Changing from 21” to 20” wheels
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Joined: Jun 2018
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From: Pasadena, Tx
2019 AMG 43 SUV
I want the stock look and staggered fitment. Ordered the 20" wheels 20 x 8.5 for front and 20 x 10 for back. The offset for the wheels are +32 front and +45 back.. The tires are Goodyear Eagle Sport Run Flat All season; 255/45-20 front and 285/40-20. These are the same size of the 21" Continental Summer tires that originally came. Ordered these from Tire Rack and the salesman assured me they would work. Dropped shipped them to Firestone and they called saying the first tire installed, the rear inside was slightly rubbing on the inside of fender well. The run flat tires look slightly bigger(sidewall) and I have little knowledge of tire science. I presume the offset is not correct? Will a wheel spacer kit solve the problem?
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I want the stock look and staggered fitment. Ordered the 20" wheels 20 x 8.5 for front and 20 x 10 for back. The offset for the wheels are +32 front and +45 back.. The tires are Goodyear Eagle Sport Run Flat All season; 255/45-20 front and 285/40-20. These are the same size of the 21" Continental Summer tires that originally came. Ordered these from Tire Rack and the salesman assured me they would work. Dropped shipped them to Firestone and they called saying the first tire installed, the rear inside was slightly rubbing on the inside of fender well. The run flat tires look slightly bigger(sidewall) and I have little knowledge of tire science. I presume the offset is not correct? Will a wheel spacer kit solve the problem?
Yeah +45 is way wrong, factory is +22 on a 9.5 inch I think. A spacer would fix it.
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2015 Challenger Hellcat, 2023 Ram 3500, 2005 E55 Wagon, 2019 GLC63s
I want the stock look and staggered fitment. Ordered the 20" wheels 20 x 8.5 for front and 20 x 10 for back. The offset for the wheels are +32 front and +45 back.. The tires are Goodyear Eagle Sport Run Flat All season; 255/45-20 front and 285/40-20. These are the same size of the 21" Continental Summer tires that originally came. Ordered these from Tire Rack and the salesman assured me they would work. Dropped shipped them to Firestone and they called saying the first tire installed, the rear inside was slightly rubbing on the inside of fender well. The run flat tires look slightly bigger(sidewall) and I have little knowledge of tire science. I presume the offset is not correct? Will a wheel spacer kit solve the problem?
R.K.
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The factory wheels are 20x8.5 +40 and the rears at 20x9.5 +22. Your new wheels are sucked in the front by 10mm for less inner clearance. The rears have 29mm less of inner clearance but the same outer fitment so your fitment isn’t the same as the factory setup. You can run a spacer but you’ll need longer studs. It will look odd if you punch out the rears only and leaving the fronts. Your call but the fitment isn’t perfect.
R.K.
R.K.
For the rear, a 20mm spacer would work. This is what you'd end up with.
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Thread Starter
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From: Pasadena, Tx
2019 AMG 43 SUV
No rubbing off the lift and on the ground
The 21" Cont's which lasted only 8K miles replaced with 20" Goodyear Eagle All Season, run flat, rated for 50K miles. Surprisingly the run flat's have a smoother ride.
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glc 43 amg
I'm not entirely surprised the 20" RFT have a smoother ride than 21" summer ones. Sure, RFT have a stiffer sidewall than non-RFT, but the other factor at play here is the extra 1/2" of sidewall, which is evidently a larger factor. I just experienced that myself when installing new 19" wheels with Winter RFT, coming from the 21" Contis for the Summer. The ride went from absurdly harsh to plush. This makes me consider switching to 20" for next Summer.
Those are nice 20" wheels. Savini brand? How much does that run, approx?
Those are nice 20" wheels. Savini brand? How much does that run, approx?
Thread Starter
Junior Member
Joined: Jun 2018
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From: Pasadena, Tx
2019 AMG 43 SUV
The wheels were $423 $433 each. Front tires $319.00 each. Rear tires $410 each I went with the original staggerd fitment. Ordered from Tire Rack. The price includes the tire mounted on wheel, balanced with new TPMS installed. Firestone charged $10 /wheel to mount. Before mounting took to a detailer and paid $25.00 each for ceramic coating.
saviniwheels.com/black-di-forza/bm13/
saviniwheels.com/black-di-forza/bm13/
Last edited by Longhorn Dad; Dec 8, 2019 at 01:11 AM.
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glc 43 amg
Longhorn, re-reading this thread, I realized that I'm not clear on whether you solved your initial rubbing issue with a spacer in the manner described by scotchy? I'm tempted to emulate your setup. It's not like we are likely to bump into one another 
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C450, GLC43
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glc 43 amg
Mr. J, Do you have an alternative recommendation if one wanted to optimize for longevity instead of cornering prowess? For example, the pirelli scorpion verde have a slightly higher AA rating (600 vs 560), but I don't know how that translates in real life.
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From: Pasadena, Tx
2019 AMG 43 SUV
When the car was off the lift there was no rubbing. Plenty of clearance. The wheels and tires fitted correctly as Tire Rack recommended.
