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Discussion Starter · #1 ·
I have a 2003 passat looking at a set 18x8 48et tires are a 225 40 18 will these fit. Im very new to the hole rim dimensions. Thanks for the help
Im also looking maybe for some input on what might look better
These with are the 18x8 48et tires are a 225 40 18
Alloy wheel Tire Rim Spoke Wheel

Or these 17" Avus Wheels 17 x 7.5 ET 45
Alloy wheel Tire Rim Wheel Automotive tire
 

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Both sets will fit fine, the 225s will be a little stretched on the 18x8s. Assuming 225s on the 17s, they would have a good sidewall profile and offer some curb protection, if that is a concern for you. The 17s will also perform better, because the rotational mass of the wheel barrel will be closer to the hub.

Stock B5.5 ET is 37, so 8mm isn't going to make a huge difference in flush, especially since the barrels are 1/2" or 1" wider (17s and 18s, respectively). But I think both would benefit greatly from spacer applications, probably 12mm on fronts and 8mm on the rears.

IMO the 17s will also feel better. 18s can be pretty harsh if you elect to install or already have a sport spring/damper suspension. If you don't, I certainly would recommend that upgrade, it will transform your car. Another consideration is that if you are going for a look, the 18s have a lot of open area between spokes, so you better have a BBK or your rotors will look like bagels behind them. ;-)
 

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Discussion Starter · #5 · (Edited)
Both sets will fit fine, the 225s will be a little stretched on the 18x8s. Assuming 225s on the 17s, they would have a good sidewall profile and offer some curb protection, if that is a concern for you. The 17s will also perform better, because the rotational mass of the wheel barrel will be closer to the hub.

Stock B5.5 ET is 37, so 8mm isn't going to make a huge difference in flush, especially since the barrels are 1/2" or 1" wider (17s and 18s, respectively). But I think both would benefit greatly from spacer applications, probably 12mm on fronts and 8mm on the rears.

IMO the 17s will also feel better. 18s can be pretty harsh if you elect to install or already have a sport spring/damper suspension. If you don't, I certainly would recommend that upgrade, it will transform your car. Another consideration is that if you are going for a look, the 18s have a lot of open area between spokes, so you better have a BBK or your rotors will look like bagels behind them. ;-)

What would be the best size spacers for the 17 the tires are 225/45?
 

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Discussion Starter · #7 ·

Here is wheels I went with... sorry not really sure i get the spacers size. If i understand the suggestion was 12 up front and 8 in back. I though most run bigger in back and smaller up front. Thanks for helping me out.

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Here is wheels I went with... sorry not really sure i get the spacers size. If i understand the suggestion was 12 up front and 8 in back. I though most run bigger in back and smaller up front. Thanks for helping me out.

Sent from my SM-G935P using Tapatalk
The reason for running thicker spacers at the front is that the suspension components are closer to the wheel and that must be compensated.
 

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With 235x45x18 tires 45et what would be the spacer size to clear suspension?
Rather than answer you in PM Eddy, here's your answer:

eddymarsh said:
The only calculator I saw told me stock size vs new size. I just want y o know how far I have to have safe backpacking. The only spacers I could get were 30 mm. I have about a half inch clearance between tire and suspension. Would 15mm be safe bet or 20
I cannot answer that without: 1. your wheel width; 2. your wheel offset in mm (ET); and 3. your tire width I'm mm. Then I can show you how to use calculator.

Stock 2004 GLX wheels are 16x7 ET38 with a 205/55 series tire. Thats a 8" wide tire mounted on a 7" wheel with a net offset of 38mm from center. If the upright clearance of the 205 series tire on a wheel with ET38 is .5", then to maintain the same upright clearance with a 235 series tire, you would need a net ET28 (because tire is 20mm wider, and half of that is on upright side of wheel, so ET38 - 10mm will "poke" wheel out an additional 10mm and create room needed for 235 series tire.)

So to fit your 235/45 18s ET45 (and assuming they are 18x8s) you would need 15mm or 20mm spacers, I would opt for 15mm. But other things to consider:
  1. Your original wheels are probably 205/55-16s. That means your circumference per wheel is equal to 2x(.55x205mm)+16"xPi (because circumference = Pi x diameter of a circle). I'll do the math 1.1(205mm)/25.4mm/inch + 16" = 24.774" and 24.774" x Pi = 77.83". So the circumference of your original wheels is 77.83"
  2. The same calculation applied to your proposed 18s is: 2x(.45x235mm)+18"xPi, or 0.9(235mm)/25.4mm/inch + 18" = 26.326" and 26.326" x Pi = 82.71". So the rolling circumference of your proposed 18s setup will be almost 5" longer (4.877") or 6% different.
This 6% will affect a number of things, it will cause your car to accelerate slower, because the force to turn a larger wheel is greater than the force required to turn a smaller diameter against the same resistance (the inertia of the the car), it will also cause your odometer and speedometer to read falsely by 6% slower (60mph indicated would actually be 63.6mph, 100mph indicated would be 106mph actual, etc.)

A possible benefit is a 6% in highway miles per gallon because you are effectively adding 6% to overdrive gear by traveling 6% farther with each revolution of the wheels.

The proper 18" tire size for the size wheels you are proposing is 235/40-18. This is again assuming your wheels are 18x8s or 18x8.5s and not some crazy 18x10s. 18x10s would be a completely new set of problems. Solvable, yes, but not as easily as 18x8/8.5s. 235/40-18s have a rolling radius of 79.8" or about a 1.2% difference from stock tire circumference.

:wrench:
 
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