 60 mph, a burnout that left 10’ long tire marks on the road, and a hard launch. The outer most part of the inner sidewall of the 325/35-18 tire sticks out past the wheel’s inner barrel by approximately 10mm, so the inner sidewall of the tire has about a 3-4mm clearance from the OEM strut body while my car is parked (under my car’s own load at the rears, not under full compression).

I’m mainly concerned about the tires rubbing (since the tire sticks out past the wheel) during a hard launch when the rear squats, not really concerned about the wheels themselves rubbing. Plus, I’ll only be driving on that setup to and from the drag strip, which will be mainly rural flat roads, and I’ll be doing quarter mile passes on ’em at the drag strip (flat road, not inclined).

If I compared my 18” wheel setup to your 20” wheel setup, my 18” wheel will be vertically 1” further away from the OEM strut body under full compression. Again, not concerned about my 18” wheel hitting the OEM strut body.

95300


What’s your actual tire size in the rear (I plugged in 325/25-20, but I’m pretty sure you’re not running this tire size, but a more stretched tire)?
 

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Thank you for your concern. But, I’d estimate that the inner barrel of my 18x11 +56mm wheel with a 5mm spacer (essentially +51mm offset) is 13-14mm away from the OEM strut body while my car is parked (under my car’s own load at the rears, not under full compression). I did not observe the wheel’s inner barrel rubbing the OEM strut body when I went for a test drive that included speed bumps at 5 mph, flat but bumpy roads at 60 mph, a burnout that left 10’ long tire marks on the road, and a hard launch. The outer most part of the inner sidewall of the 325/35-18 tire sticks out past the wheel’s inner barrel by approximately 10mm, so the inner sidewall of the tire has about a 3-4mm clearance from the OEM strut body while my car is parked (under my car’s own load at the rears, not under full compression).

I’m mainly concerned about the tires rubbing (since the tire sticks out past the wheel) during a hard launch when the rear squats, not really concerned about the wheels themselves rubbing. Plus, I’ll only be driving on that setup to and from the drag strip, which will be mainly rural flat roads, and I’ll be doing quarter mile passes on ’em at the drag strip (flat road, not inclined).

If I compared my 18” wheel setup to your 20” wheel setup, my 18” wheel will be vertically 1” further away from the OEM strut body under full compression. Again, not concerned about my 18” wheel hitting the OEM strut body.



What’s your actual tire size in the rear (I plugged in 325/25-20, but I’m pretty sure you’re not running this tire size, but a more stretched tire)?
I'm running 325/25 in the rears. The tire is so low profile that the stretch is more visible on the 12" wide wheel. Your sidewall is thick and you're on 11" wide wheel. You have enough space between the wheel and strut. Your tire will hit the strut before the wheel for sure regardless of the spacing. Just a good rule of thumb 12mm+ spacing between the tire or wheel from the strut to avoid interference issues.
 
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2017 Q50 Red Sport 400 RWD
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EQ50, when you are taking your measurements, are you running the tire pressure you'll be running on track days? I'm worried if you plan to let some air out on track days, your tire may be wider than it is in your tests.
 
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EQ50, when you are taking your measurements, are you running the tire pressure you'll be running on track days? I'm worried if you plan to let some air out on track days, your tire may be wider than it is in your tests.
Should be wider on contact patch not at the top of the tire.

May only affect a mm or two is my guess
 

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Discussion Starter #406
EQ50, when you are taking your measurements, are you running the tire pressure you'll be running on track days? I'm worried if you plan to let some air out on track days, your tire may be wider than it is in your tests.
When I test fitted the tires, did my measurements, and went on a test drive, the 325 rear tires were inflated to 35 psi.

Should be wider on contact patch not at the top of the tire.

May only affect a mm or two is my guess
I concur. I’m not too worried about lowering the tire pressure, to 20 psi ish, during track days
 

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When I test fitted the tires, did my measurements, and went on a test drive, the 325 rear tires were inflated to 35 psi.


I concur. I’m not too worried about lowering the tire pressure, to 20 psi ish, during track days
I meant mm or two at the top...should be more at the bottom.
 

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