8.5" wide wheel, +35 vs +45 Offset?????

jayy_swish

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What do you guys think about an 18x8 ET35? The wheels I'm looking at dont come in 18×8.5 and 18.9 seems a bit much for DD. I would like to keep the handling intact but with a bit better look. My other option in that size for offset is ET45
18x8 +50 is the stock sport rim size
I would go +35 for a flush look, +30 is dead center with the fender. Any extra and you’ll have a poke look.

Honda Civic 10th gen 8.5" wide wheel, +35 vs +45 Offset????? 6355303D-6DA0-4FED-88DB-61F5457DA330
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16sedan1.5

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18x8 +50 is the stock sport rim size
I would go +35 for a flush look, +30 is dead center with the fender. Any extra and you’ll have a poke look.

6355303D-6DA0-4FED-88DB-61F5457DA330.jpeg
Thanks for the info man
 

16sedan1.5

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18x8 +50 is the stock sport rim size
I would go +35 for a flush look, +30 is dead center with the fender. Any extra and you’ll have a poke look.

6355303D-6DA0-4FED-88DB-61F5457DA330.jpeg
My only other thing was I heard people say there handling feels "numb" when they go to an offset like 35 so I wasnt sure if that was common or maybe had to do with the tires they were running
 

jayy_swish

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My only other thing was I heard people say there handling feels "numb" when they go to an offset like 35 so I wasnt sure if that was common or maybe had to do with the tires they were running
I’m not sure about them, I have summer tires and have had zero issues with handling. Offset does play a factor but tires are more important in this discussion of offset vs tires
 

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18x8 +50 is the stock sport rim size
I would go +35 for a flush look, +30 is dead center with the fender. Any extra and you’ll have a poke look.

6355303D-6DA0-4FED-88DB-61F5457DA330.jpeg
GREAT PIC!
 


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I have 18x8.5 +35 Option Lab R716 with 235/40r18 (stock size) Continental DWS 06 lowered on Swift R-Spec Springs. No rubbing and rides great.
Honda Civic 10th gen 8.5" wide wheel, +35 vs +45 Offset????? FB_IMG_1585280508086
 
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I’m not sure about them, I have summer tires and have had zero issues with handling. Offset does play a factor but tires are more important in this discussion of offset vs tires
This was the case for me. On the stock wheels my steering feel was very responsive, but upgrading to 18x8.5 +35 took at lot of that away. My ride quality improved, but I miss the tight feeling I had before.
 

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This was the case for me. On the stock wheels my steering feel was very responsive, but upgrading to 18x8.5 +35 took at lot of that away. My ride quality improved, but I miss the tight feeling I had before.
Handling mods will bring that back. I have the CTR subframe brace, a DC strut bar, whiteline rear sway bar and with the summer tires I barely have to move the steering wheel to change lanes it’s so responsive. What tires are you running ?
 

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Handling mods will bring that back. I have the CTR subframe brace, a DC strut bar, whiteline rear sway bar and with the summer tires I barely have to move the steering wheel to change lanes it’s so responsive. What tires are you running ?
I’m still on the stock tires, so I know that has a lot to do with it. I have similar mods except for the strut bar, which I might get soon. I’m really looking forward to new tires once these Contis are toast.
 


jayy_swish

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I’m still on the stock tires, so I know that has a lot to do with it. I have similar mods except for the strut bar, which I might get soon. I’m really looking forward to new tires once these Contis are toast.
Summer tires DESTROY the stock Conti., it’s night a day difference. Can’t wait till these Indy’s are destroyed to pick up some Michelin PS4s.. excited for those and to see the hype on them
 

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Summer tires DESTROY the stock Conti., it’s night a day difference. Can’t wait till these Indy’s are destroyed to pick up some Michelin PS4s.. excited for those and to see the hype on them
I’m running those on my M235i and they’re awesome. When I replace tires I either get those or Pirelli P-Zero Nero.
 

jayy_swish

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I’m running those on my M235i and they’re awesome. When I replace tires I either get those or Pirelli P-Zero Nero.
The Indy’s aren’t bad for the price though they’re a good budget summer tire and I love them, just want better and the PS4’s are one of the best in the summer tire class
 

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My only other thing was I heard people say there handling feels "numb" when they go to an offset like 35 so I wasnt sure if that was common or maybe had to do with the tires they were running
This was the case for me. On the stock wheels my steering feel was very responsive, but upgrading to 18x8.5 +35 took at lot of that away. My ride quality improved, but I miss the tight feeling I had before.
The loss of responsiveness after changing your offset it due to scrub radius. Scrub radius is the distance between the center line of your tires contact patch and where your steering axis inclination (SAI) meets the ground. The SAI is essentially where a theoretical line would touch the ground if it extended from your strut at the angle it's positioned. The best way to think about it is the SAI acts as the pivot point for which the tire pivots around, so the scrub radius is the measurement of how far the center of the contact patch is away from the point which it pivots.

