zibranm

Hi,
On my 2008 RX350, I am thinking of putting rims of size 8Jx18 ET45.
I have come to know that the factory original rim size is 7JJx18 ET35 and tires are 235/55/R18.

Here are the two questions I have:
1. Since the new rims are 1.0 inch wider, will they fit and what impacts they may have?
2. I am trying to stay as close to the factory settings. So, with the wider rims, should I put narrower tires (such as 225/55/R18) to maintain clearance from the suspension components?

Thanks in advance for advices.

MattRX

Offset of 45 will likely hit the strut, especially with an 8” rim and wider tires. Someone experienced this issue when they installed 18x8 GS rims with an offset of 45. If you want to stick with OE, I would go with the 18x8 2016+ RX350 rims that have an offset of 30, that’ll help keep the rim nice and flush with the fenders, and allow you to even run 255s if you wanted to.

I would stick with your 235 tires, these heavy boats need all the grip they can get. When I put the RX rims on my Highlander, it’s apparent how much even that difference of 225 vs 235 is. That’s why I’m going to go with 245/55R18 down the road soon.

zibranm

Thank you for your reply. Yes these 8Jx18 ET45 rims are from GS450h. I was just trying to reuse these rims that I already have, just to mount winter tires (which I haven't bought yet) only on my RX350. Do you think that's not going to work, or which tires may work to the best?

Felix

As Matt mentioned, your adding a additional inch, great, But the 45mm is what gets you & I also wouldn't even think of running spacers either. Your really best off selling those wheels & getting a set of 20mm offset wheels w/ a 8''-9'' width wheels. The 235's are good for a 8.5''-9'' width wheel btw........Legend 5 or TSW offers wheels w/ a 20mm offset at Discount, which is where I ordered my wheels/tires from......

zibranm

Thank you both, for your valuable advices.

Felix

Jump on http://discountire.com using a 18'' wheel w/ a 20mm offset......

MattRX

That's what I'm going to do too, I'm going to use my 17" RX330 OEM rims for winters, and then I'm going to get some bigger plus-sized 18" rims with fatter tires for summers. I would go OE size for winter on your rims, or maybe 225/60R18 if you want something a little skinnier. This is only a 1.4% difference in the diameter so it won't have a huge impact on your ride or speedometer. Similarly, going to 245/55R18 on your new rims will also be a 1.4% difference which is also in an acceptable range, if you're trying to stay below 3%. If you want maximum thickness, you could run 255/50R18 on your wider rims and be at a 0.7% difference. I wouldn't go any wider than this as you may run into issues with fitment and will likely stop seeing benefits at that width anyway - likely even if your suspension was stiffened. 3rd gen RX rims are pretty plentiful as well - at least in my area. They are a 18x.7.5" rim with an offset of 35. Not quite at that 18x8" and 30 offset range, but at least they have a bit more width to handle a wider tire. You can also go the aftermarket route like Felix did, but I suggest getting hub-centric rings as the hub bore of aftermarket rims is going to be larger than OE.

https://tiresize.com/comparison/
https://www.willtheyfit.com/

Felix

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