m8554

I have a 2003 LS430 with original tires sized 225/55R17. I would like to go up on size slightly to 225/60R17. The online tire size calculator shows a 3% diameter difference of .88" and a 2mph speedometer difference. Would this cause any problems? Has anyone done this? If you have, I would appreciate any comments on ride, handling, clearance, etc. Thanks.

nkoppy

Does your car have navigation? If so, it MIGHT cause a problem. In addition to GPS technology, the system uses the indicated vehicle speed to determine your car's position, relative to points on the map, as you're driving. If the speedo is off, the system may show your car's position incorrectly, causing the system to promt turns, etc... at the wrong time. Granted, a 2 MPH error may not be huge, but I did read something in the owner's manual about how incorrect tire size can mess with the effectiveness of the nav. system...

m8554

I do have navigation. Not too concerned with that being a problem. Mainly want to know if tires might rub.

nkoppy

With such a small change in size, it's doubtful that you would get any rubbing, unless the suspension has been altered (lowered significantly)...

Stu

I say be careful - rubbing is NOT the only think to consider ...

I upsized too, and went from a 245/45/18 to 225/55/18

The car did not rub but it wandered all over the road and needed a lot of constant correction to go straight. Took the tires off and when back to stock size and the "issue" was resolved.

warminwisc

What are you trying to accomplish actually?

m8554

My previous cars were all LS400s with 225/60R16 tires. The ride was softer with the 60 series sidewall than with the low profile 55 series on the LS430. I'm just trying to get back to the higher sidewall without changing the wheel. This car's suspension came with the 16s as standard and the 17s optional. The ride on the LS430 is good but not as soft as the LS400 with the 60 series tires.

m8554

Still no one who has tried this?

nkoppy

If a more compliant ride is your objective, I'd suggest stepping down from the 18" to the 17" wheels on your LS. (There are definitely people looking for factory 18's for their LS's, so your used wheels would have some value). Going to the 17" wheel would net you an additional inch of sidewall, but it wouldn't change the overall (outside) circumference of wheel + tire on your car, from the Lexus specs - and that would preempt the spedo. error and the alignment issues, mentioned above. Finally, the firmness of sidewalls can vary considerably, depending upon the brand and model of tire you select. A really good "tire guy" can steer you to something that will help you get back toward the softer ride you enjoyed in your LS 400.

RA40

iTrader: (6)

A lot depends on the type of tire you want to install not just the size-aspect ratio. A summer performance tire will ride more firmly than an all season of the same size. If you are running an all season currently, there will be minimal difference going from a 55-60 aspect ratio. Our backsides vary so potentially this may be that little bit more in comfort. What tires are on there now, what tire pressures?

Can't speak of the in-vehicle integration GPS, though I was under the impression the position and speed is calculated relative to positon of vehicle from satellite. If it were based on speed data gained from the wheel sensors, it would be horribly inaccurate in accounting for tire wear, air pressure, varying tire sizes...etc. Even tires of the same size vary in diameter from manufacturer to manufacturer. Interesting and I wonder what integration Toyota builds in with GPS and in-car systems.

LexusJoey

If the only difference is the sidewall going from 55 to 60, You should not have any problems with respect to mounting and any rubbing to the car.
However, not only will you have a higher side wall, but the wall itself will extrude a little more beyond the rim. Although it's not a problem, the car may feel a little more mushy and more land yacht than it already is.

m8554

Tires on the car now are Dunlop SP Sport 270. They have a speed rating of H. I understand that the higher the speed rating, the firmer the sidewall resulting in a stiffer ride. If this is true then maybe switching to a S or T rated passenger tire would be softer riding than a H or V rated tire.

warminwisc

To go from a 55 to 60 sidewall to me seems kinda a short shot in the dark for a desired effect as pressure matters, as well as tire quality and tread pattern. Why mess with the speed rating.

RA40

iTrader: (6)

Speed rating does not effect sidewall stiffness necessarily. Although you may not drive the car at 130MPH+, the design characteristics and quality of tire generally improves with the ability to run at higher speeds. However a V rated tire from a budget line does not translate into a quality tire. Many factors to take into consideration.

The standard Michelin MX4V is the benchmark among all season rubber. It is predictable, good wearing and offers reasonable traction. There are many other contenders for varying budgets. What are your priorities in a tire?

Comfort
Tread life
Performance/handling

You will have to prioritize what characteristics you desire. Some tires can be a reasonable compromise among them to achieve your desires.

This is a good read:
https://www.clublexus.com/forums/the...son-tires.html

LexusJoey

The higher the speed rating the softer the rubber. Softer rubber = better grip, faster wear, and quieter ride (although tread pattern can counter that)