Honda Civic 10th gen 8.5" wide wheel, +35 vs +45 Offset????? 1587508305999


A scrub radius could be either positive, negative or zero based on where the SAI meets the ground in relation to the centerline of the contact patch. All three affect steering differently. Front wheel drive cars are designed to have a slightly negative scrub radius because it's geometry naturally reduces torque steer and adds stability in braking. However, the greater the scrub radius in either direction (positive or negative), the more steering feedback you feel through the steering wheel. It gives the wheels a natural tendency to want to pull straight, giving it a natural tendency to self correct the wheels but it also applies constant slight force on the steering linkage which takes up any looseness or compliance, reducing the tendency of the vehicle to wander when driven in a straight line. Increasing scrub radius (in either direction) overall makes the steering more responsive to initial steering input because when a correction is made, the linkage is already pre-stressed.

Changing your offset changes the center point of your tires contact patch, thus changing your scrub radius. Going from +50 mm to +35mm offset changes your scrub radius to change 15mm in the positive direction, which for fwd cars is a considerable change. Your suspension is a delicate balance of multiple components working together in harmony, and changing one thing can upset that balance. The only way to mitigate a change in offset on your scrub radius is to compensate by adjusting the camber accordingly. Fortunately for us our cars are equipped with some degree of camber adjustability from the factory to account for the variance in offset that one chassis can have for different trim levels. Any substantial change in offset would require an aftermarket camber kit to mitigate it's affect on steering.

I don't know what the exact scrub radius is for our cars, but lets say for example it's -10mm. Changing the offset 15mm would move the center of the contact patch 15mm in the opposite direction making the scrub radius +5mm (a smaller positive scrub radius) resulting in poorer steering response and instability under acceleration/deceleration.
 
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Feddy_Ace

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The loss of responsiveness after changing your offset it due to scrub radius. Scrub radius is the distance between the center line of your tires contact patch and where your steering axis inclination (SAI) meets the ground. The SAI is essentially where a theoretical line would touch the ground if it extended from your strut at the angle it's positioned. The best way to think about it is the SAI acts as the pivot point for which the tire pivots around, so the scrub radius is the measurement of how far the center of the contact patch is away from the point which it pivots.

1587508305999.png


A scrub radius could be either positive, negative or zero based on where the SAI meets the ground in relation to the centerline of the contact patch. All three affect steering differently. Front wheel drive cars are designed to have a slightly negative scrub radius because it's geometry naturally reduces torque steer and adds stability in braking. However, the greater the scrub radius in either direction (positive or negative), the steering feedback you feel through the steering wheel. It gives the wheels a natural tendency to want to pull straight, giving it a natural tendency to self correct the wheels but it also applies constant slight force on the steering linkage which takes up any looseness or compliance, reducing the tendency of the vehicle to wander when driven in a straight line. Increasing scrub radius (in either direction) overall makes the steering more responsive to initial steering input because when a correction is made, the linkage is already pre-stressed.

Changing your offset changes the center point of your tires contact patch, thus changing your scrub radius. Going from +50 mm to +35mm offset changes your scrub radius to change 15mm in the positive direction, which for fwd cars is a considerable change. Your suspension is a delicate balance of multiple components working together in harmony, and changing one thing can upset that balance. The only way to mitigate a change in offset on your scrub radius is to compensate by adjusting the camber accordingly. Fortunately for us our cars are equipped with some degree of camber adjustability from the factory to account for the variance in offset that one chassis can have for different trim levels. Any substantial change in offset would require an aftermarket camber kit to mitigate it's affect on steering.

I don't know what the exact scrub radius is for our cars, but lets say for example it's -10mm. Changing the offset 15mm would move the center of the contact patch 15mm in the opposite direction making the scrub radius +5mm (a smaller positive scrub radius) resulting in poorer steering response and instability under acceleration/deceleration.
Thanks for this. It matches up with a lot of research I did before buying my wheels and it was clear there was going to be some trade for wider wheels and offset due to the scrub radius.
 


 


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