TemplarGM

So I am considering purchasing an '18 GS 350 (AWD) but dislike the stock wheel size. Really, I hate the unsightly gap and prefer a streamlined appearance. I think the stock is 18x8, right? What are the largest wheels I can put on the car and not have issues with hydroplaning or rubbing? A friend suggested springs...do they lower the car? What are the benefits with springs? He's cool but can be kind of a douche about advice so I searched out this forum vs asking him with hope that y'all would be more patient with me.

I was looking at a wheel size website and they gave lots of numbers that I didn't really understand but if you check the attachment, maybe my nonsensical banter will become clearer. I'm not really certain what "ET 45" means. The rims I am looking at are the Niche 3pc Ventus from CarID and the website did not include the ET data. Also, the site suggests 19x8 but the rims are only in 19x8.5. Does the difference matter and if so, why?

Understand that I am not a car guy so lingo or anything less than very basic information will most likely not be understood. Although, I am always down to learn. Thanks for the assistance.

TXMAG

iTrader: (1)

Here's a down and dirty explanation for you. Keep in mind that this is all fairly general information and if someone wants to be pedantic about bits and pieces they certainly can be. However, it should be a good primer for someone with limited knowledge of wheel/tire setups.


When looking at wheels there are four major things you want to pay attention to. Bolt Pattern, Diameter, Width, and Offset.

• Bolt pattern determines if the wheel can be bolted to your car. Different manufacturers use different bolt patterns.
• Diameter is the height of the wheel.
• Width is the width of the wheel.
• Offset is how far out/in the wheel sits on the hub. Different offsets can give you a flush or sunken look.

In the screenshot you listed above the information you want is contained in the RIM and PCD sections.

• RIM: 8x18 ET45 means that the wheel is 18" in diameter, 8" wide, and has an offset of +45mm
• PCD: 5x114.3 is referring to the bolt pattern of this particular wheel.

When shopping for wheels on a 4th gen AWD GS keep the following in mind:

• For Lexus/Toyota (and many other manufacturers) the bolt pattern IS ALWAYS going to be 5x114.3. If you see a wheel with a different bolt pattern don't even bother looking at it.
• You want what is referred to as a "square setup" meaning that all four wheels should be the same size (e.g. 18x8 +45). This is important for AWD because it will keep you from frying your differentials due to different tire sizes and it has the added benefit of allowing you to rotate the tires so they last a little longer.
• Without having to make any modifications it's pretty widely accepted that a 9" wide wheel is the biggest you can get away with on these cars in AWD trim; the front wheel being your limiting factor due to clearance issues. How large a diameter you want to go with is largely up to you, although I think these cars look perfect with a 20" wheel due to the size of the wheel well. I wouldn't go any smaller than 18".
• Offset will be affected by the width of the wheel meaning that a 45mm offset will look different on an 8" wide wheel than it will on a 9" wide wheel. Here's a useful link for you to look at explaining this a bit more: https://www.discounttire.com/learn/offset-backspace

My advice is look at some of the wheel threads in this forum and just start scrolling through them until you see something you like. Many people will list their wheel and tire specs giving you a good idea of what a similar setup would look like on your own vehicle.


In regards to lowering springs, these are suspension components that will allow your car to sit lower than stock and help to close up the wheel gap. Don't expect any sort of performance gain in real world driving and it's quite possible you may notice your ride becoming a bit more harsh. That being said, I would bet the vast majority of owners with aftermarket wheels run either a lowering spring or coilover type setup on their cars as it just look so much more aesthetically pleasing.


TLDR; Look for wheels you like that 20x9 with an ET of ~32-40mm. For tires you should be able to run something like 245/35/20 without having any rubbing or fitment issues.

Cwang

1 buy car
2 go to wheel shop and pick the pretty wheel. It doesn't have to be any more complicated than that! I can recommend having a look through the forums for pictures, there are some nice wheels on some of the GS here. Don't be afraid to PM a user to chat about their wheels

TemplarGM

TXMAG, Your info really helped me. Thanks so much for the informative reply. I will definitely browse the threads for pics too. Thanks for explaining the four things that I must know. I had no idea.

CWANG, I would prefer to use carID versus going to a tire shop. They have never done me wrong with past vehicles. One time, I ordered a part that wasn't right for my car and customer service contacted me and worked with me to make it right prior to shipping. So now, I use them for just about everything unless they do not carry something that I am specifically searching for. I appreciate the thought though.