infinirx

Because the wheels are staggered. The rears are wider than the fronts thus the tires need to be different sizes. Need to be different sizes as to match the same circumference as I wrote before. You have to do all the home work for the specific wheels you are running. So they have the same sidewall height.

245/35-21 and 285/30-21

ZERO5RX330

Gotcha. So the reason I could go front/back 30's on the Z is because it wasnt AWD right? Also it has to be within .02% over or under stock circumference for awd to be happy? or can it be a bit under stock circumference and be ok. Just want to be absolutely clear.

BTW can I just take a tape measure and figure it out or is there a mind numbing quantum physics type mathematical equation that I have to solve to do this. Hopefully your response wont begin with a lol.

infinirx

It's not about "stock height". My RX came with the upgrade option 18's and the standard are 17's from what I remember. Either way it's about the circumference total not the stock total. Your Z could have 18's in the front and 19's in the rear and it would mean nothing but with mine I would have to make sure the circumference was the same with the rear and the front. Therefore the front tires would have to be taller than the rears with the fronts being smaller and the rear tires would need to be thinner.

I still do not really understand the math. There is a site that will help you calculate this. Even with this I needed help to pick tires.

http://www.1010tires.com/wheeloffsetCalculator.asp

ZERO5RX330

Ah I see. I will put the 20" on this afternoon and see how they ride. If it's and improvement, however slight, I will just buy new tires with a bigger sidewall and leave it at that for now. I really appreciate your input in this dude. I'll measure the circumference as well and adjust the tire sizes accordingly to b within that .02% you mentioned. I know for a fact that it will be off since both are 30m hight. My buddy reminded me that when I did initially get this rim and tire package the front tire was a 35. I switched it to a 30 because I hated how the front looked bigger than the back.

infinirx

Just be careful and do your calculations or have some one else do it I got allot of input from the guys over at Vipstylecars.com. I could not have done this project without them.

ZERO5RX330

Well good news and bad news. Good news is Im gonna be able to run the rims and tires and it looks very good on the RX. Not bad for 5 year old Senekas. Im going to have them refinished with a silver center with polished chrome lips to match the door handles Im going to be putting on over the winter. Thought about black centers but been there done that and its so prevalent so Im gonna keep her classy with some silver and chrome.

Bad news is that Im going to need spacers as the offset is off by 5mm-10mm on the rear as they are 10 inch wide rims lol. I still love and miss my Z for the ability to run these kinds of wheel sizes on an entry level sportscar. Fronts are 8.5 so they are good. Rim is touching the shock so couldnt mount em and see how they feel. I really like how its gonna look so Im going to get some thicker sidewall all seasons for her in 285 r and 255 front just like the Nittos on them now. Im thinking 240 front and 235 rear? What you guys think?

Oh heres soime Iphone pics I took. Sorry bout the sun glare couldnt be helped:

IMG_0317.jpg?t=1288824695
IMG_0315.jpg?t=1288824742
IMG_0316.jpg?t=1288824797

ZERO5RX330

Oh btw I cant use the Lexus lug nuts on the 20' rims so Im gonna have to use the slim low profile lug nuts I had when they where on the Z.

Question #1. The low profile lugs are a lot less beefy than the Lexus lugs so would they be "safe" to run on a truck this size? Im thinking OF COURSE but just want to be sure

Question #2. Regarding spacers. Ive seen two types. One where you have to knock out the 5 stock bolts and replace with the provided longer bolts and the other type that bolts onto the stock 5 bolts and have bolts already attached to the spacer so you dotn need to knock out the factory bolts. Which is safer for an SUV? Or are they both safe?

Thanks

infinirx

Wheels look nice. I was hoping to find similar styles before I discovered the Work. It's more about the offset than the width at this point. Your offset if prob. similar to mine. I needed to get 10mm spacers with LONGER bolts and use tuner lugs. For me 10mm did not even do it do I had to add another 2 1/2. But the longer bolts are very important. If your using the short ones I dunno much about them.

Here is where I got my spacers from.
http://www.ichibausa.com/10alwhsp5.html

ZERO5RX330

Yeah thats the same site with the two types of spacers. Click here for the other type. http://www.ichibausa.com/whspveii.html

Yeah sounds like our offsets are similar. I used H&R wheel spacer before on another sportscar I had back in the day so Im familiar with putting them on cars NOT trucks unfortunately hence my question to you. The extra weight of a truck just bothers me alot more than if it were a car when using things like this. Did you need spacers up front too?

BTW lug nuts that are slim and smaller than the Lexus lug nuts. My bad on the verbage of the other post. I meant tuner lugs that will fit those small holes on the Iforged rims since the Lexus lugs are just too big. I had some lightweight Motegi slim lugs on the Z but I sold the car with em on so gotta buy new ones. Just wanted to make sure some of you guys used these small lug nuts without any trouble on these trucks. Thanks again.

infinirx

It's not just cause they are too big. They are not made for ANY modifications and you might lose a wheel if you don't use Tuner Lugs. Yeah the spacer II will work

ZERO5RX330

Spacer II it is. BTW Infinirx how is the handling with the staggered rims? Does it have a rear drive feel to it? I think you may the only one with staggered rims on an RX. Couldnt find any other reference to that online.

Also of note I searched and found that the BMW X5 4.8 is AWD as we all know but it also comes with staggered rims/tires. Get this. Rears are 315 and fronts are 275 and the front is 5mm higher than the rears for that .02% you were talking bout. Myth BUSTED

infinirx

Yeah I am sure every AWD system is different. Some more sensitive/delicate than others. I did not know this about the x5. I almost got that instead of the RX What do you mean by rear drive feel (RWD?)? No it drives the same as before but the ride is allot softer with the wider tires. Lost about 2mpg though.

ZERO5RX330

Thats funny cause the X5 is what I shopped precisely because I wanted a more sporty SUV since I was coming from the sportscar world. I just love how BMW gets the stance/wheel size right straight from the factory. Wish Lexus et al would do the same. Almost went FX45 too.

Nix the rwd feel thing. This awd system is not rear wheel biased as I thought. I can deal with 2mpg loss for the gains in looks with the bigger wheels

infinirx

Yeah it's not much different really than the FWD. The trans is a bit different but not like a full on SUV. The x5 is a beast. I was looking at the V8 version. Solid car. But I needed to be more practical. Still look when I see one though.

ZERO5RX330

Yeah was looking at the 4.8 myself so I still look too but the X6 has my soul now. Man its sick, I wouldn't do a thing to it.