Why Different Size Wheels/tyres

[Rocky]

This seems like a question that must have been asked before, so sorry if repetitious.

I don't think I have ever seen another similar vehicle that comes standard with different size rims/tyres front to rear.

Clearly Lexus think this provides some sort of advantage however it has the disadvantage that it prevents rotation of tyres.

I would normally buy a matching OEM wheel/tyre to use as a full-size spare and it causes a problem here as well.

Anyone know what the reason is for the different sizes?

I imagine there must be lots of 250s around with the same size aftermarket wheels/tyres all round.

[iNoob]

A multitude of different reasons:

• BBK clearance
• Aesthetics
• To suit more rubber
• To differentiate between year model/try get you to purchase a higher spec car

That said it's easy to figure out what aftermarket wheels/rubber you can fit under the guards. Depends if you want looks/handling or a combination of both.

[Rocky]

The reason I ask is that if I was to buy an is250 with wheels I didn't like, I would prefer to fit a set of uniform size aftermarket wheels rather than try to source a set of different size fronts & rears & have the problem of not being to rotate them/get a full-size spare.

I can't see why a car like the is250 with the limited power it has needs a set of huge wheels/tyres anyhow.

[RotorRian]

Rocky don't forget you can swap the tyres from left to right in the front and rear to get extra life from a staggered setup.

I run 19x9.5 and 19x11s and I do that to get extra life from my tyres.

Just don't take your car to MRT in Rhodes. They will make you wait 4 hours for them to swap your wheels from left to right (directional tyres going backwards) then charge you for something you can do in 20 mins at home with factory tools.

Worst experience ever! Avoid them like the plague!

Rant over!

[The Mekon]

This is a question I have asked myself. Why does the early (05-08) Prestige have same size 16" wheels front & back, but the Sports Luxury has the 17" with different rolling diameters? is there a suspension difference for the SL?

I note the "new" model (2013 on) has 7.5" wheels as opposed to the older models 8". A sensible decision in my view, the tyres sit too far inside the rim on the older model.

to me the best combination of wheels / tyres would be that fitted to the old GS300. 7.5 17" rims with 225/50 tyres all around.

no need for the stupidly wide 245 rears.

[Rocky]

Mekon - my thoughts exactly.

I like most of the OE Alloys fitted to the is250 but the earlier 16" wheels always look too small for the car.

I think it's hard to make a case for a larger wheel than a 17" on a modestly powered 4 door sedan.

The 18's look fine but quality tyres are very expensive when you get into 18X255X45/40.

If going to aftermarket wheels/tyres I think 17X7.5 & 225X50s are about ideal.

Very low profile tyres look good but are totally unsuited to the pot-holed country roads where I live.

A mate with a 3 Series BMW wrecked two run-flats at $500. a piece and one of his $2500. alloys in a 6 month period.

[ilv1004s]

its just marketing ploy for the IS's back in the days by AU Lexus

in the US 16" werent even used

it'll be silly for the base model which is around 5-10 cheaper than the upper spec model to have the same size wheels

its only in Aus and few other asian markets they used the 16" wheels (only markets that didnt have the is350 in their lineups)

most others markets only got the 17" and 18"

you would see that from 2011 onwards the smallest wheels size is 17" and thats the smallest size that accomodates the is350 big brakes

Edited September 1, 2015 by ilv1004s