o2k

What are my options for wider tires for a 2004 rx330 with 18" wheels? (without the use of spacers)

RX-Fanatic

I went with 255/55/18's...

Lil4X

Is it my imagination, or are my new Bridgestone Alenza's actually smaller in diameter than my badly worn Michelin's in the same size? There appears to be about a 3/8" larger gap between the tread and the rear strut. The tire carcass - if not the tread is a bit wider because the sidewall bulges a bit more, but it carries the same OEM size for the optional 18" wheels.

oldcajun

The Alenza's are 28.2 dia, the Michelins are 28.3 so no big change in dia. The biggest spec difference between the 2 tires seems to be weight. The Alenzas at 33# are 4 pounds heavier than the Michelins.
Steve

jfelbab

The Alenza's are wider where it counts. They both show 9.5" section width but when you compare actual tread width the Alenzas are wider. The Alenza also has deeper tread depth at 12/32 vs. 9/32 which probably accounts for their UTQG rating of 600 vs. Michelin's 440.

I changed my OEM Goodyears to the Alenzas and got much better handling and ride plus they are quieter and have 1.2" wider tread contact area. IMO, this is the tire that should have been the Lexus OEM choice.

AM1

iTrader: (6)

i also use 255/55/18.

Orzel

iTrader: (1)

The 255/55/18 are apparently about as big as you can go without running into potential interference issues. We went that route with our RX after the Goodyear (POS’s) wore out in 16k miles.

Kostyan

why would anyone put wider tires on RX?? To improve performance, save the money, or both? The gains would be non-existing, but if the tire is too wide for a rim, that can cause an accident.

Just get the regular size tires and please stop making the RX something it isn't.

AM1

iTrader: (6)

while im not an expert on tires, what i do know is that putting 255/55/18 is within the size range for that size wheel. it might be on the bigger side of things but it is still safe. Hmmm lets see the tire i went with now has a longer tread life, better load handling, and helps with handling over the stock crap tires. and my MPG hasn't gone down either. I must be a damn fool for doing that. Oh yeah the tires cost 50 dollars less per tire then OEM also. So whose the fool now?

Kostyan

easy there AM1, I wasn't calling anyone as a fool. When the tire has more rubber in it, it doesnt take a rocket scientist to know that its a heavier tire. Also, changing the tire size distorts speedometer/odometer readings. Third, you must have really found a bargain, because last time I checked the OEm size tires start out at 107 per tire, thats what, 60-70 bucks cheaper than stockies.

AM1

iTrader: (6)

the people at the tire shop said that since putting 255/55/18 doesnt change the ratio and therefore doesnt mess with the speedo/odo. dealer said it was ok too. the stock goodyear eagle RS-A;s are around 180 or more a tire, you can get much better tire for around 130-140. and yes the tire is heavier since it is bigger, but it can also depedning on the tire have better load handling, plus depending on speed rating can improve handling or if you are into comfort can help make the ride better.

Kostyan

I am not saying the folks at the tire shop are wrong, but there are online tire calculators that will show you the difference in speedo/odo. Looks like some RXs with 18's come from factory with Good Year's, and some with Michelins. It does sound that people on here absolutely hate Good Year's, worse than Michelins. I did find Kumhos in correct 18" size on the discounttire.com and that's like only 107 per tire. As far as ride goes, you gotta go up in the sidewall size to make it softer, or get 19+ wheels and put on the correct size tires to stay in tune with speedo/odo, that would increase the width of the tire but at the same time lower the sidewall- now that would truly have an affect on handling, but to each his own, I wouldnt experiment at all.

Lil4X

Easy there, AM! Let's watch the sarcasm. You're better than that.

jfelbab

Trying to correct some misconceptions here. Going with a 255/55/18 tire will alter your speedo/odo by about 3%. When speedometer reads 65 mph your actual speed will be 67 mph. For every 100 miles you travel the odo will read 103.

Here is just about the most informative web site on tire sizing I've found.
http://www.rims-n-tires.com/info_specs.jsp

Going to the larger size may add a lot of unsprung weight to the wheels. This will, in general, result in poorer ride quality. As a general rule it is never advisable to add over 5 lbs. to the unsprung weight of a wheel without altering the spring/shock package to compensate. Adding too much unsprung weight will make your vehicle feel like it is lumbering and thumping it's way over potholes and the like. The wheels can't react as fast as they have significantly more momentum to overcome. Heavier wheels and tires will also slow your acceleration and braking performance for the same reason. More inertia to overcome. Something you should consider if you are looking at plus sizing and other wheel/tire options.

Here are the specs:

OEM Goodyear
Size: 235/55VR18
Load Rating: 99V SL
UTQG: 260 A A
Max. Load: 1709 lbs.
Max. Inflation: 44 psi
Tread Depth: 10/32"
Tire Weight: 29 lbs.
Rim Size: 6.5-8.5"
Meas. Rim Width: 7.5"
Section Width: 9.5"
Actual Tread Width: 6.5"
Overall Diameter: 28"
Revs per Mile: 746

OEM Michelin Specs
Size: 235/55VR18
Load Rating: 99V SL
UTQG: 440 A A
Max. Load: 1709 lbs.
Max. Inflation: 35 psi
Tread Depth: 9/32"
Tire Weight: 29 lbs.
Rim Size: 6.5-8.5"
Meas. Rim Width: 7.5"
Section Width: 9.5"
Actual Tread Width: NA
Overall Diameter: 28.3"
Revs per Mile: 736

Compare these specs to the larger 255 Khumo Road Venture APT

Size: 255/55VR18
Load Rating: 109H XL
UTQG: 600 A A
Max. Load: 2271 lbs.
Max. Inflation: 50 psi
Tread Depth: NA
Tire Weight: 38 lbs. (a whopping 9 pounds per tire more unsprung weight)
Rim Size: NA
Meas. Rim Width: 8"
Section Width: 10.4
Actual Tread Width: NA
Overall Diameter: 29.1"
Revs per Mile: NA

For those in the market for new tires and want a better performing tire I'd suggest looking to this option instead.

Bridgestone Dueler Alenza
Size: 235/55VR18
Load Rating: 100V SL
UTQG: 600 A A
Max. Load: 1764 lbs.
Max. Inflation: 51 psi
Tread Depth: 12/32"
Tire Weight: 33 lbs.
Rim Size: 6.5-8.5"
Meas. Rim Width: 7.5"
Section Width: 9.5"
Actual Tread Width: 7.7" (1.2" wider tread contact patch than GY OEM)
Overall Diameter: 28.2"
Revs per Mile: 739

This tire adds a 1.2" wider tread contact patch over the OEM Goodyear and stays under the 5 lb. unsprung weight guideline so it won't make your SUV feel like it's a heavy truck. The tire has a higher load rating than the OEM and is quieter. It will not alter your speedo/odo and has an very high UTQG treadlife score of 600.

For those who want to research their own tire options there is a lot of info available from the tire rack and the tire manufacturers directly.

I have a friend who, against my advise, upgraded to the Yokahama ADVAN 255's and his ride is quite a bit poorer than the Bridgestone Alenza 235's. The vehicle feels like a heavy truck now and he wishes he had not bought these tires. The vehicle sticks really well in hard cornering but due to the OEM spring and shocks, it emphasizes the body roll and feels quite unnerving when pressed hard. When riding over rough roads it sounds and feels like a 3/4 ton truck. Since he spent over $200/tire on this questionable upgrade he is stuck with decision for a while.

Do your homework well before you switch tires.

sama

Good Information jfelbab

Here is more information on
utqg -- Uniform Tire Quality Grading